Liquid crystal polyester, liquid crystal polyester composition, and molded article

Abstract

To provide a liquid crystal polyester enabling formation of a molded article having a high tensile elastic modulus.SOLUTION: A liquid crystal polyester comprises a monomer unit (A) represented by formula (A) and a monomer unit (B) represented by formula (B), where the content of the monomer unit (A) is 50 mol% or more relative to the total amount of all monomer units, and the content of the monomer unit (B) is 0.5 mol% or more and less than 10 mol% relative to the total amount of all monomer units. -X1-Ar1-X2- (A), -X3-Ar2-Y-Ar3-X4- (B). [In the formulae, Ar1 represents a naphthylene group, Ar2 and Ar3 each independently represent a phenylene group, a biphenylene group, or a naphthylene group, X1, X2, X3, and X4 each independently represent -CO- or -O-, and Y represents -O-, -CO-, -SO2-, or -NH-.]SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a liquid crystal polyester, a liquid crystal polyester composition, and a molded article.

Background Art

[0002] Liquid crystal polyesters are used in various applications because of their high fluidity, high heat resistance, and high dimensional accuracy of the resulting molded articles.

[0003] For example, Patent Document 1 describes a liquid crystal polymer composition containing 15% by mass or more of a specific flat glass fiber and 20% by mass or more of a specific plate-like filler.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, from the viewpoints of expansion into more diverse applications and application to more refined parts, improvement of the characteristics of liquid crystal polyester itself has been demanded.

[0006] An object of the present disclosure is to provide a liquid crystal polyester capable of forming a molded article having a high tensile modulus. Another object of the present disclosure is to provide a liquid crystal polyester composition and a molded article containing the above liquid crystal polyester.

Means for Solving the Problems

[0007] The present disclosure provides, for example, the following. [1] A monomer unit (A) represented by formula (A), and The monomer unit (B) represented by formula (B), and having the content of the monomer unit (A) is 50 mol% or more based on the total of all monomer units, the content of the monomer unit (B) is 0.5 mol% or more and less than 10 mol% based on the total of all monomer units, a liquid crystal polyester. -X 1 -Ar 1 -X 2 - …(A) -X 3 -Ar 2 -Y-Ar 3 -X 4 - …(B) [In the formula, Ar 1 represents a condensed polycyclic aromatic hydrocarbon group, Ar 2 and Ar 3 each independently represents a phenylene group, a biphenylene group or a naphthylene group, X 1 , X 2 , X 3 and X 4 each independently represents -CO- or -O-, Y represents -O-, -CO-, -SO2- or -NH-. Some or all of the hydrogen atoms possessed by Ar 1 , Ar 2 and Ar 3 may be substituted with a halogen atom, an alkyl group or an aryl group.] [2] The liquid crystal polyester according to [1], wherein the Ar 2 and the Ar 3 are phenylene groups. [3] The liquid crystal polyester according to [1] or [2], wherein the Y is -O-. [4] The liquid crystal polyester according to any one of [1] to [3], wherein the Ar 1 is a naphthylene group. [5] The liquid crystal polyester according to any one of [1] to [4], wherein the X 1 is -CO-, and the X 2 is -CO- or -O-. [6] The liquid crystal polyester according to any one of [1] to [5], wherein the content of the monomer unit (B) is 1 mol% or more and 8 mol% or less based on the total of all monomer units. [7] Said X 3 and said X 4 are -CO-, the liquid crystal polyester according to any one of [1] to [6]. [8] The monomer unit (A) is Said X 1 is -CO-, and said X 2 is -O-, the monomer unit (A-1), and Said X 1 and said X 2 are -CO-, the monomer unit (A-2), and The liquid crystal polyester according to any one of [1] to [7], comprising. [9] The liquid crystal polyester according to any one of [1] to [8], wherein the content of the monomer unit (A) is 60 mol% or more and 85 mol% or less based on the total of all monomer units.

[10] The liquid crystal polyester according to any one of [1] to [9], further having a monomer unit (C) represented by the formula (C). -X 5 -Ar 4 -X 6 - …(C) [In the formula, Ar 4 represents a phenylene group or a biphenylene group, and X 5 and X 6 each independently represent -CO- or -O-. Some or all of the hydrogen atoms of Ar 4 may be substituted with a halogen atom, an alkyl group or an aryl group.]

[11] The liquid crystal polyester according to

[10] , wherein the content of the monomer unit (C) is 10 mol% or more and 40 mol% or less based on the total of all monomer units.

[12] A liquid crystal polyester composition containing the liquid crystal polyester according to any one of [1] to

[11] .

[13] A molded article containing the liquid crystal polyester according to any one of [1] to

[11] , wherein the molded article is a connector, socket, relay part, coil bobbin, optical pickup, oscillator, semiconductor package, IC tray, wafer carrier, household electrical appliance part, lighting fixture part, audio product part, ferrule for optical cable, telephone part, facsimile part, modem part, separation claw, heater holder, impeller, fan gear, gear, bearing, motor part, motor case, engine part, engine room interior part, electrical component, automotive interior part, pot for microwave cooking, heat-resistant tableware, floor material, wall material, beam, column, roof material, aircraft part, spacecraft part, space equipment part, atomic reactor, marine facility member, cleaning jig, optical equipment part, valves, pipes, nozzles, filters, medical equipment parts, medical materials, sensor parts, sanitary equipment, sports goods, or leisure goods.

