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

Abstract

This liquid crystal polyester contains a monomer unit (I) derived from a monomer (i) having an ether bond, wherein the content of the monomer unit (I) is 0.5 × 10-5 mol% to 3.0 × 10-1 mol% inclusive with respect to the total amount of all monomer units.

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] Japanese Patent Application Laid-Open No. 2003-268252

[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 flexural 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 polymerizable composition comprising a polymerizable monomer (I) derived from a monomer (i) having an ether bond, wherein the content of the polymerizable monomer (I) is 0.5 × 10 based on the total amount of all the polymerizable monomers. －５ mol% or more 3.0 × 10 －１ [2] The liquid crystal polyester according to [1], wherein the monomer (i) is a compound represented by the following formula (i): X １ -Ar １ -O-Ar ２ -X ２ (i) [wherein, Ar １ and Ar ２ each independently represents a phenylene group or a condensed polycyclic aromatic hydrocarbon group; X １ and X ２ each independently represents a hydroxy group, an amino group, or a carboxy group. １ and Ar ２may be substituted with a halogen atom, an alkyl group, or an aryl group.] [3] The liquid crystal polyester according to [1] or [2], wherein the monomer (i) comprises at least one selected from the group consisting of 4-(4-hydroxyphenoxy)benzenecarboxylic acid and 4,4'-dicarboxydiphenyl ether. [4] The liquid crystal polyester according to [1] or [2], wherein the monomer (i) is 4-(4-hydroxyphenoxy)benzenecarboxylic acid. [5] The liquid crystal polyester according to any one of [1] to [4], further comprising a monomer unit (II) derived from a monomer (ii) represented by the following formula (ii): X １１ -Ar １１ -X １２ (ii) [wherein, Ar １１ represents a phenylene group, a biphenylene group or a condensed polycyclic aromatic hydrocarbon group; X １１ and X １２ each independently represents a hydroxy group, an amino group, or a carboxy group. １１ may be substituted with a halogen atom, an alkyl group, or an aryl group.] [6] The liquid crystal polyester according to [5], wherein the monomer (ii) contains 4-hydroxybenzoic acid. [7] The liquid crystal polyester according to [5] or [6], wherein the content of the monomer unit (II) is 90 mol% or more based on the total of all monomer units. [8] The liquid crystal polyester according to any one of [1] to [7], wherein the liquid crystal polyester has a flow initiation temperature of 230°C or more. [9] A liquid crystal polyester composition comprising the liquid crystal polyester according to any one of [1] to [8].

[10] A molded article comprising the liquid crystal polyester according to any one of [1] to [8].

[0008] According to the present disclosure, there is provided a liquid crystalline polyester capable of being formed into a molded article having a high flexural 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") contains a monomer unit (I) derived from a monomer (i) having an ether bond. In the liquid crystal polyester, the content of the monomer unit (I) is 0.5 × 10 with respect to the total of all monomer units. －５ mol% or more 3.0 × 10 －１ % or less by mole.

[0011] The liquid crystal polyester of this embodiment can be formed into a molded article having a high flexural modulus, and therefore, the liquid crystal polyester of this embodiment can be suitably used as a material for fine electronic components.

[0012] In this embodiment, the liquid crystal polyester contains a very small amount of the monomer unit (I) derived from the monomer (i) having an ether bond, thereby realizing a high bending modulus while maintaining good heat resistance and tensile strength. Although the reason for this effect is not necessarily clear, it is thought that the inclusion of an appropriate amount of bending components in the rigid molecular chain of the liquid crystal polyester makes the resulting molded article less likely to deform under stress.

[0013] 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.

[0014] The liquid crystal polyester has constituent units (also referred to as 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 referred to as a wholly aromatic liquid crystal polyester.

[0015] The aromatic compound is a compound having an aromatic ring. The aromatic compound suitable as a raw material monomer may have one or more aromatic rings and two or more polymerizable groups (e.g., hydroxy groups, amino groups, or carboxy groups, preferably hydroxy groups or carboxy groups) bonded to the aromatic rings.

[0016] The liquid crystal polyester contains a monomer unit (I) derived from a monomer (i) having an ether bond. The monomer (i) is preferably an aromatic compound.

[0017] Monomer (i) may have, for example, a first aromatic ring, a second aromatic ring, an ether bond (—O—) bonding the first aromatic ring and the second aromatic ring, a first polymerizable group bonded to the first aromatic ring, and a second polymerizable group bonded to the second aromatic ring.

[0018] The monomer (i) may be, for example, a compound represented by the following formula (i): １ -Ar １ -O-Ar ２ -X ２ (i) [wherein, Ar １ and Ar ２ each independently represents a phenylene group, a biphenylene group, or a condensed polycyclic aromatic hydrocarbon group; X １ and X ２ each independently represents a hydroxy group, an amino group, or a carboxy group. １ and Ar ２ Some or all of the hydrogen atoms of may be substituted with halogen atoms, alkyl groups or aryl groups.

