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

Abstract

Disclosed is a liquid crystal polyester which has a monomer unit (A) represented by formula (A) and a monomer unit (B) represented by formula (B), wherein the content of the monomer unit (A) is 50 mol% or more relative to the total content 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 content of all monomer units.　(A): -X1-Ar1-X2- (B): -X3-Ar2-Y-Ar3-X4- (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-.)

Description

Liquid crystal polyester, liquid crystal polyester composition and molded article

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

[0002] Liquid crystal polyesters have high fluidity and heat resistance, and the dimensional accuracy of the molded articles obtained is also high, and therefore they are used in a variety of applications.

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

[0004] JP 2003-268252 A International Publication No. 2023 / 045821

[0005] In recent years, there has been a demand for improving the properties of liquid crystalline polyesters themselves in order to expand their applications to more diverse uses and to apply them to more precise parts.

[0006] An object of the present disclosure is to provide a liquid crystalline polyester that can be formed into a molded article having a high tensile modulus. Another object of the present disclosure is to provide a liquid crystalline polyester composition and a molded article containing the liquid crystalline polyester.

[0007] The present disclosure provides, for example, the following: [1] A liquid crystal polyester having a monomer unit (A) represented by formula (A) and a monomer unit (B) represented by formula (B), wherein 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. -X １ -Ar １ -X ２ - ... (A) -X ３ -Ar ２ -Y-Ar ３ -X ４ -...(B) [wherein, Ar １ represents a condensed polycyclic aromatic hydrocarbon group, and 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—, and Y represents —O—, —CO—, or —SO ２ - or -NH-. １ , Ar ２ and Ar ３ A part or all of the hydrogen atoms of Ar may be substituted with a halogen atom, an alkyl group, or an aryl group. ２ and the Ar ３ [3] The liquid crystal polyester according to [1] or [2], wherein Y is —O—. [4] The liquid crystal polyester according to [1] or [2], wherein Ar １ [5] The liquid crystal polyester according to any one of [1] to [3], wherein X is a naphthylene group. １ is —CO—, and ２ [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 with respect to the total of all monomer units. [7] 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 with respect to the total of all monomer units. ３ and the X ４ [8] The liquid crystal polyester according to any one of [1] to [6], wherein the monomer unit (A) is —CO—. １ is —CO—, and the X ２ a monomer unit (A-1) in which X is —O—; １ and the X ２ and a monomer unit (A-2) in which -CO- is -CO-. [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 comprising a monomer unit (C) represented by formula (C): -X ５ -Ar ４ -X ６ -...(C) [wherein, Ar ４represents a phenylene group or a biphenylene group, and X ５ and X ６ each independently represents —CO— or —O—. 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 comprising the liquid crystal polyester according to any one of [1] to

[11] .

[13] A molded article comprising the liquid crystalline polyester according to any one of [1] to

[11] , the molded article being a connector, a socket, a relay part, a coil bobbin, an optical pickup, an oscillator, a semiconductor package, an IC tray, a wafer carrier, a household electrical appliance part, a lighting fixture part, an audio product part, a ferrule for an optical cable, a telephone part, a facsimile part, a modem part, a separation claw, a heater holder, an impeller, a fan gear, a gear, a bearing, a motor part, a motor case, an engine part, an engine room interior part, an electrical component, an automobile interior part, a microwave cooking pot, a heat-resistant tableware, a flooring material, a wall material, a beam, a pillar, a roofing material, an aircraft part, a spacecraft part, a space equipment part, a nuclear reactor, a marine facility member, a cleaning jig, an optical equipment part, a valve, a pipe, a nozzle, a filter, a medical equipment part, a medical material, a sensor part, a sanitary fixture, a sporting goods, or a leisure goods.

[0008] According to the present disclosure, there is provided a liquid crystalline polyester capable of being formed into a molded article having a high tensile modulus. Also, according to the present disclosure, there is provided a liquid crystalline polyester composition and a molded article containing the liquid crystalline polyester.

[0009] Preferred embodiments of the present disclosure will be described in detail below.