Advantages of the Invention

[0008] According to the present disclosure, a liquid crystal polyester capable of forming a molded article having a high tensile modulus is provided. Further, according to the present disclosure, a liquid crystal polyester composition and a molded article containing the above liquid crystal polyester are provided.

Modes for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present disclosure will be described in detail.

[0010] The liquid crystal polyester of the present embodiment (hereinafter, also simply referred to as "liquid crystal polyester") has a monomer unit (A) represented by the formula (A) and a monomer unit (B) represented by the formula (B). -X 1 -Ar 1 -X 2 - …(A) -X 3 -Ar 2 -Y-Ar 3 -X4 - …(B)

[0011] In formula (A), Ar 1 represents a condensed polycyclic aromatic hydrocarbon group. Ar 1 Some or all of the hydrogen atoms that Ar has may be substituted with substituents. That is, Ar 1 may be a condensed polycyclic aromatic hydrocarbon group that may have a substituent. The substituent may be a halogen atom, an alkyl group, or an aryl group.

[0012] In formula (A), X 1 and X 2 each independently represent -CO- or -O-.

[0013] In formula (B), Ar 2 and Ar 3 each independently represent a phenylene group, a biphenylene group, or a naphthylene group. Ar 2 and Ar 3 Some or all of the hydrogen atoms that Ar has may be substituted with substituents. That is, Ar 2 and Ar 3 may each independently be a phenylene group that may have a substituent, a biphenylene group that may have a substituent, or a naphthylene group that may have a substituent. The substituent may be a halogen atom, an alkyl group, or an aryl group.

[0014] In formula (B), X 3 and X 4 each independently represent -CO- or -O-, and Y represents -O-, -CO-, -SO2-, or -NH-.

[0015] In the liquid crystal polyester of the present embodiment, the content of the monomer unit (A) is 50 mol% or more with respect to the total of all monomer units, and the content of the monomer unit (B) is 0.5 mol% or more and less than 10 mol% with respect to the total of all monomer units.

[0016] The liquid crystal polyester of this embodiment can form a molded article having a high tensile modulus. Therefore, the liquid crystal polyester of this embodiment can be suitably used as a material for fine electronic components and the like.

[0017] The reason for the above effect is not necessarily clear, but it is considered as follows. Usually, when an ether-based monomer unit is introduced into a liquid crystal polyester, the stacking between molecular chains is inhibited by the bent structure of the ether-based monomer unit, resulting in a decrease in the rigidity of the liquid crystal polyester and a decrease in the tensile modulus. For example, International Publication No. 2023 / 045821 (Patent Document 2) discloses that the introduction of an ether-based monomer unit (repeating unit C) significantly decreases the tensile modulus. In contrast, since the liquid crystal polyester of this embodiment contains 50 mol% or more of a monomer unit (A) having a condensed polycyclic aromatic hydrocarbon group, the stacking between molecular chains is relatively strong. Therefore, in this embodiment, a bent structure due to the monomer unit (B) can be introduced while sufficiently maintaining the stacking between molecular chains. In this embodiment, it is considered that a high tensile modulus is realized by the synergistic effect of this stacking and the entanglement of molecular chains due to the bent structure.

[0018] The liquid crystal polyester may be any polyester that exhibits liquid crystallinity in a molten state. The liquid crystal polyester may be a single polymer or a mixture of two or more polymers.

[0019] The liquid crystal polyester has a constitutional unit (monomer unit) derived from a raw material monomer. The liquid crystal polyester may have main monomer units (for example, monomer units that are 90 mol% or more, 95 mol% or more, or 99 mol% or more based on the total of all monomer units, preferably all monomer units) that are monomer units derived from an aromatic compound. A liquid crystal polyester in which all monomer units are monomer units derived from an aromatic compound is also referred to as an all-aromatic liquid crystal polyester.

[0020] In this specification, "derived from" means that in the monomer unit of the liquid crystal polyester formed by the polymerization of the raw material monomer, while the chemical structure of the functional group contributing to the polymerization possessed by the raw material monomer has changed, no other structural changes have occurred. The "derived from" here is a concept that also includes the case where it is derived from a polymerizable derivative of the raw material monomer (for example, a compound obtained by converting the functional group contributing to the polymerization possessed by the raw material monomer into another polymerizable group).

[0021] The liquid crystal polyester has a monomer unit (A) represented by formula (A). -X 1 -Ar 1 -X 2 - …(A)

[0022] In formula (A), Ar 1 represents a condensed polycyclic aromatic hydrocarbon group. Some or all of the hydrogen atoms possessed by Ar 1 may be substituted with substituents. That is, Ar 1 may be a condensed polycyclic aromatic hydrocarbon group that may have substituents. The substituents may be a halogen atom, an alkyl group or an aryl group.

[0023] The condensed polycyclic aromatic hydrocarbon group is a group obtained by removing two hydrogen atoms from a condensed polycyclic aromatic hydrocarbon. The condensed polycyclic aromatic hydrocarbon may be, for example, naphthalene, anthracene, phenanthrene, tetracene, pyrene, triphenylene, perylene or fluorene, and naphthalene is preferred from the viewpoints of availability and price.

[0024] The condensed polycyclic aromatic hydrocarbon group may be a naphthylene group, and the naphthylene group may be, for example, 1,3-naphthylene group, 1,4-naphthylene group, 1,5-naphthylene group, 1,6-naphthylene group, 1,7-naphthylene group, 1,8-naphthylene group, 2,4-naphthylene group, 2,5-naphthylene group, 2,6-naphthylene group or 2,7-naphthylene group, preferably 2,6-naphthylene group or 2,7-naphthylene group, and more preferably 2,6-naphthylene group.

