Liquid crystal polyester resin, molded article, and electrical and electronic parts

Abstract

[Problem] To provide a liquid crystal polyester resin with low dielectric loss tangent and excellent dimensional stability. [Solution] The liquid crystal polyester resin based on the present invention comprises at least 90 mol% of aromatic hydroxycarboxylic acid-derived constituent units in all constituent units. The liquid crystal polyester resin is characterized in that it further comprises constituent units derived from aromatic diols and / or aromatic diamines, as well as constituent units derived from aromatic dicarboxylic acids, and has a dielectric loss tangent of 1.0 × 10⁻⁶ at a frequency of 10 GHz. ‑3 Hereinafter, the difference (anisotropy) between the molding shrinkage rate (MD) in the flow direction (MD) and the direction perpendicular to the flow direction (TD) of the injection-molded sheet of the liquid crystal polyester resin is 1.00 or less, the melting point of the liquid crystal polyester resin is 280°C or more, and the melt viscosity of the liquid crystal polyester resin measured under the conditions of melting point to melting point +20°C and shear rate of 1000 / s is 25 Pas or more.

Description

Technical Field

[0001] This invention relates to a liquid crystal polyester resin, and more specifically to a liquid crystal polyester resin having a low dielectric loss tangent, a molded article comprising the liquid crystal polyester resin, and an electrical and electronic component comprising the molded article. Background Technology

[0002] In recent years, with the increase in information communication volume in the communications field, the use of high-frequency signals, especially those with a frequency of 10, has increased in electronic and communication devices. 9 The use of signals in the gigahertz (GHz) frequency band above Hz is becoming increasingly common. For example, the GHz band is used in the automotive industry. Specifically, millimeter-wave radar and quasi-millimeter-wave radar, which are designed to prevent car collisions, use high frequencies of 76 GHz to 79 GHz and 24 GHz respectively, and further widespread adoption is expected in the future.

[0003] However, as the frequency of the signal used increases, the quality of the output signal may deteriorate, potentially leading to misidentification of information; that is, transmission loss increases. This transmission loss includes conductor loss caused by the conductor itself and dielectric loss caused by the insulating resin used in the electrical and electronic components, such as the substrate, of electronic or communication equipment. Conductor loss is proportional to the 0.5 power of the operating frequency, while dielectric loss is proportional to the 1st power of the frequency. Therefore, in high-frequency bands, especially the GHz band, the impact of dielectric loss is very significant. Furthermore, dielectric loss also increases proportionally to the dielectric loss tangent of the resin; therefore, to prevent information degradation, resins with low dielectric loss tangents are required.

[0004] In addition, resins used to make electrical and electronic components are also required to have good heat resistance and moldability. For example, in Patent Document 1, a fully aromatic polyester resin with excellent heat resistance and moldability is proposed, which contains 40 mol% to 75 mol% of constituent units derived from 6-hydroxy-2-naphthoic acid, 8.5 mol% to 30 mol% of constituent units derived from terephthalic acid, 8.5 mol% to 30 mol% of constituent units derived from 4,4'-dihydroxybiphenyl, and 0.1 mol% to 8 mol% of constituent units derived from p-hydroxybenzoic acid in a specific composition ratio.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2002-179776 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, the inventors have gained the following insight: even when using the fully aromatic polyester resin proposed in Patent Document 1, it is impossible to obtain a liquid crystal polyester resin with sufficiently low dielectric loss tangent and excellent dimensional stability.

[0010] Therefore, the inventors have conducted intensive research to solve the aforementioned problem and have found that by adjusting specific properties (dielectric loss tangent, anisotropy, melt viscosity) or specific composition ratios of constituent units in a liquid crystal polyester resin containing constituent units derived from aromatic hydroxycarboxylic acids at a rate of 90 mol% or more of all constituent units, a liquid crystal polyester resin with low dielectric loss tangent and excellent dimensional stability can be obtained.

[0011] Therefore, the object of the present invention is to provide a liquid crystal polyester resin having low dielectric loss tangent and excellent dimensional stability. Furthermore, another object of the present invention is to provide a molded article comprising the liquid crystal polyester resin and an electrical and electronic component comprising the molded article.

[0012] Methods for solving problems

[0013] That is, according to the present invention, the following invention is provided.

[0014] [1] A liquid crystal polyester resin comprising at least 90 mol% of constituent units derived from aromatic hydroxycarboxylic acids, wherein the liquid crystal polyester resin is characterized in that:

[0015] The liquid crystal polyester resin further comprises constituent units derived from aromatic diols and / or aromatic diamines, as well as constituent units derived from aromatic dicarboxylic acids, and

[0016] The dielectric loss tangent at a measured frequency of 10 GHz is 1.0 × 10⁻⁶. -3 the following,

[0017] The difference (anisotropy) in the molding shrinkage rate (longitudinal (machine direction, MD)) and the direction perpendicular to the flow direction (transverse (TD)) of the injection-molded sheet of the liquid crystal polyester resin is less than 1.00.

[0018] The melting point of the liquid crystal polyester resin is above 280°C.

[0019] The melt viscosity of the liquid crystal polyester resin, measured under conditions of melting point to melting point +20°C and shear rate of 1000 / s, is 25 Pa. s or more.

[0020] [2] A liquid crystal polyester resin comprising at least 90 mol% of constituent units derived from aromatic hydroxycarboxylic acids, wherein the liquid crystal polyester resin is characterized in that:

[0021] The aromatic hydroxycarboxylic acid comprises a building block (A) derived from p-hydroxybenzoic acid, a building block (B) derived from 6-hydroxy-2-naphthoic acid, and a building block (C) derived from hydroxycarboxylic acids other than the building blocks (A) and (B).

[0022] The liquid crystal polyester resin further comprises a constituent unit (D) derived from an aromatic diol and / or a constituent unit (E) derived from an aromatic diamine, and a constituent unit (F) derived from an aromatic dicarboxylic acid.