[0019] Ar in the formula １ corresponds to the first aromatic ring, and Ar ２ corresponds to the second aromatic ring, and X １ corresponds to the first polymerizable group, and X ２ corresponds to the second polymerizable group.

[0020] 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.

[0021] The biphenylene group may be, for example, a 4,4'-biphenylylene group.

[0022] The condensed polycyclic aromatic hydrocarbon group is a group in which two hydrogen atoms have been removed from a condensed polycyclic aromatic hydrocarbon. Examples of the condensed polycyclic aromatic hydrocarbon include naphthalene, anthracene, phenanthrene, tetracene, pyrene, triphenylene, perylene, and fluorene. Among these, naphthalene is preferred from the viewpoints of availability and cost.

[0023] Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0024] 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.

[0025] 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.

[0026] Ar １ and Ar ２ The number of substituents that the has may be, for example, 0 to 2, or may be 0 or 1, or may be 0.

[0027] Ar １ and Ar ２ is preferably a phenylene group, more preferably a 1,4-phenylene group.

[0028] In one embodiment, X １ is preferably a hydroxy group or an amino group, more preferably a hydroxy group. ２ is preferably a carboxy group.

[0029] In another embodiment, X １is preferably a carboxy group. ２ is preferably a carboxy group.

[0030] As the monomer (i), at least one selected from the group consisting of 4-(4-hydroxyphenoxy)benzenecarboxylic acid and 4,4'-dicarboxydiphenyl ether is preferred, with 4-(4-hydroxyphenoxy)benzenecarboxylic acid being particularly preferred.

[0031] The monomer unit (I) derived from the monomer (i) may be, for example, a monomer unit represented by the following formula (I): -Y １ -Ar １ -O-Ar ２ -Y ２ - (I) [wherein, Ar １ and Ar ２ is as defined above, and Y １ and Y ２ each independently represents an oxygen atom (—O—), an imino group (—NH—), or a carbonyl group (—CO—).

[0032] X １ is a hydroxy group, １ is an oxygen atom (—O—), and X １ is an amino group, Y １ is an imino group (—NH—), and X １ is a carboxy group, Y １ is a carbonyl group (—CO—).

[0033] X ２ is a hydroxy group, ２ is an oxygen atom (—O—), and X ２ is an amino group, Y ２ is an imino group (—NH—), and X ２ is a carboxy group, Y ２ is a carbonyl group (—CO—).

[0034] In the monomer unit (I), Ar １ and Ar ２ is preferably a phenylene group, more preferably a 1,4-phenylene group. １is preferably an oxygen atom (—O—) or an imino group (—NH—), more preferably an oxygen atom (—O—), and Y ２ is preferably a carbonyl group (—CO—). １ is preferably a carbonyl group (—CO—), and Y ２ is preferably a carbonyl group (—CO—).

[0035] The content of the monomer unit (I) in the liquid crystal polyester is 0.5×10 with respect to the total of all monomer units. －５ % or more, and from the viewpoint of obtaining the above-mentioned effect more significantly, it is 1.0 × 10 －５ mol% or more, 5.0 × 10 －５ mol% or more or 1.0 × 10 －４ The content of the monomer unit (I) in the liquid crystal polyester may be 3.0×10 mol % or more relative to the total of all the monomer units. －１ % or less, and from the viewpoint of obtaining the above-mentioned effect more significantly, －１ mol% or less or 2.0 × 10 －１ That is, the content of the monomer unit (I) in the liquid crystal polyester may be 0.5×10 mol % or less with respect to the total of all the monomer units. －５ ~3.0 x 10 －１ Mol%, 0.5 × 10 －５ ~2.5 x 10 －１ Mol%, 0.5 × 10 －５ ~2.0 x 10 －１ Mol%, 1.0 x 10 －５ ~3.0 x 10 －１ Mol%, 1.0 x 10 －５ ~2.5 x 10 －１ Mol%, 1.0 x 10 －５ ~2.0 x 10 －１ mol%, 5.0 × 10 －５ ~3.0 x 10 －１ mol%, 5.0 × 10 －５ ~2.5 x 10 －１ mol%, 5.0 × 10 －５ ~2.0 x 10 －１ Mol%, 1.0 x 10 －４ ~3.0 x 10 －１Mol%, 1.0 x 10 －４ ~2.5 x 10 －１ mol%, or 1.0 x 10 －４ ~2.0 x 10 －１ It may be in mole percent.

