JPWO2018139393A1 - Totally aromatic polyester and polyester resin composition - Google Patents

Abstract

A fully aromatic polyester having high thermal stability and good hydrolysis resistance, and a polyester resin composition thereof are provided.
60-85 mol% of 6-hydroxy-2-naphthoic acid, 12-40 mol% of 4-hydroxybenzoic acid, 0.1 of 1,4-phenylenedicarboxylic acid or 4,4'-dihydroxybiphenyl By using a wholly aromatic polyester composed of ˜3 mol%, the above problem is solved.
[Selection figure] None

Description

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

  Liquid crystalline polymers represented by liquid crystalline polyester resins have excellent fluidity, mechanical strength, heat resistance, chemical resistance, electrical properties, etc. in a well-balanced manner, and are therefore widely used as high-performance engineering plastics. Yes.

  Patent Document 1 discloses an improved method for producing a heat-stable thermotropic liquid crystalline polyester having a predetermined chain length. In this document, thermal stability is improved by adding a small amount of 1,4-phenylenedicarboxylic acid to liquid crystalline polyester. However, the thermal stability of this liquid crystalline polyester is not always sufficient.

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

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

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

JP-A-60-040127 JP-A-60-245631 JP 2004-250620 A

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

  As a result of intensive studies, the present inventors have found that 6-hydroxy-2-naphthoic acid is 60 to 85 mol%, 4-hydroxybenzoic acid is 12 to 40 mol%, 1,4-phenylenedicarboxylic acid or 4,4. The present inventors have found that the above problem can be solved by using a wholly aromatic polyester comprising 0.1 to 3 mol% of '-dihydroxybiphenyl, and the present inventors have completed the present invention. More specifically, the present invention provides the following.

(1) As an essential constituent, the following constituent units (I), (II), and (III) or (IV) consist of:
Content of structural unit (I) is 60 to 85 mol% with respect to all structural units,
The content of the structural unit (II) is 12 to 40 mol% with respect to all the structural units,
Content of structural unit (III) or (IV) is 0.1-3 mol% with respect to all the structural units,
The total content of the structural units (I), (II), and (III) or (IV) is 100 mol% with respect to all the structural units.
Totally aromatic polyester.

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

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

(4) The wholly aromatic polyester according to any one of (1) to (3), which has a melting point of 380 ° C. or lower.

(5) The wholly aromatic polyester according to any one of (1) to (4), which has a melting point of 250 to 370 ° C.

(6) The wholly aromatic polyester according to any one of (1) to (5), wherein the crystallization heat amount 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) A polyester resin composition containing the wholly aromatic polyester according to any one of (1) to (7).

(9) A polyester molded product 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 a wholly aromatic polyester having high thermal stability and good hydrolysis resistance, and this polyester resin composition.

  Hereinafter, an embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within a range that does not impair the effects of the present invention.

[Totally aromatic polyester]
The wholly aromatic polyester according to the present invention comprises the following constituent units (I), (II), and (III) or (IV) as essential constituent components, and the constituent units (I) Content is 60-85 mol%, content of structural unit (II) is 12-40 mol% with respect to all the structural units, and structural unit (III) or (IV) of all structural units The content is 0.1 to 3 mol%, and the total content of the structural units (I), (II), and (III) or (IV) is 100 mol% with respect to all the structural units.

  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 structural unit (I) with respect to all the structural units. When the content of the structural unit (I) is less than 60 mol%, the melting point is lowered and the heat resistance is insufficient. If 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%, still more preferably 65 to 80 mol%, and most preferably 68. ˜80 mol%.

  The structural unit (II) is derived from 4-hydroxybenzoic acid (hereinafter also referred to as “HBA”). The wholly aromatic polyester of the present invention contains 12 to 40 mol% of the structural unit (II) with respect to the total structural units. When the content of the structural unit (II) is less than 12 mol%, the polymer is solidified in the polymerization vessel during production, and the polymer cannot be discharged. When content of structural unit (II) exceeds 40 mol%, melting | fusing point will fall and heat resistance will run short. 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%, still more preferably 18 to 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 also referred to as 4,4′-dihydroxybiphenyl (hereinafter also referred to as “BP”). .) The wholly aromatic polyester of the present invention contains 0.1 to 3 mol% of the structural unit (III) or the structural unit (IV) with respect to all the structural units. Thermal stability falls that content of structural unit (III) or structural unit (IV) is less than 0.1 mol%. When the content of the structural unit (III) or the 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 the structural unit (IV) is preferably 0.2 to 2.5 mol%, more preferably 0.2 to 2 mol%, still more preferably. Is 0.3-2 mol%, more preferably 0.3-1.5 mol%, and most preferably 0.4-1.5 mol%.

