JP2020132849A - Liquid crystal polyester powder, liquid crystal polyester composition, production method of film, and production method of laminate - Google Patents

Abstract

To provide a liquid crystal polyester powder, a liquid crystal polyester composition and a method for manufacturing a liquid crystal polyester film, by which a liquid crystal polyester film having qualities suitable as a film for an electronic component can be produced.SOLUTION: A liquid crystal polyester powder 1 comprises a liquid crystal polyester having a number average molecular weight of 10000 or less and has an average particle diameter of 0.5 to 20 μm. A liquid crystal polyester composition 30 comprises a medium 3 and the liquid crystal polyester powder 1. A method for manufacturing a liquid crystal polyester film 10 comprises applying the liquid crystal polyester composition 30 on a support 12 and heat-treating the composition to obtain the liquid crystal polyester film 10 comprising the liquid crystal polyester.SELECTED DRAWING: Figure 1

Description

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

Insulating materials are used for printed circuit boards on which electronic components are mounted. In recent years, with the development of communication systems and the like, it has been desired to further improve the physical properties of insulating materials such as dielectric properties.
For example, Patent Document 1 describes an insulating resin composition containing an epoxy resin containing a silyl group, a curing agent, and an inorganic filler such as silica for the purpose of reducing dielectric loss.

JP-A-2017-66360

However, when an inorganic filler is added to the resin composition as in the method described in Patent Document 1, there is a problem that the adhesion strength with the metal foil and the mechanical strength of the insulating base material are lowered.
Further, considering the application to the next-generation mobile communication system, it is highly possible that the conventional substrate material has insufficient dielectric properties at high frequencies.

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

An object of the present invention is to provide a liquid crystal polyester powder and a liquid crystal polyester composition capable of producing a liquid crystal polyester film having suitable quality as a film for electronic parts.
Another object of the present invention is to provide a method for producing a liquid crystal polyester film and a method for producing a laminate, which can produce a liquid crystal polyester film having suitable quality as a film for electronic parts.

As a result of diligent studies to solve the above problems, the present inventors can produce a high-quality liquid crystal polyester film by using a liquid crystal polyester powder containing a liquid crystal polyester having a predetermined molecular weight and having a predetermined average particle size. This has led to the completion of the present invention.
That is, one aspect of the present invention is the following method for producing a liquid crystal polyester powder, a liquid crystal polyester composition, a film, and a method for producing a laminate.

<1> A liquid crystal polyester powder containing a liquid crystal polyester having a number average molecular weight of 10,000 or less and having an average particle size of 0.5 to 20 μm.
<2> The liquid crystal polyester powder according to <1>, wherein the relative permittivity at a frequency of 1 GHz is 3 or less, and the dielectric loss tangent at a frequency of 1 GHz is 0.005 or less.
<3> The liquid crystal polyester powder according to <1> or <2>, wherein the liquid crystal polyester has a structural unit containing a naphthalene structure.
<4> The liquid crystal polyester powder according to <3>, wherein the content of the structural unit containing the naphthalene structure is 40 mol% or more with respect to 100 mol% of the total amount of all the structural units in the liquid crystal polyester.
<5> The liquid crystal polyester has a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3). > Or the liquid crystal polyester powder according to <4>.
(1) -O-Ar ^1- CO-
(2) -CO-Ar ^2- CO-
(3) -O-Ar ^3- O-
(Ar ¹ represents a 2,6-naphthalenedyl group, a 1,4-phenylene group, or a 4,4'-biphenylylene group.
Ar ² and Ar ³ independently have a 2,6-naphthalenedyl group, a 2,7-naphthalenedyl group, a 1,4-phenylene group, a 1,3-phenylene group, or a 4,4'-biphenylylene group. Represent.
The hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is 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. May be good. )
<6> A liquid crystal polyester composition containing a medium and the liquid crystal polyester powder according to any one of <1> to <5>.
<7> A method for producing a liquid crystal polyester film, which comprises applying the liquid crystal polyester composition according to <6> to a support and heat-treating it to obtain a liquid crystal polyester film containing the liquid crystal polyester.
<8> The support and the liquid crystal polyester film are formed by applying the liquid crystal polyester composition according to <6> on the support and heat-treating it to form a liquid crystal polyester film containing the liquid crystal polyester. A method for producing a laminate, which comprises obtaining a laminate to be provided.

According to the present invention, it is possible to provide a liquid crystal polyester powder and a liquid crystal polyester composition capable of producing a liquid crystal polyester film having suitable quality as a film for electronic parts.
Further, according to the present invention, it is possible to provide a method for producing a liquid crystal polyester film and a method for producing a laminate, which can produce a liquid crystal polyester film having suitable quality as a film for electronic parts.

It is a schematic diagram which shows the manufacturing process of the liquid crystal polyester film and the laminate of one Embodiment of this invention. It is a schematic diagram which shows the structure of the film of one Embodiment of this invention. It is a schematic diagram which shows the structure of the laminated body of one Embodiment of this invention.

Hereinafter, embodiments of the liquid crystal polyester powder, the liquid crystal polyester composition, the film manufacturing method, and the laminate manufacturing method of the present invention will be described.

≪Liquid crystal polyester powder≫
The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less, and has an average particle size of 0.5 to 20 μm. The liquid crystal polyester powder of the embodiment is suitable as a raw material for the method for producing a liquid crystal polyester film or a laminate according to the present invention. According to the liquid crystal polyester powder satisfying the above specifications, it is possible to produce a liquid crystal polyester film having suitable quality as a film for electronic parts. The quality criteria include the isotropic, thickness, and appearance of the film (presence or absence of holes or through holes). Details of the liquid crystal polyester film will be described later.

The average particle size of the liquid crystal polyester powder is 20 μm or less, preferably 18 μm or less, more preferably 15 μm or less, and further preferably 10 μm or less. If the average particle size of the liquid crystal polyester exceeds 20 μm, it becomes difficult to obtain a liquid crystal polyester film having a good appearance. For example, as shown in Examples described later, when the average particle size of the liquid crystal polyester exceeds 20 μm, through holes may occur in the produced liquid crystal polyester film. The formation of through holes is likely to occur at a thickness range of 50 μm or less, which is a suitable thickness range for a film for electronic components. That is, since the average particle size of the liquid crystal polyester is 20 μm or less, it is possible to easily produce a film having both a thickness and an appearance suitable for a film for electronic parts.
From the viewpoint of ease of handling the powder, the average particle size of the liquid crystal polyester powder is preferably 0.5 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more.
As an example of the numerical range of the value of the average particle size of the liquid crystal polyester powder, it may be 0.5 μm or more and 20 μm or less, 3 μm or more and 18 μm or less, or 5 μm or more and 15 μm or less. It may be 5 μm or more and 10 μm or less.

In the present specification, the "average particle size" is a particle having a cumulative volume of 50% when the whole is 100% in the volume-based cumulative particle size distribution curve measured by the laser diffraction / scattering method. The value of the diameter (50% cumulative volume particle size D ₅₀ ).

As a method of controlling the particle size in the above range, for example, when a jet mill is used, it can be controlled by changing the rotation speed of the classification rotor, the crushing nozzle pressure, the processing speed, and the like.

Further, in the method for producing a liquid crystal polyester film or a laminate according to the present invention described later, it is not necessary to dissolve the liquid crystal polyester powder in a solvent, so that the liquid crystal polyester powder having excellent dielectric properties can be used as a raw material. A liquid crystal polyester film having excellent dielectric properties can be produced from the liquid crystal polyester powder having excellent dielectric properties.
As used herein, the term "dielectric property" refers to a property relating to the relative permittivity and the dielectric loss tangent.

The liquid crystal polyester powder of the embodiment preferably has a relative permittivity of 3 or less, preferably 2.9 or less, preferably 2.8 or less, and less than 2.8 at a frequency of 1 GHz. Is more preferable, 2.78 or less is further preferable, and 2.76 or less is particularly preferable. Further, the relative permittivity of the liquid crystal polyester powder may be 2.5 or more, 2.6 or more, or 2.7 or more.
As an example of the numerical range of the value of the relative permittivity of the liquid crystal polyester powder, it may be 2.5 or more and 3 or less, 2.6 or more and 2.78 or less, or 2.7 or more. It may be 2.76 or less.

