CN118647672A - Liquid crystal polyester composition, method for producing liquid crystal polyester composition, film, and method for producing film - Google Patents

Abstract

The present invention relates to a liquid crystal polyester composition, which contains a liquid crystal polyester (A) and a liquid crystal polyester (B), wherein the liquid crystal polyester (B) has a repeating unit represented by the formula (B1)-O-Ar ^b1 -CO-(Ar ^b1 represents a phenylene group, a naphthylene group or a biphenylene group. The hydrogen atoms in the above-mentioned group represented by Ar ^b1 can also be independently substituted by halogen atoms, alkyl groups or aryl groups.), and the number of repeating units represented by the above formula (B1) is greater than 80% relative to the total number (100%) of all repeating units constituting the above liquid crystal polyester (B).

Description

Liquid crystal polyester composition, method for producing liquid crystal polyester composition, film, and method for producing film

Technical Field

The present invention relates to a liquid crystal polyester composition, a method for producing the liquid crystal polyester composition, a film, and a method for producing the film.

This application claims priority based on Japanese Patent Application No. 2022-011708 filed in Japan on January 28, 2022, the contents of which are incorporated herein by reference.

Background Art

Liquid crystal polyester films have attracted attention as electronic substrate materials because they have excellent high-frequency characteristics and low water absorption.

The liquid crystal polyester film can be provided in the form of a laminate having the liquid crystal polyester film as an insulating material (for example, copper clad laminate: Copper Clad Laminate, CCL; flexible copper clad laminate: Flexible Copper Clad Laminate, FCCL; double-sided CCL having copper foil on both sides, etc.).

Patent Document 1 discloses an aromatic liquid crystal polyester having a specific repeating unit derived from an aromatic hydroxycarboxylic acid. By using this aromatic liquid crystal polyester, dielectric loss can be suppressed, a film having excellent heat resistance and excellent film processability can be provided.

On the other hand, Patent Document 2 describes an insulating material for a circuit board composed of a liquid crystalline aromatic polyester containing a specific structural unit, and the dielectric loss tangent of the insulating material is small in a high frequency region.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2005-272819

Patent Document 2: Japanese Patent No. 4363057

Summary of the invention

Problems to be solved by the invention

However, although the material disclosed in Patent Document 1 is excellent in dielectric loss tangent, there is still room for further improvement in terms of improvement in processing characteristics during film formation.

Furthermore, although the material disclosed in Patent Document 2 is considered to be excellent in dielectric loss tangent, there is room for further improvement in properties required in recent years.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a liquid crystal polyester composition having an excellent balance between dielectric loss tangent and processing characteristics.

Another object of the present invention is to provide a film of the above-mentioned liquid crystal polyester composition and a method for producing the same.

Means for solving problems

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, focusing on the processing characteristics in film formation of the film, have found that the viscosity increase caused by the temperature drop of the molding material is less likely to occur, and that the viscosity increase caused by the temperature drop of the liquid crystal polyester composition can be suppressed by making the liquid crystal polyester composition contain a specific liquid crystal polyester (B), thereby completing the present invention.

That is, the present invention has the following aspects.

<1> A liquid crystal polyester composition comprising a liquid crystal polyester (A) and a liquid crystal polyester (B),

The liquid crystal polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-X-Ar ³ -Y-

(Ar ¹ represents a phenylene group, a naphthylene group or a biphenylene group.

Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (A4).

X and Y each independently represent an oxygen atom or an imino group (—NH—).

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be independently substituted by halogen atoms, alkyl groups or aryl groups.

(A4)-Ar ⁴ -Z-Ar ⁵ -

(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group.

Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group.)

The number of the repeating units represented by the formula (A1) is 30% or more and 80% or less relative to 100% of the total number of all repeating units constituting the liquid crystal polyester (A),

The liquid crystal polyester (B) has a repeating unit represented by the following formula (B1):

(B1)-O-Ar ^b1 -CO-

(Ar ^b1 represents a phenylene group, a naphthylene group or a biphenylene group.

The hydrogen atoms in the above groups represented by Ar ^b1 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

The number of the repeating unit represented by the formula (B1) is greater than 80% based on 100% of the total number of all repeating units constituting the liquid crystal polyester (B).

<2> The liquid crystal polyester composition according to <1> above, wherein the repeating unit represented by the formula (B1) comprises a repeating unit represented by the following formula (B1-1),

(B1-1)-O-Ar ^b1-1 -CO-

(Ar ^b1-1 represents a naphthylene group.

The hydrogen atoms in the above groups represented by Ar ^b1-1 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

The number of the repeating units represented by the above formula (B1-1) is greater than 50% and less than 90% relative to the total number of the repeating units satisfying the above formula (B1) (100%).

<3> The liquid crystal polyester composition according to <1> or <2>, wherein the ratio of the content of the liquid crystal polyester (A) to the content of the liquid crystal polyester (B) in the liquid crystal polyester composition is liquid crystal polyester (A)/liquid crystal polyester (B) = 95/5 to 25/75 in terms of mass ratio.

<4> The liquid crystal polyester composition according to <1> or <2>, wherein the ratio of the content of the liquid crystal polyester (A) to the content of the liquid crystal polyester (B) in the liquid crystal polyester composition is liquid crystal polyester (A)/liquid crystal polyester (B) = 95/5 to 50/50 in terms of mass ratio.

<5> The liquid crystal polyester composition according to any one of <1> to <4>, wherein the total content of the liquid crystal polyester (A) and the liquid crystal polyester (B) is 80% by mass or more relative to 100% by mass of the total mass of the liquid crystal polyester composition.

<6> The liquid crystal polyester composition according to any one of <1> to <5>, wherein the liquid crystal polyester (B) consists only of a repeating unit represented by the formula (B1).

<7> The liquid crystal polyester composition according to any one of <1> to <6>, wherein the liquid crystal polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-O-Ar ³ -O-

(Ar ¹ represents 2,6-naphthylene, 1,4-phenylene, or 4,4'-biphenylene.

Ar ² and Ar ³ each independently represent a 2,6-naphthylene group, a 2,7-naphthylene group, a 1,4-phenylene group, a 1,3-phenylene group, or a 4,4′-biphenylene group.

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be substituted by a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

<8> The liquid crystal polyester composition according to any one of <1> to <7>, wherein the repeating unit represented by the formula (B1) consists only of a repeating unit represented by the following formula (B1-1) and a repeating unit represented by the following formula (B1-2).

(B1-1)-O-Ar ^b1-1 -CO-

(B1-2)-O-Ar ^b1-2 -CO-

(Ar ^b1-1 represents a naphthylene group.

Ar ^b1-2 represents a phenylene group.

The hydrogen atoms in the above groups represented by Ar ^b1-1 or Ar ^b1-2 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

<9> A liquid crystal polyester composition according to any one of <1> to <8>, wherein the amine decomposition product obtained by subjecting the liquid crystal polyester composition to the following amine decomposition conditions contains a component detected within a retention time range of 17.4 to 17.5 minutes by liquid chromatography analysis under the following analysis conditions, and the relative content of the component determined from the peak area of the chromatogram analyzed by the liquid chromatography analysis using 4-(4-hydroxyphenoxy)benzoic acid as a standard substance is 0.0001% by mass or more and 0.5% by mass or less, relative to 100% by mass of the total mass of the liquid crystal polyester composition.

(Amine decomposition conditions)

The liquid crystal polyester composition and butylamine are mixed, treated at 200°C for 2 hours or more, and then the butylamine is removed by reduced pressure treatment at 60°C, followed by neutralization treatment by adding formic acid to obtain the amine decomposition product.

(Analysis conditions)

Column: base material (porous spherical silica), modified group (octadecyl), film thickness 3μm, 3mmφ×15cm

Mobile phase: A) 0.1 vol% acetic acid in water

B) 0.1% by volume of acetic acid and acetonitrile

Gradient: Start with 90% by volume of mobile phase A and 10% by volume of mobile phase B, slowly increase the concentration to 100% by volume of mobile phase B over 30 minutes, and measure for 10 minutes with 100% by volume of mobile phase B

Column temperature: 45°C

Detector: UV-254nm

Flow rate: 0.4 mL/min

Injection volume: 1μL

<10> The liquid crystal polyester composition according to any one of <1> to <9>, wherein the weight average molecular weight of the liquid crystal polyester contained in the liquid crystal polyester composition, as measured using polystyrene as a standard substance, is 270,000 or more.

<11> The method for producing a liquid crystal polyester composition according to any one of <1> to <10>, comprising the step of mixing the liquid crystal polyester (A) and the liquid crystal polyester (B).

<12> A film comprising a liquid crystal polyester (A) and a liquid crystal polyester (B),

The liquid crystal polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-X-Ar ³ -Y-

(Ar ¹ represents a phenylene group, a naphthylene group or a biphenylene group.

Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (A4).

X and Y each independently represent an oxygen atom or an imino group (—NH—).

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be independently substituted by halogen atoms, alkyl groups or aryl groups.

(A4)-Ar ⁴ -Z-Ar ⁵ -

(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group.

Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group.)

The number of the repeating units represented by the formula (A1) is 30% or more and 80% or less relative to 100% of the total number of all repeating units constituting the liquid crystal polyester (A),

The liquid crystal polyester (B) has a repeating unit represented by the following formula (B1):

(B1)-O-Ar ^b1 -CO-

(Ar ^b1 represents a phenylene group, a naphthylene group or a biphenylene group.

The hydrogen atoms in the above groups represented by Ar ^b1 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

The number of the repeating unit represented by the formula (B1) is greater than 80% based on 100% of the total number of all repeating units constituting the liquid crystal polyester (B).

<13> The method for producing a film according to <12>, comprising the step of melt-molding a film using the liquid crystal polyester composition according to any one of <1> to <10> as a molding material.

<14> The method for producing a film according to <13> above, wherein the melt molding is molding using an inflation method or molding using a T-die method.

Effects of the Invention

According to the present invention, a liquid crystal polyester composition having an excellent balance between dielectric loss tangent and processing characteristics can be provided.

Furthermore, according to the present invention, a film of the liquid crystal polyester composition and a method for producing the same can be provided.

DETAILED DESCRIPTION

Hereinafter, embodiments of the liquid crystal polyester composition, the method for producing the liquid crystal polyester composition, the film, and the method for producing the film of the present invention will be described.

《Liquid crystal polyester composition》

The liquid crystal polyester composition of the embodiment is a liquid crystal polyester composition containing the following liquid crystal polyester (A) and the following liquid crystal polyester (B).