[0036] The liquid crystal polyester may further contain a monomer unit (II) derived from a monomer (ii) represented by the following formula (ii). The monomer (ii) is an aromatic compound. X １１ -Ar １１ -X １２ (ii) [wherein, Ar １１ represents a phenylene group, a biphenylene group or a condensed polycyclic aromatic hydrocarbon group; X １１ and X １２ each independently represents a hydroxy group, an amino group, or a carboxy group. １１ Some or all of the hydrogen atoms of may be substituted with halogen atoms, alkyl groups or aryl groups.

[0037] Ar １１ The phenylene group in may be, for example, a 1,4-phenylene group or a 1,3-phenylene group.

[0038] Ar １１ The biphenylene group in may be, for example, a 4,4'-biphenylylene group.

[0039] Ar １１ The condensed polycyclic aromatic hydrocarbon group in the formula (I) is a group in which two hydrogen atoms have been removed from a condensed polycyclic aromatic hydrocarbon. Examples of the condensed polycyclic aromatic hydrocarbon include naphthalene, anthracene, phenanthrene, tetracene, pyrene, triphenylene, perylene, and fluorene. Among these, naphthalene is preferred from the viewpoints of availability and cost.

[0040] Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0041] 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.

[0042] 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.

[0043] Ar １１ The number of substituents that the has may be, for example, 0 to 2, or may be 0 or 1, or may be 0.

[0044] The monomer unit (II) derived from the monomer (ii) may be, for example, a monomer unit represented by the following formula (II): -Y １１ -Ar １１ -Y １２ - (II) [wherein, Ar １１ is as defined above, and Y １１ and Y １２ each independently represents an oxygen atom (—O—), an imino group (—NH—), or a carbonyl group (—CO—).

[0045] X １１ is a hydroxy group, １１ is an oxygen atom (—O—), and X １１ is an amino group, Y １１ is an imino group (—NH—), and X １１ is a carboxy group, Y １１ is a carbonyl group (—CO—).

[0046] X １２ is a hydroxy group, １２ is an oxygen atom (—O—), and X １２is an amino group, Y １２ is an imino group (—NH—), and X １２ is a carboxy group, Y １２ is a carbonyl group (—CO—).

[0047] The content of the monomer unit (II) in the liquid crystal polyester may be, for example, 90 mol % or more, 95 mol % or more, 97 mol % or more, or 99 mol % or more, based on the total of all monomer units.

[0048] In the liquid crystal polyester, the total content of the monomer unit (I) and the monomer unit (II) may be, for example, 90 mol% or more, 95 mol% or more, 97 mol% or more, or 99 mol% or more, or may be 100 mol%, based on the total of all monomer units.

[0049] A suitable example of the monomer (ii) is 4-hydroxybenzoic acid (i.e., Ar in formula (ii) １１ is a 1,4-phenylene group, X １１ is a hydroxy group, X １２ is a carboxy group) That is, the liquid crystal polyester may contain a monomer unit (II-1) derived from 4-hydroxybenzoic acid.

[0050] When the liquid crystal polyester contains the monomer unit (II-1), the content of the monomer unit (II-1) may be, for example, 10 mol% or more, 20 mol% or more, 30 mol% or more, or 40 mol% or more, relative to the total of all monomer units. Furthermore, the content of the monomer unit (II-1) in the liquid crystal polyester may be, for example, 90 mol% or less, 80 mol% or less, 75 mol% or less, 70 mol% or less, or 60 mol% or less, relative to the total of all monomer units. That is, when the liquid crystal polyester contains the monomer unit (II-1), the content of the monomer unit (II-1) relative to the total of all monomer units may be, for example, 10 to 90 mol%, 10 to 80 mol%, 10 to 75 mol%, 10 to 70 mol%, 10 to 60 mol%, 20 to 90 mol%, 20 to 80 mol%, 20 to 75 mol%, 20 to 70 mol%, 20 to 60 mol%, 30 to 90 mol%, 30 to 80 mol%, 30 to 75 mol%, 30 to 70 mol%, 30 to 60 mol%, 40 to 90 mol%, 40 to 80 mol%, 40 to 75 mol%, 40 to 70 mol%, or 40 to 60 mol%.

[0051] A suitable example of the monomer (ii) is terephthalic acid (i.e., Ar in formula (ii) １１ is a 1,4-phenylene group, X １１ and X １２ is a carboxy group). That is, the liquid crystal polyester may further contain a monomer unit (II-2) derived from terephthalic acid.

[0052] When the liquid crystal polyester contains the monomer unit (II-2), the content of the monomer unit (II-2) may be, for example, 2.5 mol% or more, 5 mol% or more, 10 mol% or more, or 15 mol% or more, relative to the total of all monomer units. Furthermore, the content of the monomer unit (II-2) in the liquid crystal polyester may be, for example, 30 mol% or less, 27 mol% or less, 25 mol% or less, 24 mol% or less, or 21 mol% or less, relative to the total of all monomer units. That is, when the liquid crystal polyester contains the monomer unit (II-2), the content of the monomer unit (II-2) may be, for example, 2.5 to 30 mol%, 2.5 to 27 mol%, 2.5 to 25 mol%, 2.5 to 24 mol%, 2.5 to 21 mol%, 5 to 30 mol%, 5 to 27 mol%, 5 to 25 mol%, 5 to 24 mol%, 5 to 21 mol%, 10 to 30 mol%, 10 to 27 mol%, 10 to 25 mol%, 10 to 24 mol%, 10 to 21 mol%, 15 to 30 mol%, 15 to 27 mol%, 15 to 25 mol%, 15 to 24 mol%, or 15 to 21 mol%, based on the total of all monomer units.