[0010] The liquid crystal polyester of this embodiment (hereinafter also simply referred to as "liquid crystal polyester") has a monomer unit (A) represented by formula (A) and a monomer unit (B) represented by formula (B). １ -Ar １ -X ２ - ... (A) -X３ -Ar ２ -Y-Ar ３ -X ４ - ... (B)

[0011] In formula (A), Ar １ represents a condensed polycyclic aromatic hydrocarbon group. １ A part or all of the hydrogen atoms of Ar may be substituted with a substituent. １ may be a fused polycyclic aromatic hydrocarbon group which 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 represents —CO— or —O—.

[0013] In formula (B), Ar ２ and Ar ３ each independently represents a phenylene group, a biphenylene group, or a naphthylene group. ２ and Ar ３ A part or all of the hydrogen atoms of Ar may be substituted with a substituent. ２ and Ar ３ may 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.

[0014] In formula (B), X ３ and X ４ each independently represents —CO— or —O—, and Y represents —O—, —CO—, or —SO ２ - or -NH-.

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

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

[0017] The reason for this effect is not entirely clear, but is thought to be as follows. Typically, when an ether-based monomer unit is introduced into a liquid crystal polyester, the bent structure of the ether-based monomer unit inhibits stacking between molecular chains, reducing the rigidity of the liquid crystal polyester and decreasing 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 reduces the tensile modulus. In contrast, the liquid crystal polyester of this embodiment contains 50 mol% or more of a monomer unit (A) having a condensed polycyclic aromatic hydrocarbon group, and therefore exhibits relatively strong stacking between molecular chains. Therefore, in this embodiment, a bent structure due to the monomer unit (B) can be introduced while sufficiently maintaining stacking between molecular chains. In this embodiment, it is thought that a high tensile modulus is achieved due to 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 one type of polymer or a mixture of two or more types of polymers.

[0019] The liquid crystal polyester has constituent units (monomer units) derived from raw material monomers. The liquid crystal polyester may have a main monomer unit (for example, 90 mol% or more, 95 mol% or more, or 99 mol% or more of the monomer units relative to the total of all monomer units, preferably all monomer units) derived from an aromatic compound. A liquid crystal polyester in which all monomer units are derived from an aromatic compound is also called a wholly aromatic liquid crystal polyester.

[0020] In this specification, "derived" means that in the monomer units of the liquid crystal polyester formed by polymerization of the raw material monomers, the chemical structure of the functional group that contributes to polymerization of the raw material monomers has changed, but other structural changes have not occurred. Here, "derived" is a concept that also includes cases where the monomer unit is derived from a polymerizable derivative of the raw material monomer (for example, a compound obtained by converting the functional group that contributes to polymerization of the raw material monomers into another polymerizable group).

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

[0022] In formula (A), Ar １ represents a condensed polycyclic aromatic hydrocarbon group. １ A part or all of the hydrogen atoms of Ar may be substituted with a substituent. １ may be a fused polycyclic aromatic hydrocarbon group which may have a substituent. The substituent 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 cost.

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

[0027] The aryl group as a substituent may be a monocyclic ring or a fused 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, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group. 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.

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

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

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

[0031] The monomer unit (A) may be X １ is —CO—, and X ２ Monomer units (A-1) in which X is —O— １ and X ２ Monomer unit (A-2) in which X is —CO— １ and X ２ 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 units (A-1) in the monomer units (A) may be, for example, 50 mol % or more, 60 mol % or more, 65 mol % or more, or 70 mol % or more. The proportion of the monomer units (A-1) in the monomer units (A) may be, for example, 95 mol % or less, 90 mol % or less, or 85 mol % or less. That is, the proportion of the monomer unit (A-1) represented by 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 units (A-2) in the monomer units (A) may be, for example, 5 mol % or more, 10 mol % or more, or 15 mol % or more. The proportion of the monomer units (A-2) in the monomer units (A) may be, for example, 50 mol % or less, 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, 60 mol% or more, 65 mol% or more, or even 70 mol% or more, based on the total of all monomer units constituting the liquid crystal polyester. This tends to further improve the dielectric properties and to more significantly obtain the above-mentioned effects. Furthermore, 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, based on the total of all monomer units constituting the liquid crystal polyester. This tends to improve moldability and processability at low temperatures. That is, the content of the monomer unit (A) relative to the total of all monomer units constituting the liquid crystal polyester may be, 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.