  As described above, the wholly aromatic polyester of the present invention contains the specific structural units (I) to (IV) in a specific amount with respect to the total structural units, so that the generated gas is small and the thermal stability is low. In addition to being high, hydrolysis resistance is good. In addition, the wholly aromatic polyester of this invention contains 100 mol% of structural units (I)-(IV) in total with respect to all the structural units.

  Next, the properties of the wholly aromatic polyester will be described. The wholly aromatic polyester of the present invention exhibits optical anisotropy when melted. An optical anisotropy when melted means that the wholly aromatic polyester of the present invention is a liquid crystalline polymer.

  In the present invention, the fact that the wholly aromatic polyester is a liquid crystalline polymer is an indispensable element for the wholly aromatic polyester has both thermal stability and easy processability. The wholly aromatic polyesters composed of the structural units (I) to (IV) may not form an anisotropic melt phase depending on the constituent components and the sequence distribution in the polymer. Limited to wholly aromatic polyesters that exhibit optical anisotropy when melted.

  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 Co., Ltd. using a polarizing microscope manufactured by Olympus and observing it at a magnification of 150 times in a nitrogen atmosphere. The liquid crystalline 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.

  Since a nematic liquid crystalline polymer causes a significant decrease in viscosity at the melting point or higher, generally exhibiting liquid crystallinity at the melting point or higher is an index of workability. The melting point is preferably as high as possible from the viewpoint of heat resistance, but it is preferably 380 ° C. or lower in consideration of thermal deterioration during the melt processing of the polymer, the heating ability of the molding machine, and the like. In addition, melting | fusing point becomes like this. More preferably, it is 250-370 degreeC, More preferably, it is 270-370 degreeC, More preferably, it is 270-350 degreeC, Most preferably, it is 290-350 degreeC.

  The melt viscosity of the wholly aromatic polyester at a temperature 10 to 30 ° C. higher than the melting point of the wholly aromatic polyester of the present invention and a shear rate of 1000 / sec is preferably 1000 Pa · s or less, more preferably 3 to 500 Pa. · S, even 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 easy to ensure fluidity at the time of molding, and the filling pressure becomes excessive. Hateful. In addition, in this specification, melt viscosity means the melt viscosity measured based on ISO11443.

The amount of crystallization heat 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. If the crystallization heat amount, which indicates the crystallization state of the polymer determined by differential calorimetry, is less than 2.5 J / g, the crystallinity is lowered and the hydrolysis resistance is deteriorated. Moreover, when the amount of crystallization heat exceeds 4.4 J / g, toughness will become low and it is not preferable.
It should be noted that the heat of crystallization is 2 at a temperature of (Tm1 + 40) ° C. after observing the endothermic peak temperature (Tm1) observed when the polymer is measured at room temperature from 20 ° C./min. It refers to the calorific value of the exothermic peak obtained from the peak of the exothermic peak temperature that is observed when the temperature is measured for 20 ° C./min.

 In addition, the wholly aromatic polyester in the present invention preferably has a value of [melting point−crystallization temperature], which is a value obtained by subtracting the crystallization temperature from the melting point, and is preferably 30 to 90 ° C. More preferred. 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 easy to ensure fluidity at the time of molding, Filling pressure is unlikely to be excessive.

  Subsequently, the manufacturing method of the wholly aromatic polyester of this invention is demonstrated. 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, etc., or a combination of two or more of these are used, and a melt polymerization method or a combination of a melt polymerization method and a solid phase polymerization method is used. Is preferably used.

  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 fatty acid anhydrides such as acetic anhydride.

  In the polymerization, various catalysts can be used. Typical examples include potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, tris (2 , 4-pentanedionato) cobalt (III) and the like, and organic compound catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of the 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.

[Polyester resin composition]
Various fibrous, granular, and plate-like inorganic and organic fillers can be blended in the wholly aromatic polyester of the present invention according to the purpose of use.

  As an inorganic filler mix | blended with the polyester resin composition of this invention, there exist a fibrous form, a granular form, and a plate-shaped thing.