[0053] A suitable example of the monomer (ii) is isophthalic acid (i.e., Ar in formula (ii) １１ is a 1,3-phenylene group, X １１ and X １２ is a carboxy group). That is, the liquid crystal polyester may further contain a monomer unit (II-3) derived from isophthalic acid.

[0054] When the liquid crystal polyester contains the monomer unit (II-3), the content of the monomer unit (II-3) may be, for example, 0.5 mol% or more, 1 mol% or more, 5 mol% or more, 10 mol% or more, or 12 mol% or more, based on the total of all monomer units. Furthermore, the content of the monomer unit (II-3) in the liquid crystal polyester may be, for example, 30 mol% or less, 25 mol% or less, 20 mol% or less, or 15 mol% or less, based on the total of all monomer units. That is, when the liquid crystal polyester contains the monomer unit (II-3), the content of the monomer unit (II-3) may be, for example, 0.5 to 30 mol%, 0.5 to 25 mol%, 0.5 to 20 mol%, 0.5 to 15 mol%, 1 to 30 mol%, 1 to 25 mol%, 1 to 20 mol%, 1 to 15 mol%, 5 to 30 mol%, 5 to 25 mol%, 5 to 20 mol%, 5 to 15 mol%, 10 to 30 mol%, 10 to 25 mol%, 10 to 20 mol%, 10 to 15 mol%, 12 to 30 mol%, 12 to 25 mol%, 12 to 20 mol%, or 12 to 15 mol%, based on the total of all monomer units.

[0055] A preferred example of the monomer (ii) is 4,4'-dihydroxybiphenyl (i.e., Ar in formula (ii) １１ is a 4,4'-biphenylylene group, X １１ and X １２ is a hydroxy group) That is, the liquid crystal polyester may further contain a monomer unit (II-4) derived from 4,4'-dihydroxybiphenyl.

[0056] When the liquid crystal polyester contains the monomer unit (II-4), the content of the monomer unit (II-4) may be, for example, 2 mol% or more, 5 mol% or more, 10 mol% or more, or 15 mol% or more, relative to the total of all monomer units. Furthermore, the content of the monomer unit (II-4) in the liquid crystal polyester may be, for example, 32 mol% or less, 28 mol% or less, 25 mol% or less, 24 mol% or less, or 20 mol% or less, relative to the total of all monomer units. That is, when the liquid crystal polyester contains the monomer unit (II-4), the content of the monomer unit (II-4) may be, for example, 2 to 32 mol%, 2 to 28 mol%, 2 to 25 mol%, 2 to 24 mol%, 2 to 20 mol%, 5 to 32 mol%, 5 to 28 mol%, 5 to 25 mol%, 5 to 24 mol%, 5 to 20 mol%, 10 to 32 mol%, 10 to 28 mol%, 10 to 25 mol%, 10 to 24 mol%, 10 to 20 mol%, 15 to 32 mol%, 15 to 28 mol%, 15 to 25 mol%, 15 to 24 mol%, or 15 to 20 mol%, based on the total of all monomer units.

[0057] A suitable example of the monomer (ii) is 2-hydroxy-6-naphthoic acid (i.e., Ar in formula (ii) １１ is a 2,6-naphthylene group, X １１ is a hydroxy group, X １２ is a carboxy group) That is, the liquid crystal polyester may further contain a monomer unit (II-5) derived from 2-hydroxy-6-naphthoic acid.

[0058] When the liquid crystal polyester contains the monomer unit (II-5), the content of the monomer unit (II-5) may be, for example, 10 mol% or more, 20 mol% or more, 30 mol% or more, or 40 mol% or more, relative to the total of all monomer units. Furthermore, the content of the monomer unit (II-5) in the liquid crystal polyester may be, for example, 90 mol% or less, 80 mol% or less, 75 mol% or less, 70 mol% or less, 65 mol% or less, or 60 mol% or less, relative to the total of all monomer units. That is, when the liquid crystal polyester contains the monomer unit (II-5), the content of the monomer unit (II-5) relative to the total of all monomer units may be, for example, 10 to 90 mol%, 10 to 80 mol%, 10 to 75 mol%, 10 to 70 mol%, 10 to 65 mol%, 10 to 60 mol%, 20 to 90 mol%, 20 to 80 mol%, 20 to 75 mol%, 20 to 70 mol%, 20 to 65 mol%, 20 to 60 mol%, 30 to 90 mol%, 30 to 80 mol%, 30 to 75 mol%, 30 to 70 mol%, 30 to 65 mol%, 30 to 60 mol%, 40 to 90 mol%, 40 to 80 mol%, 40 to 75 mol%, 40 to 70 mol%, 40 to 65 mol%, or 40 to 60 mol%.