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

[0037] In formula (B), Ar ２ and Ar ３ each independently represents a phenylene group, a biphenylene group, or a naphthylene group. ２ and Ar ３ A part or all of the hydrogen atoms of Ar may be substituted with a substituent. 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 is 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, and is 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, and is preferably a 2,6-naphthylene group.

[0042] 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, or may be a fluorine atom, a chlorine atom, or a fluorine atom.

[0043] 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, and an n-decyl group.

[0044] The aryl group as a substituent may be a monocyclic ring or a fused 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, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group. 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.

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

[0046] In formula (B), X ３ and X ４ each independently represents —CO— or —O—, and Y represents —O—, —CO—, or —SO ２ - or -NH-.

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

[0048] The monomer unit (B) is X ３ and X ４ Monomer unit (B-1) in which X is —CO— ３ and X ４ Monomer unit (B-2) in which X is —O— 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 units (B-1) in the monomer units (B) may be, for example, 50 mol% or more, 70 mol% or more, 90 mol% or more, 95 mol% or more, or 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 relative to the sum of all monomer units constituting the liquid crystal polyester, and from the viewpoint of obtaining the above-mentioned effects more significantly, it may be 1 mol% or more, 1.5 mol% or more, 2 mol% or more, or 3 mol% or more. Moreover, the content of the monomer unit (B) is less than 10 mol% relative to the sum of all monomer units constituting the liquid crystal polyester, and from the viewpoint of obtaining the above-mentioned effects more significantly, 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) relative to the total of all monomer units constituting the liquid crystal polyester may be, for example, 0.5 mol% or more and less than 10 mol%, 0.5 mol% or more and less than 9 mol%, 0.5 mol% or more and less than 8 mol%, 0.5 mol% or more and less than 7.5 mol%, 1 mol% or more and less than 10 mol%, 1 mol% or more and less than 9 mol%, 1 mol% or more and less than 8 mol%, 1 mol% or more and less than 7.5 mol%, 1.5 mol% or more and less than 10 mol%, 1.5 mol% or more and less than 9 mol%, 1.5 mol% or more and less than 8 mol%, 1.5 mol% or more and less than 7.5 mol%, 2 mol% or more and less than 10 mol%, 2 mol% or more and less than 9 mol%, 2 mol% or more and less than 8 mol%, 2 mol% or more and less than 7.5 mol%, 3 mol% or more and less than 10 mol%, 3 mol% or more and less than 9 mol%, 3 mol% or more and less than 8 mol%, or 3 mol% or more and less than 7.5 mol%.

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

[0053] In formula (C), Ar ４ represents a phenylene group or a biphenylene group. ４ A part or all of the hydrogen atoms of Ar may be substituted with a substituent. ４ may be a phenylene group which may have a substituent or a biphenylene group which 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, or may be a fluorine atom, a chlorine atom, or 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, and an n-decyl group.

[0059] The aryl group as a substituent may be a monocyclic ring or a fused 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, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group. 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 the has may be, for example, 0 to 3, 0 to 2, 0 or 1, or 0.

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

[0062] The monomer unit (C) is X ５ and X ６ Monomer units (C-1) in which X is —O— ５ and X ６ Monomer unit (C-2) in which X is —CO—５ is —O—, and X ６ is —CO—.

[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 units (C-1) in the monomer units (C) may be, for example, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 80 mol% or more, or may be 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 units (C-2) in the monomer units (C) may be, for example, 50 mol% or less, 40 mol% or less, 30 mol% or less, or 20 mol% or less, or may 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, 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, 15 mol% or more, or 20 mol% or more, relative to the total of all monomer units constituting the liquid crystal polyester. Also, the content of the monomer unit (C) may be, for example, 45 mol% or less, 40 mol% or less, 35 mol% or less, or 30 mol% or less, relative to the total of all monomer units constituting the liquid crystal polyester. That is, the content of the monomer unit (C) relative to the sum of all monomer units constituting the liquid crystal polyester 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.