The liquid crystal polyester composition of the embodiment contains the liquid crystal polyester (A) and the liquid crystal polyester (B), and therefore has an excellent balance between dielectric loss tangent and processing characteristics.

In this specification, the term "excellent processing properties" of a liquid crystal polyester composition means that, for a liquid crystal polyester composition heated to a temperature higher than the endothermic peak detected by a differential scanning calorimeter, when the temperature is lowered after heating, the viscosity of the liquid crystal polyester composition increases only slightly.

The degree of viscosity increase can be confirmed by the difference (η Tm -20°C - η Tm ) between the viscosity at the temperature of the top position of the endothermic peak detected by a differential scanning calorimeter of the liquid crystal polyester composition and the viscosity at the time when the temperature drops by 20°C from the top position of the endothermic peak. The smaller the value of the difference (η _Tm -20° _C - _{η Tm )} , the smaller the degree of viscosity increase can be evaluated.

The degree of viscosity increase can be confirmed, for example, by the ratio of the viscosity at the temperature of the top position of the endothermic peak detected by a differential scanning calorimeter of the liquid crystal polyester composition to the viscosity at the time when the temperature drops by 20° C. from the top position of the endothermic peak (η _Tm -20° C./η _Tm ). The smaller the value of this ratio (η _{Tm-20° C./η Tm} ), the smaller the degree of viscosity increase can be evaluated.

The lower the value of the dielectric loss tangent of the liquid crystal polyester composition, the more excellent the dielectric loss tangent can be said to be.

As a liquid crystal polyester composition having an excellent balance between dielectric loss tangent and processing characteristics, a preferred dielectric loss tangent value of the liquid crystal polyester composition is, for example, a dielectric loss tangent value of 0.0010 or less at a frequency of 10 GHz measured for a test piece in the [Dielectric Property Evaluation] described later.

In this specification, the term "dielectric property" refers to properties related to relative dielectric constant and dielectric loss tangent.

Preferred dielectric properties of the liquid crystal polyester composition include a relative dielectric constant of 3 or more and 4 or less at a frequency of 10 GHz measured for a test piece in the later-described [Evaluation of Dielectric Properties], and a dielectric loss tangent of 0.0002 or more and 0.0010 or less at a frequency of 10 GHz.

The liquid crystal polyester contained in the liquid crystal polyester composition of the present embodiment is a polyester that exhibits liquid crystallinity in a molten state, and is preferably a polyester that melts at a temperature of 450° C. or lower.

The liquid crystal polyester contained in the liquid crystal polyester composition of the present embodiment is preferably a wholly aromatic liquid crystal polyester obtained using only an aromatic compound as a raw material monomer.

The liquid crystal polyester is preferably a wholly aromatic liquid crystal polyester having only repeating units derived from aromatic compounds as repeating units.

Typical examples of liquid crystal polyesters include polymers obtained by polymerizing (polycondensing) aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, and at least one compound selected from the group consisting of aromatic diols, aromatic hydroxyamines, and aromatic diamines; polymers obtained by polymerizing a plurality of aromatic hydroxycarboxylic acids; polymers obtained by polymerizing aromatic dicarboxylic acids and at least one compound selected from the group consisting of aromatic diols, aromatic hydroxyamines, and aromatic diamines; and polymers obtained by polymerizing polyesters such as polyethylene terephthalate and aromatic hydroxycarboxylic acids.

Here, the aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, aromatic hydroxyamine and aromatic diamine may be replaced with a part or all of their polymerizable derivatives, respectively, independently of each other.

Examples of polymerizable derivatives of compounds having a carboxyl group such as aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids include esters obtained by converting a carboxyl group into an alkoxycarbonyl group or an aryloxycarbonyl group; acid halides obtained by converting a carboxyl group into a haloformyl group; and acid anhydrides obtained by converting a carboxyl group into an acyloxycarbonyl group.

Examples of polymerizable derivatives of compounds having a hydroxyl group such as aromatic hydroxycarboxylic acids, aromatic diols, and aromatic hydroxyamines include acylated products obtained by acylation of the hydroxyl group to an acyloxy group.

Examples of polymerizable derivatives of compounds having an amino group such as aromatic hydroxyamine and aromatic diamine include acylated products obtained by acylation of the amino group to convert it into an acylamino group.

Hereinafter, the details of the liquid crystal polyester (A) and the liquid crystal polyester (B) contained in the liquid crystal polyester composition of the embodiment will be described.

<Liquid Crystal Polyester (A)>

The liquid crystal polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-X-Ar ³ -Y-

(Ar ¹ represents a phenylene group, a naphthylene group or a biphenylene group.

Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (A4).

X and Y each independently represent an oxygen atom or an imino group (—NH—).

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be independently substituted by halogen atoms, alkyl groups or aryl groups.

(A4)-Ar ⁴ -Z-Ar ⁵ -

(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group.

Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group.)

With respect to the total number (100%) of all repeating units constituting the liquid crystal polyester (A),

The number of repeating units represented by the above formula (A1) is 30% or more and 80% or less.

The ratio of each repeating unit in the liquid crystal polyester (A) will be described in detail below.

From the viewpoint of achieving a more excellent dielectric loss tangent, the liquid crystal polyester (A) listed above preferably has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

Preferred examples of Ar ¹ , Ar ² and Ar ³ in the formulae (A1) to (A3) are shown below.

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-O-Ar ³ -O-

(Ar ¹ , Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group or a biphenylene group.

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be substituted by halogen atoms, alkyl groups or aryl groups, respectively.

Specifically, from the viewpoint of achieving a more excellent dielectric loss tangent, the liquid crystal polyester (A) listed above preferably has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

Preferred examples of Ar ¹ , Ar ² and Ar ³ in the formulae (A1) to (A3) are shown below.

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-O-Ar ³ -O-

(Ar ¹ represents 2,6-naphthylene, 1,4-phenylene, or 4,4'-biphenylene.

Ar ² and Ar ³ each independently represent a 2,6-naphthylene group, a 2,7-naphthylene group, a 1,4-phenylene group, a 1,3-phenylene group, or a 4,4′-biphenylene group.

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be substituted by a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

Examples of the halogen atom that may be substituted with a hydrogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkyl group having 1 to 10 carbon atoms which may be substituted with a hydrogen atom include methyl, ethyl, 1-propyl, isopropyl, 1-butyl, isobutyl, sec-butyl, tert-butyl, 1-hexyl, 2-ethylhexyl, 1-octyl and 1-decyl.

Examples of the aryl group having 6 to 20 carbon atoms which may be substituted with a hydrogen atom include monocyclic aromatic groups such as phenyl, o-tolyl, m-tolyl, p-tolyl, and the like, and condensed-ring aromatic groups such as 1-naphthyl, 2-naphthyl, and the like.

When one or more hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ are substituted with the above halogen atoms, the above alkyl group having 1 to 10 carbon atoms or the above aryl group having 6 to 20 carbon atoms, the number of the groups replacing the above hydrogen atoms is preferably 1 or 2, more preferably 1, in each group represented by Ar ¹ , Ar ² or Ar ³ , respectively and independently.

The hydrogen atom possessed by Ar ¹ , Ar ² or Ar ³ may not be substituted by the above-mentioned groups.

The liquid crystal polyester (A) preferably contains a repeating unit having a naphthalene structure. The liquid crystal polyester containing a repeating unit having a naphthalene structure tends to have a more excellent dielectric loss tangent than a liquid crystal polyester not containing a repeating unit having a naphthalene structure.

As the liquid crystal polyester having a repeating unit containing a divalent naphthalene structure, in the liquid crystal polyester having a repeating unit represented by the above formula (A1), a repeating unit represented by the above formula (A2) and a repeating unit represented by the above formula (A3), at least one of the plurality of Ar ¹ , Ar ² and Ar ³ is preferably a naphthylene group, more preferably a 2,6-naphthylene group.

The content of the repeating units containing a naphthalene structure in the liquid crystal polyester (A) is preferably 40% or more, preferably 50% or more, more preferably 55% or more, and further preferably 60% or more relative to the total number (100%) of all repeating units in the liquid crystal polyester (A). By making the content of the repeating units containing a naphthalene structure greater than the above lower limit, the dielectric loss tangent of the liquid crystal polyester can be further reduced.

The content of the repeating units containing a naphthalene structure in the liquid crystal polyester (A) is preferably 90% or less, more preferably 85% or less, and further preferably 80% or less relative to the total number (100%) of all repeating units in the liquid crystal polyester. By making the content of the repeating units containing a naphthalene structure below the above upper limit, the reaction stability during the production of the liquid crystal polyester can be ensured.

As an example of the numerical range of the value of the content number of the above-mentioned repeating units containing a naphthalene structure in the liquid crystal polyester (A), it can be 40% to 90%, 50% to 85%, 55% to 85%, or 60% to 80%.

The liquid crystal polyester having repeating units represented by the above formulae (A1) to (A3) preferably has a repeating unit in which Ar ¹ and/or Ar ² is a 2,6-naphthylene group.

For the liquid crystal polyester (A), relative to the total number (100%) of all repeating units in the liquid crystal polyester (A), the repeating units in which Ar ¹ and/or Ar ² are 2,6-naphthylene among the repeating units represented by the above formulas (A1) to (A3) may contain 40% or more, 40% or more and 90% or less, 50% or more and 85% or less, 55% or more and 85% or less, or 60% or more and 80% or less.

The repeating unit represented by the above formula (A1) is a repeating unit derived from an aromatic hydroxycarboxylic acid.

Examples of the aromatic hydroxycarboxylic acid include p-hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-3-naphthoic acid, 1-hydroxy-5-naphthoic acid, 4-hydroxy-4'-carboxy diphenyl ether, and aromatic hydroxycarboxylic acids in which a portion of hydrogen atoms on the aromatic ring of these aromatic hydroxycarboxylic acids are substituted with a substituent selected from the group consisting of an alkyl group, an aryl group, and a halogen atom. The aromatic hydroxycarboxylic acids may be used alone or in combination of two or more in the production of the liquid crystal polyester.

Preferred repeating units represented by the formula (A1) include repeating units wherein Ar ¹ is 1,4-phenylene (e.g., repeating units derived from 4-hydroxybenzoic acid) and repeating units wherein Ar ¹ is 2,6-naphthylene (e.g., repeating units derived from 6-hydroxy-2-naphthoic acid).