[0023] The composition ratio (molar percentage) of the constituent units (A) to (E) satisfies the following condition:

[0024] 10 mol% ≤ Constituent Unit (A) ≤ 35 mol%

[0025] 50 mol% ≤ Constituent Unit (B) ≤ 85 mol%

[0026] 0.01 mol% ≤ Constituent unit (C) < 15 mol%

[0027] 0.01 mol% ≤ constituent unit (D) + constituent unit (E) + constituent unit (F) ≤ 5 mol%.

[0028] [3] According to the liquid crystal polyester resin of [2], wherein the constituent unit (C) is a constituent unit derived from at least one selected from the group consisting of 4-(4-hydroxyphenyl)benzoic acid, 6-hydroxynicotinic acid, m-hydroxybenzoic acid, 4-hydroxy-3-methylbenzoic acid, 2-fluoro-4-hydroxybenzoic acid, 4-acetamide benzoic acid, 4-(4-hydroxyphenoxy)benzoic acid, and coumaric acid.

[0029] [4] According to the liquid crystal polyester resin of [2], wherein the constituent unit (C) is a constituent unit derived from at least one selected from the group consisting of 4-(4-hydroxyphenyl)benzoic acid, 6-hydroxynicotinic acid and m-hydroxybenzoic acid.

[0030] [5] The liquid crystal polyester resin according to any one of [1] to [4], wherein the melting point is below 350°C.

[0031] [6] The liquid crystal polyester resin according to [5], wherein the temperature difference between the melting point and the crystallization point is 30°C or more.

[0032] [7] A fibrous molded article comprising a liquid crystal polyester resin according to any one of [1] to [6].

[0033] [8] A sheet-like molded article comprising a liquid crystal polyester resin according to any one of [1] to [6].

[0034] [9] An injection-molded article comprising a liquid crystal polyester resin according to any one of [1] to [6].

[0035]

[10] An electrical and electronic component comprising a molded article according to [7].

[0036]

[11] An electrical and electronic component comprising a molded article according to [8].

[0037]

[12] An electrical and electronic component comprising a molded article according to [9].

[0038] The effects of the invention

[0039] This invention provides a liquid crystal polyester resin exhibiting low dielectric loss tangent and excellent dimensional stability. By using the liquid crystal polyester resin of this invention, the dimensional stability of the manufactured articles can be improved. Therefore, when processing and using it as an article, degradation of the output signal quality in electrical and electronic equipment or communication equipment using high-frequency signals can be prevented. Detailed Implementation

[0040] (Liquid crystal polyester resin)

[0041] The liquid crystal polyester resin based on the present invention comprises at least 90 mol% of constituent units derived from aromatic hydroxycarboxylic acids, and further comprises constituent units derived from aromatic diols and / or aromatic diamines, as well as constituent units derived from aromatic dicarboxylic acids. Furthermore, the liquid crystal polyester resin based on the present invention can be an element or a mixture (polymer blend). In the present invention, by satisfying the structures of the first and / or second embodiments described below, a liquid crystal polyester resin having low dielectric loss tangent and excellent dimensional stability can be obtained.

[0042] (First Implementation)

[0043] In the first embodiment of the present invention, the liquid crystal polyester resin is characterized by having the following specific properties (dielectric loss tangent, anisotropy, melting point, melt viscosity).

[0044] The upper limit of the dielectric loss tangent of the liquid crystal polyester resin based on the present invention at a measurement frequency of 10 GHz is 1.0 × 10⁻⁶. -3 The preferred value is 0.90×10. -3 Hereinafter, 0.80×10 is more preferred. -3The preferred value is 0.75 × 10⁻⁶. -3 The following describes how, by setting the dielectric loss tangent of the liquid crystal polyester resin based on the present invention within the stated numerical range, molded articles with low dielectric loss tangent can be manufactured. Therefore, when used as articles, degradation of the output signal quality in electrical and electronic equipment or communication equipment using high-frequency signals can be prevented.

[0045] Furthermore, in this specification, the dielectric loss tangent of the liquid crystal polyester resin at 10 GHz can be measured using a network analyzer such as the Keysight Technologies N5247A at an environment of 23°C and 50%RH, by the split post dielectric resonator method (SPDR method).

[0046] The absolute value of the difference (anisotropy) between the flow direction (MD) and the molding shrinkage rate (TD) in the direction perpendicular to the flow direction of the injection-molded sheet based on the liquid crystal polyester resin of the present invention is 1.00 or less, preferably 0.95 or less, more preferably 0.90 or less, and even more preferably 0.85 or less. By setting the anisotropy of the liquid crystal polyester resin based on the present invention within the aforementioned value range, the dimensional stability of the molded articles made using the liquid crystal polyester resin can be improved.

[0047] Furthermore, in this specification, the anisotropy of the liquid crystal polyester resin is calculated based on the difference in molding shrinkage (molding shrinkage on TD - molding shrinkage on MD) of a 50 mm × 50 mm × 1 mm flat test piece obtained by heating and melting the liquid crystal polyester resin at melting point to melting point +20°C.

[0048] Taking heat resistance into consideration, the lower limit of the melting point of the liquid crystal polyester resin based on the present invention is 280°C or higher, preferably 285°C or higher, more preferably 290°C or higher, even more preferably 295°C or higher, even more preferably 300°C or higher, and most preferably 305°C or higher. Furthermore, the upper limit is not particularly limited and can be 350°C or lower, 340°C or lower, 330°C or lower, 325°C or lower, or 320°C or lower. By setting the melting point of the liquid crystal polyester resin based on the present invention within the aforementioned numerical range, the heat resistance of molded articles made using the liquid crystal polyester resin to heat processing can be improved.