[0025] Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The halogen atom as a substituent may be a fluorine atom, a chlorine atom, or a bromine atom, may be a fluorine atom or a chlorine atom, or may be a fluorine atom.

[0026] The alkyl group as a substituent may be linear, branched, or cyclic. The alkyl group may be, for example, an alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, an n-decyl group, and the like.

[0027] The aryl group as a substituent may be monocyclic or condensed. The aryl group may be, for example, an aryl group having 6 to 20 carbon atoms. Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, a 2-naphthyl group, and the like. The aryl group may also be a group in which a hydrogen atom of an aromatic ring is substituted with an alkyl group, such as a tolyl group.

[0028] Ar 1 The number of substituents that Ar has may be, for example, 0 to 2, may be 0 or 1, or may be 0.

[0029] In formula (A), X 1 and X 2 each independently represent -CO- or -O-.

[0030] X 1 is preferably -CO-. X 2 may be -CO- or -O-.

[0031] Examples of the monomer unit (A) include a monomer unit (A-1) in which X 1 is -CO- and X 2 is -O-, a monomer unit (A-2) in which X 1 and X 2 are -CO-, and X1 and X 2 Examples of the monomer unit (A-3) where is -O-

[0032] The monomer unit (A) preferably contains the monomer unit (A-1), and more preferably contains the monomer unit (A-1) and the monomer unit (A-2).

[0033] The proportion of the monomer unit (A-1) in the monomer unit (A) may be, for example, 50 mol% or more, and may be 60 mol% or more, 65 mol% or more, or 70 mol% or more. Also, the proportion of the monomer unit (A-1) in the monomer unit (A) may be, for example, 95 mol% or less, and may be 90 mol% or less, or 85 mol% or less. That is, the proportion of the monomer unit (A-1) in the monomer unit (A) may be, for example, 50 mol% or more and 95 mol% or less, 50 mol% or more and 90 mol% or less, 50 mol% or more and 85 mol% or less, 60 mol% or more and 95 mol% or less, 60 mol% or more and 90 mol% or less, 60 mol% or more and 85 mol% or less, 65 mol% or more and 95 mol% or less, 65 mol% or more and 90 mol% or less, 65 mol% or more and 85 mol% or less, 70 mol% or more and 95 mol% or less, 70 mol% or more and 90 mol% or less, or 70 mol% or more and 85 mol% or less.

[0034] The proportion of the monomer unit (A-2) in the monomer unit (A) may be, for example, 5 mol% or more, and may be 10 mol% or more, or 15 mol% or more. The proportion of the monomer unit (A-2) in the monomer unit (A) may be, for example, 50 mol% or less, and may be 40 mol% or less, 35 mol% or less, or 30 mol% or less. That is, the proportion of the monomer unit (A-2) in the monomer unit (A) may be, for example, 5 mol% or more and 50 mol% or less, 5 mol% or more and 40 mol% or less, 5 mol% or more and 35 mol% or less, 5 mol% or more and 30 mol% or less, 10 mol% or more and 50 mol% or less, 10 mol% or more and 40 mol% or less, 10 mol% or more and 35 mol% or less, 10 mol% or more and 30 mol% or less, 15 mol% or more and 50 mol% or less, 15 mol% or more and 40 mol% or less, 15 mol% or more and 35 mol% or less, or 15 mol% or more and 30 mol% or less.

[0035] In the liquid crystal polyester, the content of the monomer unit (A) is 50 mol% or more, and may be 60 mol% or more, 65 mol% or more, or 70 mol% or more with respect to the total of all monomer units constituting the liquid crystal polyester. Thereby, the dielectric properties are further improved, and the above-described effects tend to be obtained more remarkably. Further, the content of the monomer unit (A) may be, for example, 90 mol% or less, 85 mol% or less, 80 mol% or less, or 75 mol% or less with respect to the total of all monomer units constituting the liquid crystal polyester. Thereby, the moldability and processability at low temperatures tend to be good. That is, the content of the monomer unit (A) is, for example, 50 mol% or more and 90 mol% or less, 50 mol% or more and 85 mol% or less, 50 mol% or more and 80 mol% or less, 50 mol% or more and 75 mol% or less, 60 mol% or more and 90 mol% or less, 60 mol% or more and 85 mol% or less, 60 mol% or more and 80 mol% or less, 60 mol% or more and 75 mol% or less, 65 mol% or more and 90 mol% or less, 65 mol% or more and 85 mol% or less, 65 mol% or more and 80 mol% or less, 65 mol% or more and 75 mol% or less, 70 mol% or more and 90 mol% or less, 70 mol% or more and 85 mol% or less, 70 mol% or more and 80 mol% or less, or 70 mol% or more and 75 mol% or less with respect to the total of all monomer units constituting the liquid crystal polyester.

[0036] The liquid crystal polyester has a monomer unit (B) represented by the formula (B). -X 3 -Ar 2 -Y-Ar 3 -X 4 - …(B)

[0037] In the formula (B), Ar 2 and Ar 3 each independently represent a phenylene group, a biphenylene group, or a naphthylene group. Some or all of the hydrogen atoms of Ar 2 and Ar 3 may be substituted with substituents. That is, Ar 2 and Ar 3may each independently be a phenylene group which may have a substituent, a biphenylene group which may have a substituent or a naphthylene group which may have a substituent. The substituent may be a halogen atom, an alkyl group or an aryl group.