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

[0070] In this specification, the number of each monomer unit contained in the liquid crystal polyester is determined by the analytical method described in JP 2000-19168 A. Specifically, the liquid crystal polyester is depolymerized by reacting it with a lower alcohol in a supercritical state, and the depolymerization product (monomers that derive each monomer unit) is quantified by liquid chromatography, whereby the number of each monomer unit relative to the total monomer units can be calculated.

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

[0072] The dielectric loss 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 loss tangent of a liquid crystal polyester at 20 GHz is measured by the following method. The liquid crystal polyester is pressed using a hot / cold press (e.g., KVHC II, manufactured by Kitagawa Seiki Co., Ltd.) to obtain a test piece having a width of 35 mm, a length of 35 mm, and a thickness of 0.5 mm. The dielectric loss tangent of the obtained test piece at 20 GHz at 23°C and 50% RH is measured using a vector network analyzer (e.g., N5290A, manufactured by Keysight Technologies, Inc.) and a split cylinder resonator (e.g., 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, may be 60,000 or more, 80,000 or more, or 100,000 or more. 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, 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 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. The obtained solution is cooled to 50°C, and then 4 mL of chloroform is added. After stirring, the solution 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 GPC, and the weight average molecular weight in terms of standard polystyrene is calculated.

[0076] The liquid crystal polyester of the present embodiment can be suitably used as a molding material for obtaining a molded product. The liquid crystal polyester may be used, for example, in the form of 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 one or more resins other than the liquid crystal polyester, such as 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-based resin, and thermosetting resin.

[0079] 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 release agent, or 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, in the form of pellets.

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

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

[0083] The molding method for the molded article is preferably melt molding, and examples of the melt molding method include injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, and press molding.

[0084] Examples of the molded article of this embodiment include connectors, sockets, relay parts, coil bobbins, optical pickups, oscillators, semiconductor packages, IC trays, wafer carriers, household electrical appliance parts, lighting fixture parts, audio product parts, ferrules for optical cables, telephone parts, facsimile parts, modem parts, separation claws, heater holders, impellers, fan gears, gears, bearings, motor parts, motor cases, engine parts, engine room parts, electrical parts, automotive interior parts, microwave cooking pots, heat-resistant tableware, flooring materials, wall materials, beams, pillars, roofing materials, aircraft parts, spacecraft parts, space equipment parts, nuclear reactors, marine facility components, cleaning jigs, optical equipment parts, valves, pipes, nozzles, filters, medical equipment parts, medical materials, sensor parts, sanitary fixtures, sporting goods, and leisure goods.

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

[0086] The invention according to the present disclosure will be explained in more detail below using 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) A reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser was charged with 1035.0 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 255.2 g (2.32 mol: used in 0.07 molar 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, and 0.052 g of 1-methylimidazole was added as a catalyst. After thoroughly replacing the atmosphere in 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 while refluxing for 1 hour. Thereafter, the temperature was raised to 310°C over 3 hours and 30 minutes while distilling off the by-product acetic acid and unreacted acetic anhydride. After maintaining the temperature at 310°C for 2 hours and 10 minutes, the contents of the reactor were removed. The resulting solid was cooled to room temperature and pulverized to obtain a powder. The resulting 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 allow the polymerization reaction to proceed in the solid phase, yielding a liquid crystalline polyester (A-1). The weight average molecular weight (Mw) of the resulting 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 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, stirred, and then filtered using a filter with a pore size of 0.45 μm to obtain a measurement sample. The obtained measurement sample was analyzed by GPC method, and the weight average molecular weight in terms of standard polystyrene was calculated.