The liquid crystal polyester powder of the embodiment has a dielectric loss tangent of 0.005 or less, preferably 0.004 or less, more preferably 0.003 or less, and 0.0025 or less at a frequency of 1 GHz. It is more preferably present, and particularly preferably 0.002 or less. Further, the dielectric loss tangent of the liquid crystal polyester powder may be 0.0003 or more, 0.0005 or more, or 0.001 or more.
As an example of the numerical range of the value of the dielectric tangent of the liquid crystal polyester powder, it may be 0.0003 or more and 0.005 or less, 0.0005 or more and 0.004 or less, 0.001. It may be 0.003 or more, 0.001 or more and 0.0025 or less, and 0.001 or more and 0.002 or less.
The relative permittivity and dielectric loss tangent of the liquid crystal polyester powder at a frequency of 1 GHz can be measured by the capacitive method using an impedance analyzer under the conditions described in the examples.

The relative permittivity and dielectric loss tangent of the liquid crystal polyester powder of the embodiment may be different from those of the liquid crystal polyester film produced from the powder as a raw material. It is considered that this is due to the difference in the molecular weight of the liquid crystal polyester contained.

The liquid crystal polyester powder is preferably insoluble in the medium contained in the liquid crystal polyester composition described later.
Here, whether or not it is insoluble in the medium can be confirmed by performing the following test. In the following test method, a case where the medium is an aprotic solvent will be described.

Test method The liquid crystal polyester powder (5 parts by weight) was stirred in an aprotic solvent (medium) (95 parts by weight) at a temperature of 180 ° C. using an anchor blade under stirring conditions of 200 rpm for 6 hours, and then to room temperature. Cooling. Then, after filtering using a membrane filter having a mesh size of 5 μm and a pressure type filter, the residue on the membrane filter is confirmed. At this time, if no solid matter is confirmed, it is judged to be soluble in an aprotic solvent (medium). If a solid substance with a minor axis of 5 μm or more is confirmed, it is judged to be insoluble in an aprotic solvent (medium). Solids having a minor axis of 5 μm or more can be confirmed by microscopic observation.

The content ratio of the liquid crystal polyester to 100% by mass of the liquid crystal polyester powder of the embodiment may be 50 to 100% by mass or 80 to 95% by mass.

The number average molecular weight of the liquid crystal polyester in the liquid crystal polyester powder of the embodiment is 10,000 or less, more preferably 3000 to 10000, further preferably 4000 to 8000, and particularly preferably 5000 to 7000. When the number average molecular weight of the liquid crystal polyester in the liquid crystal polyester powder exceeds 10,000, the liquid crystal polyester composition becomes gel-like, and it becomes difficult to form a film having excellent isotropic properties. Further, the smaller the number average molecular weight of the liquid crystal polyester is, the more the thermal conductivity in the thickness direction of the film after heat treatment tends to be improved, and preferably, when the number average molecular weight of the liquid crystal polyester is equal to or more than the above lower limit value, the film after heat treatment is used. Has good heat resistance, strength and rigidity.

As used herein, the "number average molecular weight" is an absolute value measured using a gel permeation chromatograph-a multi-angle light scattering photometer.

Hereinafter, the details of the liquid crystal polyester contained in the liquid crystal polyester powder of the embodiment will be described.

(Liquid crystal polyester)
The liquid crystal polyester is a liquid crystal polyester that exhibits liquid crystal properties in a molten state, and is preferably melted at a temperature of 450 ° C. or lower. The liquid crystal polyester may be a liquid crystal polyester amide, a liquid crystal polyester ether, a liquid crystal polyester carbonate, or a liquid crystal polyester imide. The liquid crystal polyester is preferably a total aromatic liquid crystal polyester having only a structural unit derived from an aromatic compound as a raw material monomer.
In the present specification, the term "origin" means that the chemical structure of the functional group that contributes to the polymerization changes due to the polymerization of the raw material monomer, and no other structural change occurs.

Typical examples of liquid crystal polyesters include:
1) (i) Aromatic hydroxycarboxylic acid, (ii) Aromatic dicarboxylic acid, and at least one compound selected from the group consisting of (iii) aromatic diol, aromatic hydroxyamine and aromatic diamine. It is polymerized (polycondensed).
2) A product obtained by polymerizing multiple types of aromatic hydroxycarboxylic acids.
3) A compound obtained by polymerizing (i) an aromatic dicarboxylic acid and (ii) at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine and an aromatic diamine.
4) (i) Polyester such as polyethylene terephthalate and (ii) aromatic hydroxycarboxylic acid are polymerized.
Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are independently used in place of a part or all of them, and a polymerizable derivative thereof is used. May be good.

Examples of polymerizable derivatives of compounds having a carboxy group, such as aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids, are those obtained by converting a carboxy group into an alkoxycarbonyl group or an aryloxycarbonyl group (ester), carboxy. Examples thereof include those obtained by converting a group into a haloformyl group (acid halide) and those obtained by converting a carboxy group into an acyloxycarbonyl group (acid anhydride). Examples of polymerizable derivatives of compounds having a hydroxy group, such as aromatic hydroxycarboxylic acids, aromatic diols and aromatic hydroxyamines, are those obtained by acylating a hydroxy group into an acyloxy group (acylated product). Can be mentioned. Examples of polymerizable derivatives of compounds having an amino group, such as aromatic hydroxyamines and aromatic diamines, include those obtained by acylating an amino group and converting it into an acylamino group (acylated product).

The liquid crystal polyester preferably has a structural unit containing a divalent aromatic hydrocarbon group.
As a liquid crystal polyester having a structural unit containing a divalent aromatic hydrocarbon group,
It has a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3), or is represented by the following formula (2). Those having a structural unit and a structural unit represented by the following formula (3),
Can be mentioned.
(1) -O-Ar ^1- CO-
(2) -CO-Ar ^2- CO-
(3) -O-Ar ^3- O-
(Ar ¹ , Ar ² and Ar ³ each independently represent a divalent aromatic hydrocarbon group.
The hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is 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. May be good. )

Examples of the divalent aromatic hydrocarbon group in Ar ¹ , Ar ² and Ar ³ include a phenylene group, a naphthylene group, and a biphenylylene group.

Here, examples of the halogen atom in Ar ¹ , Ar ² and Ar ³ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group and 2-ethylhexyl group. Examples thereof include an n-octyl group and an n-decyl group, which usually have 1 to 10 carbon atoms. Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group and a 2-naphthyl group, which usually have 6 to 20 carbon atoms. .. When the hydrogen atom is substituted with these groups, the number is usually 2 or less, preferably 1 for each of the groups represented by Ar ¹ , Ar ² or Ar ^3. It is as follows.

The liquid crystal polyester more preferably has a structural unit containing a naphthalene structure.
Examples of liquid crystal polyesters having a structural unit containing a divalent naphthalene structure include, for example.
It has a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3), or is represented by the following formula (2). Those having a structural unit and a structural unit represented by the following formula (3),
Can be mentioned.
(1) -O-Ar ^1- CO-
(2) -CO-Ar ^2- CO-
(3) -O-Ar ^3- O-
(Ar ¹ , Ar ² and Ar ³ each independently represent a divalent aromatic hydrocarbon group (however, at least one of a plurality of Ar ¹ , Ar ² and Ar ³ is a naphthylene group).
The hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is 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. May be good. )

Even if the Ar ¹ , Ar ² and Ar ³ independently represent a naphthylene group or a phenylene group (however, at least one of a plurality of Ar ¹ , Ar ² and Ar ³ is a naphthylene group). Good.

The liquid crystal polyester has a structural unit represented by the above formula (1), a structural unit represented by the above formula (2), and a structural unit represented by the above (3), and there are a plurality of Ar ¹ and Ar ^2. And when at least one of Ar ³ is a naphthylene group, it is preferable that at least one of a plurality of Ar ¹ and / or Ar ² is a naphthylene group.
When the liquid crystal polyester has a structural unit represented by the above formula (2) and a structural unit represented by the above formula (3), and at least one of a plurality of Ar ² and Ar ³ is a naphthylene group. It is preferable that at least one of the plurality of Ar ² is a naphthylene group.