[0059] A suitable example of the monomer (ii) is 2,6-naphthalenedicarboxylic acid (i.e., Ar in formula (ii) １１ is a 2,6-naphthylene group, X １１ and X １２ is a carboxy group) That is, the liquid crystal polyester may further contain a monomer unit (II-6) derived from 2,6-naphthalenedicarboxylic acid.

[0060] When the liquid crystal polyester contains the monomer unit (II-6), the content of the monomer unit (II-6) may be, for example, 0.5 mol% or more, 1 mol% or more, 5 mol% or more, or 10 mol% or more, based on the total of all monomer units. Furthermore, the content of the monomer unit (II-6) in the liquid crystal polyester may be, for example, 30 mol% or less, 25 mol% or less, or 20 mol% or less, based on the total of all monomer units. That is, when the liquid crystal polyester contains the monomer unit (II-6), the content of the monomer unit (II-6) may be, for example, 0.5 to 30 mol%, 0.5 to 25 mol%, 0.5 to 20 mol%, 1 to 30 mol%, 1 to 25 mol%, 1 to 20 mol%, 5 to 30 mol%, 5 to 25 mol%, 5 to 20 mol%, 10 to 30 mol%, 10 to 25 mol%, 10 to 20 mol%, 12 to 30 mol%, 12 to 25 mol%, or 12 to 20 mol%, based on the total of all monomer units.

[0061] Examples of the liquid crystal polyester include a liquid crystal polyester containing a monomer unit (I), a monomer unit (II-1), and a monomer unit (II-5); a liquid crystal polyester containing a monomer unit (I), a monomer unit (II-1), a monomer unit (II-2), and a monomer unit (II-4); and a liquid crystal polyester containing a monomer unit (I), a monomer unit (II-1), a monomer unit (II-2), a monomer unit (II-3), and a monomer unit (II-4).

[0062] 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.

[0063] 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.

[0064] The flow initiation temperature of the liquid crystal polyester may be, for example, 230° C. or higher, 250° C. or higher, 270° C. or higher, 290° C. or higher, or 310° C. or higher. The flow initiation temperature of the liquid crystal polyester may be, for example, 400° C. or lower, 390° C. or lower, 385° C. or lower, or 380° C. or lower.

[0065] In this specification, the flow initiation temperature of the liquid crystal polyester is measured by the following method. <Measurement of Flow Initiation Temperature> The flow initiation temperature is measured using a flow tester. Specifically, the flow initiation temperature is measured at a pressure of 9.8 MPa (100 kg / cm ２ The liquid crystalline polyester is extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm while heating at a rate of 4°C / min under a load of 1000 kJ / min, and the temperature at which the viscosity of the liquid crystalline polyester becomes 4800 Pa·s (48000 poise) is determined.

[0066] 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.

[0067] The liquid crystal polyester may be used as a composition (liquid crystal polyester composition) mixed with other components.

[0068] The liquid crystal polyester composition may contain one or more resins other than the liquid crystal polyester, such as polyolefins, cyclic polyolefins, polyvinyl chloride, polysulfones, (meth)acrylic resins, polyphenylene ether resins, polyacetal resins, polyamide resins, imide resins, cellulose resins, polyether ether keto resins, fluororesins, polycarbonate resins, styrene-based resins, and thermosetting resins.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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, automobile 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, membranes, medical equipment parts, medical materials, sensor parts, sanitary fixtures, sporting goods, and leisure goods.

[0075] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments.

[0076] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Hereinafter, percentages and parts representing content or amount used are based on mass unless otherwise specified.