[0049] The lower limit of the melt viscosity of the liquid crystal polyester resin based on the present invention, measured under conditions of melting point to melting point +20°C and shear rate (1000 / s), is 25 Pa. s or more, preferably 30 Pa s or more, preferably 35 Pa s or more, and more preferably 40 Pa s or more, and more preferably 50 Pa Above s. Furthermore, the upper limit is preferably 1000 Pa. Below s, more preferably 500 Pa Below s, and more preferably 200 Pa Below s, and more preferably 150 Pa Below s. By setting the melt viscosity of the liquid crystal polyester resin based on the present invention within the stated numerical range, the dielectric loss tangent can be further reduced, thereby improving the mechanical strength of the molded article.

[0050] Furthermore, in this specification, the viscosity of the liquid crystal polyester resin can be measured using a capillary rheometer according to Japanese Industrial Standards (JIS) K7199.

[0051] (Second Implementation)

[0052] In a second embodiment of the present invention, the liquid crystal polyester resin comprises a constituent unit (A) derived from p-hydroxybenzoic acid, which is an aromatic hydroxycarboxylic acid; a constituent unit (B) derived from 6-hydroxy-2-naphthoic acid, which is an aromatic hydroxycarboxylic acid; and a constituent unit (C) derived from hydroxycarboxylic acids other than the constituent unit (A) and the constituent unit (B). It also comprises a constituent unit (D) derived from an aromatic diol and / or a constituent unit (E) derived from an aromatic diamine; and a constituent unit (F) derived from an aromatic dicarboxylic acid.

[0053] The composition ratio (molar percentage) of the constituent units (A) to (F) is characterized by satisfying the following condition:

[0054] 10 mol% ≤ Constituent Unit (A) ≤ 35 mol%

[0055] 50 mol% ≤ Constituent Unit (B) ≤ 85 mol%

[0056] 0.01 mol% ≤ Constituent unit (C) < 15 mol%

[0057] 0.01 mol% ≤ constituent unit (D) + constituent unit (E) + constituent unit (F) ≤ 5 mol%.

[0058] The composition ratio (molar percentage) of the constituent units (A) to (F) of the liquid crystal polyester resin based on the present invention preferably satisfies the following conditions:

[0059] 15 mol% ≤ Constituent Unit (A) ≤ 33 mol%

[0060] 55 mol% ≤ Constituent Unit (B) ≤ 83 mol%

[0061] 0.05 mol% ≤ constitutive unit (C) ≤ 12 mol%

[0062] 0.03 mol% ≤ 4 mol% of constituent unit (D) + 4 mol% of constituent unit (E) + 4 mol% of constituent unit (F)

[0063] More preferably, to satisfy:

[0064] 18 mol% ≤ Constituent Unit (A) ≤ 30 mol%

[0065] 57 mol% ≤ Constituent Unit (B) ≤ 80 mol%

[0066] 0.1 mol% ≤ constitutive unit (C) ≤ 10 mol%

[0067] 0.05 mol% ≤ 3 mol% of constituent unit (D) + constituent unit (E) + constituent unit (F)

[0068] Therefore, the preferred option is to satisfy:

[0069] 19 mol% ≤ Constituent Unit (A) ≤ 29 mol%

[0070] 60 mol% ≤ Constituent Unit (B) ≤ 78 mol%

[0071] 0.5 mol% ≤ constitutive unit (C) ≤ 8 mol%

[0072] 0.1 mol% ≤ constituent unit (D) + constituent unit (E) + constituent unit (F) ≤ 2.5 mol%.

[0073] The preferred option is to satisfy:

[0074] 20 mol% ≤ Constituent Unit (A) ≤ 28 mol%

[0075] 63 mol% ≤ Constituent Unit (B) ≤ 75 mol%

[0076] 1 mole% ≤ constitutive unit (C) ≤ 5 moles%

[0077] 0.2 mol% ≤ constituent unit (D) + constituent unit (E) + constituent unit (F) ≤ 2 mol%.

[0078] Furthermore, the liquid crystal polyester resin in the second embodiment is preferably one that has the specific properties described in the first embodiment (dielectric loss tangent, anisotropy, melting point, melt viscosity).

[0079] Furthermore, the liquid crystal polyester resin in the first and second embodiments is preferably characterized by having the following specific property (temperature difference between melting point and crystallization point).

[0080] The lower limit of the crystallization point of the liquid crystal polyester resin based on the present invention is preferably 220°C or higher, more preferably 225°C or higher, even more preferably 230°C or higher, even more preferably 240°C or higher, and the upper limit is preferably 300°C or lower, more preferably 295°C or lower, even more preferably 290°C or lower, even more preferably 280°C or lower.

[0081] The lower limit of the temperature difference between the melting point and the crystallization point of the liquid crystal polyester resin based on the present invention (= "melting point (°C)" - "crystallization point (°C)") is preferably 30°C or higher, more preferably 35°C or higher, and even more preferably 40°C or higher. Furthermore, the upper limit is preferably 80°C or lower, more preferably 75°C or lower, and even more preferably 70°C or lower. By setting the temperature difference between the melting point and the crystallization point of the liquid crystal polyester resin based on the present invention within the aforementioned numerical range, sufficient time can be taken from melting to solidification when the liquid crystal polyester is melted and molded, thereby increasing the freedom in setting temperature conditions such as molding temperature.

[0082] Furthermore, in this specification, the melting point and crystallization point of the liquid crystal polyester resin are values ​​measured using a differential scanning calorimeter (DSC). Specifically, the liquid crystal polyester resin is heated from room temperature to 340°C to 360°C at a heating rate of 10°C / min until it is completely melted. Then, it is cooled to 30°C at a heating rate of 10°C / min, and the peak of the resulting heating peak is designated as the crystallization point (Tc). Finally, the temperature is increased to 360°C at a heating rate of 10°C / min, and the peak of the resulting endothermic peak is designated as the melting point (Tm).