The repeating unit represented by the above formula (A2) is a repeating unit derived from an aromatic dicarboxylic acid.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, biphenyl-4,4'-dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl sulfide-4,4'-dicarboxylic acid, and aromatic dicarboxylic acids in which a portion of hydrogen atoms on the aromatic ring of these aromatic dicarboxylic acids are substituted with a substituent selected from the group consisting of an alkyl group, an aryl group, and a halogen atom.

The above aromatic dicarboxylic acids may be used alone or in combination of two or more kinds in the production of the liquid crystal polyester.

Preferred repeating units of the formula (A2) include repeating units in which Ar ² is 1,4-phenylene (e.g., repeating units derived from terephthalic acid), repeating units in which Ar ² is 1,3-phenylene (e.g., repeating units derived from isophthalic acid), repeating units in which Ar ² is 2,6-naphthylene (e.g., repeating units derived from 2,6-naphthalenedicarboxylic acid), and repeating units in which Ar ² is diphenyl ether-4,4'-diyl (e.g., repeating units derived from diphenyl ether-4,4'-dicarboxylic acid).

The repeating unit represented by the above formula (A3) is a repeating unit derived from an aromatic diol, an aromatic hydroxyamine or an aromatic diamine.

Examples of the aromatic diol, aromatic hydroxyamine or aromatic diamine include 4,4'-dihydroxybiphenyl, hydroquinone, methylhydroquinone, resorcinol, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether, bis(4-hydroxyphenyl)methane, 1,2-bis(4-hydroxyphenyl)ethane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 2,6-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 4-aminophenol, 1,4-phenylenediamine, 4-amino-4'-hydroxybiphenyl and 4,4'-diaminobiphenyl.

The above-mentioned aromatic diol, aromatic hydroxyamine or aromatic diamine may be used alone or in combination of two or more kinds in the production of the liquid crystal polyester.

The repeating unit represented by the above formula (A3) is preferably a repeating unit in which Ar ³ is a 1,4-phenylene group (for example, a repeating unit derived from hydroquinone, 4-aminophenol or 1,4-phenylenediamine) and a repeating unit in which Ar ³ is a 4,4'-biphenylene group (for example, a repeating unit derived from 4,4'-dihydroxybiphenyl, 4-amino-4'-hydroxybiphenyl or 4,4'-diaminobiphenyl).

In this specification, the term "origin" means that the chemical structure changes due to polymerization of raw material monomers and no other structural changes occur.

The term “origin” herein is a concept that also includes the case where the source is a polymerizable derivative of the compound. For example, each repeating unit may be a repeating unit derived from an acylate of an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic hydroxyamine.

In addition, when the liquid crystal polyester composition of the embodiment is required to have particularly good heat resistance, the number of these substituents is preferably small, and it is particularly preferred that there is no substituent such as an alkyl group.

The content of the repeating unit represented by the above formula (A1) in the liquid crystal polyester (A) (hereinafter also referred to as repeating unit (A1)) is, based on number, 30% to 80%, preferably 40% to 70%, and more preferably 45% to 65%, relative to the total number of all repeating units (100%).

The content of the repeating unit represented by the above formula (A2) in the liquid crystal polyester (A) (hereinafter also referred to as repeating unit (A2)) on a number basis is preferably 35% or less, more preferably 10% or more and 35% or less, further preferably 15% or more and 30% or less, and particularly preferably 17.5% or more and 27.5% or less, relative to the total number of all repeating units (100%).

The content of the repeating unit represented by the above formula (A3) in the liquid crystal polyester (A) (hereinafter also referred to as repeating unit (A3)) on a number basis is preferably 35% or less, more preferably 10% or more and 35% or less, further preferably 15% or more and 30% or less, and particularly preferably 17.5% or more and 27.5% or less, relative to the total number of all repeating units (100%).

The higher the content of the repeating unit (A1) in the liquid crystal polyester (A), the higher the melt fluidity, heat resistance, strength and rigidity. However, if too much, the melting temperature and melt viscosity tend to increase, and the temperature required for molding tends to increase.

The ratio of the content of the repeating unit (A2) to the content of the repeating unit (A3) in the liquid crystal polyester (A) is expressed as [content of the repeating unit (A2)]/[content of the repeating unit (A3)] (number/number), and is preferably 0.9/1 to 1/0.9, more preferably 0.95/1 to 1/0.95, and further preferably 0.98/1 to 1/0.98.

It should be noted that the liquid crystal polyester (A) may also have two or more repeating units (A1) to (A3) independently. In addition, the liquid crystal polyester may also have repeating units other than the repeating units (A1) to (A3), but the content thereof is preferably 10% or less, more preferably 5% or less, and further preferably 0% relative to the total number (100%) of all repeating units constituting the liquid crystal polyester (A).

The sum of the content of the repeating unit (A1) of the liquid crystal polyester (A), the content of the repeating unit (A2) of the liquid crystal polyester (A) and the content of the repeating unit (A3) of the liquid crystal polyester (A) is not more than 100% on a number basis.

In the present specification, the number of each repeating unit (polymerization degree of each repeating unit) refers to a value determined by the analysis method described in JP-A-2000-19168.

Specifically, the liquid crystal polyester resin is reacted with a lower alcohol (alcohol having 1 to 3 carbon atoms) in a supercritical state to depolymerize the liquid crystal polyester resin to monomers from which its repeating units are derived, and the monomers from which each repeating unit is derived obtained as a depolymerization product are quantified by liquid chromatography, thereby calculating the number of each repeating unit.

For example, when a liquid crystal polyester resin contains repeating units (A1) to (A3), the number of repeating units (A1) can be determined by the following steps: the molar concentrations of monomers from which the repeating units (A1) to (A3) are respectively derived are calculated by liquid chromatography, and the ratio of the molar concentrations of the monomers from which the repeating units (A1) to (A3) are calculated when the total molar concentrations of the monomers from which the repeating units (A1) to (A3) are respectively derived is set to 100%.

<Liquid Crystal Polyester (B)>

The liquid crystal polyester (B) has a repeating unit represented by the following formula (B1):

(B1)-O-Ar ^b1 -CO-

(Ar ^b1 represents a phenylene group, a naphthylene group or a biphenylene group.

The hydrogen atoms in the above groups represented by Ar ^b1 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

The number of the repeating unit represented by the formula (B1) is greater than 80% of the total number (100%) of all repeating units constituting the liquid crystal polyester (B).

Examples of the phenylene group, naphthylene group, and biphenylene group in Ar ^b1 include the same groups as exemplified in the above-mentioned liquid crystal polyester (A).

Examples of the halogen atom and the alkyl group or aryl group in Ar ^b1 include the same groups as exemplified in the above-mentioned liquid crystal polyester (A).

In the liquid crystal polyester (B), the larger the content ratio of the repeating unit represented by the formula (B1) is, the more excellent the effect of suppressing the viscosity increase caused by temperature drop in the liquid crystal polyester composition is.

From the above viewpoint, the number of repeating units represented by the above formula (B1) is greater than 80% relative to the total number (100%) of all repeating units constituting the above liquid crystal polyester (B), preferably greater than 85% and less than 100%, preferably greater than 90% and less than 100%, more preferably greater than 95% and less than 100%, and further preferably greater than 98% and less than 100%. The above liquid crystal polyester (B) is particularly preferably composed essentially only of repeating units represented by the above formula (B1) (the number of repeating units represented by the above formula (B1) is 100%).

From the viewpoint of further improving the effect of suppressing the viscosity increase caused by temperature drop by being contained in the liquid crystal polyester composition, the liquid crystal polyester (B) listed above is

The repeating unit represented by the above formula (B1) preferably includes a repeating unit represented by the following formula (B1-1).

(B1-1)-O-Ar ^b1-1 -CO-

(Ar ^b1-1 represents a naphthylene group.

The hydrogen atoms in the above groups represented by Ar ^b1-1 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

The number of repeating units represented by the above formula (B1-1) is preferably greater than 50% and less than 90%, more preferably greater than 65% and less than 80%, relative to the total number (100%) of repeating units satisfying the above formula (B1).

In the liquid crystal polyester (B), if the content ratio of the repeating unit represented by the above formula (B1-1) is within the above numerical range, the effect of suppressing the viscosity increase caused by temperature drop in the liquid crystal polyester composition is further excellent, and an excellent dielectric loss tangent can be exerted.

More specifically, as the liquid crystal polyester (B) listed above, the repeating unit represented by the above formula (B1) preferably includes a repeating unit represented by the following formula (B1-1) and a repeating unit represented by the following formula (B1-2), and more preferably consists only of a repeating unit represented by the following formula (B1-1) and a repeating unit represented by the following formula (B1-2).

(B1-1)-O-Ar ^b1-1 -CO-

(B1-2)-O-Ar ^b1-2 -CO-

(Ar ^b1-1 represents a naphthylene group.

Ar ^b1-2 represents a phenylene group.

The hydrogen atoms in the above groups represented by Ar ^b1-1 or Ar ^b1-2 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

Examples of the naphthylene group in Ar ^b1-1 include the same groups as exemplified in the above-mentioned liquid crystal polyester (A).

Examples of the phenylene group in Ar ^b1-2 include the same groups as exemplified in the above-mentioned liquid crystal polyester (A).

Examples of the halogen atom, alkyl group or aryl group in Ar ^b1-1 and Ar ^b1-2 include the same atoms or groups as exemplified in the above-mentioned liquid crystal polyester (A).

More specifically, the liquid crystal polyester (B) listed above is preferably composed only of repeating units represented by the above formula (B1), and the repeating units represented by the above formula (B1) include repeating units represented by the following formula (B1-1) and repeating units represented by the following formula (B1-2), and more preferably consists only of repeating units represented by the following formula (B1-1) and repeating units represented by the following formula (B1-2).

(B1-1)-O-Ar ^b1-1 -CO-

(B1-2)-O-Ar ^b1-2 -CO-

(Ar ^b1-1 represents 2,6-naphthylene.

Ar ^b1-2 represents 1,4-phenylene.

The hydrogen atoms in the above groups represented by Ar ^b1-1 or Ar ^b1-2 may be substituted independently by a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

The repeating unit represented by the above formula (B1) is a repeating unit derived from an aromatic hydroxycarboxylic acid. Examples of the repeating unit derived from an aromatic hydroxycarboxylic acid include the same repeating units as exemplified as the repeating unit represented by the above formula (A1).

The liquid crystal polyester of the embodiment may have the following aspects.