The naphthylene group in Ar ¹ , Ar ² and Ar ³ is preferably a 2,6-naphthalene diyl group or a 2,7-naphthalene diyl group, and more preferably a 2,6-naphthalene diyl group.

The content of the structural unit including the naphthalene structure in the liquid crystal polyester is 100 mol% of the total amount of all the structural units in the liquid crystal polyester (the mass of each structural unit constituting the liquid crystal polyester is divided by the formula amount of each structural unit. 40 mol% or more, more preferably 50 mol% or more, and 60 mol% or more, based on the amount equivalent to the amount of substance (mol) of each structural unit and the total value of them). Is more preferable. When the content of the structural unit including the naphthalene structure is at least the above lower limit value, the relative permittivity of the liquid crystal polyester can be further reduced.
The content of the structural unit including the naphthalene structure in the liquid crystal polyester is preferably 90 mol% or less, more preferably 80 mol% or less, based on 100 mol% of the total amount of all the structural units in the liquid crystal polyester. preferable. When the content of the structural unit including the naphthalene structure is not more than the above upper limit value, the reaction stability at the time of producing the liquid crystal polyester can be ensured.
As an example of the numerical range of the content value of the structural unit including the naphthalene structure, it may be 40 mol% or more and 90 mol% or less, 50 mol% or more and 80 mol% or less, 60. It may be mol% or more and 80 mol% or less.

The liquid crystal polyester contains the structural units represented by the above formulas (2) and the structural units represented by the above formula (3) among the structural units represented by the above formulas (1) to (3). It may have all kinds of structural units represented by the above formulas (1) to (3).
The liquid crystal polyester is composed of the structural unit represented by the above formula (2) and the structural unit represented by the above formula (3) among the structural units represented by the above formulas (1) to (3). It may be composed of all kinds of structural units represented by the above formulas (1) to (3).

Examples of the liquid crystal polyester having the structural units represented by the above formulas (1) to (3) include the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), and the following. Examples thereof include those having a structural unit represented by the formula (3).
(1) -O-Ar ^1- CO-
(2) -CO-Ar ^2- CO-
(3) -O-Ar ^3- O-
(Ar ¹ represents Ar ² and Ar ³ independently represent a naphthalenediyl group, a phenylene group, or a biphenylylene group, respectively.
The hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is 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. May be good. )

The above liquid crystal polyester includes the following liquid crystal polyester.
A liquid crystal polyester having a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3).
(1) -O-Ar ^1- CO-
(2) -CO-Ar ^2- CO-
(3) -O-Ar ^3- O-
(Ar ¹ represents a 2,6-naphthalenedyl group, a 1,4-phenylene group, or a 4,4'-biphenylylene group.
Ar ² and Ar ³ independently have a 2,6-naphthalenedyl group, a 2,7-naphthalenedyl group, a 1,4-phenylene group, a 1,3-phenylene group, or a 4,4'-biphenylylene group. Represent.
The hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is 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. May be good. )

Examples of the liquid crystal polyester having the structural units represented by the above formulas (1) to (3) include the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), and the following. Examples thereof include those having a structural unit represented by the formula (3).
(1) -O-Ar ^1- CO-
(2) -CO-Ar ^2- CO-
(3) -O-Ar ^3- O-
(Ar ¹ represents a naphthalenediyl group, Ar ² represents a naphthalenediyl group or a phenylene group, and Ar ³ represents a phenylene group.
The hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is 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. May be good. )

When the liquid crystal polyester has all kinds of structural units represented by the above formulas (1) to (3), the ratio of the preferable content of each structural unit in the liquid crystal polyester can be exemplified as follows.

The ratio of the content of the structural unit (1) in the liquid crystal polyester is preferably 30 mol% or more and 80 mol% or less, preferably 40 mol% or more and 70 mol%, based on 100 mol% of the total amount of all structural units in the liquid crystal polyester. The following is more preferable, and 45 mol% or more and 65 mol% or less are further preferable.
The ratio of the content of the structural unit (2) in the liquid crystal polyester is preferably 10 mol% or more and 35 mol% or less, preferably 15 mol% or more and 30 mol% or more, based on 100 mol% of the total amount of all structural units in the liquid crystal polyester. More preferably, it is 17.5 mol% or more, and further preferably 27.5 mol% or less.
The ratio of the content of the structural unit (3) in the liquid crystal polyester is preferably 10 mol% or more and 35 mol% or less, preferably 15 mol% or more and 30 mol% or more, based on 100 mol% of the total amount of all structural units in the liquid crystal polyester. More preferably, it is 17.5 mol% or more, and further preferably 27.5 mol% or less.
Further, the content of the structural unit (2) and the content of the structural unit (3) in the liquid crystal polyester are preferably equal to each other, but when the contents are different, the structural unit (2) and the structural unit (3) The difference in the content of is preferably 5 mol% or less.

In the example of the liquid crystal polyester having high heat resistance and melt tension, the content of Ar ¹ of the structural unit (1) being a 2,6-naphthalenedyl group (for example, a structural unit derived from 2-hydroxy-6-naphthoic acid). Is preferably 40 mol% or more and 74.8 mol% or less, more preferably 40 mol% or more and 64.5 mol% or less, and 50 mol% or more and 58, based on the total amount of all structural units in the liquid crystal polyester. More preferably, it is mol% or less.

In the liquid crystal polyester, the ratio of the content of Ar ² of the structural unit (2) being a 2,6-naphthalenediyl group (for example, a structural unit derived from 2,6-naphthalenedicarboxylic acid) is the total structure in the liquid crystal polyester. It is preferably 10.0 mol% or more and 35 mol% or less, more preferably 12.5 mol% or more and 30 mol% or less, and further preferably 15 mol% or more and 25 mol% or less, based on the total amount of the units.

Further, in the liquid crystal polyester, the ratio of the content of Ar ² of the structural unit (2) having a 1,4-phenylene group (for example, a structural unit derived from terephthalic acid) is the total amount of all structural units in the liquid crystal polyester. On the other hand, 0.2 mol% or more and 15 mol% or less is preferable, 0.5 mol% or more and 12 mol% or less is more preferable, and 2 mol% or more and 10 mol% or less is further preferable.

In the liquid crystal polyester, the ratio of the content of Ar ³ of the structural unit (3) being a 1,4-phenylene group (for example, a structural unit derived from hydroquinone) is the total amount of all structural units in the liquid crystal polyester. It is preferably 12.5 mol% or more and 30 mol% or less, more preferably 17.5 mol% or more and 30 mol% or less, and further preferably 20 mol% or more and 25 mol% or less.
In the liquid crystal polyester, among the structural units (2), those in which Ar ² is a 2,6-naphthalenedyl group and Ar ² is a 2,6-naphthalenedyl group and Ar ² are 1,4- For example, the content of the structural unit derived from 2,6-naphthalenedicarboxylic acid is the content of the structural unit derived from 2,6-naphthalenedicarboxylic acid and the structural unit derived from terephthalic acid with respect to the total amount of the phenylene group. 0.5 mol times or more is preferable, and 0.6 mol times or more is more preferable with respect to the total amount.

The blending ratio of each structural unit to the total amount of 100 mol% of all structural units in the above liquid crystal polyester may be the blending ratio to the total amount of 100 mol% of all structural units derived from the aromatic compound in the liquid crystal polyester. Good.

The liquid crystal polyester of the embodiment can be produced, for example, by melt polycondensing each monomer giving a structural unit.
At that time, it is preferable to use an ester-forming derivative of each of the monomers in order to rapidly promote melt polycondensation.

Here, as an example of the ester-forming derivative, if it is a compound having a carboxyl group such as aromatic hydroxycarboxylic acid or aromatic dicarboxylic acid, the carboxyl group is converted into a haloformyl group, and the carboxyl group is acyloxycarbonyl. Examples thereof include those converted into a group and those in which a carboxyl group is converted into an alkoxycarbonyl group or an aryloxycarbonyl group.