[0083] The liquid crystal properties of the liquid crystal polyester resin based on the present invention can be confirmed by using a polarizing microscope (trade name: BH-2) manufactured by Olympus (stock), including a microscope heating stage (trade name: FP82HT) manufactured by Mettler, etc., heating and melting the liquid crystal polyester resin on the microscope heating stage, and then observing whether there is optical anisotropy.

[0084] The constituent units contained in the liquid crystal polyester resin based on the present invention will be described in detail below.

[0085] (Derived from the building block (A) of aromatic hydroxycarboxylic acids)

[0086] The building block (A) derived from aromatic hydroxycarboxylic acids is derived from p-hydroxybenzoic acid (HBA). Monomers that provide building block (A) include p-hydroxybenzoic acid, its acetylated derivatives, ester derivatives, acyl halides, etc.

[0087] The composition ratio (mol%) of the constituent unit (A) in the liquid crystal polyester resin is preferably 10 mol% or more and 35 mol% or less. From the viewpoint of reducing the dielectric loss tangent and improving the dimensional stability of the liquid crystal polyester resin, the lower limit of the composition ratio (mol%) of the constituent unit (A) is preferably 15 mol% or more, more preferably 18 mol% or more, more preferably 19 mol% or more, more preferably 20 mol% or more, and the upper limit is preferably 33 mol% or less, more preferably 30 mol% or less, more preferably 29 mol% or less, and more preferably 28 mol% or less.

[0088] (Based on the building block (B) of aromatic hydroxycarboxylic acids)

[0089] The building block (B) derived from aromatic hydroxycarboxylic acids is derived from 6-hydroxy-2-naphthoic acid (HNA). Monomers that provide building block (B) include 6-hydroxy-2-naphthoic acid, its acetylated derivatives, ester derivatives, acyl halides, etc.

[0090] The composition ratio (mol%) of the constituent unit (B) in the liquid crystal polyester resin is preferably 50 mol% or more and 85 mol% or less. From the viewpoint of reducing the dielectric loss tangent and improving the dimensional stability of the liquid crystal polyester resin, the lower limit of the composition ratio (mol%) of the constituent unit (B) is preferably 55 mol% or more, more preferably 57 mol% or more, more preferably 60 mol% or more, more preferably 63 mol% or more, and the upper limit is preferably 83 mol% or less, more preferably 80 mol% or less, more preferably 78 mol% or less, and more preferably 75 mol% or less.

[0091] (Derived from the building block (C) of aromatic hydroxycarboxylic acids)

[0092] The constituent unit (C) derived from an aromatic hydroxycarboxylic acid is not particularly limited if it is a constituent unit derived from a hydroxycarboxylic acid other than constituent units (A) and (B). The constituent unit (C) is preferably derived from at least one of the group consisting of 4-(4-hydroxyphenyl)benzoic acid, 6-hydroxynicotinic acid, m-hydroxybenzoic acid, 4-hydroxy-3-methylbenzoic acid, 2-fluoro-4-hydroxybenzoic acid, 4-(4-hydroxyphenoxy)benzoic acid, and coumaric acid. Among these, 4-(4-hydroxyphenyl)benzoic acid, 6-hydroxynicotinic acid, and m-hydroxybenzoic acid are more preferred. Examples of monomers providing the constituent unit (C) include these monomers, as well as their acetylated, ester derivatives, acyl halides, etc.

[0093] The composition ratio (mol%) of the constituent unit (C) in the liquid crystal polyester resin is preferably 0.01 mol% or more and less than 15 mol%. From the viewpoint of reducing the dielectric loss tangent and improving the dimensional stability of the liquid crystal polyester resin, the lower limit of the composition ratio (mol%) of the constituent unit (C) is preferably 0.05 mol% or more, more preferably 0.1 mol% or more, more preferably 0.5 mol% or more, more preferably 1 mol% or more, and the upper limit is preferably 12 mol% or less, more preferably 10 mol% or less, more preferably 8 mol% or less, and more preferably 5 mol% or less.

[0094] (Derived from the building block (D) of aromatic diols)

[0095] The constituent unit (D) derived from the aromatic diol is preferably the constituent unit derived from the aromatic diol represented by the following formula (1). In addition, the constituent unit (D) may contain only one type or more types.

[0096] [Chemistry 1]

[0097]

[0098] In the formula, Ar 1 The alkyl group may have substituents and be a divalent hydrocarbon group with an aromatic ring, as needed. Examples of hydrocarbon groups with an aromatic ring include phenyl, biphenyl, 4,4'-isopropylidene diphenyl, naphthyl, anthraceneyl, and phenanthrene. Examples of substituents include hydrogen, alkyl, alkoxy, and fluorine. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5. Furthermore, it may be a straight-chain alkyl group or a branched-chain alkyl group. The alkoxy group preferably has 1 to 10 carbon atoms, more preferably 1 to 5.

[0099] Monomers that provide the constituent unit (D) include, for example, 4,4-dihydroxybiphenyl (BP), hydroquinone (HQ), methylhydroquinone (MeHQ), 4,4'-isopropylidene diphenol (BisPA), and their acylates, ester derivatives, acyl halides, etc.

[0100] (Derived from the building block (E) of aromatic diamines)

[0101] The constituent unit (E) derived from an aromatic diamine is preferably the constituent unit derived from an aromatic diamine as represented by the following formula (2). Furthermore, the constituent unit (E) may contain only one type or may contain two or more types.

[0102] [Chemistry 2]

[0103]

[0104] In the formula, Ar 2 The alkyl group may have substituents and be a divalent hydrocarbon group with an aromatic ring, as needed. Examples of hydrocarbon groups with an aromatic ring include phenyl, biphenyl, 4,4'-isopropylidene diphenyl, naphthyl, anthraceneyl, and phenanthrene. Examples of substituents include hydrogen, alkyl, alkoxy, and fluorine. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5. Furthermore, it may be a straight-chain alkyl group or a branched-chain alkyl group. The alkoxy group preferably has 1 to 10 carbon atoms, more preferably 1 to 5.