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

[0090] (3) Measurement of tensile modulus Using the obtained pellets as a raw material, an ASTM No. 4 test piece having a thickness of 2.5 mm was injection molded using an injection molding machine (NEX50IV-5EG, manufactured by Nissei Plastic Industrial Co., Ltd.). The tensile modulus of the obtained test piece was measured using a tensile tester (Tensilon RTG-1250, manufactured by A&D Co., Ltd.) in accordance with ASTM D638. 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 / cold press (e.g., KVHC II, manufactured by Kitagawa Seiki Co., Ltd.) to obtain a test piece having a width of 35 mm, a length of 35 mm, and a thickness of 0.5 mm. The dielectric loss tangent of the obtained test piece at 20 GHz at 23°C and 50% RH was measured using a vector network analyzer (e.g., N5290A, manufactured by Keysight Technologies Inc.) and a split cylinder resonator (e.g., 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 crystalline 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 crystalline 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]

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

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

[0099] (Reference Example 1) A reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser was charged with 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, and 0.19 g of 1-methylimidazole was added as a catalyst. After the atmosphere inside the reactor was thoroughly purged 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. Thereafter, the temperature was raised to 300 ° C. over 4 hours and 20 minutes while distilling off the by-product acetic acid. The point at which an increase in torque was observed was considered to be the end of the reaction, and the contents were removed. The flow temperature of the obtained solid content was 245° C. The obtained solid content was cooled to room temperature and pulverized in a coarse pulverizer, and then heated from room temperature to 240° C. over 1 hour in a nitrogen atmosphere, heated from 240° C. to 284° C. over 5 hours and 40 minutes, and maintained at 284° C. for 5 hours, to allow a polymerization reaction to proceed in the solid phase, thereby obtaining a liquid crystal polyester.

[0100] The tensile modulus of elasticity of the obtained liquid crystal polyester was measured in the same manner as in Example 1.

[0101] A liquid crystalline 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. The tensile modulus of the obtained liquid crystalline polyester was measured in the same manner as in Example 1, and the tensile modulus was calculated when the tensile modulus of the liquid crystalline polyester of Reference Example 1 was set to 1.

[0102] A liquid crystalline polyester was produced in the same manner as in Reference Example 1, except that 0.6 mol of 4,4'-dicarboxydiphenyl ether was added without using isophthalic acid. The tensile modulus of the obtained liquid crystalline polyester was measured in the same manner as in Example 1, and the tensile modulus was calculated based on the tensile modulus of the liquid crystalline polyester of Reference Example 1 being 1.

[0103]

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

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

Claims

1. A liquid crystal polyester having a monomer unit (A) represented by formula (A) and a monomer unit (B) represented by formula (B), wherein the content of the monomer unit (A) is 50 mol% or more based on 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% based on the total of all monomer units. -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-, Y represents -O-, -CO-, -SO ２ -, or -NH-. Some or all of the hydrogen atoms of Ar １ , Ar ２ and Ar ３ may be substituted with a halogen atom, an alkyl group or an aryl group.] 2. The above Ar ２ and the above 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 Ar １ The liquid crystal polyester according to claim 1, wherein Ar is a naphthylene group.

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

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. The monomer unit (A) is the X １ is -CO-, and the X ２ is -O- monomer unit (A-1), and the X １ and the X ２ is -CO- monomer unit (A-2), and the liquid crystal polyester according to claim 1.

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 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 represents -CO- or -O-. Some or all of the hydrogen atoms that Ar ４ has 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 comprising the liquid crystal polyester according to any one of claims 1 to 11.

13. A molded article comprising 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 electrical appliance component, lighting fixture component, audio product component, ferrule for optical cable, telephone component, facsimile component, modem component, separation claw, heater holder, impeller, fan gear, gear, bearing, motor component, motor case, engine component, engine room interior component, electrical component, automotive interior component, pot for microwave cooking, heat-resistant tableware, floor material, wall material, beam, column, roofing material, aircraft component, spacecraft component, space equipment component, atomic reactor, marine facility member, cleaning jig, optical instrument component, valves, pipes, nozzles, filters, medical device component, medical material, sensor component, sanitary fixture, sports goods, or leisure goods.

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