<15> The liquid crystal polyester composition according to any one of <1> to <10>, wherein, when the repeating unit represented by the formula (B1) comprises a repeating unit represented by the following formula (B1-1) and a repeating unit represented by the following formula (B1-2), relative to the total number (100%) of all repeating units constituting the liquid crystal polyester (B), as an example,

The number of repeating units represented by the above formula (B1-1) is greater than 50% and less than 90%,

The number of repeating units represented by the above formula (B1-2) may be 10% or more and less than 50%.

The number of repeating units represented by the above formula (B1-1) is 65% or more and 80% or less,

The number of repeating units represented by the above formula (B1-2) may be 20% or more and 35% or less.

It should be noted that the liquid crystal polyester (B) may independently have two or more repeating units represented by the above formula (B1). In addition, the liquid crystal polyester may also have repeating units other than the repeating units represented by the above formula (B1), but the content thereof is preferably 10% or less, more preferably 5% or less, and further preferably 0% relative to the total number (100%) of all repeating units constituting the liquid crystal polyester (B).

As a particularly preferred combination of the types of the liquid crystal polyester (A) and the liquid crystal polyester (B) exemplified above, the liquid crystal polyester of the embodiment may have the following aspects.

<16> The liquid crystal polyester composition according to any one of <1> to <10> and <15>, wherein the liquid crystal polyester (A) is a liquid crystal polyester having a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3),

More preferably, the liquid crystal polyester (A) is a liquid crystal polyester consisting only of a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-O-Ar ³ -O-

(Ar ¹ represents a 2,6-naphthylene group.

Ar ² and Ar ³ each independently represent a 2,6-naphthylene group or a 1,4-phenylene group.

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be substituted by a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

The liquid crystal polyester (B) consists only of a repeating unit represented by the following formula (B1-1) and a repeating unit represented by the following formula (B1-2).

(B1-1)-O-Ar ^b1-1 -CO-

(B1-2)-O-Ar ^b1-2 -CO-

(Ar ^b1-1 represents 2,6-naphthylene.

Ar ^b1-2 represents 1,4-phenylene.

The hydrogen atoms in the above groups represented by Ar ^b1-1 or Ar ^b1-2 may be substituted independently by a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

In addition, the ratio of the content of the above-mentioned liquid crystal polyester (A) to the above-mentioned liquid crystal polyester (B) in the liquid crystal polyester composition described in <16> is preferably liquid crystal polyester (A)/liquid crystal polyester (B) = 95/5 to 25/75 in terms of mass ratio, preferably 95/5 to 30/70, preferably 95/5 to 40/60, preferably 95/5 to 50/50, more preferably 95/5 to 50/50 (except 50/50), further preferably 90/10 to 60/40, and on the other hand, preferably 80/20 to 30/70, more preferably 80/20 to 60/40, and further preferably 70/30 to 60/40.

The flow start temperature of the liquid crystal polyester composition of the embodiment containing the liquid crystal polyester (A) and the liquid crystal polyester (B) is preferably 260°C or higher, more preferably 260°C or higher and 400°C or lower, and further preferably 260°C or higher and 380°C or lower.

The higher the flow start temperature of the liquid crystal polyester composition, the higher the heat resistance and strength of the liquid crystal polyester composition tend to be. On the other hand, if the flow start temperature of the liquid crystal polyester composition is greater than 400°C, the melting temperature and melt viscosity of the liquid crystal polyester composition tend to be higher. Therefore, there is a tendency for the temperature required for molding the liquid crystal polyester composition to be higher.

In addition, as a preferable value of the flow start temperature of the liquid crystal polyester (A), the same numerical values as the respective numerical values exemplified as the flow start temperature of the liquid crystal polyester composition of the embodiment can be cited.

In addition, as a preferable value of the flow start temperature of the liquid crystal polyester (B), the same numerical values as the respective numerical values exemplified as the flow start temperature of the liquid crystal polyester composition of the embodiment can be cited.

In this specification, the flow start temperature of the liquid crystal polyester composition is also referred to as the fluid temperature or the flow temperature, which is a temperature that serves as a standard for the molecular weight of the liquid crystal polyester (see Naoyuki Koide, "Liquid Crystal Polymers - Synthesis, Forming, and Applications -", CMC Co., Ltd., June 5, 1987, p. 95).

The flow start temperature is the temperature at which the liquid crystal polyester composition shows a viscosity of 4800 Pa·s ( ⁴⁸⁰⁰⁰ poise) when the liquid crystal polyester composition is melted and extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm using a flow tester while heating at a rate of 4°C/min under a load of 9.8 MPa (100 kg/cm 2 ).

The weight average molecular weight (Mw) of the liquid crystal polyester contained in the liquid crystal polyester composition is preferably 50,000 or more, more preferably 100,000 or more, and further preferably 270,000 or more.

The weight average molecular weight (Mw) of the liquid crystal polyester contained in the liquid crystal polyester composition is preferably 1,000,000 or less, more preferably 700,000 or less, and further preferably 500,000 or less.

As an example of the numerical range of the weight average molecular weight (Mw) of the liquid crystal polyester contained in the liquid crystal polyester composition, it is preferably 50,000 to 1,000,000, more preferably 100,000 to 700,000, and further preferably 270,000 to 500,000.

When the weight average molecular weight of the liquid crystal polyester is below the upper limit, film processing with excellent isotropy is further facilitated. When the weight average molecular weight of the liquid crystal polyester is above the lower limit, further excellent mechanical strength can be exerted, which is preferred.

The number average molecular weight (Mn) of the liquid crystal polyester contained in the liquid crystal polyester composition is preferably 1,000 or more, more preferably 5,000 or more, and even more preferably 7,000 or more.

The number average molecular weight (Mn) of the liquid crystal polyester contained in the liquid crystal polyester composition is preferably 500,000 or less, more preferably 300,000 or less, and further preferably 100,000 or less.

As an example of the numerical range of the number average molecular weight (Mn) of the liquid crystal polyester contained in the liquid crystal polyester composition, it is preferably 1,000 to 500,000, more preferably 5,000 to 300,000, and further preferably 7,000 to 100,000.

When the number average molecular weight of the liquid crystal polyester is below the upper limit, film processing with excellent isotropy is further facilitated. When the number average molecular weight of the liquid crystal polyester is above the lower limit, further excellent mechanical strength can be exerted, which is preferred.

In the present specification, a film having excellent isotropy refers to a film having a small difference in the direction of molecular orientation of the liquid crystal polyester contained in the film between the film forming direction (MD: Machine Direction) and the direction perpendicular to the MD (TD: Transverse Direction).

The polydispersity (Mw/Mn) of the liquid crystal polyester contained in the liquid crystal polyester composition is not particularly limited, but can be exemplified by being 1.0 or more and 4.0 or less.

The liquid crystal polyester contained in the liquid crystal polyester composition of the embodiment may contain the above-mentioned liquid crystal polyester (A) and the above-mentioned liquid crystal polyester (B).

In addition, as the values of the weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mw/Mn) of the above-mentioned liquid crystal polyester (A) contained in the liquid crystal polyester composition, the same numerical values as the respective numerical values exemplified as the respective items (weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mw/Mn)) of the liquid crystal polyester contained in the liquid crystal polyester composition can be listed.

In addition, as the values of the weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mw/Mn) of the above-mentioned liquid crystal polyester (B) contained in the liquid crystal polyester composition, the same numerical values as the respective numerical values exemplified as the respective items (weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mw/Mn)) of the liquid crystal polyester contained in the liquid crystal polyester composition can be listed.

In this specification, the “weight average molecular weight” and “number average molecular weight” can be determined by gel permeation chromatography (GPC) analysis, and refer to values determined by standard polystyrene conversion based on a calibration curve obtained by measuring the molecular weight of standard polystyrene.

The liquid crystal polyester composition of the embodiment preferably contains a component detected within a retention time range of 17.4 to 17.5 minutes by liquid chromatography analysis under the following analysis conditions as an amine decomposition product obtained by the above-mentioned liquid crystal polyester composition under the following amine decomposition conditions.

(Amine decomposition conditions)

The liquid crystal polyester composition and butylamine are mixed, treated at 200°C for 2 hours or more, and then the butylamine is removed by reduced pressure treatment at 60°C, followed by neutralization treatment by adding formic acid to obtain the amine decomposition product.

(Analysis conditions)

Column: base material (porous spherical silica), modified group (octadecyl), film thickness 3μm, 3mmφ×15cm

Mobile phase: A) 0.1 vol% acetic acid in water

B) 0.1% by volume of acetic acid and acetonitrile

Gradient: Start with 90% by volume of mobile phase A and 10% by volume of mobile phase B, slowly increase the concentration to 100% by volume of mobile phase B over 30 minutes, and measure for 10 minutes with 100% by volume of mobile phase B

Column temperature: 45°C

Detector: UV-254nm

Flow rate: 0.4mL/min

Injection volume: 1μL

The amount of butylamine used in the above-mentioned amine decomposition conditions is set to an amount that can sufficiently decompose the liquid crystal polyester in the liquid crystal polyester composition.

Relative to the total mass (100 mass%) of the above-mentioned liquid crystal polyester composition, the relative content of the component detected within the above-mentioned retention time range of 17.4 to 17.5 minutes, determined from the peak area of the chromatogram analyzed by the above-mentioned liquid chromatography using 4-(4-hydroxyphenoxy)benzoic acid as a standard substance, is preferably 0.5 mass% or less, more preferably 0.1 mass% or less, and further preferably 0.05 mass% or less.

Relative to the total mass (100 mass%) of the above-mentioned liquid crystal polyester composition, the relative content of the component detected within the above-mentioned retention time range of 17.4 to 17.5 minutes, determined from the peak area of the chromatogram analyzed by the above-mentioned liquid chromatography using 4-(4-hydroxyphenoxy)benzoic acid as a standard substance, is preferably 0.0001 mass% or more, more preferably 0.005 mass% or more, and even more preferably 0.01 mass% or more.

As an example of the above-mentioned numerical range of the above-mentioned relative content of the above-mentioned components, it is preferably 0.0001 mass % or more and 0.5 mass % or less, more preferably 0.005 mass % or more and 0.1 mass % or less, and further preferably 0.01 mass % or more and 0.05 mass % or less, relative to the total mass (100 mass %) of the above-mentioned polyester composition.

If the relative content of the components detected within the above retention time range of 17.4 to 17.5 minutes, calculated from the peak area of the chromatogram analyzed by the above liquid chromatography using 4-(4-hydroxyphenoxy)benzoic acid as the standard substance, is within the above numerical range, film processing with excellent isotropy is further facilitated, and further better mechanical strength can be exerted.