  As the fibrous inorganic filler, 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 Examples thereof include inorganic fiber materials such as silicate fibers, magnesium sulfate fibers, aluminum borate fibers, and metal fibers such as stainless steel, aluminum, titanium, copper, and brass. A particularly typical fibrous filler is glass fiber.

  In addition, powdered inorganic fillers include carbon black, graphite, silica, quartz powder, glass beads, glass balloons, glass powder, calcium oxalate, aluminum oxalate, kaolin, clay, diatomaceous earth, and wollastonite. Acid salts, iron oxide, titanium oxide, zinc oxide, antimony trioxide, oxides of metals such as alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, sulfates of metals such as calcium sulfate and barium sulfate, and other ferrites , Silicon carbide, silicon nitride, boron nitride, various metal powders, and the like.

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

  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 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 inorganic filler and the granular or plate-like inorganic filler is a preferable combination in order to combine mechanical strength, dimensional accuracy, electrical properties, and the like. Particularly preferably, the fibrous filler is glass fiber, and the platy filler is mica and talc. The blending amount thereof is 120 parts by mass or less, preferably 20 to 80 parts by mass with respect to 100 parts by mass of the wholly aromatic polyester. It is. By combining glass fiber with mica or talc, the polyester resin composition is particularly prominent in improving the heat distortion temperature and mechanical properties.

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

  As described above, the polyester resin composition of the present invention contains the wholly aromatic polyester of the present invention and, if necessary, an inorganic or organic filler as essential components, as long as the effects of the present invention are not impaired. Other components may be included. Here, the other component may be any component, and examples thereof include other resins, antioxidants, stabilizers, pigments, crystal nucleating agents and the like.

  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 product]
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 employed. Examples of general molding methods include injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, inflation molding, and the like.

  A polyester molded product formed by molding the wholly aromatic polyester of the present invention is excellent in heat resistance. Moreover, since the polyester molded product formed by shape | molding the polyester resin composition of this invention is excellent in heat resistance, and contains an inorganic or organic filler as needed, mechanical strength etc. are further improved.

  Moreover, since the wholly aromatic polyester and the polyester resin composition of the present invention are excellent in moldability, they can be processed into various three-dimensional molded products, fibers, films and the like.

  Preferred applications of the polyester molded product 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 heat fixing rolls for OA equipment. It is done.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

<Example 1>
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a decompression / outflow line was charged with the following raw material monomers, fatty acid metal salt catalyst, and acylating agent, and nitrogen substitution was started.
(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) Terephthalic acid 0.1 mol (0.7 mol%) (TA)
Potassium acetate catalyst 22.5mg
196 g of acetic anhydride (1.02 times the total hydroxyl equivalent of HNA and HBA)
After the raw materials were charged, the temperature of the reaction system was raised to 140 ° C. and reacted at 140 ° C. for 2 hours. Thereafter, the temperature is further increased to 340 ° C. over 4.1 hours, and then reduced to 10 Torr (ie, 1330 Pa) over 15 minutes, and acetic acid, excess acetic anhydride, and other low-boiling components are distilled off. Condensation was performed. 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.

<Evaluation>
About the wholly aromatic polyester of Example 1, evaluation of melting | fusing point, crystallization temperature, crystallization calorie | heat amount, melt viscosity, thermal stability, and hydrolysis resistance was performed with the following method. The evaluation results are shown in Table 1.

[Melting point]
After observation of the endothermic peak temperature (Tm1) observed when the wholly aromatic polyester was measured under a temperature rising condition from room temperature to 20 ° C./min with a differential scanning calorimeter (DSC, manufactured by Perkin Elmer), (Tm1 + 40) ) After holding at a temperature of 2 ° C. for 2 minutes, after cooling to room temperature under a temperature drop condition of 20 ° C./minute, measure the temperature of the endothermic peak observed when measuring again under a temperature rise condition of 20 ° C./minute did.

[Crystallizing temperature]
After observation of the endothermic peak temperature (Tm1) observed when the wholly aromatic polyester was measured under a temperature rising condition from room temperature to 20 ° C./min with a differential scanning calorimeter (DSC, manufactured by Perkin Elmer), (Tm1 + 40) ) After holding at a temperature of 2 ° C. for 2 minutes, an exothermic peak temperature observed when measured under a temperature drop condition of 20 ° C./min was measured.