[0077] (Example A-1) (1) Production of Liquid Crystalline Polyester (A-1) Into a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 759.7 g (5.5 mol) of 4-hydroxybenzoic acid, 512.2 g (2.75 mol) of 4,4′-dihydroxybiphenyl, 434.0 g (2.6125 mol) of terephthalic acid, 22.8 g (0.1375 mol) of isophthalic acid, 5.24 mg (2.28×10 －２ 1235.3 g (12.1 mol) of acetic anhydride (1 mmol) and 1,235.3 g (12.1 mol) of acetic anhydride were charged, and 0.052 g of 1-methylimidazole was added as a catalyst. After thoroughly purging 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 while refluxing for 1 hour. Thereafter, the temperature was raised to 300°C over 2 hours and 45 minutes while distilling off the by-product acetic acid. The reaction was considered to be complete when an increase in torque was observed, and the contents of the reactor were removed. The flow initiation temperature of the resulting solid was 250°C. The resulting solid was cooled to room temperature and pulverized. After that, the temperature was raised from room temperature to 250°C over 1 hour under a nitrogen atmosphere, then from 250°C to 329°C over 10 hours, and maintained at 329°C for 5 hours, allowing the polymerization reaction to proceed in the solid phase, yielding a liquid crystalline polyester (A-1). The flow initiation temperature of the resulting liquid crystalline polyester (A-1) was 378°C. The flow initiation temperature was measured by the following method. <Measurement of flow initiation temperature> Using a flow tester (Shimadzu Corporation, "CFT-500 model"), a sample amount of about 2 g was filled into a capillary rheometer equipped with a die having an inner diameter of 1 mm and a length of 10 mm. ２ When the liquid crystalline polyester was extruded from a nozzle under a load of 1000 psi at a temperature increase rate of 4° C. / min, the temperature at which the melt viscosity reached 4800 Pa·s (48000 poise) was defined as the flow initiation temperature.

[0078] (2) Pelletization The obtained liquid crystal polyester (A-1) was pelletized at 397° C. using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) to form pellets.

[0079] (3) Measurement of Tensile Strength and Tensile Elongation The pellets obtained in (2) above were injection molded using an injection molding machine (PNX40-5A, manufactured by Nissei Plastic Industrial Co., Ltd.) to prepare a 2.5 mm thick ASTM No. 4 test piece. Using this test piece, the tensile strength and tensile elongation were measured in accordance with ASTM D638.

[0080] (4) Measurement of flexural strength and flexural modulus The pellets obtained in (2) above were injection molded using an injection molding machine (PNX40-5A, manufactured by Nissei Plastic Industrial Co., Ltd.) to prepare test pieces measuring 127 mm in length, 12.7 mm in width, and 6.4 mm in thickness. Using the test pieces, flexural strength and flexural modulus were measured in accordance with ASTM D790. The results are shown in Table 1.

[0081] In Table 1, "HPBA content" means the content of monomer units derived from 4-(4-hydroxyphenoxy)benzenecarboxylic acid relative to the total of all monomer units of the liquid crystal polyester.

[0082] Example A-2 Liquid crystalline polyester (A-2) was obtained in the same manner as in Example A-1, except that the amount of 4-(4-hydroxyphenoxy)benzenecarboxylic acid was changed to 873 mg (3.79 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (A-2) was 375°C.

[0083] The liquid crystal polyester (A-2) was evaluated in the same manner as in Example A-1. The results are shown in Table 1.

[0084] Example A-3 Liquid crystalline polyester (A-3) was obtained in the same manner as in Example A-1, except that the amount of 4-(4-hydroxyphenoxy)benzenecarboxylic acid was changed to 1746 mg (7.58 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (A-3) was 374°C.

[0085] The liquid crystal polyester (A-3) was evaluated in the same manner as in Example A-1. The results are shown in Table 1.

[0086] Example A-4 Liquid crystalline polyester (A-4) was obtained in the same manner as in Example A-1, except that the amount of 4-(4-hydroxyphenoxy)benzenecarboxylic acid was changed to 4,320 mg (18.8 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (A-4) was 379°C.

[0087] The liquid crystal polyester (A-4) was evaluated in the same manner as in Example A-1. The results are shown in Table 1.

[0088] Comparative Example X-1 Liquid crystalline polyester (X-1) was obtained in the same manner as in Example A-1, except that 4-(4-hydroxyphenoxy)benzenecarboxylic acid was not used. The flow initiation temperature of the obtained liquid crystalline polyester (X-1) was 379°C.

[0089] The liquid crystal polyester (X-1) was evaluated in the same manner as in Example A-1. The results are shown in Table 1.

[0090] Comparative Example X-2 Liquid crystalline polyester (X-2) was obtained in the same manner as in Example A-1, except that the amount of 4-(4-hydroxyphenoxy)benzenecarboxylic acid was changed to 10,480 mg (45.5 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (X-2) was 379°C.

[0091] The liquid crystal polyester (X-2) was evaluated in the same manner as in Example A-1. The results are shown in Table 1.

[0092] Comparative Example X-3 Liquid crystalline polyester (X-3) was obtained in the same manner as in Example A-1, except that the amount of 4-(4-hydroxyphenoxy)benzenecarboxylic acid was changed to 15,600 mg (67.8 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (X-3) was 377°C.

[0093] The liquid crystal polyester (X-3) was evaluated in the same manner as in Example A-1. The results are shown in Table 1.

[0094]

[0095] As shown in Table 1, in Examples A-1 to A-4, a flexural modulus of 7 GPa or more was obtained, which was higher than that of Comparative Examples X-1 to X-3. It was confirmed that the liquid crystal polyester of the present disclosure can form a molded article having a high flexural modulus.