From the viewpoint of excellent balance between dielectric loss tangent and processing characteristics, the ratio of the content of the above-mentioned liquid crystal polyester (A) and the above-mentioned liquid crystal polyester (B) in the above-mentioned liquid crystal polyester composition is preferably liquid crystal polyester (A)/liquid crystal polyester (B) = 95/5 to 25/75 in terms of mass ratio, preferably 95/5 to 30/70, preferably 95/5 to 40/60, preferably 95/5 to 50/50, more preferably 95/5 to 50/50 (except 50/50), and further preferably 90/10 to 60/40.

From the viewpoint of better mechanical strength, the ratio of the content of the above-mentioned liquid crystal polyester (A) to the above-mentioned liquid crystal polyester (B) is preferably liquid crystal polyester (A)/liquid crystal polyester (B) = 80/20 to 30/70, more preferably 80/20 to 60/40, and further preferably 70/30 to 60/40 in terms of mass ratio.

The content of the liquid crystal polyester may be 50% by mass or more, 80% by mass or more, or 100% by mass relative to the total mass (100% by mass) of the liquid crystal polyester composition.

The total content of the liquid crystal polyester (A) and the liquid crystal polyester (B) may be 50% by mass or more, 80% by mass or more, or 100% by mass relative to 100% by mass of the total mass of the liquid crystal polyester contained in the liquid crystal polyester composition.

The total content of the liquid crystal polyester (A) and the liquid crystal polyester (B) may be 50% by mass or more, 80% by mass or more, or 100% by mass relative to the total mass (100% by mass) of the liquid crystal polyester composition.

(Method for producing liquid crystal polyester)

Liquid crystal polyesters are preferably produced by melt-polymerizing raw material monomers corresponding to the repeating units constituting the polyesters and, if necessary, solid-phase polymerizing the resulting polymers. This allows the production of high molecular weight liquid crystal polyesters with good operability and high heat resistance, strength, and rigidity.

Melt polymerization can also be carried out in the presence of a catalyst. Examples of the catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide, and nitrogen-containing heterocyclic compounds such as 4-(dimethylamino)pyridine and 1-methylimidazole. Preferably, nitrogen-containing heterocyclic compounds are used.

<Optional Ingredients>

The liquid crystal polyester composition of the present embodiment may further contain an optional component other than the above-mentioned liquid crystal polyester.

The liquid crystal polyester composition of the embodiment may contain the liquid crystal polyester (A), the liquid crystal polyester (B) and other optional components used as needed such that the total content (mass %) of these components in the liquid crystal polyester composition is not greater than the total mass (100 mass %) of the liquid crystal polyester composition.

Optional components include fillers, resins other than the above-mentioned liquid crystal polyesters, flame retardants, conductivity-imparting materials, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration dampers, antibacterial agents, insect repellents, deodorants, anti-coloring agents, heat stabilizers, mold release agents, antistatic agents, plasticizers, lubricants, dyes, foaming agents, foaming agents, viscosity modifiers, surfactants, and the like.

Since the liquid crystal polyester composition described above contains the liquid crystal polyester (A) and the liquid crystal polyester (B), the viscosity increase due to temperature drop can be suppressed and the processing characteristics are improved compared with the case of containing only the liquid crystal polyester (A).

In the liquid crystal polyester composition, the suppression of the viscosity increase caused by the temperature drop can be confirmed by the following difference (η _Tm-20°C -η _Tm ) in the following [Evaluation of Curing Speed]. The smaller the value calculated by this evaluation, the slower the curing speed of the sample, the lower the degree of viscosity increase caused by the temperature drop, and the better the processing characteristics.

〔Evaluation of curing speed〕

Using a rheometer (e.g., TA Instruments, Discovery HR-20), a sample of the liquid crystal polyester composition of the measurement object is melted at a temperature higher than the endothermic peak detected by a differential scanning calorimeter, and the viscosity is measured when cooled at a cooling rate of 10°C/min. The measurement conditions are described below. The ratio of the viscosity at the temperature of the apex position of the endothermic peak detected by the differential scanning calorimeter to the viscosity at the moment when the temperature drops by 20°C from the apex position of the endothermic peak is calculated (η _Tm -20°C/η _Tm ). Furthermore, the difference between the viscosity at the temperature of the apex position of the endothermic peak detected by the differential scanning calorimeter and the viscosity at the moment when the temperature drops by 20°C from the apex position of the endothermic peak is calculated (η _Tm-20°C -η _Tm ).

Measurement start temperature: A temperature higher than the endothermic peak detected by a differential scanning calorimeter.

Cooling rate: 10℃/min

Frequency: 1Hz

Strain: 0.05

As a liquid crystal polyester composition having an excellent balance between dielectric loss tangent and processing characteristics, as an example of the value of the above-mentioned difference in viscosity (η _Tm-20℃ -η _Tm ) of the liquid crystal polyester composition, it can be 700 Pa·s or less, can be 600 Pa·s or less, can be 50 Pa·s or more and 680 Pa·s or less, can be 50 Pa·s or more and 650 Pa·s or more, can be 50 Pa·s or more and 500 Pa·s or less, can be 100 Pa·s or more and 400 Pa·s or less.

As a liquid crystal polyester composition having an excellent balance between dielectric loss tangent and processing characteristics, an example of the value of the above ratio (η _Tm-20°C /η _Tm ) of the viscosity of the liquid crystal polyester composition may be 1.52 or less, 1 or more and 1.51 or less, or 1.3 or more and 1.50 or less.

It should be noted that the temperature of the endothermic peak of the liquid crystal polyester contained in the liquid crystal polyester composition detected by differential scanning calorimetry is preferably 250°C or higher, more preferably 250°C or higher and 350°C or lower, further preferably 280°C or higher and 340°C or lower, and particularly preferably 300°C or higher and 330°C or lower.

When the temperature of the endothermic peak of the liquid crystal polyester is equal to or higher than the above lower limit, heat resistance is good, which is preferred.

The temperature of the endothermic peak of the liquid crystal polyester is measured using a differential scanning calorimeter (e.g., "DSC-60A Plus" manufactured by Shimadzu Corporation) as the temperature (°C) at the top position of the endothermic peak of the liquid crystal polyester sample obtained by heating from room temperature (23°C) at a rate of 10°C/min.

Since the liquid crystal polyester composition contains the liquid crystal polyester (A) and the liquid crystal polyester (B), the value of the dielectric loss tangent measured by the following dielectric property evaluation is smaller than that of the case where the liquid crystal polyester (B) is contained alone.

The dielectric properties of the liquid crystal polyester composition can be determined by the following [Dielectric Property Evaluation].

〔Dielectric property evaluation〕

An injection molding machine (e.g., PNX40-5A manufactured by Nissei Plastic Industry Co., Ltd.) is used to prepare a molded body with a width of 64 mm, a length of 64 mm, and a thickness of 1 mm using the sample to be measured as a molding material, and then cut from both sides to obtain a test piece with a thickness of 0.2 mm. For the obtained test piece, a vector network analyzer (e.g., N5290A manufactured by Keysight Technologies Co., Ltd.) and a split cylindrical resonator (e.g., CR710 manufactured by EM labs Co., Ltd.) are used to measure the relative dielectric constant and dielectric loss tangent at 10 GHz.

·Measurement environment: 23℃, 50%RH

The relative dielectric constant of the liquid crystal polyester composition of the embodiment at a frequency of 10 GHz measured on the test piece in the above [Evaluation of Dielectric Properties] is preferably 4 or less, more preferably 3.8 or less, and further preferably 3.6 or less. In addition, the relative dielectric constant of the liquid crystal polyester composition of the embodiment at a frequency of 10 GHz measured on the test piece in the above [Evaluation of Dielectric Properties] may be 3 or more, 3.2 or more, or 3.4 or more.

The upper limit and lower limit of the relative dielectric constant of the liquid crystal polyester composition can be freely combined. As an example of the numerical range of the relative dielectric constant of the liquid crystal polyester composition, it can be 3 or more and 4 or less, 3.2 or more and 3.8 or less, or 3.4 or more and 3.6 or less.

The dielectric loss tangent value of the liquid crystal polyester composition of the embodiment at a frequency of 10 GHz measured on the test piece in the above [Dielectric Property Evaluation] is preferably 0.0010 or less, more preferably 0.0009 or less, and further preferably 0.0008 or less. In addition, the lower limit of the dielectric loss tangent value of the liquid crystal polyester composition of the embodiment at a frequency of 10 GHz measured on the test piece in the above [Dielectric Property Evaluation] is not particularly limited, but may be 0.0002 or more, 0.0003 or more, or 0.0004 or more.

The upper limit and lower limit of the dielectric loss tangent of the above-mentioned liquid crystal polyester composition can be freely combined. As an example of the numerical range of the dielectric loss tangent of the above-mentioned liquid crystal polyester composition, it can be 0.0002 or more and 0.0010 or less, 0.0003 or more and 0.0009 or less, or 0.0004 or more and 0.0008 or less.

Since the liquid crystal polyester composition contains the liquid crystal polyester (A) and the liquid crystal polyester (B), the mechanical strength value can be improved compared with the case where it contains only the liquid crystal polyester (A) or the case where it contains only the liquid crystal polyester (B).

The mechanical strength of the liquid crystal polyester composition can be evaluated using the flexural strength and flexural modulus measured on the test piece described below in the "Evaluation of Flexural Properties" as indicators.

〔Bending property evaluation〕

An injection molding machine (e.g., PNX40-5A manufactured by Nissei Plastic Industry Co., Ltd.) was used to produce a rod-shaped test piece of each example having a width of 12.7 mm, a length of 127 mm, and a thickness of 6.4 mm using the sample to be measured as a molding material. The obtained rod-shaped test piece was subjected to a bending test in accordance with ASTM D790 to measure the bending strength and bending modulus at 23°C.

The flexural strength of the liquid crystal polyester composition of the embodiment measured on the test piece in the above-mentioned [Flexural Property Evaluation] may be, for example, 124 MPa or more, 130 MPa or more, 140 MPa or more and 300 MPa or less, or 150 MPa or more and 200 MPa or less.

The flexural modulus of the liquid crystal polyester composition of the embodiment measured on the test piece in the above [Flexural Property Evaluation] may be, for example, 5 GPa or more, 5.5 MPa or more and 20 GPa or less, or 7 MPa or more and 10 GPa or less.