Further, in the case of a compound having a hydroxyl group such as an aromatic hydroxycarboxylic acid or an aromatic diol, a compound in which the hydroxyl group is converted into an acyloxy group can be mentioned. Among them, those in which the hydroxyl group is converted to an acyloxy group are preferably used, that is, as the ester-forming derivative of the aromatic hydroxycarboxylic acid, the aromatic acyloxycarboxylic acid in which the hydroxyl group is acylated is preferably used. Further, as the ester-forming derivative of the aromatic diol, an aromatic diacyloxy compound in which the hydroxyl group thereof is acylated is preferably used. The acylation is preferably acetylation with acetic anhydride, and the ester-forming derivative by this acetylation can be deacetic acid polycondensed.

The melt polymerization may be carried out in the presence of a catalyst, and examples of this catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide. , 4- (Dimethylamino) pyridine, and nitrogen-containing heterocyclic compounds such as 1-methylimidazole are mentioned, and nitrogen-containing heterocyclic compounds are preferably used. The melt polymerization may be further solid-phase polymerized, if necessary.

The liquid crystal polyester in the liquid crystal polyester powder of the embodiment has a flow start temperature of preferably 250 ° C. or higher, more preferably 250 ° C. or higher and 350 ° C. or lower, and further preferably 260 ° C. or higher and 330 ° C. or lower. The higher the flow start temperature of the liquid crystal polyester, the easier it is to improve the heat resistance, strength and rigidity, but if it is too high, the pulverizability deteriorates and it becomes difficult to obtain a powder having a target particle size.

The flow start temperature, also called the flow temperature or the flow temperature, melts the liquid crystal polyester while raising the temperature at a rate of 4 ° C./min under a load of 9.8 MPa (100 kg / cm ² ) using a capillary rheometer. It is a temperature showing a viscosity of 4800 Pa · s (48,000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and is a guideline for the molecular weight of liquid crystal polyester (edited by Naoyuki Koide, “Liquid Crystal Polymer”. -Synthesis / Molding / Application- ", CMC Co., Ltd., June 5, 1987, p.95).

The liquid crystal polyester powder of the embodiment is, for example, a liquid crystal polyester powder having a number average molecular weight of 10,000 or less produced by the above method for producing a liquid crystal polyester, and if necessary so that the average particle size is 0.5 to 20 μm. It can be obtained by pulverizing with a jet mill or the like.

The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less and an average particle size of 0.5 to 20 μm, which is a structure derived from 2-hydroxy-6-naphthoic acid. Units, liquid polyester consisting of structural units derived from 2,6-naphthalenedicarboxylic acid, structural units derived from terephthalic acid, and structural units derived from hydroquinone, excluding those having a volume average particle size of 9 μm) There may be.

The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less and an average particle size of 0.5 to 20 μm (however, 2-hydroxy-6-naphthoic acid (5.5)). Mol), 2,6-naphthalenedicarboxylic acid (1.75 mol), terephthalic acid (0.5 mol), hydroquinone (2.475 mol), acetic anhydride (12 mol), and a mixture of 1-methylimidazole as a catalyst. It may be made of liquid crystal polyester which is a polymer obtained by reacting with (excluding liquid crystal polyester powder having a volume average particle size of 9 μm).

The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less and an average particle size of 0.5 to 20 μm, which is a structure derived from a liquid crystal polyester powder (however, 2-hydroxy-6-naphthoic acid). A crushed liquid polyester having a flow start temperature of 265 ° C. consisting of a unit, a structural unit derived from 2,6-naphthalenedicarboxylic acid, a structural unit derived from terephthalic acid, and a structural unit derived from hydroquinone, and having a volume average particle size (Excluding 9 μm liquid polyester powder) may be used.

The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less and an average particle size of 0.5 to 20 μm, which is a structure derived from 2-hydroxy-6-naphthoic acid. Units, structural units derived from 2,6-naphthalenedicarboxylic acid, structural units derived from terephthalic acid, and structural units derived from hydroquinone, excluding liquid crystal polyester powder having a volume average particle size of 9 μm). You may.

The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less and an average particle size of 0.5 to 20 μm (however, 2-hydroxy-6-naphthoic acid (5.5)). Mol), 2,6-naphthalenedicarboxylic acid (1.75 mol), terephthalic acid (0.5 mol), hydroquinone (2.475 mol), acetic anhydride (12 mol), and a mixture of 1-methylimidazole as a catalyst. (Excluding the liquid crystal polyester powder which is a polymer obtained by reacting and has a volume average particle size of 9 μm).

The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less and an average particle size of 0.5 to 20 μm, which is a structure derived from a liquid crystal polyester powder (however, 2-hydroxy-6-naphthoic acid). Volume average grain of crushed liquid polyester containing a unit, a structural unit derived from 2,6-naphthalenedicarboxylic acid, a structural unit derived from terephthalic acid, and a structural unit derived from hydroquinone, and having a flow start temperature of 265 ° C. It may be (excluding liquid crystal polyester powder having a diameter of 9 μm).

The liquid crystal polyester powder of the embodiment contains a liquid crystal polyester having a number average molecular weight of 10,000 or less and an average particle size of 0.5 to 20 μm (however, 2-hydroxy-6-naphthoic acid (5.5)). Mol), 2,6-naphthalenedicarboxylic acid (1.75 mol), terephthalic acid (0.5 mol), hydroquinone (2.475 mol), acetic anhydride (12 mol), and a mixture of 1-methylimidazole as a catalyst. (Excluding the liquid crystal polyester powder having a volume average particle size of 9 μm, which is obtained by crushing the polymer having a flow start temperature of 265 ° C.).

The "volume average particle diameter" here refers to the scattering particle size of the dispersion of the liquid crystal polyester powder obtained by dispersing 0.01 g of the liquid crystal polyester powder in about 10 g of pure water by ultrasonic waves for 5 minutes. It is assumed that the refractive index of pure water is 1.333 and measured using a distribution measuring device (for example, "LA-950V2" of HORIBA Co., Ltd.). The "volume average particle size" is the particle size at a point where the cumulative volume is 50% when the whole is 100% in the volume-based cumulative particle size distribution curve measured by the scattering type particle size distribution measuring device. (50% cumulative volume particle size D ₅₀ ).

Further, acetic acid derived from acetic anhydride, which is a raw material of the liquid crystal polyester, may remain in the liquid crystal polyester powder of the present invention, but the upper limit of the residual acetic acid amount that can be contained in 100% by mass of the liquid crystal polyester powder of the embodiment is From the viewpoint of mechanical properties after processing the film, it is preferably 1% by mass or less, more preferably 500% by mass or less, and further preferably 300% by mass or less. The lower limit of the amount of residual acetic acid contained in 100% by mass of the liquid crystal polyester powder of the embodiment is preferably 30% by mass or more, more preferably 50% by mass or more, and 100% by mass or more from the viewpoint of pulverizability. It is more preferable to have.
As an example of the numerical range of the value of the residual acetic acid amount that can be contained in the above 100% by mass of the liquid crystal polyester powder, it may be 30% by mass or more and 1% by mass or less, and 50% by mass or more and 500% by mass or less. It may be 100 mass ppm or more and 300 mass ppm or less.

According to the liquid crystal polyester powder of the embodiment, it is possible to produce a liquid crystal polyester film having suitable quality as a film for electronic parts. The quality criteria include the isotropic, thickness, and appearance of the film (presence or absence of holes or through holes).
When the number average molecular weight of the liquid crystal polyester in the liquid crystal polyester powder of the embodiment is a relatively small value of 10,000 or less, the liquid crystal polyester composition has properties suitable for coating, and the liquid crystal polyester film is melted during heat treatment. The condition of the above becomes good, and the liquid crystal polyester film having excellent isotropic properties can be produced, and the filming process becomes possible. Further, since the liquid crystal polyester powder of the embodiment has an average particle size of 0.5 to 20 μm, it has a thinness suitable for use as a film for electronic parts and has high quality in which the generation of holes or through holes is suppressed. A polyester film can be obtained.