[0038] Ar 2 and Ar 3 are preferably a phenylene group or a biphenylene group, more preferably a phenylene group.

[0039] The phenylene group may be, for example, a 1,4-phenylene group or a 1,3-phenylene group, preferably a 1,4-phenylene group.

[0040] The biphenylene group may be, for example, a 4,4'-biphenylene group.

[0041] The naphthylene group may be, for example, a 2,6-naphthylene group or a 2,7-naphthylene group, preferably a 2,6-naphthylene group.

[0042] Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The halogen atom as the substituent may be a fluorine atom, a chlorine atom or a bromine atom, may be a fluorine atom or a chlorine atom, and may be a fluorine atom.

[0043] The alkyl group as the substituent may be linear, branched or cyclic. The alkyl group may be, for example, an alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, an n-decyl group and the like.

[0044] The aryl group as a substituent may be a monocyclic ring or a condensed ring. The aryl group may be, for example, an aryl group having 6 to 20 carbon atoms. Examples of the aryl group include a phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 1-naphthyl group, 2-naphthyl group, and the like. The aryl group may be a group in which a hydrogen atom of the aromatic ring is substituted with an alkyl group, such as a tolyl group.

[0045] Ar 2 and Ar 3 The number of substituents that each has may be, for example, 0 to 3, 0 to 2, 0 or 1, or may be 0.

[0046] In formula (B), X 3 and X 4 each independently represents -CO- or -O-, and Y represents -O-, -CO-, -SO2- or -NH-.

[0047] From the viewpoint of dielectric properties, Y is preferably -O-.

[0048] Examples of the monomer unit (B) include a monomer unit (B-1) in which X 3 and X 4 are -CO-, a monomer unit (B-2) in which X 3 and X 4 are -O-, and a monomer unit (B-3) in which X 3 is -O- and X 4 is -CO-.

[0049] The monomer unit (B) preferably contains at least one selected from the group consisting of the monomer unit (B-1) and the monomer unit (B-2), and more preferably contains the monomer unit (B-1).

[0050] The proportion of the monomer unit (B-1) in the monomer unit (B) may be, for example, 50 mol% or more, 70 mol% or more, 90 mol% or more, 95 mol% or more, 99 mol% or more, or may be 100 mol%.

[0051] In the liquid crystal polyester, the content of the monomer unit (B) is 0.5 mol% or more based on the total of all monomer units constituting the liquid crystal polyester, and from the viewpoint of more significantly obtaining the above-described effects, it may be 1 mol% or more, 1.5 mol% or more, 2 mol% or more, or 3 mol% or more. Further, the content of the monomer unit (B) is less than 10 mol% based on the total of all monomer units constituting the liquid crystal polyester, and from the viewpoint of more significantly obtaining the above-described effects, it may be 9 mol% or less, 8 mol% or less, or 7.5 mol% or less. That is, the content of the monomer unit (B) is, for example, 0.5 mol% or more and less than 10 mol%, 0.5 mol% or more and 9 mol% or less, 0.5 mol% or more and 8 mol% or less, 0.5 mol% or more and 7.5 mol% or less, 1 mol% or more and less than 10 mol%, 1 mol% or more and 9 mol% or less, 1 mol% or more and 8 mol% or less, 1 mol% or more and 7.5 mol% or less, 1.5 mol% or more and less than 10 mol%, 1.5 mol% or more and 9 mol% or less, 1.5 mol% or more and 8 mol% or less, 1.5 mol% or more and 7.5 mol% or less, 2 mol% or more and less than 10 mol%, 2 mol% or more and 9 mol% or less, 2 mol% or more and 8 mol% or less, 2 mol% or more and 7.5 mol% or less, 3 mol% or more and less than 10 mol%, 3 mol% or more and 9 mol% or less, 3 mol% or more and 8 mol% or less, or 3 mol% or more and 7.5 mol% or less based on the total of all monomer units constituting the liquid crystal polyester.

[0052] The liquid crystal polyester may further have a monomer unit (C) represented by the formula (C). -X 5 -Ar 4 -X 6 - …(C)

[0053] In the formula (C), Ar 4 represents a phenylene group or a biphenylene group. Some or all of the hydrogen atoms that Ar 4 has may be substituted with substituents. That is, Ar 4 may be a phenylene group that may have a substituent or a biphenylene group that may have a substituent. The substituent may be a halogen atom, an alkyl group, or an aryl group.

[0054] Ar 4 is preferably a phenylene group.

[0055] The phenylene group may be, for example, a 1,4-phenylene group or a 1,3-phenylene group, and is preferably a 1,4-phenylene group.

[0056] The biphenylene group may be, for example, a 4,4'-biphenylene group.

[0057] Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The halogen atom as a substituent may be a fluorine atom, a chlorine atom, or a bromine atom, may be a fluorine atom or a chlorine atom, and may be a fluorine atom.

[0058] The alkyl group as a substituent may be linear, branched, or cyclic. The alkyl group may be, for example, an alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, an n-decyl group, and the like.

[0059] The aryl group as a substituent may be monocyclic or condensed. The aryl group may be, for example, an aryl group having 6 to 20 carbon atoms. Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, a 2-naphthyl group, and the like. The aryl group may be a group in which a hydrogen atom of an aromatic ring is substituted with an alkyl group, such as a tolyl group.