According to the liquid crystal polyester composition of the embodiment described above, since the liquid crystal polyester (A) and the liquid crystal polyester (B) are contained, the dielectric loss tangent and the processing characteristics are excellently balanced.

The liquid crystal polyester composition has excellent processing properties, that is, in the heated liquid crystal polyester composition, the viscosity increase caused by the subsequent temperature drop is suppressed, so the processable state is easily maintained for a long time and can be easily processed into a desired shape.

[Method for producing liquid crystal polyester composition]

The method for producing the liquid crystal polyester composition of the present embodiment is a method including mixing the liquid crystal polyester (A) and the liquid crystal polyester (B).

The liquid crystal polyester composition of the present embodiment can be obtained by mixing the liquid crystal polyester (A) and the liquid crystal polyester (B) obtained by separate polymerization in advance.

The liquid crystal polyester composition of the embodiment can be obtained by mixing the above-mentioned liquid crystal polyester (A), the above-mentioned liquid crystal polyester (B), and optional components used as required simultaneously or in an appropriate order.

As the above-mentioned mixing, the powdered liquid crystal polyester (A) and the powdered liquid crystal polyester (B) may be mixed with a mixer or the like to obtain a mixture, but it is preferred that the powdered liquid crystal polyester (A) and the powdered liquid crystal polyester (B) are mixed with a mixer or the like and then melt-kneaded. The liquid crystal polyester composition of this embodiment can be provided as pellets obtained by melt-kneading the liquid crystal polyester (A), the liquid crystal polyester (B) and the optional components used as needed using an extruder.

In the method for producing a liquid crystal polyester composition of the embodiment, the liquid crystal polyester (A), the liquid crystal polyester (B), and the optional components may be the same components as those described in the above-mentioned "Liquid Crystalline Polyester Composition".

From the viewpoint of an excellent balance between dielectric loss tangent and processing characteristics, the ratio of the amount of the liquid crystal polyester (A) to the amount of the liquid crystal polyester (B) in the method for producing the liquid crystal polyester composition is preferably, by mass ratio, liquid crystal polyester (A)/liquid crystal polyester (B) = 95/5 to 25/75, preferably 95/5 to 30/70, preferably 95/5 to 40/60, preferably 95/5 to 50/50, more preferably 95/5 to 50/50 (except 50/50), and further preferably 90/10 to 60/40.

From the viewpoint of better mechanical strength, the ratio of the amount of the liquid crystal polyester (A) to the amount of the liquid crystal polyester (B) is preferably liquid crystal polyester (A)/liquid crystal polyester (B) = 80/20 to 30/70, more preferably 80/20 to 60/40, and even more preferably 70/30 to 60/40, in terms of mass ratio.

The liquid crystal polyester composition obtained in this manner, in particular, pellets of the liquid crystal polyester composition can be suitably used as a film-forming material composition used in the production of a film described later.

"membrane"

The film of the embodiment is a film produced using the liquid crystal polyester composition of the embodiment described above. The film of the embodiment can be obtained by molding the liquid crystal polyester composition of the embodiment into a film shape.

As the film of the present embodiment, a film including the liquid crystal polyester composition of the embodiment can be exemplified.

As the film of the present embodiment, a film formed from the liquid crystal polyester composition of the embodiment can be exemplified.

The film of the embodiment contains a liquid crystal polyester (A) and a liquid crystal polyester (B), and the following films can be exemplified.

A film comprising a liquid crystal polyester (A) and a liquid crystal polyester (B),

The liquid crystal polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2), and a repeating unit represented by the following formula (A3).

(A1)-O-Ar ¹ -CO-

(A2)-CO-Ar ² -CO-

(A3)-X-Ar ³ -Y-

(Ar ¹ represents a phenylene group, a naphthylene group or a biphenylene group.

Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylene group or a group represented by the following formula (A4).

X and Y each independently represent an oxygen atom or an imino group (—NH—).

The hydrogen atoms in the above groups represented by Ar ¹ , Ar ² or Ar ³ may be independently substituted by halogen atoms, alkyl groups or aryl groups.

(A4)-Ar ⁴ -Z-Ar ⁵ -

(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group.

Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group.)

The number of the repeating units represented by the formula (A1) is 30% or more and 80% or less relative to the total number (100%) of all repeating units constituting the liquid crystal polyester (A),

The liquid crystal polyester (B) has a repeating unit represented by the following formula (B1):

(B1)-O-Ar ^b1 -CO-

(Ar ^b1 represents a phenylene group, a naphthylene group or a biphenylene group.

The hydrogen atoms in the above groups represented by Ar ^b1 may be independently substituted by halogen atoms, alkyl groups or aryl groups.

The number of the repeating unit represented by the formula (B1) is greater than 80% of the total number (100%) of all repeating units constituting the liquid crystal polyester (B).

The film of the embodiment may further contain an optional component other than the liquid crystal polyester (A) and the liquid crystal polyester (B).

Regarding the types and contents of the liquid crystal polyester (A), the liquid crystal polyester (B), and the optional components in the film of the embodiment, the same ones as described in the above-mentioned "Liquid Crystalline Polyester Composition" can be exemplified.

The film of the embodiment can be suitably used for electronic component film applications such as printed circuit wiring boards. The film of the embodiment can be provided in the form of a substrate (e.g., a flexible substrate), a laminate (e.g., a flexible copper-clad laminate), a printed substrate, a printed circuit wiring board, a printed circuit board, etc. having the film as an insulating material.

The thickness of the film of the embodiment is not particularly limited, but as a thickness suitable for a film for electronic components, it is preferably 5 μm to 50 μm, more preferably 7 μm to 40 μm, further preferably 10 μm to 33 μm, and particularly preferably 15 μm to 20 μm.

In addition, in this specification, "thickness" is set as the average value of the value obtained by measuring the thickness of 10 places selected randomly according to JIS standard (K7130-1992).

The content ratio of the liquid crystal polyester with respect to 100 mass % of the total mass of the film of the embodiment may be 50 mass % or more and 100 mass % or less, or 80 mass % or more and 95 mass % or less.

Conventionally, in film formation using liquid crystal polyester as a molding material, molecular orientation in the film formation direction is easily generated, and viscosity increases rapidly due to a temperature drop, so it is difficult to provide a film with excellent isotropy.

Since the film of the embodiment is produced using the liquid crystal polyester composition of the embodiment as a raw material, the film can be produced in a state with good processing characteristics, has excellent isotropy, and can exhibit an excellent dielectric loss tangent.

《Method for producing membrane》

The method for producing a film of the embodiment is a method including melt-molding a film using the liquid crystal polyester composition of the above-mentioned embodiment as a molding material.

In the melt molding method, the liquid crystal polyester composition is heated to soften it and can be molded into a desired shape.

Examples of the melt molding method include injection molding, extrusion molding such as a T-die method or inflation method, compression molding, blow molding, vacuum molding, and press molding. Among them, the inflation method or the T-die method is preferred.

Conventionally, in film formation using liquid crystal polyester as a molding material, molecular orientation in the film formation direction is easily generated, and viscosity increases rapidly due to a temperature drop, so it is difficult to produce a film with excellent isotropy.

According to the method for producing a film of the embodiment, since the film is produced using the liquid crystal polyester composition of the embodiment as a raw material, a film can be produced with good processing characteristics and can exhibit an excellent dielectric loss tangent.

The liquid crystal polyester composition has excellent processing characteristics in the film manufacturing method, that is, the viscosity increase caused by the subsequent temperature drop in the heated liquid crystal polyester composition is suppressed, so the processable state is easily maintained for a long time. Therefore, if the film manufacturing method of the embodiment is used, it is easy to promote the relaxation of the orientation of the liquid crystal polyester during film formation, for example, it is easy to achieve film processing with excellent isotropy.

Example

Next, the present invention will be described in further detail with reference to Examples, but the present invention is not limited to the following Examples.

《Measurement and Evaluation》

[Measurement of flow initiation temperature of liquid crystal polyester sample]

Using a flow tester (manufactured by Shimadzu Corporation, CFT-500 model), about 2 g of a liquid crystal polyester sample was filled into a cylinder equipped with a die head having a nozzle with an inner diameter of 1 mm and a length of 10 mm. The liquid crystal polyester sample was melted while being heated at a rate of 4°C/min under a load of 9.8 MPa (100 kg/cm ² ), extruded from the nozzle, and the temperature (FT) at which a viscosity of 4800 Pa·s (48000 P) was measured.

[Measurement of endothermic peak of liquid crystal polyester sample]

Using a differential scanning calorimeter (DSC-60A Plus, manufactured by Shimadzu Corporation), the endothermic peak of the liquid crystal polyester sample was measured while increasing the temperature from room temperature (23°C) at a rate of 10°C/min, and the temperature (°C) of the top position was determined.

〔Evaluation of dielectric properties of liquid crystal polyester samples〕

Using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., PNX40-5A), the pellets of the liquid crystal polyester or the pellets of the liquid crystal polyester composition obtained in each embodiment or comparative example were used as molding materials, and a molded body with a width of 64 mm, a length of 64 mm, and a thickness of 1 mm was prepared under the conditions shown in Table 1, and then cut from both sides to obtain a test piece with a thickness of 0.2 mm. For the obtained test piece, a vector network analyzer (manufactured by Keysight Technologies Co., Ltd., N5290A) and a split cylindrical resonator (manufactured by EM labs Co., Ltd., CR710) were used to measure the relative dielectric constant and dielectric loss tangent at 10 GHz.

·Measurement environment: 23℃, 50%RH

Table 1

[Evaluation of curing speed of liquid crystal polyester samples]

Using a rheometer (manufactured by TA Instruments, Discovery HR-20), the pellets of the liquid crystal polyester or the pellets of the liquid crystal polyester composition obtained in each example or comparative example were used as samples, and the viscosity was measured when it was cooled at a cooling rate of 10°C/min after being melted at 340°C. The measurement conditions are described below. The ratio of the viscosity at the temperature of the apex position of the endothermic peak detected by the differential scanning calorimeter to the viscosity at the time when the temperature at the apex position of the endothermic peak dropped by 20°C (η _T m- _20°C /η _T m) and the difference between the viscosity at the temperature of the apex position of the endothermic peak detected by the differential scanning calorimeter and the viscosity at the time when the temperature at the apex position of the endothermic peak dropped by 20°C (η _T m- _20°C -η _T m) were calculated.