According to the liquid crystal polyester powder of the embodiment, a liquid crystal polyester film having excellent isotropic properties can be produced.
Conventionally, a liquid crystal polyester film is generally produced by a melt molding method or a casting method in which a liquid crystal polyester is melted.
The melt molding method is a method of molding a film by extruding a kneaded product from an extruder. However, the film produced by the melt molding method has a film-forming direction (also referred to as an extrusion direction) rather than a lateral direction with respect to the extrusion direction (direction perpendicular to the extrusion direction and the thickness direction of the film, Transverse Direction (TD)). Since the liquid crystal polyester molecules are oriented in the Machine Direction (MD), it is difficult to obtain a liquid crystal polyester having excellent isotropic properties.
On the other hand, according to the liquid crystal polyester powder of the embodiment, a liquid crystal polyester film having excellent isotropic properties can be produced. The liquid crystal polyester powder of the embodiment is suitable as a raw material for the method for producing a liquid crystal polyester film according to the present invention, and by applying the method, the liquid crystal polyester having excellent isotropic properties does not require the molding operation by extrusion. The film can be easily manufactured.
Here, "excellent in isotropic properties" of the liquid crystal polyester film means that the value of the molecular orientation (MOR) of the liquid crystal polyester film is in the range of 1 to 1.1.

According to the liquid crystal polyester powder of the embodiment, it is possible to produce a liquid crystal polyester film having both dielectric properties and isotropic properties.
The liquid crystal polyester film produced by the solution casting method has an isotropic orientation of the liquid crystal polyester as compared with the liquid crystal polyester film formed by the melt molding method. However, in order to apply the solution casting method, there is a limitation that a liquid crystal polyester having a solvent-soluble property must be used. In the liquid crystal polyester having improved solubility in a solvent, the dielectric property may be deteriorated, for example, due to the increased polarity. As described above, it has been difficult to achieve both the dielectric property and the isotropic property of the liquid crystal polyester film at a high level.
On the other hand, according to the liquid crystal polyester powder of the embodiment, it is possible to produce a liquid crystal polyester film having both dielectric properties and isotropic properties. The liquid crystal polyester powder of the embodiment is suitable as a raw material for the method for producing a liquid crystal polyester film according to the present invention, and by applying the method, the liquid crystal polyester powder does not require an operation of dissolution in a solvent and is isotropic. An excellent liquid crystal polyester film can be easily produced. Further, since a liquid crystal polyester having excellent dielectric properties can be used as a raw material, a liquid crystal polyester film having excellent dielectric properties and isotropic properties can be easily produced.

≪Liquid crystal polyester composition≫
The liquid crystal polyester composition of the embodiment contains a medium and the liquid crystal polyester powder according to the present invention. The liquid crystal polyester composition is suitably used for producing a liquid crystal polyester film described later.

As for the liquid crystal polyester powder, those described in << Liquid crystal polyester powder >> above can be exemplified, and the description thereof will be omitted.

The medium is not particularly limited as long as the liquid crystal polyester powder is insoluble, and is preferably a dispersion medium. Further, the medium is preferably a fluid, more preferably a liquid. The term "dispersion" as used herein is a term for distinguishing from a state in which the liquid crystal polyester powder is dissolved (excluding a state in which the liquid crystal polyester powder is dissolved in the liquid crystal polyester composition). The distribution of the liquid crystal polyester powder in the composition may have non-uniform portions. The state of the liquid crystal polyester powder in the composition may be a state in which the liquid crystal polyester composition can be applied onto the support in the method for producing a liquid crystal polyester film described later.

Examples of media include halogenated hydrocarbons such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, 1-chlorobutane, chlorobenzene, o-dichlorobenzene; Halogenated phenols such as p-chlorophenol, pentachlorophenol and pentafluorophenol; ethers such as diethyl ether, tetrahydrofuran and 1,4-dioxane; ketones such as acetone and cyclohexanone; esters such as ethyl acetate and γ-butyrolactone; ethylene Carbonates such as carbonate and propylene carbonate; amines such as triethylamine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; nitriles such as acetonitrile and succinonitrile; N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl Examples thereof include amides such as pyrrolidone, urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethylsulfoxide and sulfolane; and phosphorus compounds such as hexamethylphosphate amide and trin-butylphosphate. Two or more of them may be used.

As the medium, an aprotic compound, particularly a medium containing an aprotic compound having no halogen atom as a main component is preferable because it is low in corrosiveness and easy to handle, and the ratio of the aprotic compound to the whole medium is It is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 90 to 100% by mass. Further, as the aprotic compound, it is preferable to use an amide such as N, N-dimethylformamide, N, N-dimethylacetamide, tetramethylurea, N-methylpyrrolidone or an ester such as γ-butyrolactone, and N, More preferred are N-dimethylformamide, N, N-dimethylacetamide, and N-methylpyrrolidone.

Further, as the medium, a medium containing a compound having a boiling point of 220 ° C. or lower at 1 atm as a main component is preferable because it is easy to remove, and the ratio of the compound having a boiling point of 220 ° C. or lower at 1 atm to the entire medium is A compound having a boiling point of 220 ° C. or lower at 1 atm is preferably used as the aproton compound, preferably 50 to 100% by mass, more preferably 70 to 100% by mass, still more preferably 90 to 100% by mass. Is preferable.

The ratio of the liquid crystal polyester powder contained in the liquid crystal polyester composition is preferably 0.1 to 60% by mass, more preferably 1 to 50% by mass, based on the total amount of the liquid crystal polyester powder and the medium. It is more preferably 3 to 40% by mass, and particularly preferably 5 to 30% by mass.

The liquid crystal polyester composition can be obtained by mixing the medium, the liquid crystal polyester powder, and other components used as necessary in a batch or in an appropriate order.

The liquid crystal polyester composition may contain one or more other components such as a filler, an additive, and a resin other than the liquid crystal polyester.

Examples of fillers include inorganic fillers such as silica, alumina, titanium oxide, barium titanate, strontium titanate, aluminum hydroxide and calcium carbonate; and organic fillers such as cured epoxy resin, crosslinked benzoguanamine resin and crosslinked acrylic resin. The material may be mentioned, and the content thereof may be 0 with respect to 100 parts by mass of the liquid crystal polyester, and is preferably 100 parts by mass or less.

Examples of the additive include a leveling agent, a defoaming agent, an antioxidant, an ultraviolet absorber, a flame retardant and a colorant, and the content thereof is 0 with respect to 100 parts by mass of the liquid crystal polyester. It may be 5 parts by mass or less.

Examples of resins other than liquid crystal polyester include polypropylene, polyamide, polyester other than liquid crystal polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene ether and its modified products, heat other than liquid crystal polyester such as polyetherimide. Examples thereof include plastic resins; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and thermosetting resins such as phenol resins, epoxy resins, polyimide resins and cyanate resins, and the content thereof is based on 100 parts by mass of liquid crystal polyester. It may be 0, preferably 20 parts by mass or less.

The liquid crystal polyester composition of the embodiment may contain more than 70% by mass and 100% by mass or less of the liquid crystal polyester of the above embodiment with respect to 100% by mass of the total liquid crystal polyester contained, and is 80 to 100% by mass. It may include. Examples of the liquid crystal polyester include those exemplified by the liquid crystal polyester powder of the embodiment. For example, the liquid crystal polyesters of 1) to 4) above, the structural unit represented by the above formula (1), and the above formula (2). A liquid crystal having a structural unit represented by the above formula (3), a structural unit represented by the above formula (2), and a structural unit represented by the above formula (3). It is polyester.

The liquid crystal polyester composition of the embodiment contains a medium and a liquid crystal polyester powder (however, the content of the liquid crystal polyester soluble in an aprotic solvent is 5% by mass with respect to the total of 100% by mass of the liquid crystal polyester. Is less than).

The liquid crystal polyester composition of the embodiment contains a medium and a liquid crystal polyester powder (however, when the liquid crystal polyester powder is contained as the resin powder, the liquid crystal polyester soluble in an aprotic solvent is excluded). You can.

The liquid crystal polyester soluble in an aprotic solvent may be a liquid crystal polyester containing 4-hydroxyacetaminophen, a structural unit derived from it.
The liquid crystal polyester soluble in an aprotic solvent is a liquid crystal composed of a structural unit derived from 6-hydroxy-2-naphthoic acid, a structural unit derived from 4-hydroxyacetaminophen, and a structural unit derived from isophthalic acid. It may be polyester.
Examples of the liquid polyester soluble in an aprotic solvent include 6-hydroxy-2-naphthoic acid (5.0 mol), 4-hydroxyacetaminophen (2.5 mol), isophthalic acid (2.5 mol), and the like. It may be a liquid crystal polyester which is a polymer obtained by reacting a mixture of acetic anhydride (8.4 mol) and acetic anhydride.