[0060] Ar 4 The number of substituents that Ar has may be, for example, 0 to 3, may be 0 to 2, may be 0 or 1, and may be 0.

[0061] In formula (C), X 5 and X 6 each independently represents -CO- or -O-.

[0062] As the monomer unit (C), X 5 and X 6 is the monomer unit (C-1) where -O-, X 5 and X 6 is the monomer unit (C-2) where -CO-, X 5 is -O-, and X 6 is the monomer unit (C-3) where -CO- can be mentioned.

[0063] The monomer unit (C) preferably contains the monomer unit (C-1), and may contain the monomer unit (C-1) and the monomer unit (C-2).

[0064] The proportion of the monomer unit (C-1) in the monomer unit (C) may be, for example, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or even 100 mol%.

[0065] When the monomer unit (C) contains the monomer unit (C-1) and the monomer unit (C-2), the proportion of the monomer unit (C-1) in the monomer unit (C) may be, for example, 97 mol% or less, 95 mol% or less, 93 mol% or less, or 90 mol% or less. That is, when the monomer unit (C) contains the monomer unit (C-1) and the monomer unit (C-2), the proportion of the monomer unit (C-1) in the monomer unit (C) may be, for example, 50 mol% or more and 97 mol% or less, 50 mol% or more and 95 mol% or less, 50 mol% or more and 93 mol% or less, 50 mol% or more and 90 mol% or less, 60 mol% or more and 97 mol% or less, 60 mol% or more and 95 mol% or less, 60 mol% or more and 93 mol% or less, 60 mol% or more and 90 mol% or less, 70 mol% or more and 97 mol% or less, 70 mol% or more and 95 mol% or less, 70 mol% or more and 93 mol% or less, 70 mol% or more and 90 mol% or less, 80 mol% or more and 97 mol% or less, 80 mol% or more and 95 mol% or less, 80 mol% or more and 93 mol% or less, or 80 mol% or more and 90 mol% or less.

[0066] The proportion of the monomer unit (C-2) in the monomer unit (C) may be, for example, 50 mol% or less, may be 40 mol% or less, 30 mol% or less, or 20 mol% or less, and may even be 0 mol%.

[0067] When the monomer unit (C) contains the monomer unit (C-1) and the monomer unit (C-2), the proportion of the monomer unit (C-2) in the monomer unit (C) may be, for example, 3 mol% or more, may be 5 mol% or more, 7 mol% or more, or 10 mol% or more. That is, when the monomer unit (C) contains the monomer unit (C-1) and the monomer unit (C-2), the proportion of the monomer unit (C-2) in the monomer unit (C) may be, for example, 3 mol% or more and 50 mol% or less, 3 mol% or more and 40 mol% or less, 3 mol% or more and 30 mol% or less, 3 mol% or more and 20 mol% or less, 5 mol% or more and 50 mol% or less, 5 mol% or more and 40 mol% or less, 5 mol% or more and 30 mol% or less, 5 mol% or more and 20 mol% or less, 7 mol% or more and 50 mol% or less, 7 mol% or more and 40 mol% or less, 7 mol% or more and 30 mol% or less, 7 mol% or more and 20 mol% or less, 10 mol% or more and 50 mol% or less, 10 mol% or more and 40 mol% or less, 10 mol% or more and 30 mol% or less, or 10 mol% or more and 20 mol% or less.

[0068] In the liquid crystal polyester, the content of the monomer unit (C) may be, for example, 10 mol% or more, may be 15 mol% or more, or may be 20 mol% or more with respect to the total of all the monomer units constituting the liquid crystal polyester. Also, the content of the monomer unit (C) may be, for example, 45 mol% or less, may be 40 mol% or less, may be 35 mol% or less, or may be 30 mol% or less with respect to the total of all the monomer units constituting the liquid crystal polyester. That is, the content of the monomer unit (C) may be, for example, 10 mol% or more and 45 mol% or less, 10 mol% or more and 40 mol% or less, 10 mol% or more and 35 mol% or less, 10 mol% or more and 30 mol% or less, 15 mol% or more and 45 mol% or less, 15 mol% or more and 40 mol% or less, 15 mol% or more and 35 mol% or less, 15 mol% or more and 30 mol% or less, 20 mol% or more and 45 mol% or less, 20 mol% or more and 40 mol% or less, 20 mol% or more and 35 mol% or less, or 20 mol% or more and 30 mol% or less with respect to the total of all monomer units constituting the liquid crystal polyester.

[0069] The liquid crystal polyester may have, for example, monomer units (A-1), monomer units (A-2), monomer units (B-1), monomer units (C-1), and monomer units (C-2).

[0070] In this specification, the number of each monomer unit of the liquid crystal polyester is determined by the analysis method described in JP-A-2000-19168. Specifically, the liquid crystal polyester is reacted with a lower alcohol in a supercritical state for depolymerization, and the depolymerization product (the monomer that induces each monomer unit) is quantified by liquid chromatography, whereby the number of each monomer unit with respect to all monomer units can be calculated.

[0071] The liquid crystal polyester can be produced by polymerizing raw material monomers corresponding to the monomer units constituting it. For example, it can be produced according to the method described in Patent No. 6439027.

[0072] The dielectric tangent of the liquid crystal polyester at 20 GHz may be, for example, 0.002 or less, preferably 0.0015 or less, and more preferably 0.0012 or less.