Measurement start temperature: 340°C

Cooling rate: 10℃/min

Frequency: 1Hz

Strain: 0.05

[Evaluation of bending properties of liquid crystal polyester samples]

An injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., PNX40-5A) was used to produce a rod-shaped test piece of each example having a width of 12.7 mm, a length of 127 mm, and a thickness of 6.4 mm using the pellets of the liquid crystal polyester or the pellets of the liquid crystal polyester composition obtained in each example or comparative example as a molding material under the conditions shown in Table 1. Next, a bending test was performed on the obtained rod-shaped test piece in accordance with ASTM D790 to measure the bending strength and bending elastic modulus at 23°C.

[Determination of Molecular Weight of Liquid Crystal Polyester Sample]

A high-efficiency GPC apparatus (HLC-8220 manufactured by Tosoh), a column (TSKgel SuperHM-H (2 pieces), φ6.0 mm×15 cm manufactured by Tosoh), and a solvent (pentafluorophenol/chloroform (weight ratio 35/65)) were used. The pellets of the liquid crystal polyester obtained in each embodiment or comparative example or the pellets of the liquid crystal polyester composition were freeze-ground to form a powdered substance as a sample, and the number average molecular weight (Mn) and weight average molecular weight (Mw) of the liquid crystal polyester contained in the sample were measured. The sample solution for measurement was prepared as follows: 2 mg of the sample was added to 1.4 g of pentafluorophenol, dissolved at 80°C for 2 hours, cooled to room temperature, 2.6 g of chloroform was added, and further diluted 2 times with a solvent (pentafluorophenol/chloroform (weight ratio 35/65)), and filtered using a filter with a pore size of 0.45 μm. The molecular weight was calculated using polystyrene as a standard substance.

[LC Analysis of Amine Decomposition Products of Liquid Crystalline Polyesters]

The pellets of each liquid crystal polyester composition of Examples 1 to 8 and the pellets of each liquid crystal polyester of Comparative Examples 1 to 2 were freeze-pulverized to form powders, and amine decomposition was performed under the following conditions using an ultra-high performance liquid chromatography apparatus (Nexera, manufactured by Shimadzu Corporation) to perform LC analysis. 4-(4-hydroxyphenoxy)benzoic acid was used as a standard substance, and the content of the component detected at a retention time of 17.4 to 5 minutes was quantified from the peak area of the liquid chromatogram.

(Amine decomposition step)

1) Collect about 0.05g of powdered sample into a flat-bottom flask

2) Add 30 mL of NMP (special grade) and 10 mL of butylamine (special grade) into the above flat-bottom flask using a full-capacity pipette.

3) Place the flat-bottom flask in a reflux device and heat it in a sand bath set at 200°C until the sample is completely dissolved.

4) After the sample is dissolved, heat for another 2 hours

5) Lift the reflux device from the sand bath and cool it for 1 hour under water flow to obtain the amine decomposition liquid.

6) Remove the flat-bottom flask from the reflux device and transfer the amine decomposition solution to a 100 mL pear-shaped flask.

7) Rinse the flat-bottom flask with methanol twice (20 mL in total) and recover the remaining amine decomposition solution.

8) Methanol and butylamine were removed by evaporation under the following conditions to obtain amine decomposition products:

1. Methanol removal

Water bath temperature: 60°C

Evaporator pressure: 100 mmHg (about 133 hPa), 5 minutes after starting to pump

2. Butylamine removal

Water bath temperature: 60°C

Evaporator pressure: 15 minutes at 50 mmHg (about 67 hPa)

9) 1 mL of formic acid (special grade) was added to the amine decomposition product using a full-volume pipette to neutralize the solution to obtain an amine decomposition product (neutralized product).

10) Gently shake the container to mix, and transfer the amine decomposition product (neutralized product) to a 50 mL volumetric flask.

11) Cool to room temperature while washing with NMP, and add NMP to make the volume 50 mL to obtain a sample for LC analysis. Perform LC analysis under the following measurement conditions:

(LC measurement conditions)

Column: L-Column ODS, base material (porous spherical silica, high-purity silica: silica 99.99 mass % or more), modification group (octadecyl), film thickness 3 μm, 3 mm φ × 15 cm

Mobile phase: A) 0.1 vol% acetic acid in water

B) 0.1% by volume of acetic acid and acetonitrile

Gradient: Start with 90% by volume of mobile phase A and 10% by volume of mobile phase B, slowly increase the concentration to 100% by volume of mobile phase B over 30 minutes, and measure for 10 minutes with 100% by volume of mobile phase B

Column temperature: 45°C

Detector: UV-254nm

Flow rate: 0.4mL/min

Injection volume of sample for LC analysis: 1 μL

It should be noted that the configuration of the LC device is as follows.

Degassing unit: DGU-20A5

Liquid delivery unit: LC-30AD×2

Automatic sample injector: SIL-30AC

Column oven: CTO-20AC

Absorbance detector: SPD-20A

System controller: CBM-20A

System software: LabSolution

"manufacture"

Hereinafter, the production of each liquid crystal polyester and liquid crystal polyester composition will be described.

The liquid crystal polyester (a2) is included in the concept of the liquid crystal polyester (A) in the composition of the present invention. The liquid crystal polyester (b1) is included in the concept of the liquid crystal polyester (B) in the composition of the present invention.

[Comparative Example 1: Production of Liquid Crystalline Polyester (a2)]

In a reactor equipped with a stirrer, a torque meter, a nitrogen inlet pipe, a thermometer, and a reflux cooler, 1034.99 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 378.33 g (1.75 mol) of 2,6-naphthalenedicarboxylic acid, 83.07 g (0.5 mol) of terephthalic acid, 272.52 g (2.475 mol, 0.225 mol excess relative to the total molar amount of 2,6-naphthalenedicarboxylic acid and terephthalic acid), 1226.87 g (12 mol) of acetic anhydride, and 0.17 g of 1-methylimidazole as a catalyst were added. After replacing the gas in the reactor with nitrogen, the temperature was raised from room temperature to 145° C. over 15 minutes while stirring under a nitrogen flow, and refluxed at 145° C. for 1 hour.

Next, while removing by-product acetic acid and unreacted acetic anhydride by distillation, the temperature was raised from 145°C to 310°C in 3 hours and 30 minutes, and after being kept at 310°C for 3 hours, the contents were taken out and cooled to room temperature. The obtained solid was crushed with a grinder to obtain a powdered liquid crystal polyester (a1). The flow start temperature of the liquid crystal polyester (a1) was 265°C.

Liquid crystal polyester (a1) was heated from room temperature to 215°C in a nitrogen atmosphere for 50 minutes, then from 215°C to 230°C for 1 hour, then from 230°C to 300°C for 11 hours and 40 minutes, and then maintained at 300°C for 10 hours to obtain a powdery liquid crystal polyester (a2) by solid phase polymerization. The flow start temperature of the liquid crystal polyester (a2) was 328.7°C.

Next, the liquid crystal polyester (a2) was granulated at a barrel temperature of 345° C. using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30) to obtain pellets of the liquid crystal polyester (a2). The flow start temperature of the granulated liquid crystal polyester (a2) was 307.2° C. In addition, the temperature at the top position of the endothermic peak of the granulated liquid crystal polyester (a2) was 322° C.

[Comparative Example 2: Production of Liquid Crystalline Polyester (b1)]

According to the method described in Example 1 described in Japanese Patent Application Laid-Open No. 2004-250620, 1511.1 g (8.03 mol) of 2-hydroxy-6-naphthoic acid and 410.2 g (2.97 mol) of p-hydroxybenzoic acid were used as raw materials to synthesize a liquid crystal polyester (b1). The flow initiation temperature of the liquid crystal polyester (b1) was 303.5°C.

Next, the liquid crystal polyester (b1) was granulated at a barrel temperature of 320°C using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30) to obtain pellets of the liquid crystal polyester (b1). The flow start temperature of the granulated liquid crystal polyester (b1) was 291.8°C. In addition, the temperature at the top position of the endothermic peak of the granulated liquid crystal polyester (b1) was 312°C.

[Example 1: Production of Liquid Crystal Polyester Composition (c)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed in a mass ratio of a2/b1=90/10 to obtain a liquid crystal polyester composition (c). The flow start temperature of the liquid crystal polyester composition (c) is 323.0°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (c) is granulated at a barrel temperature of 340°C to obtain pellets of the liquid crystal polyester composition (c). The flow start temperature of the granulated liquid crystal polyester composition (c) is 304.6°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (c) is 322°C.

[Example 2: Production of Liquid Crystal Polyester Composition (d)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed at a mass ratio of a2/b1=80/20 to obtain a liquid crystal polyester composition (d). The flow start temperature of the liquid crystal polyester composition (d) is 315.1°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (d) is granulated at a barrel temperature of 330°C to obtain pellets of the liquid crystal polyester composition (d). The flow start temperature of the granulated liquid crystal polyester composition (d) is 302.5°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (d) is 321°C.

[Example 3: Production of liquid crystal polyester composition (e)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed in a mass ratio of a2/b1=70/30 to obtain a liquid crystal polyester composition (e). The flow start temperature of the liquid crystal polyester composition (e) is 312.5°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (e) is granulated at a barrel temperature of 330°C to obtain pellets of the liquid crystal polyester composition (e). The flow start temperature of the granulated liquid crystal polyester composition (e) is 302.2°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (e) is 319°C.

[Example 4: Production of Liquid Crystal Polyester Composition (f)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed at a mass ratio of a2/b1=60/40 to obtain a liquid crystal polyester composition (f). The flow start temperature of the liquid crystal polyester composition (f) is 311.0°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (f) is granulated at a barrel temperature of 325°C to obtain pellets of the liquid crystal polyester composition (f). The flow start temperature of the granulated liquid crystal polyester composition (f) is 300.5°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (f) is 320°C.

[Example 5: Production of Liquid Crystal Polyester Composition (g)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed in a mass ratio of a2/b1=50/50 to obtain a liquid crystal polyester composition (g). The flow start temperature of the liquid crystal polyester composition (g) is 309.4°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (g) is granulated at a barrel temperature of 325°C to obtain pellets of the liquid crystal polyester composition (g). The flow start temperature of the granulated liquid crystal polyester composition (g) is 299.9°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (g) is 315°C.