Hereinafter, the liquid crystal polyester soluble in an aprotic solvent will be described.

≪ (X) component ≫
The component (X) is a liquid crystal polyester that is soluble in an aprotic solvent. Here, "soluble in aprotic solvent" can be confirmed by performing the following test.

-Test method The liquid crystal polyester is stirred in an aprotic solvent at a temperature of 120 ° C. to 180 ° C. for 1 hour to 6 hours, and then cooled to room temperature (23 ° C.). Then, after filtering using a 5 μm membrane filter and a pressure type filter, the residue on the membrane filter is confirmed. At this time, if no solid matter is confirmed, it is judged to be soluble in an aprotic solvent.
More specifically, 1 part by mass of the liquid crystal polyester is stirred in 99 parts by mass of an aprotic solvent at 140 ° C. for 4 hours, and then cooled to 23 ° C. Then, after filtering using a 5 μm membrane filter and a pressure type filter, the residue on the membrane filter is confirmed. At this time, if no solid matter is confirmed, it is judged to be soluble in an aprotic solvent.

The liquid crystal polyester (X) preferably contains the structural units represented by the following formulas (X1), (X2), and (X3) as structural units.

As one aspect, the content of the structural unit represented by the formula (X1) is 30 to 80 mol% with respect to the total content of all the structural units constituting the component (X), which is represented by the formula (X2). The content of the structural unit is 35 to 10 mol%, and the content of the structural unit represented by the formula (X3) is 35 to 10 mol%.
However, the total content of the structural unit represented by the formula (X1), the structural unit represented by the formula (X2) and the structural unit represented by the formula (X3) does not exceed 100 mol%.
(X1) -O-Ar1-CO-
(X2) -CO-Ar2-CO-
(X3) -X-Ar3-Y-
(In X1 to X3, Ar1 represents a 1,4-phenylene group, a 2,6-naphthalenedyl group, or a 4,4'-biphenylene group. Ar2 is a 1,4-phenylene group, 1,3-phenylene. Represents a group or a 2,6-naphthalenedyl group. Ar3 represents a 1,4-phenylene group or a 1,3-phenylene group. X is -NH- and Y is -O- or NH-. Represent.)

The structural unit (X1) is a structural unit derived from an aromatic hydroxycarboxylic acid, the structural unit (X2) is a structural unit derived from an aromatic dicarboxylic acid, and the structural unit (X3) is an aromatic having an aromatic diamine or a phenolic hydroxyl group. It is a structural unit derived from a group amine. As the component (X), an ester or an amide-forming derivative of the above-mentioned structural unit may be used instead of the above-mentioned structural unit.

In this embodiment, Ar1 is a 2,6-naphthalenediyl group, Ar2 is a 1,3-phenylene group, Ar3 is a 1,4-phenylene group, and Y is −O−. It is preferable to have.

Examples of the ester-forming derivative of carboxylic acid include those in which the carboxy group is a derivative having high reaction activity such as an acid form and an acid anhydride that promotes the reaction for producing polyester, and the carboxy group. , Alcohols that form polyester by transesterification reaction, ethylene glycol, etc., and those that form an ester.
Examples of the ester-forming derivative of the phenolic hydroxyl group include those in which the phenolic hydroxyl group forms an ester with carboxylic acids.
Examples of the amide-forming derivative of the amino group include those in which the amino group forms an amide with a carboxylic acid.

Examples of the repeating structural unit of the component (X) used in the present embodiment include, but are not limited to, the following.

Examples of the structural unit represented by the formula (X1) include structural units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid or 4'-hydroxy-4-biphenylcarboxylic acid. Two or more of the structural units may be included in all structural units. Among these structural units, it is preferable to use the component (X) containing the structural unit derived from 6-hydroxy-2-naphthoic acid.
The content of the structural unit (X1) may be 30 mol% or more and 80 mol% or less, and 40 mol% or more and 70 mol% or less, based on the content of all the structural units constituting the component (X). It is preferably 45 mol% or more and 65 mol% or less.
If the number of structural units (X1) is large, the solubility in a solvent tends to be significantly reduced, and if the number is too small, the liquid crystal property tends not to be exhibited. That is, when the content of the structural unit (X1) is within the above range, the solubility in the solvent is good and the liquid crystal property is easily exhibited.

Examples of the structural unit represented by the formula (X2) include a structural unit derived from terephthalic acid, isophthalic acid, or 2,6-naphthalenedicarboxylic acid, and two or more of the structural units are included in the total structural unit. It may be included in. Among these structural units, it is preferable to use a liquid crystal polyester containing a structural unit derived from isophthalic acid from the viewpoint of solubility in a solvent.
The content of the structural unit (X2) is preferably 10 mol% or more and 35 mol% or less, more preferably 15 mol% or more and 30 mol% or less, based on the content of all the structural units constituting the component (X). It is particularly preferably 17.5 mol% or more and 27.5 mol% or less. If the number of structural units (X2) is too large, the liquid crystallinity tends to decrease, and if it is too small, the solubility in a solvent tends to decrease. That is, when the content of the structural unit (X2) is within the above range, the liquid crystallinity is good and the solubility in the solvent is also good.

Examples of the structural unit represented by the formula (X3) include a structural unit derived from 3-aminophenol, 4-aminophenol, 1,4-phenylenediamine, 1,3-phenylenediamine, and the like, and two or more kinds thereof. The structural unit of the above may be included in all structural units. Among these structural units, it is preferable to use a liquid crystal polyester containing a structural unit derived from 4-aminophenol from the viewpoint of reactivity.

The content of the structural unit (X3) is preferably 10 mol% or more and 35 mol% or less, more preferably 15 mol% or more and 30 mol% or less, based on the content of all the structural units constituting the component (X). It is particularly preferably 17.5 mol% or more and 27.5 mol% or less. If the number of structural units (3) is too large, the liquid crystallinity tends to decrease, and if it is too small, the solubility in a solvent tends to decrease. That is, when the content of the structural unit (X3) is within the above range, the liquid crystal property is good and the solubility in the solvent is also good.

The structural unit (X3) is preferably used in substantially the same amount as the structural unit (X2), but the content of the structural unit (X3) is -10 to +10 mol with respect to the content of the structural unit (X2). The degree of polymerization of the liquid crystal polyester can also be controlled by setting the percentage to%.

The method for producing the component (X) according to the present embodiment is not particularly limited, but for example, an aromatic hydroxy acid corresponding to the structural unit (X1) and an aromatic amine having a phenolic hydroxyl group corresponding to the structural unit (X3). , Or, an ester-amide exchange between an acylated product obtained by acylating a phenolic hydroxyl group or amino group of an aromatic diamine with an excess amount of fatty acid anhydride and an aromatic dicarboxylic acid corresponding to the structural unit (X2). Examples thereof include a method of (hypercondensation) and melt polymerization (see JP-A-2002-240444 and JP-A-2002-146003).

In the acylation reaction, the amount of fatty acid anhydride added is preferably 1.0 to 1.2 times equivalent to the total amount of phenolic hydroxyl groups and amino groups, and more preferably 1.05-1. . 1 time equivalent. If the amount of fatty acid anhydride added is too small, acylates and raw material monomers tend to sublimate during transesterification and amide exchange (polycondensation), and the reaction system tends to be clogged. If the amount is too large, the resulting liquid crystal will be obtained. Coloring of sex polyester tends to be remarkable. That is, when the amount of fatty acid anhydride added is within the above range, the reaction of the acylated product and the raw material monomer during transesterification / amide exchange (polycondensation) is good, and the obtained liquid crystal polyester may be overcolored. Absent.

The acylation reaction is preferably carried out at 130 to 180 ° C. for 5 minutes to 10 hours, and more preferably at 140 to 160 ° C. for 10 minutes to 3 hours.

The fatty acid anhydride used in the acylation reaction is not particularly limited, and is, for example, acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, -2ethylhexanic anhydride, monochloroanhydride. Acetic acid, dichloroacetic anhydride, trichloracetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, β-chloride. -Bromopropionic acid and the like can be mentioned, and two or more of these may be mixed and used. In the present embodiment, acetic anhydride, propionic anhydride, butyric anhydride, or isobutyric anhydride is preferable, and acetic anhydride is more preferable.