[0073] In this specification, the dielectric tangent of the liquid crystal polyester at 20 GHz is measured by the following method. The liquid crystal polyester is pressed by a hot and cold press machine (for example, KVHC II manufactured by Kitakawa Seiki Co., Ltd.) to obtain a test piece with a width of 35 mm, a length of 35 mm, and a thickness of 0.5 mm. For the obtained test piece, the dielectric tangent at 20 GHz at 23°C and 50% RH is measured using a vector network analyzer (for example, N5290A manufactured by Keysight Technologies, Inc.) and a split cylinder resonator (for example, CR710 manufactured by EM Lab Co., Ltd.).

[0074] The weight average molecular weight (Mw) of the liquid crystal polyester may be, for example, 40,000 or more, and from the viewpoint of mechanical strength, it may be 60,000 or more, 80,000 or more, or 100,000 or more. Also, the weight average molecular weight (Mw) of the liquid crystal polyester may be, for example, 500,000 or less, and from the viewpoint of moldability, it may be 400,000 or less, 300,000 or less, or 200,000 or less.

[0075] In this specification, the weight average molecular weight (Mw) of the liquid crystal polyester is measured by the following method. 5 mg of the liquid crystal polyester and 2 mL of pentafluorophenol are placed in a sample bottle and heated to an internal temperature of 120°C to obtain a solution. After cooling the obtained solution to 50°C, 4 mL of chloroform is added, and after stirring, it is filtered using a filter with a pore size of 0.45 μm to obtain a measurement sample. The obtained measurement sample is analyzed by the GPC method to calculate the weight average molecular weight in terms of standard polystyrene.

[0076] The liquid crystal polyester of this embodiment can be suitably used as a molding material for obtaining a molded product. The liquid crystal polyester may be used, for example, as pellets.

[0077] The liquid crystal polyester may be used as a composition (liquid crystal polyester composition) mixed with other components.

[0078] The liquid crystal polyester composition may contain, for example, one or more resins other than liquid crystal polyester. Examples of such resins include polyolefin, cyclic polyolefin, polyvinyl chloride, polysulfone, (meth)acrylic resin, polyphenylene ether resin, polyacetal resin, polyamide resin, imide resin, cellulose resin, polyether ether ketone resin, fluororesin, polycarbonate resin, styrene resin, thermosetting resin, and the like.

[0079] In addition, the liquid crystal polyester composition may further contain an inorganic filler, a colorant, a dispersant, a plasticizer, an antioxidant, a curing agent, a flame retardant, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a surfactant, a lubricant, a mold release agent, and the like.

[0080] The liquid crystal polyester composition can be suitably used as a molding material. The liquid crystal polyester composition may be used, for example, as pellets.

[0081] The molded article of the present embodiment may be a molded article containing the above-described liquid crystal polyester, or may be a molded article containing the above-described liquid crystal polyester composition.

[0082] The molded article of the present embodiment can be obtained, for example, by molding the above-described liquid crystal polyester or liquid crystal polyester composition into a desired shape and performing a processing treatment as necessary.

[0083] As a molding method of the molded article, melt molding is preferable. Examples of the melt molding method include an injection molding method, an extrusion molding method, a compression molding method, a blow molding method, a vacuum molding method, a foam molding, and a press molding.

[0084] The molded article of the present embodiment may be, for example, a connector, a socket, a relay component, a coil bobbin, an optical pickup, an oscillator, a semiconductor package, an IC tray, a wafer carrier, a household electrical appliance component, a lighting fixture component, an audio product component, a ferrule for an optical cable, a telephone component, a facsimile component, a modem component, a separating claw, a heater holder, an impeller, a fan gear, a gear, a bearing, a motor component, a motor case, an engine component, an engine room interior component, an electrical component, an automotive interior component, a pot for microwave cooking, a heat-resistant tableware, a floor material, a wall material, a beam, a column, a roof material, an aircraft component, a spacecraft component, a space equipment component, a nuclear reactor, an ocean facility member, a cleaning jig, an optical instrument component, valves, pipes, nozzles, filters, a medical device component, a medical material, a sensor component, a sanitary fixture, a sports good, a leisure good, etc.

[0085] As described above, the preferred embodiments of the present disclosure have been described, but the present disclosure is not limited to the above embodiments.

Example

[0086] Hereinafter, the invention according to the present disclosure will be described in more detail by way of examples, but the invention according to the present disclosure is not limited to these examples.

[0087] (Example 1) (1) Production of liquid crystal polyester (A-1) Into a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet pipe, a thermometer and a reflux condenser, 1035.0 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 255.2 g (2.32 mol: used in 0.07 mol excess) of hydroquinone, 49.8 g (0.30 mol) of terephthalic acid, 51.6 g (0.20 mol) of 4,4'-dicarboxydiphenyl ether, 378.3 g (1.75 mol) of 2,6-naphthalenedicarboxylic acid and 1189.9 g (11.7 mol) of acetic anhydride were charged, and 0.052 g of 1-methylimidazole was added as a catalyst. After thoroughly replacing the inside of the reactor with nitrogen gas, the temperature was raised to 145°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained and refluxed for 1 hour. Thereafter, while distilling off the by-produced acetic acid and unreacted acetic anhydride, the temperature was raised to 310 °C over 3 hours and 30 minutes, and after holding at the same temperature for 2 hours and 10 minutes, the content in the reactor was taken out. The obtained solid content was cooled to room temperature and pulverized to obtain a powder. The obtained powder was heated from room temperature to 260 °C over 1 hour under a nitrogen atmosphere, then heated from 260 °C to 280 °C over 1 hour, and held at 280 °C for 5 hours to proceed with the polymerization reaction in the solid phase, thereby obtaining a liquid crystalline polyester (A-1). The weight average molecular weight (Mw) of the obtained liquid crystalline polyester (A-1) was 180,000. The weight average molecular weight (Mw) was measured by the following method.