[Example 6: Production of liquid crystal polyester composition (h)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed at a mass ratio of a2/b1=40/60 to obtain a liquid crystal polyester composition (h). The flow start temperature of the liquid crystal polyester composition (h) is 311.6°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (h) is granulated at a barrel temperature of 325°C to obtain pellets of the liquid crystal polyester composition (h). The flow start temperature of the granulated liquid crystal polyester composition (h) is 299.1°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (h) is 310°C.

[Example 7: Preparation of Liquid Crystalline Polyester Composition (i)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed at a mass ratio of a2/b1=30/70 to obtain a liquid crystal polyester composition (i). The flow start temperature of the liquid crystal polyester composition (i) is 310.2°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (i) is granulated at a barrel temperature of 330°C to obtain pellets of the liquid crystal polyester composition (i). The flow start temperature of the granulated liquid crystal polyester composition (i) is 298.2°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (i) is 312°C.

[Example 8: Production of liquid crystal polyester composition (j)]

The powdered liquid crystal polyester (a2) obtained above and the powdered liquid crystal polyester (b1) are mixed in a mass ratio of a2/b1=95/5 to obtain a liquid crystal polyester composition (j). The flow start temperature of the liquid crystal polyester composition (j) is 327.3°C. Next, using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30), the liquid crystal polyester composition (j) is granulated at a barrel temperature of 340°C to obtain pellets of the liquid crystal polyester composition (j). The flow start temperature of the granulated liquid crystal polyester composition (j) is 305.2°C. In addition, the temperature of the apex position of the endothermic peak of the granulated liquid crystal polyester composition (j) is 320°C.

Table 2 shows the results of evaluation of each item for the liquid crystal polyester composition.

Table 2

The liquid crystal polyester compositions of Examples 1 to 8 are less likely to experience a viscosity increase evaluated by the viscosity difference at the endothermic peak position (η _Tm-20°C -η _Tm ) than the liquid crystal polyester of Comparative Example 1, have excellent processing characteristics, and have a smaller dielectric loss tangent value than the liquid crystal polyester of Comparative Example 2.

This indicates that the liquid crystal polyester compositions of Examples 1 to 8 containing the liquid crystal polyester (a2) and the liquid crystal polyester (b1) are excellent in the balance between the dielectric loss tangent and the processing characteristics.

In addition, referring to the bending properties, the molded articles of the liquid crystal polyester compositions of Examples 2 to 7 had improved bending strength and bending modulus compared to the molded articles of the liquid crystal polyesters of Comparative Examples 1 and 2.

Thus, it was confirmed that the inclusion of both the liquid crystal polyester (a2) and the liquid crystal polyester (b1) provided a synergistic improvement effect of the bending properties exceeding the expected one.

Each configuration and combination thereof in each embodiment is an example, and changes such as addition, omission, and substitution of the configuration may be made without departing from the gist of the present invention. In addition, the present invention is not limited to each embodiment but only to the claims (claims).

Claims (14)

1. A liquid-crystalline polyester composition comprising a liquid-crystalline polyester (A) and a liquid-crystalline polyester (B),

The liquid crystal polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2) and a repeating unit represented by the following formula (A3),

(A1)-O-Ar¹-CO-

(A2)-CO-Ar²-CO-

(A3)-X-Ar³-Y-

Ar ¹ represents phenylene, naphthylene or biphenylene,

Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (A4),

X and Y each independently represent an oxygen atom or an imino group (-NH-),

The hydrogen atoms in the groups represented by Ar ¹、Ar² or Ar ³ may also be each independently substituted with a halogen atom, an alkyl group or an aryl group,

(A4)-Ar⁴-Z-Ar⁵-

Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group,

Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group,

The number of repeating units represented by the formula (A1) is 30% to 80% relative to 100% of the total number of repeating units constituting the liquid crystal polyester (A),

The liquid crystal polyester (B) has a repeating unit represented by the following formula (B1),

(B1)-O-Ar^b1-CO-

Ar ^b1 represents phenylene, naphthylene or biphenylene,

The hydrogen atoms in the groups represented by Ar ^b1 may also be each independently substituted with a halogen atom, an alkyl group or an aryl group,

The number of repeating units represented by the formula (B1) is more than 80% relative to 100% of the total number of repeating units constituting the liquid crystal polyester (B).

2. The liquid-crystalline polyester composition according to claim 1, wherein the repeating unit represented by the formula (B1) comprises a repeating unit represented by the following formula (B1-1),

(B1-1)-O-Ar^b1-1-CO-

Ar ^b1-1 represents a naphthylene group,

The hydrogen atoms in the groups represented by Ar ^b1-1 may also be each independently substituted with a halogen atom, an alkyl group or an aryl group,

The number of repeating units represented by the formula (B1-1) is more than 50% and not more than 90% relative to 100% of the total number of repeating units conforming to the formula (B1).

3. The liquid crystal polyester composition according to claim 1 or 2, wherein the ratio of the content of the liquid crystal polyester (a) to the content of the liquid crystal polyester (B) in the liquid crystal polyester composition is liquid crystal polyester (a)/liquid crystal polyester (B) =95/5 to 25/75 in terms of mass ratio.

4. The liquid crystal polyester composition according to claim 1 or 2, wherein the ratio of the content of the liquid crystal polyester (a) to the content of the liquid crystal polyester (B) in the liquid crystal polyester composition is liquid crystal polyester (a)/liquid crystal polyester (B) =95/5 to 50/50 in terms of mass ratio.

5. The liquid crystal polyester composition according to claim 1 or 2, wherein the ratio of the total content of the liquid crystal polyester (a) and the liquid crystal polyester (B) is 80 mass% or more relative to 100 mass% of the total mass of the liquid crystal polyester composition.

6. The liquid-crystalline polyester composition according to claim 1 or 2, wherein the liquid-crystalline polyester (B) consists of only the repeating unit represented by the formula (B1).

7. The liquid-crystalline polyester composition according to claim 1 or 2, wherein the liquid-crystalline polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2) and a repeating unit represented by the following formula (A3),

(A1)-O-Ar¹-CO-

(A2)-CO-Ar²-CO-

(A3)-O-Ar³-O-

Ar ¹ represents 2, 6-naphthylene, 1, 4-phenylene, or 4,4' -biphenylene,

Ar ² and Ar ³ each independently represent 2, 6-naphthylene, 2, 7-naphthylene, 1, 4-phenylene, 1, 3-phenylene, or 4,4' -biphenylene,

The hydrogen atoms in the groups represented by Ar ¹、Ar² or Ar ³ may be independently substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

8. The liquid-crystalline polyester composition according to claim 1 or 2, wherein the repeating unit represented by the formula (B1) consists of only the repeating unit represented by the following formula (B1-1) and the repeating unit represented by the following formula (B1-2),

(B1-1)-O-Ar^b1-1-CO-

(B1-2)-O-Ar^b1-2-CO-

Ar ^b1-1 represents a naphthylene group,

Ar ^b1-2 represents a phenylene group,

The hydrogen atoms in the groups represented by Ar ^b1-1 or Ar ^b1-2 may also be each independently substituted with a halogen atom, an alkyl group, or an aryl group.

9. The liquid-crystalline polyester composition according to claim 1 or 2, wherein the amine-decomposed product obtained by subjecting the liquid-crystalline polyester composition to the following amine-decomposing conditions contains a component detected by liquid chromatography analysis under the following analytical conditions for a holding time in the range of 17.4 to 17.5 minutes,

The relative content of the components, which is determined by the peak area of a chromatogram analyzed by the liquid chromatography using 4- (4-hydroxyphenoxy) benzoic acid as a standard substance, is 0.0001 to 0.5 mass% inclusive with respect to 100 mass% of the total mass of the liquid crystal polyester composition,

(Conditions for amine decomposition)

Mixing the liquid crystal polyester composition with butylamine, treating at 200deg.C for more than 2 hr, removing butylamine by reduced pressure treatment at 60deg.C, neutralizing with formic acid to obtain amine decomposition product,

(Analysis conditions)

Column: base material (porous spherical silica), modifier (octadecyl), film thickness 3 μm, 3mm phi x 15cm

Mobile phase: a) 0.1% by volume acetic acid water

B) 0.1% by volume acetonitrile acetate

Gradient: starting the liquid passage with the ratio of the mobile phase A being 90% by volume and the ratio of the mobile phase B being 10% by volume, gradually increasing the concentration to 100% by volume for 30 minutes, and measuring for 10 minutes with the ratio of the mobile phase B being 100% by volume

Column temperature: 45 DEG C

A detector: UV-254nm

Flow rate: 0.4 mL/min

Injection amount: 1 mul.

10. The liquid crystal polyester composition according to claim 1 or 2, wherein the liquid crystal polyester contained in the liquid crystal polyester composition has a weight average molecular weight of 270000 or more as measured with polystyrene as a standard substance.

11. The method for producing a liquid-crystalline polyester composition according to claim 1 or 2, comprising a step of mixing the liquid-crystalline polyester (a) with the liquid-crystalline polyester (B).

12. A film comprising a liquid crystalline polyester (A) and a liquid crystalline polyester (B),

The liquid crystal polyester (A) has a repeating unit represented by the following formula (A1), a repeating unit represented by the following formula (A2) and a repeating unit represented by the following formula (A3),

(A1)-O-Ar¹-CO-

(A2)-CO-Ar²-CO-

(A3)-X-Ar³-Y-

Ar ¹ represents phenylene, naphthylene or biphenylene,

Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (A4),

X and Y each independently represent an oxygen atom or an imino group (-NH-),

The hydrogen atoms in the groups represented by Ar ¹、Ar² or Ar ³ may also be each independently substituted with a halogen atom, an alkyl group or an aryl group,

(A4)-Ar⁴-Z-Ar⁵-

Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group,

Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylene group,

The number of repeating units represented by the formula (A1) is 30% to 80% relative to 100% of the total number of repeating units constituting the liquid crystal polyester (A),

The liquid crystal polyester (B) has a repeating unit represented by the following formula (B1),

(B1)-O-Ar^b1-CO-

Ar ^b1 represents phenylene, naphthylene or biphenylene,

The hydrogen atoms in the groups represented by Ar ^b1 may also be each independently substituted with a halogen atom, an alkyl group or an aryl group,

The number of repeating units represented by the formula (B1) is more than 80% relative to 100% of the total number of repeating units constituting the liquid crystal polyester (B).

13. The method for producing a film according to claim 12, which comprises the step of melt-molding a film using the liquid crystal polyester composition according to claim 1 or 2 as a molding material.

14. The method for producing a film according to claim 13, wherein the melt molding is molding by inflation or molding by T-die method.