[0105] Monomers that provide the constituent unit (E) include, for example, p-diaminobenzene, 4,4'-diaminobiphenyl, naphthyldiamine and their acylates, ester derivatives, acyl halides, etc.

[0106] (Derived from the building block (F) of aromatic dicarboxylic acids)

[0107] The constituent unit (F) derived from an aromatic dicarboxylic acid is preferably the constituent unit derived from an aromatic dicarboxylic acid represented by the following formula (3). Furthermore, the constituent unit (F) may contain only one type or may contain two or more types.

[0108] [Chemistry 3]

[0109]

[0110] In the formula, Ar 3The alkyl group may have substituents and be a divalent hydrocarbon group with an aromatic ring, as needed. Examples of hydrocarbon groups with an aromatic ring include phenyl, biphenyl, 4,4'-isopropylidene diphenyl, naphthyl, anthraceneyl, and phenanthrene. Examples of substituents include hydrogen, alkyl, alkoxy, and fluorine. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5. Furthermore, it may be a straight-chain alkyl group or a branched-chain alkyl group. The alkoxy group preferably has 1 to 10 carbon atoms, more preferably 1 to 5.

[0111] Monomers that provide the constituent unit (F) include: terephthalic acid (TPA), isophthalic acid (IPA), 2,6-naphthalene dicarboxylicacid (NADA), and their acylates, ester derivatives, acyl halides, etc.

[0112] The total composition ratio (mol%) of constituent units (D), (E), and (F) in the liquid crystal polyester resin is preferably 0.01 mol% or more and 5 mol% or less. From the viewpoint of reducing the dielectric loss tangent and improving the dimensional stability of the liquid crystal polyester resin, the lower limit of the total composition ratio (mol%) of constituent units (D), (E), and (F) is preferably 0.03 mol% or more, more preferably 0.05 mol% or more, more preferably 0.1 mol% or more, more preferably 0.2 mol% or more, and the upper limit is preferably 4 mol% or less, more preferably 3 mol% or less, more preferably 2.5 mol% or less, and more preferably 2 mol% or less.

[0113] (Manufacturing method of liquid crystal polyester resin)

[0114] The liquid crystal polyester resin of the present invention can be manufactured by the following method (two-stage polymerization), the method comprising: a step of melt polymerization of at least one of the monomers providing constituent units (A) to (C), the monomers providing constituent unit (D), and the monomers providing constituent unit (E), and the monomers providing constituent unit (F) to obtain a polymer; and a step of solid-state polymerization of the polymer to obtain the liquid crystal polyester resin.

[0115] Regarding melt polymerization, from the viewpoint of efficiently obtaining liquid crystal polyester resin, it is preferable to have 1.03 to 1.15 molar equivalents of acetic anhydride present relative to all hydroxyl groups of all monomers and to carry out the process under reflux of acetic acid, and more preferably to have 1.03 to 1.10 molar equivalents of acetic anhydride present and to carry out the process under reflux of acetic acid.

[0116] The reaction temperature for melt polymerization is preferably in the range of melting point to (melting point + 70) °C, and more preferably in the range of (melting point + 20) °C to (melting point + 50) °C.

[0117] Melt polymerization is preferably carried out in the presence of a catalyst and in the absence of a solvent. As a catalyst, those known for polymer polymerization can be used. Examples of catalysts include: metal salt catalysts such as potassium acetate, magnesium acetate, stannous acetate, lead acetate, sodium acetate, tetrabutyl titanate, and antimony trioxide, and organic compound catalysts such as nitrogen-containing heterocyclic compounds such as N-methylimidazole. The amount of catalyst used is not particularly limited, but is preferably (10 to 100) mg / mol of the total number of monomers.

[0118] In solid-state polymerization, the polymer obtained through melt polymerization can be cooled, solidified, and then pulverized to form powder or fragments. Alternatively, polymer strands obtained through melt polymerization can be granulated to form granules. The reaction temperature for solid-state polymerization is preferably below the melting point, preferably between (melting point -30) °C and (melting point -10) °C. Solid-state polymerization can be carried out while stirring, or it can be carried out in a static state without stirring.

[0119] The polymerization apparatus is not particularly limited, and it is preferable to use the reaction apparatus used in the reaction of general high-viscosity fluids. Examples of such reaction apparatus include: stirred tank type polymerization apparatus with stirring devices having anchor type, multi-stage type, spiral ribbon type, spiral shaft type, etc., or various shapes of these modified stirring blades; or mixing devices such as kneaders, roller mills, and Banbury mixers, which are generally used for mixing resins.

[0120] (Made product)

[0121] The molded article based on the present invention comprises the liquid crystal polyester resin of the present invention, and may also further comprise other liquid crystal polyester resins, other resins, and fillers. The content of resin components in the molded article (the total content of the liquid crystal polyester resin of the present invention, other liquid crystal polyester resins, and other resins) relative to the total amount of the molded article is preferably 30% by mass or more and 99% by mass or less, more preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and more preferably 55% by mass or more and 85% by mass or less.

[0122] (filler)

[0123] Examples of fillers include: carbon fiber, graphite, glass fiber, talc, mica, glass fragments, clay, sericite, calcium carbonate, calcium sulfate, calcium silicate, silicon dioxide, alumina, aluminum hydroxide, calcium hydroxide, graphite, potassium titanate, titanium dioxide, fluorocarbon fiber, fluorocarbon resin, barium sulfate, and various whiskers. These fillers can be used individually or in combination.

[0124] Relative to the total amount of the molded article, the filler content in the molded article is preferably 1% by mass or more and 70% by mass or less, more preferably 5% by mass or more and 60% by mass or less, further preferably 10% by mass or more and 50% by mass or less, and even more preferably 15% by mass or more and 45% by mass or less. When two or more fillers are included, it is preferable that their total content is within the aforementioned range. If the filler content in the molded article is within the aforementioned range, a molded article with superior mechanical properties can be obtained, and therefore is preferred.