[0088] <Measurement of weight average molecular weight (Mw)> 5 mg of the liquid crystal polyester and 2 mL of pentafluorophenol were placed in a sample bottle and heated to an internal temperature of 120 °C to obtain a solution. After the obtained solution was cooled to 50 °C, 4 mL of chloroform was added, and after stirring, it was filtered using a filter with a pore size of 0.45 μm to obtain a measurement sample. The obtained measurement sample was analyzed by the GPC method to calculate the weight average molecular weight in terms of standard polystyrene.

[0089] (2) Production of pellets The obtained liquid crystalline polyester (A-1) was granulated at a cylinder temperature of 330 to 350 °C using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30) to obtain pellets.

[0090] (3) Measurement of tensile modulus Using the obtained pellets as raw materials, an ASTM No. 4 test piece with a thickness of 2.5 mm was injection molded using an injection molding machine (manufactured by Nissei Plastic Industrial Co., Ltd., NEX50IV-5EG). For the obtained test piece, in accordance with ASTM D638, the tensile modulus was measured using a tensile testing machine (manufactured by A&D Company, Ltd., Tensilon RTG-1250). The results are shown in Table 1.

[0091] (4) Measurement of dielectric loss tangent The liquid crystal polyester obtained above was pressed using a hot and cold press machine (for example, KVHC II manufactured by Kitakawa Seiki Co., Ltd.) to obtain test pieces with a width of 35 mm, a length of 35 mm, and a thickness of 0.5 mm. For the obtained test pieces, the dielectric tangent at 20 GHz at 23 °C and 50% RH was measured using a vector network analyzer (for example, N5290A manufactured by Keysight Technologies, Inc.) and a split cylinder resonator (for example, CR710 manufactured by EM Lab Co., Ltd.). The results are shown in Table 1.

[0092] (Example 2) A liquid crystal polyester was produced and evaluated in the same manner as in Example 1, except that terephthalic acid was not used and the amount of 4,4'-dicarboxydiphenyl ether used was changed to 129.1 g (0.50 mol).

[0093] (Example 3) A liquid crystal polyester was produced and evaluated in the same manner as in Example 1, except that the amount of 4,4'-dicarboxydiphenyl ether used was changed to 193.7 g (0.75 mol), the amount of terephthalic acid used was changed to 83.1 g (0.50 mol), and the amount of 2,6-naphthalenedicarboxylic acid used was changed to 216.2 g (1.0 mol).

[0094] (Comparative Example 1) A liquid crystal polyester was produced and evaluated in the same manner as in Example 1, except that 4,4'-dicarboxydiphenyl ether was not used and the amount of terephthalic acid used was changed to 83.1 g (0.5 mol).

[0095] (Comparative Example 2) A liquid crystal polyester was produced and evaluated in the same manner as in Example 1, except that terephthalic acid was not used and the amount of 4,4'-dicarboxydiphenyl ether used was changed to 322.8 g (1.25 mol) and the amount of 2,6-naphthalenedicarboxylic acid used was changed to 216.2 g (1.0 mol).

[0096]

Table 1

[0097] In Table 1, A1 represents the ratio (mol%) of monomer units derived from 2-hydroxy-6-naphthoic acid, A2 represents the ratio (mol%) of monomer units derived from 2,6-naphthalenedicarboxylic acid, B1 represents the ratio (mol%) of monomer units derived from 4,4'-dicarboxydiphenyl ether, C1 represents the ratio (mol%) of monomer units derived from hydroquinone, and C2 represents the ratio (mol%) of monomer units derived from terephthalic acid.

[0098] As shown in Table 1, in Examples 1 to 3, while maintaining a dielectric tangent equivalent to that of Comparative Example 1, a higher tensile elastic modulus was obtained than in Comparative Examples 1 to 2, and it was confirmed that the liquid crystal polyester of the present disclosure can achieve both good dielectric properties and a high tensile elastic modulus.

[0099] (Reference Example 1) Into a reactor equipped with a stirring device, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 994.5 g (7.2 mol) of 4-hydroxybenzoic acid, 446.9 g (2.4 mol) of 4,4'-dihydroxybiphenyl, 299.0 g (1.8 mol) of terephthalic acid, 99.7 g (0.6 mol) of isophthalic acid, and 1347.6 g (13.2 mol) of acetic anhydride were charged, and 0.19 g of 1-methylimidazole was added as a catalyst. After thoroughly purging the inside of the reactor with nitrogen gas, the temperature was raised to 140°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained and refluxed for 1 hour. Next, 0.92 g of 1-methylimidazole was added. Then, while distilling off the by-produced acetic acid, the temperature was raised to 300°C over 4 hours and 20 minutes, and the point at which an increase in torque was observed was regarded as the end of the reaction, and the contents were taken out. The flow temperature of the obtained solid content was 245°C. The obtained solid content was cooled to room temperature, pulverized with a coarse pulverizer, and then the temperature was raised from room temperature to 240°C over 1 hour under a nitrogen atmosphere, the temperature was raised from 240°C to 284°C over 5 hours and 40 minutes, and held at 284°C for 5 hours to proceed with the polymerization reaction in a solid layer to obtain a liquid crystal polyester.