[0096] (Example B-1) (1) Production of Liquid Crystalline Polyester (B-1) Into a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 1,109.1 g (8.0 mol) of 4-hydroxybenzoic acid, 558.9 g (3.0 mol) of 2-hydroxy-6-naphthoic acid, and 5.00 mg (2.17×10 －２ 1235.3 g (12.1 mol) of acetic anhydride (1 mmol) and 1,235.3 g (12.1 mol) of acetic anhydride were charged, and 0.167 g of 1-methylimidazole was added as a catalyst. After thoroughly purging 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 while refluxing for 1 hour. Thereafter, the temperature was raised to 280°C over 4 hours and 5 minutes while distilling off the by-product acetic acid. The reaction was considered to be complete when an increase in torque was observed, and the contents of the reactor were removed. The flow initiation temperature of the resulting solid was 230°C. The resulting solid was cooled to room temperature and pulverized. After that, the temperature was raised from room temperature to 220°C over 1 hour under a nitrogen atmosphere, then from 220°C to 245°C over 20 hours and 50 minutes, and the temperature was maintained at 245°C for 10 hours, allowing the polymerization reaction to proceed in the solid phase, yielding a liquid crystalline polyester (B-1). The flow initiation temperature of the resulting liquid crystalline polyester (B-1) was 284°C. The flow initiation temperature was measured in the same manner as in the liquid crystal polyester (A-1).

[0097] (2) Pelletization The obtained liquid crystal polyester (B-1) was pelletized at 320° C. using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) to form pellets.

[0098] (3) Measurement of Tensile Strength and Tensile Elongation The pellets obtained in (2) above were injection molded using an injection molding machine (PNX40-5A, manufactured by Nissei Plastic Industrial Co., Ltd.) to prepare a 2.5 mm thick ASTM No. 4 test piece. Using this test piece, the tensile strength and tensile elongation were measured in accordance with ASTM D638.

[0099] (4) Measurement of flexural strength and flexural modulus The pellets obtained in (2) above were injection molded using an injection molding machine (PNX40-5A, manufactured by Nissei Plastic Industrial Co., Ltd.) to prepare test pieces measuring 127 mm in length, 12.7 mm in width, and 6.4 mm in thickness. The test pieces were used to measure flexural strength and flexural modulus in accordance with ASTM D790. The results are shown in Table 2.

[0100] In Table 2, "HPBA content" means the content of monomer units derived from 4-(4-hydroxyphenoxy)benzenecarboxylic acid relative to the total of all monomer units of the liquid crystal polyester.

[0101] Example B-2 Liquid crystalline polyester (B-2) was obtained in the same manner as in Example B-1, except that the amount of 4-(4-hydroxyphenoxy)benzenecarboxylic acid was changed to 41.7 mg (0.18 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (B-2) was 282°C.

[0102] The liquid crystal polyester (B-2) was evaluated in the same manner as in Example B-1. The results are shown in Table 2.

[0103] Comparative Example Y-1 Liquid crystalline polyester (Y-1) was obtained in the same manner as in Example B-1, except that 4-(4-hydroxyphenoxy)benzenecarboxylic acid was not used. The flow initiation temperature of the obtained liquid crystalline polyester (Y-1) was 280°C.

[0104] The liquid crystal polyester (Y-1) was evaluated in the same manner as in Example B-1. The results are shown in Table 2.

[0105] Comparative Example Y-2 Liquid crystalline polyester (Y-2) was obtained in the same manner as in Example B-1, except that the amount of 4-(4-hydroxyphenoxy)benzenecarboxylic acid used was changed to 10,000 mg (43.4 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (Y-2) was 278°C.

[0106] The liquid crystal polyester (Y-2) was evaluated in the same manner as in Example B-1. The results are shown in Table 2.

[0107]

[0108] As shown in Table 2, in Examples B-1 and B-2, a flexural modulus of 7 GPa or more was obtained, which was higher than that of Comparative Examples Y-1 and Y-2. It was confirmed that the liquid crystal polyester of the present disclosure can be used to form a molded article having a high flexural modulus.