In transesterification / amide exchange (polycondensation), the acyl group of the acylated product is preferably 0.8 to 1.2 times the equivalent of the carboxyl group.

Transesterification and amide exchange (polycondensation) are preferably carried out while raising the temperature to 400 ° C. at a rate of 0.1 to 50 ° C./min, and to 350 ° C. at a rate of 0.3 to 5 ° C./min. It is more preferable to carry out while doing so.

When the acylated product and the carboxylic acid are transesterified or amide exchanged (polycondensed), it is preferable that the by-produced fatty acid and the unreacted fatty acid anhydride are distilled off from the system by evaporation or the like.

The acylation reaction and transesterification / amide exchange (polycondensation) may be carried out in the presence of a catalyst. As the catalyst, those conventionally known as catalysts for polymerizing polyester can be used, for example, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide and the like. Metal salt catalysts, organic compound catalysts such as N, N-dimethylaminopyridine, N-methylimidazole and the like can be mentioned.
Among these catalysts, heterocyclic compounds containing at least two nitrogen atoms such as N, N-dimethylaminopyridine and N-methylimidazole are preferably used (see JP-A-2002-146003).
The catalyst is usually charged at the time of charging the monomers, and it is not always necessary to remove the catalyst even after acylation. If the catalyst is not removed, transesterification can be carried out as it is.

Polycondensation by transesterification and amide exchange is usually carried out by melt polymerization, but melt polymerization and solid phase polymerization may be used in combination. The solid-phase polymerization is preferably carried out by a known solid-state polymerization method after extracting the polymer from the melt polymerization step and then pulverizing the polymer into powder or flakes. Specifically, for example, a method of heat-treating in a solid-state state at 20 to 350 ° C. for 1 to 30 hours in an inert atmosphere such as nitrogen can be mentioned. The solid-phase polymerization may be carried out with or without stirring in a stationary state. The melt polymerization tank and the solid phase polymerization tank can be made into the same reaction tank by providing an appropriate stirring mechanism. After solid-phase polymerization, the obtained liquid crystal polyester may be pelletized and molded by a known method. Further, it may be pulverized by a known method.
The liquid crystal polyester can be produced, for example, by using a batch device, a continuous device, or the like.
When the liquid crystal polyester (X) is in the form of powder, the volume average particle size is preferably 100 to 2000 μm. The volume average particle size of the powdery liquid crystal polyester (X) can be measured by a dry sieving method (for example, RPS-105 manufactured by Seishin Enterprise Co., Ltd.).

As one aspect, the content of the component (X) is preferably 5 to 10% by mass with respect to the total mass of the liquid crystal polyester liquid composition.

[Production example of liquid crystal polyester (X)]
In a reactor equipped with a stirrer, torque meter, nitrogen gas introduction tube, thermometer and reflux condenser, 940.9 g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 4-hydroxyacetaminophen 377. After adding 9 g (2.5 mol), 415.3 g (2.5 mol) of isophthalic acid and 867.8 g (8.4 mol) of anhydrous acetate, the gas in the reactor was replaced with nitrogen gas, and then a nitrogen gas stream. Below, with stirring, the temperature is raised from room temperature (23 ° C.) to 140 ° C. over 60 minutes, and the mixture is refluxed at 140 ° C. for 3 hours. Then, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150 ° C. to 300 ° C. over 5 hours, held at 300 ° C. for 30 minutes, and then the contents were taken out from the reactor to room temperature ( 23 ° C.). The obtained solid matter can be pulverized with a pulverizer to obtain a powdery liquid crystal polyester (X-1). The flow start temperature of the liquid crystal polyester (X-1) may be 193.3 ° C.

The liquid crystal polyester (X-1) was heated in a nitrogen atmosphere from room temperature (23 ° C.) to 160 ° C. over 2 hours and 20 minutes, and then from 160 ° C. to 180 ° C. over 3 hours and 20 minutes. By holding at 180 ° C. for 5 hours, solid-state polymerization is carried out, the mixture is cooled to 23 ° C., and then pulverized with a pulverizer to obtain a powdery liquid crystal polyester (X-2). The flow start temperature of the liquid crystal polyester (X-2) may be 220 ° C.

The liquid crystal polyester (X-2) was heated from room temperature to 180 ° C. over 1 hour and 25 minutes in a nitrogen atmosphere, then from 180 ° C. to 255 ° C. over 6 hours and 40 minutes, and then heated at 255 ° C. for 5 hours. By holding the mixture, it is possible to obtain a powdery liquid crystal polyester (X) having a volume average particle size of 871 μm by solid-phase polymerization and then cooling to 23 ° C. The volume average particle diameter of the liquid crystal polyester (X) is measured by RPS-105 manufactured by Seishin Enterprise Co., Ltd. The flow start temperature of the liquid crystal polyester (X) may be 302 ° C.

[Preparation of liquid crystal polyester solution (X')]
8 parts by mass of liquefied polyester (X) was added to 92 parts by mass of N-methylpyrrolidone (boiling point (1 atm) 204 ° C.), and the mixture was stirred at 140 ° C. for 4 hours under a nitrogen atmosphere to prepare a liquefied polyester solution (X'. ) Can be prepared. The viscosity of this liquid crystal polyester solution (X') may be 955 mPa · s.

≪Manufacturing method of liquid crystal polyester film≫
The method for producing a liquid crystal polyester film of the embodiment includes applying the liquid crystal polyester composition according to the present invention on a support and heat-treating it to obtain a liquid crystal polyester film containing the liquid crystal polyester.

The manufacturing method may include the following steps.
A step (coating step) of applying the liquid crystal polyester composition according to the present invention onto a support to form a precursor of a liquid crystal polyester film on the support.
A step of heat-treating a precursor of the liquid crystal polyester film to obtain a liquid crystal polyester film (heat treatment step).

The coating step in the method for producing a liquid crystal polyester film includes a step (drying step) of applying the liquid crystal polyester composition according to the present invention on the support and then removing the medium from the applied liquid crystal polyester composition. You may.
That is, in the method for producing a liquid crystal polyester film of the embodiment, the liquid crystal polyester composition according to the present invention is applied onto a support, the medium is removed from the applied liquid crystal polyester composition, and heat treatment is performed to obtain the liquid crystal polyester. It may include obtaining a liquid crystal polyester film containing.

Further, the method for producing the liquid crystal polyester film may further include a step (separation step) of separating the support from the laminate. Since the liquid crystal polyester film can be suitably used as a film for electronic components even while being formed on the support as a laminate, the separation step is not an essential step in the manufacturing process of the liquid crystal polyester film.

Hereinafter, an example of the method for producing the liquid crystal polyester film of the embodiment will be described with reference to the drawings.

FIG. 1 is a schematic view showing an example of a manufacturing process of the liquid crystal polyester film and the laminate of the embodiment.
First, the liquid crystal polyester composition 30 is applied onto the support 12 (FIG. 1 (a) coating step). The liquid crystal polyester composition 30 contains the liquid crystal polyester powder 1 and the medium 3. The liquid crystal polyester liquid composition can be applied onto the support by a roller coating method, a dip coating method, a spray coating method, a spinner coating method, a curtain coating method, a slot coating method, a screen printing method, or the like. , A method capable of applying the surface smoothly and uniformly on the support can be appropriately selected. Further, in order to make the distribution of the liquid crystal polyester powder uniform, an operation of stirring the liquid crystal polyester composition may be performed before coating.

Examples of the support 12 include a glass plate, a resin film, and a metal foil. Among them, a resin film or a metal foil is preferable, and a copper foil is particularly preferable because it has excellent heat resistance, is easy to apply a liquid composition, and is easy to remove from a liquid crystal polyester film.
Examples of commercially available polyimide (PI) films include "U-Pyrex S" and "U-Pyrex R" from Ube Industries, Ltd., "Kapton" from Toray DuPont Co., Ltd., and "SKC Kolon PI". "IF30", "IF70" and "LV300" can be mentioned. The thickness of the resin film is usually 25 μm or more and 75 μm or less, preferably 50 μm or more and 75 μm or less. The thickness of the metal foil is usually 3 μm or more and 75 μm or less, preferably 5 μm or more and 30 μm or less, and more preferably 10 μm or more and 25 μm or less.