[0100] For the obtained liquid crystal polyester, the tensile elastic modulus was measured in the same manner as in Example 1.

[0101] (Reference Example 2) A liquid crystal polyester was produced in the same manner as in Reference Example 1, except that the amount of isophthalic acid used was changed to 0.36 mol and 0.24 mol of 4,4'-dicarboxydiphenyl ether was added. For the obtained liquid crystal polyester, the tensile elastic modulus was measured in the same manner as in Example 1, and the tensile elastic modulus was calculated when the tensile elastic modulus of the liquid crystal polyester of Reference Example 1 was taken as 1.

[0102] (Reference Example 3) A liquid crystal polyester was produced in the same manner as in Reference Example 1, except that isophthalic acid was not used and 0.6 mol of 4,4'-dicarboxydiphenyl ether was added. For the obtained liquid crystal polyester, the tensile elastic modulus was measured in the same manner as in Example 1, and the tensile elastic modulus was calculated when the tensile elastic modulus of the liquid crystal polyester of Reference Example 1 was taken as 1.

[0103]

Table 2

[0104] In Table 2, B1 represents the ratio (mol%) of the monomer unit derived from 4,4'-dicarboxydiphenyl ether, C3 represents the ratio (mol%) of the monomer unit derived from 4-hydroxybenzoic acid, C4 represents the ratio (mol%) of the monomer unit derived from 4,4'-dihydroxybiphenyl, C5 represents the ratio (mol%) of the monomer unit derived from terephthalic acid, and C6 represents the ratio (mol%) of the monomer unit derived from isophthalic acid.

[0105] As shown in Table 2, it was confirmed that in the liquid crystal polyester not containing the monomer unit having a condensed polycyclic aromatic hydrocarbon group, the tensile elastic modulus decreased significantly by the introduction of the monomer unit (B).

Claims

1. a monomer unit (A) represented by formula (A), a monomer unit (B) represented by formula (B), having, wherein the content of the monomer unit (A) is 50 mol% or more based on the total of all monomer units, the content of the monomer unit (B) is 0.5 mol% or more and less than 10 mol% based on the total of all monomer units, a liquid crystal polyester. -X １ -Ar １ -X ２ - …(A) -X ３ -Ar ２ -Y-Ar ３ -X ４ - …(B) [In the formula, Ar １ represents a condensed polycyclic aromatic hydrocarbon group, Ar ２ and Ar ３ each independently represent a phenylene group, a biphenylene group or a naphthylene group, X １ , X ２ , X ３ and X ４ each independently represent -CO- or -O-, and Y represents -O-, -CO-, -SO ２ -, or -NH-. Some or all of the hydrogen atoms possessed by Ar １ , Ar ２ and Ar ３ may be substituted with halogen atoms, alkyl groups or aryl groups. ]

2. said Ar ２ and said Ar ３ The liquid crystal polyester according to claim 1, wherein is a phenylene group.

3. The liquid crystal polyester according to claim 1, wherein Y is -O-.

4. The above-mentioned Ar １ The liquid crystal polyester according to claim 1, wherein is a naphthylene group.

5. said X １ is -CO-, Said X ２ The liquid crystal polyester according to claim 1, wherein said X is -CO- or -O-.

6. The liquid crystal polyester according to claim 1, wherein the content of the monomer unit (B) is 1 mol% or more and 8 mol% or less based on the total of all monomer units.

7. Said X ３ and said X ４ is -CO-, the liquid crystal polyester according to claim 1.

8. wherein the monomer unit (A) is Said X １ is -CO-, and said X ２ is -O- monomer unit (A-1), and Said X １ and said X ２ a monomer unit (A-2) in which is —CO—, The liquid crystal polyester according to claim 1, including.

9. The liquid crystal polyester according to claim 1, wherein the content of the monomer unit (A) is 60 mol% or more and 85 mol% or less based on the total of all monomer units.

10. The liquid crystal polyester according to claim 1, further having a monomer unit (C) represented by formula (C). -X ５ -Ar ４ -X ６ -…(C) [In the formula, Ar ４ represents a phenylene group or a biphenylene group, and X ５ and X ６ each independently represent -CO- or -O-. Some or all of the hydrogen atoms possessed by Ar ４ may be substituted with a halogen atom, an alkyl group, or an aryl group.]

11. The liquid crystal polyester according to claim 10, wherein the content of the monomer unit (C) is 10 mol% or more and 40 mol% or less based on the total of all monomer units.

12. A liquid crystal polyester composition containing the liquid crystal polyester according to any one of claims 1 to 11.

13. A molded article containing the liquid crystal polyester according to any one of claims 1 to 11, wherein the molded article is a connector, socket, relay component, coil bobbin, optical pickup, oscillator, semiconductor package, IC tray, wafer carrier, household electric appliance part, lighting fixture part, audio product part, ferrule for optical cable, telephone part, facsimile part, modem part, separating claw, heater holder, impeller, fan gear, gear, bearing, motor part, motor case, engine part, engine room interior part, electrical equipment part, automobile interior part, pot for microwave cooking, heat-resistant tableware, floor material, wall material, beam, column, roofing material, aircraft part, spacecraft part, space equipment part, atomic reactor, marine facility member, cleaning jig, optical instrument part, valves, pipes, nozzles, filters, medical equipment part, medical material, sensor parts, sanitary equipment, sports goods, or leisure goods.

Images