[0109] (Example C-1) (1) Production of Liquid Crystal Polyester (C-1) A reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser was charged with 759.7 g (5.5 mol) of 4-hydroxybenzoic acid, 512.2 g (2.75 mol) of 4,4'-dihydroxybiphenyl, 434.0 g (2.6125 mol) of terephthalic acid, 22.8 g (0.1375 mol) of isophthalic acid, 34.9 mg (0.14 mmol) of 4,4'-dicarboxydiphenyl ether, and 1235.3 g (12.1 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 140 ° C. under a nitrogen gas stream over 30 minutes, and the temperature was maintained and refluxed for 1 hour. Thereafter, the temperature was increased to 300°C over 2 hours and 45 minutes while distilling off the by-product acetic acid. The reaction was considered to be complete when an increase in torque was observed, and the contents of the reactor were removed. The flow initiation temperature of the obtained solid was 250°C. The obtained solid was cooled to room temperature and pulverized, and then heated from room temperature to 250°C over 1 hour in a nitrogen atmosphere, then heated from 250°C to 329°C over 10 hours, and maintained at 329°C for 5 hours, allowing the polymerization reaction to proceed in the solid phase, yielding a liquid crystalline polyester (C-1). The flow initiation temperature of the obtained liquid crystalline polyester (C-1) was 377°C. The flow initiation temperature was measured in the same manner as for the liquid crystalline polyester (A-1).

[0110] (2) Pelletization The obtained liquid crystal polyester (C-1) was pelletized at 397° C. using a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) to form pellets.

[0111] (3) Measurement of Tensile Strength and Tensile Elongation The pellets obtained in (2) above were injection molded using an injection molding machine (PNX40-5A, manufactured by Nissei Plastic Industrial Co., Ltd.) to prepare a 2.5 mm thick ASTM No. 4 test piece. Using this test piece, the tensile strength and tensile elongation were measured in accordance with ASTM D638.

[0112] (4) Measurement of flexural strength and flexural modulus The pellets obtained in (2) above were injection molded using an injection molding machine (PNX40-5A, manufactured by Nissei Plastic Industrial Co., Ltd.) to prepare test pieces measuring 127 mm in length, 12.7 mm in width, and 6.4 mm in thickness. Using the test pieces, flexural strength and flexural modulus were measured in accordance with ASTM D790. The results are shown in Table 3.

[0113] In Table 3, "DEDA content" means the content of monomer units derived from 4,4'-dicarboxydiphenyl ether relative to the total of all monomer units of the liquid crystal polyester.

[0114] Comparative Example Z-1 Liquid crystalline polyester (Z-1) was obtained in the same manner as in Example C-1, except that the amount of 4,4'-dicarboxydiphenyl ether used was changed to 10,480 mg (40.6 mmol). The flow initiation temperature of the obtained liquid crystalline polyester (Z-1) was 376°C.

[0115] The liquid crystal polyester (Z-1) was evaluated in the same manner as in Example C-1. The results are shown in Table 3.

[0116]

[0117] As shown in Table 3, Example C-1 achieved a flexural modulus of 7 GPa or more, which is higher than those of Comparative Examples X-1 and Z-1. It was confirmed that the liquid crystal polyester of the present disclosure can be used to form a molded article having a high flexural modulus.

Claims

1. The copolymer contains a monomer unit (I) derived from a monomer (i) having an ether bond, and the content of the monomer unit (I) is 0.5×10 based on the total content of all monomer units. －５ mol% or more 3.0 x 10 －１ % or less by mole.

2. The liquid crystal polyester according to claim 1, wherein the monomer (i) is a compound represented by the following formula (i): １ -Ar １ -O-Ar ２ -X ２ (i) [wherein, Ar １ and Ar ２ each independently represents a phenylene group or a condensed polycyclic aromatic hydrocarbon group; X １ and X ２ each independently represents a hydroxy group, an amino group, or a carboxy group. １ and Ar ２ A part or all of the hydrogen atoms of may be substituted with a halogen atom, an alkyl group or an aryl group.

3. The liquid crystal polyester according to claim 1, wherein the monomer (i) comprises at least one member selected from the group consisting of 4-(4-hydroxyphenoxy)benzenecarboxylic acid and 4,4'-dicarboxydiphenyl ether.

4. The liquid crystalline polyester according to claim 1, wherein the monomer (i) is 4-(4-hydroxyphenoxy)benzenecarboxylic acid.

5. The liquid crystal polyester according to claim 1, further comprising a monomer unit (II) derived from a monomer (ii) represented by the following formula (ii): １１ -Ar １１ -X １２ (ii) [wherein, Ar １１ represents a phenylene group, a biphenylene group or a condensed polycyclic aromatic hydrocarbon group; X １１ and X １２ each independently represents a hydroxy group, an amino group, or a carboxy group. １１ A part or all of the hydrogen atoms of may be substituted with a halogen atom, an alkyl group or an aryl group.

6. The liquid crystalline polyester of claim 5, wherein the monomer (ii) comprises 4-hydroxybenzoic acid.

7. The liquid crystal polyester according to claim 5, wherein the content of the monomer unit (II) is 90 mol % or more based on the total amount of all the monomer units.

8. The liquid crystal polyester according to claim 1, which has a flow initiation temperature of 230° C. or higher.

9. A liquid crystal polyester composition comprising the liquid crystal polyester according to any one of claims 1 to 8.

10. A molded article comprising the liquid crystal polyester according to any one of claims 1 to 8.

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