[0125] (Other liquid crystal polyester resins besides the liquid crystal polyester resin of this invention)

[0126] As for other liquid crystal polyester resins, there are no particular limitations if they are liquid crystal polyester resins other than those described in this invention, and existing known liquid crystal polyester resins can be used. Preferred forms of other liquid crystal polyester resins include, for example, liquid crystal polyester resins having constituent units derived from hydroxycarboxylic acids. A particularly preferred form is a liquid crystal polyester resin containing 65 mol% to 80 mol% (preferably 70 mol% to 75 mol%) of p-hydroxybenzoic acid and 20 mol% to 35 mol% (preferably 25 mol% to 30 mol%) of 6-hydroxy-2-naphthoic acid. Furthermore, as other preferred forms, liquid crystal polyester resins that, in addition to having constituent units derived from hydroxycarboxylic acids, also contain at least one of constituent units derived from aromatic dicarboxylic acids and constituent units derived from aromatic diols can be included. As a particularly preferred form, a liquid crystal polyester resin containing 60 mol% to 80 mol% (preferably 65 mol% to 75 mol%) of p-hydroxybenzoic acid, 1 mol% to 5 mol% of 6-hydroxy-2-naphthoic acid, 0 mol% to 20 mol% (preferably 1 mol% to 15 mol%) of constituent units derived from aromatic dicarboxylic acids, and 0 mol% to 20 mol% (preferably 1 mol% to 15 mol%) of constituent units derived from aromatic diols can be listed here. Here, as constituent units derived from aromatic dicarboxylic acids, constituent units derived from at least one of 4,4'-dihydroxybiphenyl and hydroquinone can be listed. Furthermore, as constituent units derived from aromatic diols, constituent units derived from at least one of terephthalic acid, isophthalic acid, and 4'-hydroxy-4-biphenylcarboxylic acid can be listed. The composition ratio of each constituent unit is not limited to the preferred form and can be appropriately adjusted. In addition, other liquid crystal polyester resins can be used alone or in combination with two or more other types.

[0127] Relative to the total of 100 parts by weight of the liquid crystal polyester resin of the present invention and other liquid crystal polyester resins, the upper limit of the content of other liquid crystal polyester resins besides the liquid crystal polyester resin of the present invention in the molded article is preferably 90 parts by weight or less, more preferably 75 parts by weight or less, and even more preferably 50 parts by weight or less. The lower limit can be 1 part by weight or more, or 3 parts by weight or more, or 5 parts by weight or more.

[0128] (Resins other than liquid crystal polyester resin)

[0129] Without departing from the spirit of the invention, molded articles based on the invention may also contain resins other than liquid crystal polyester resin. Other resins include, for example: polyethylene terephthalate, polyethylene naphthalate, polyarylates, polycyclohexylene dimethylene terephthalate, and polybutylene terephthalate, etc.; polyethylene, polypropylene, and other polyolefin resins; cycloolefin polymers; polyvinyl chloride and other vinyl resins; polyacrylates; polymethyl methacrylate and other (meth)acrylic resins; polyphenylene ether resins; polyacetal resins; polyamide resins; polyimide and polyetherimide, etc.; polystyrene, high-impact polystyrene, acrylonitrile-styrene (AS) resin and acrylonitrile-butadiene-styrene (ABS) resin, etc.; thermosetting resins such as epoxy resins; cellulose resins; polyetheretherketone resins; fluoropolymers; and polycarbonate resins. These other resins may be used alone or in combination.

[0130] Regarding the content of resins other than liquid crystal polyester resin in the molded article, the upper limit is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, relative to the total of 100 parts by weight of the liquid crystal polyester resin and other liquid crystal polyester resins of the present invention.

[0131] (Other additives)

[0132] Without departing from the spirit of the invention, molded articles based on the invention may also contain other additives, such as colorants, dispersants, plasticizers, antioxidants, hardeners, flame retardants, heat stabilizers, ultraviolet absorbers, antistatic agents, and surfactants. These other additives may be used alone or in combination.

[0133] The shape of the molded article can be appropriately changed according to its application, and there are no particular limitations. Examples of shapes for molded articles include fibrous, plate-like, sheet-like, and rod-like forms.

[0134] The molded articles based on the present invention can be manufactured using a resin composition comprising liquid crystal polyester resin and fillers or other resins as needed, by existing known molding methods. Examples of molding methods include melt spinning, solution spinning, injection molding, compression molding, injection compression molding, calendering, stamping, etc.

[0135] (Electrical and electronic components)

[0136] The electrical and electronic components based on the present invention include molded articles (e.g., fibrous molded articles or injection molded articles) comprising liquid crystal polyester resin. Examples of electrical and electronic components including said molded articles include: antennas used in electronic or communication devices such as electronic toll collection (ETC), global positioning system (GPS), wireless area network (LAN) and mobile phones; high-speed transmission connectors; central processing unit (CPU) sockets; circuit boards; flexible printed circuit boards (FPC); circuit boards for stacking; millimeter-wave radar and quasi-millimeter-wave radar such as collision avoidance radar; radio frequency identification (RFID) tags; capacitors; inverter parts; cable sheathing materials; insulating materials for secondary batteries such as lithium-ion batteries; speaker diaphragms, etc.

[0137] Example

[0138] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the embodiments.