[Amount of crystallization]
After observation of the endothermic peak temperature (Tm1) observed when the wholly aromatic polyester was measured under a temperature rising condition from room temperature to 20 ° C./min with a differential scanning calorimeter (DSC, manufactured by Perkin Elmer), (Tm1 + 40) ) After holding at a temperature of 2 ° C. for 2 minutes, the calorific value of the exothermic peak obtained from the peak of the exothermic peak temperature observed when the temperature was measured under a temperature decreasing condition of 20 ° C./min was measured.

[Melt viscosity]
ISO 11443 using a capilograph manufactured by Toyo Seiki Seisakusho Co., Ltd., using an orifice having an inner diameter of 0.5 mm and a length of 30 mm at a temperature 10 to 30 ° C. higher than the melting point of the wholly aromatic polyester and a shear rate of 1000 / sec. The melt viscosity of the wholly aromatic polyester was measured.

[Thermal stability]
Using a differential thermal thermogravimetric simultaneous measurement device (TG / DTA, manufactured by Seiko Instruments Inc.), 10mg of total aromatic polyester is reduced in weight when held at 370 ° C for 30 minutes under a nitrogen stream. Measured as gas amount. In addition, it was judged that it was favorable if the amount of generated gas was less than 15000 ppm.

[Hydrolysis resistance]
The fully aromatic polyester was subjected to a pressure cooker test for 100 hours under the conditions of 121 ° C., 100% humidity and 2 atm. The melt viscosity of the wholly aromatic polyester was measured to determine the retention rate relative to the initial value. In addition, it was judged that the retention rate relative to the initial value was 90% or more.

<Example 2>
A polymer was obtained in the same manner as in Example 1 except that the type of raw material monomer and the charging ratio (mol%) 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 further polymer. Moreover, the same evaluation as Example 1 was performed. The evaluation results are shown in Table 1.

<Example 3>
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a decompression / outflow line was charged with the following raw material monomers, fatty acid metal salt catalyst, and acylating agent, and nitrogen substitution was started.
(I) 1.51 mol (81 mol%) of 6-hydroxy-2-naphthoic acid (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 the raw materials were charged, the temperature of the reaction system was raised to 140 ° C. and reacted at 140 ° C. for 2 hours. Thereafter, the temperature is further increased to 370 ° C. over 4.7 hours, and then the pressure is reduced to 10 Torr (ie, 1330 Pa) over 15 minutes. Condensation was performed. 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. Moreover, the same evaluation as Example 1 was performed. The evaluation results are shown in Table 1.

<Examples 4-8, Comparative Examples 1-8>
A polymer was obtained in the same manner as in Example 1 except that the type of raw material monomer and the charging ratio (mol%) were as shown in Tables 1 and 2. Moreover, the same evaluation as Example 1 was performed. The evaluation results are shown in Tables 1 and 2. In Comparative Example 4, the polymer was solidified in the polymerization vessel during production, and the polymer could not be discharged.

Claims (9)

As an essential constituent, it consists of the following structural units (I), (II), and (III) or (IV),
Content of structural unit (I) is 60 to 85 mol% with respect to all structural units,
The content of the structural unit (II) is 12 to 40 mol% with respect to all the structural units,
Content of structural unit (III) or (IV) is 0.1-3 mol% with respect to all the structural units,
The total content of the structural units (I), (II), and (III) or (IV) is 100 mol% with respect to all the structural units.
Totally aromatic polyester.

  The wholly aromatic polyester according to claim 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.   The wholly aromatic polyester according to claim 1 or 2, having a melt viscosity of 3 to 500 Pa · s at a temperature 10 to 30 ° C higher than the melting point of the wholly aromatic polyester.   The wholly aromatic polyester according to any one of claims 1 to 3, having a melting point of 380 ° C or lower.   The wholly aromatic polyester according to any one of claims 1 to 4, having a melting point of 250 to 370 ° C.   The wholly aromatic polyester according to any one of claims 1 to 5, wherein the amount of crystallization heat is 2.5 J / g or more.   The wholly aromatic polyester according to any one of claims 1 to 6, wherein a value of [melting point-crystallization temperature] is 20 ° C or higher.   The polyester resin composition containing the wholly aromatic polyester as described in any one of Claim 1 to 7.   A polyester molded product obtained by molding the wholly aromatic polyester or polyester resin composition according to any one of claims 1 to 8.