[0139] <Manufacturing of Liquid Crystal Polyester Resin>

[0140] (Example 1)

[0141] In a polymerization vessel equipped with stirring blades, 24 mol% of p-hydroxybenzoic acid (HBA), 73 mol% of 6-hydroxy-2-naphthoic acid (HNA), 2 mol% of m-hydroxybenzoic acid (mHBA), 0.5 mol% of 4,4'-dihydroxybiphenyl (BP), and 0.5 mol% of terephthalic acid (TPA) were added. Potassium acetate was added as a catalyst, and the polymerization vessel was subjected to three cycles of vacuum-nitrogen injection. Then, acetic anhydride (1.05 molar equivalent relative to hydroxyl groups) was added, and the temperature was raised to 150°C. The acetylation reaction was carried out under reflux for 2 hours.

[0142] After acetylation, the polymerization vessel, in the acetic acid distillation state, is heated at 0.5°C / min until the temperature of the melt zone in the tank reaches 310°C. The polymer is then extracted and cooled to solidify. The obtained polymer is pulverized to a size that passes through a 2.0 mm mesh sieve. Next, the obtained polymer is subjected to solid-state polymerization at 300°C using an oven heater manufactured by Yamato Scientific (stock).

[0143] Subsequently, the polymer was allowed to dissipate heat naturally at room temperature to obtain the polyester resin of the present invention. Using a polarizing microscope (trade name: BH-2) manufactured by Olympus (stock), including a microscope heating stage (trade name: FP82HT) manufactured by Mettler, the polyester resin was heated and melted on the microscope heating stage, and the liquid crystal properties were confirmed based on the presence or absence of optical anisotropy.

[0144] (Example 2)

[0145] Regarding the monomer loading, the amounts were changed to 24 mol% HBA, 72 mol% HNA, 2 mol% mHBA, 1 mol% BP, and 1 mol% TPA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0146] (Example 3)

[0147] Regarding the monomer composition, the following was changed: HBA 24 mol%, HNA 73 mol%, mHBA 2 mol%, hydroquinone (HQ) 0.5 mol%, and 2,6-naphthalenedicarboxylic acid (NADA) 0.5 mol%. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0148] (Example 4)

[0149] Regarding the monomer composition, the following was changed: HBA 22 mol%, HNA 73 mol%, mHBA 2 mol%, 6-hydroxynicotinic acid (HNIA) 2 mol%, BP 0.5 mol%, and TPA 0.5 mol%. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0150] (Example 5)

[0151] Regarding the monomer composition, the amounts were changed to 34 mol% HBA, 64.8 mol% HNA, 1 mol% mHBA, 0.1 mol% BP, and 0.1 mol% TPA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0152] (Comparative Example 1)

[0153] Regarding the monomer loading, the composition was changed to 73 mol% HBA and 27 mol% HNA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed in the same manner as above.

[0154] (Comparative Example 2)

[0155] Regarding the monomer composition, the composition was changed to 60 mol% HBA, 20 mol% BP, 15 mol% TPA, and 5 mol% isophthalic acid (IPA). Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystallization properties of the polyester resin were confirmed in the same manner as above.

[0156] (Comparative Example 3)

[0157] Regarding the monomer loading, the amounts were changed to 6 mol% HBA, 40 mol% HNA, 27 mol% BP, and 27 mol% NADA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0158] (Comparative Example 4)

[0159] Regarding the monomer composition, the amounts were changed to 35 mol% HBA, 50 mol% HNA, and 15 mol% 4-acetamide benzoic acid (ABA). Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0160] (Comparative Example 5)

[0161] Regarding the monomer loading, the amounts were changed to 19 mol% HBA, 79 mol% HNA, and 2 mol% mHBA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0162] (Comparative Example 6)

[0163] Regarding the monomer composition, the amounts were changed to 23.8 mol% HBA, 75.5 mol% HNA, and 0.7 mol% IPA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0164] (Comparative Example 7)

[0165] Regarding the monomer composition, the amounts were changed to 14.9 mol% HBA, 84.4 mol% HNA, and 0.7 mol% IPA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystallinity of the polyester resin was confirmed as described above.

[0166] (Comparative Example 8)

[0167] Regarding the monomer composition, the amounts were changed to 23.8 mol% HBA, 75.5 mol% HNA, and 0.7 mol% TPA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0168] (Comparative Example 9)

[0169] Regarding the monomer loading, the amounts were changed to 18 mol% HBA, 81 mol% HNA, and 1 mol% BP. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0170] (Comparative Example 10)

[0171] Regarding the monomer loading, the composition was changed to 21 mol% HBA, 78 mol% HNA, 0.5 mol% BP, and 0.5 mol% TPA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed in the same manner as above.

[0172] (Comparative Example 11)

[0173] Regarding the monomer loading, the amounts were changed to 21 mol% HBA, 77 mol% HNA, and 2 mol% mHBA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed in the same manner as described above.

[0174] (Comparative Example 12)

[0175] Regarding the monomer composition, the amounts were changed to 21 mol% HBA, 78 mol% HNA, 0.5 mol% HQ, and 0.5 mol% NADA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0176] (Comparative Example 13)

[0177] Regarding the monomer loading, the amounts were changed to 21 mol% HBA, 68 mol% HNA, 3 mol% mHBA, 4 mol% BP, and 4 mol% IPA. Otherwise, the polyester resin was obtained in the same manner as in Example 1. Next, the liquid crystal properties of the polyester resin were confirmed as described above.

[0178] The composition ratio (mol%) of the constituent units of the polyester resins manufactured in the embodiments and comparative examples is shown in Table 1.

[0179] <Determination of Melting Point and Crystallization Point>

[0180] The melting point and crystallization point of the liquid crystal polyester resins obtained in the examples and comparative examples were determined using a differential scanning calorimeter (DSC) manufactured by Hitachi High-Tech Science (Co., Ltd.). First, the liquid crystal polyester resin was heated from room temperature to 340°C–380°C at a heating rate of 10°C / min until it was completely melted. Then, it was cooled to 30°C at a heating rate of 10°C / min, and the peak of the resulting heating peak was designated as the crystallization point (Tc). Next, the temperature was increased to 380°C at a heating rate of 10°C / min, and the peak of the resulting endothermic peak was designated as the melting point (Tm). The difference between the melting point and the crystallization point was calculated based on the obtained melting point and crystallization point. The melting point (Tm), crystallization point (Tc), and the difference between the melting point and the crystallization point (Tm-Tc) are shown in Table 1. Note that "-" in Table 1 indicates that the measurement was not performed.

[0181] <Preparation of Flat Plate Test Sheets A>

[0182] The liquid crystal polyester resin obtained in the examples and comparative examples was heated and melted at melting point to melting point +20°C and then injection molded to produce a flat test piece A of 30 mm × 30 mm × 0.4 mm.

[0183] <Preparation of Plate-Shaped Test Sheets B>

[0184] The liquid crystal polyester resin obtained in the examples and comparative examples was heated and melted at melting point to melting point +20°C and then injection molded to produce a 50 mm × 50 mm × 1 mm flat test piece B.

[0185] <Measurement of dielectric loss tangent (10 GHz)>

[0186] The dielectric loss tangent (tanδ) in the in-plane direction of the fabricated flat test piece A was measured at a frequency of 10 GHz using a Keysight Technologies N5247A network analyzer via the Split-Column Dielectric Resonator (SPDR) method, under conditions of 23°C and 50% RH. The results are shown in Table 1. Note that "-" in Table 1 indicates that the measurement was not performed.

[0187] <Determination of Anisotropy>

[0188] The molding shrinkage (%) of the prepared flat plate test piece B along the flow direction (MD) and in the direction perpendicular to the flow direction (TD) was measured, and the difference between these molding shrinkage rates (molding shrinkage rate on TD - molding shrinkage rate on MD) was calculated to evaluate anisotropy. The calculated results are shown in Table 1. The smaller the difference value, the smaller the anisotropy. In addition, "-" in Table 1 indicates that it was not measured.

[0189] <Determination of Melt Viscosity>

[0190] The melt viscosity (Pa·s) of the liquid crystal polyester resins obtained in the examples and comparative examples was measured under various conditions, including melting point +20°C and shear rate 1000 / s, using a capillary rheometer (Capilograph 1D, Toyo Seiki Co., Ltd.) and a 1 mm inner diameter capillary, according to JIS K7199. The measurement results are shown in Table 1.

[0191] As is evident from the results in Table 1, the liquid crystal polyester resins of Examples 1 to 5 are resins with low dielectric loss tangent, high melting point and excellent heat resistance, as well as low anisotropy and excellent dimensional stability.

[0192] [Table 1]

[0193]

Claims

1. A liquid crystal polyester resin comprising, in which at least 90 mol% of all constituent units are derived from aromatic hydroxycarboxylic acids, characterized in that: The liquid crystal polyester resin further comprises constituent units derived from aromatic diols and / or aromatic diamines, as well as constituent units derived from aromatic dicarboxylic acids, and The dielectric loss tangent at a frequency of 10 GHz was 1.0 x 10 -3 Hereinafter, The difference (anisotropy) in the molding shrinkage rate (longitudinal) of the injection-molded sheet of the liquid crystal polyester resin in the flow direction (longitudinal) and the direction perpendicular to the flow direction (transverse) is less than 1.

00. The melting point of the liquid crystal polyester resin is above 280°C. The liquid crystalline polyester resin has a melt viscosity of 25 Pa s or more.

2. A liquid crystal polyester resin comprising at least 90 mol% of constituent units derived from aromatic hydroxycarboxylic acids, wherein the liquid crystal polyester resin is characterized in that: The aromatic hydroxycarboxylic acid comprises a building block (A) derived from p-hydroxybenzoic acid, a building block (B) derived from 6-hydroxy-2-naphthoic acid, and a building block (C) derived from hydroxycarboxylic acids other than the building blocks (A) and (B). The liquid crystal polyester resin further comprises a constituent unit (D) derived from an aromatic diol and / or a constituent unit (E) derived from an aromatic diamine, and a constituent unit (F) derived from an aromatic dicarboxylic acid. The composition ratio (molar percentage) of the constituent units (A) to (F) satisfies the following condition: 10 mol% ≤ Constituent Unit (A) ≤ 35 mol% 50 mol% ≤ Constituent Unit (B) ≤ 85 mol% 0.01 mol% ≤ Constituent unit (C) < 15 mol% 0.01 mol% ≤ constituent unit (D) + constituent unit (E) + constituent unit (F) ≤ 5 mol%.

3. The liquid crystal polyester resin according to claim 2, wherein the constituent unit (C) is a constituent unit derived from at least one selected from the group consisting of 4-(4-hydroxyphenyl)benzoic acid, 6-hydroxynicotinic acid, m-hydroxybenzoic acid, 4-hydroxy-3-methylbenzoic acid, 2-fluoro-4-hydroxybenzoic acid, 4-(4-hydroxyphenoxy)benzoic acid, and coumaric acid.

4. The liquid crystal polyester resin according to claim 2, wherein the constituent unit (C) is a constituent unit derived from at least one selected from the group consisting of 4-(4-hydroxyphenyl)benzoic acid, 6-hydroxynicotinic acid, and m-hydroxybenzoic acid.

5. The liquid crystal polyester resin according to any one of claims 1 to 4, wherein the melting point is below 350°C.

6. The liquid crystal polyester resin according to claim 5, wherein the temperature difference between the melting point and the crystallization point is 30°C or more.

7. A fibrous molded article comprising the liquid crystal polyester resin as described in any one of claims 1 to 4.

8. A sheet-like molded article comprising the liquid crystal polyester resin as described in any one of claims 1 to 4.

9. An injection-molded article comprising the liquid crystal polyester resin as described in any one of claims 1 to 4.

10. An electrical and electronic component comprising the molded article as described in claim 7.

11. An electrical and electronic component comprising the molded article as described in claim 8.

12. An electrical and electronic component comprising the molded article as described in claim 9.

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