Next, the medium 3 is removed from the liquid crystal polyester composition 30 applied on the support 12 (FIG. 1 (b) drying step). The liquid crystal polyester composition from which the medium 3 has been removed becomes the liquid crystal polyester film precursor 40 to be heat-treated. The medium 3 does not have to be completely removed from the liquid crystal polyester composition, and a part of the medium contained in the liquid crystal polyester composition may be removed, or the entire medium may be removed. The ratio of the solvent contained in the liquid crystal polyester film precursor 40 is preferably 50% by mass or less, more preferably 3% by mass or more and 12% by mass or less, based on the total mass of the liquid crystal polyester film precursor. It is more preferably 5% by mass or more and 10% by mass or less. When the solvent content in the liquid crystal polyester film precursor is at least the above lower limit value, the possibility that the thermal conductivity of the liquid crystal polyester film is lowered is reduced. Further, when the solvent content in the liquid crystal polyester film precursor is not more than the above upper limit value, the possibility that the appearance of the liquid crystal polyester film is deteriorated due to foaming or the like during heat treatment is reduced.

The removal of the medium is preferably carried out by evaporating the medium, and examples thereof include heating, depressurization and ventilation, and these may be combined. Further, the medium may be removed by a continuous method or a single-wafer method. From the viewpoint of productivity and operability, the medium is preferably removed by heating in a continuous manner, and more preferably by heating while ventilating in a continuous manner. The removal temperature of the medium is preferably a temperature lower than the melting point of the liquid crystal polyester powder, for example, 40 ° C. or higher and 200 ° C. or lower, preferably 60 ° C. or higher and 200 ° C. The medium removal time is appropriately adjusted so that the medium content in the liquid crystal polyester film precursor is, for example, 3 to 12% by mass. The time for removing the medium is, for example, 0.2 hours or more and 12 hours or less, preferably 0.5 hours or more and 8 hours or less.

The laminate precursor 22 having the support 12 and the liquid crystal polyester film precursor 40 thus obtained is heat-treated to form the support 12 and the liquid crystal polyester film 10 (a film obtained by heat-treating the liquid crystal polyester film precursor 40). 20 is obtained (FIG. 1 (c) heat treatment step). At this time, the liquid crystal polyester film 10 formed on the support is obtained.
The heat treatment conditions include, for example, raising the temperature from the boiling point of the medium of −50 ° C. to reach the heat treatment temperature, and then heat-treating at a temperature equal to or higher than the melting point of the liquid crystal polyester.
At the time of this temperature rise, the polymerization reaction of the liquid crystal polyester may proceed due to heating, but by increasing the rate of temperature rise until the heat treatment temperature is reached, the increase in the molecular weight of the liquid crystal polyester in the liquid crystal polyester powder can be suppressed to some extent. The liquid crystal polyester powder melts well, and a high-quality film can be easily obtained. The rate of temperature rise from the boiling point of the solvent to −50 ° C. to the heat treatment temperature is preferably 3 ° C./min or higher, more preferably 5 ° C./min or higher.
The heat treatment temperature is preferably at least the melting point of the liquid crystal polyester, more preferably at a temperature higher than the melting point of the liquid crystal polyester, and further preferably at a temperature of + 5 ° C. or higher at the melting point of the liquid crystal polyester. The heat treatment temperature may be appropriately determined depending on the type of liquid crystal polyester, but as an example, 230 ° C. or higher and 400 ° C. or lower is preferable, 300 ° C. or higher and 380 ° C. or lower is more preferable, and 320 ° C. or higher and 350 ° C. or lower is further preferable. By performing the heat treatment at a temperature higher than the melting point of the liquid crystal polyester, the liquid crystal polyester powder melts well, and a high quality liquid crystal polyester film can be formed. The fact that the liquid crystal polyester powder could be melted can be confirmed by the fact that the liquid crystal polyester film precursor 40 became transparent.
The boiling point of the medium referred to here means the boiling point at the pressure at the time of temperature rise. When heating the laminate precursor 22 is started from the boiling point of the medium below −50 ° C., the heating rate is set within the range from reaching the boiling point of the medium of −50 ° C. to reaching the heat treatment temperature. Just do it. The time it takes for the medium to reach the boiling point −50 ° C. is arbitrary. Further, the time after reaching the heat treatment temperature may be considered as the heat treatment time. The heat treatment time may be, for example, 0.5 hours or more, 1 hour or more and 24 hours or less, and 3 hours or more and 12 hours or less.

Similar to the removal of the medium, the heat treatment may be carried out continuously or in a single-wafered manner, but from the viewpoint of productivity and operability, it is preferably carried out in a continuous manner, and the heat treatment is preferably carried out following the removal of the medium. It is more preferable to carry out the continuous method.

Next, by separating the liquid crystal polyester film 10 from the laminate 20 having the support 12 and the liquid crystal polyester film 10, the liquid crystal polyester film 10 can be obtained as a single-layer film (FIG. 1 (d) separation step). .. When a glass plate is used as the support 12, the liquid crystal polyester film 10 may be separated from the laminate 20 by peeling the liquid crystal polyester film 10 from the laminate 20. When a resin film is used as the support 12, it is preferable to peel off the resin film or the liquid crystal polyester film 10 from the laminate 20. When a metal foil is used as the support 12, it is preferable to separate the metal foil from the laminate 20 by etching and removing the metal foil. When a resin film, particularly a polyimide film, is used as the support, the polyimide film or the liquid crystal polyester film is easily peeled off from the laminate 20, and a liquid crystal polyester film having a good appearance can be obtained. When a metal foil is used as the support, the laminate 20 may be used as a metal-clad laminate for a printed wiring board without separating the liquid crystal polyester film from the laminate 20.

According to the method for producing a liquid crystal polyester film of the embodiment, a liquid crystal polyester film having excellent isotropic properties can be produced.
In the conventional melt molding method, a thin film of the liquid crystal polyester is produced by forming the melted liquid crystal polyester into a film, whereas in the above-mentioned production method of the embodiment, the liquid crystal polyester is thinly formed in advance on the support. It differs significantly from conventional film manufacturing methods in that the powder is placed and then melted.
In the method for producing a liquid crystal polyester film or a laminate of the embodiment, the liquid crystal polyester powder is thinly arranged on the support in advance to form a film, which causes a bias in molecular orientation such as extrusion molding. It is possible to produce a liquid crystal polyester film having excellent isotropic properties without applying any force.
Further, when the number average molecular weight of the liquid crystal polyester in the liquid crystal polyester powder is a relatively small value of 10,000 or less, the liquid crystal polyester composition has properties suitable for coating, and the state of melting of the liquid crystal polyester film during heat treatment. It is possible to produce a high-quality liquid crystal polyester film having excellent isotropic properties, which is suitable for use as a film for electronic parts.
Furthermore, by using a liquid crystal polyester powder having an average particle size of 0.5 to 20 μm as a raw material, it has a thinness suitable for use as a film for electronic parts and has high quality in which the generation of holes or through holes is suppressed. A polyester film can be easily produced.
Moreover, in the liquid crystal polyester composition, since there is no restriction that the liquid crystal polyester powder should be soluble in the medium, the liquid crystal polyester having excellent dielectric properties can be adopted, and the liquid crystal polyester having excellent dielectric properties and isotropic properties can be used. It is possible to easily obtain a film.

≪Manufacturing method of laminated body≫
In the method for producing a laminated body of the embodiment, the liquid crystal polyester composition according to the present invention is applied onto a support and heat-treated to form a liquid crystal polyester film containing the liquid crystal polyester, whereby the support and the liquid crystal are formed. It includes obtaining a laminate comprising a polyester film.

The manufacturing method may include the following steps.
A step of applying the liquid crystal polyester composition according to the present invention on a support to form a liquid crystal polyester film precursor on the support (coating step).
A step (heat treatment step) of heat-treating the liquid crystal polyester film precursor to obtain a laminate having the support and the liquid crystal polyester film.

Similar to the above-mentioned method for producing a liquid crystal polyester film, in the coating step in the method for producing a laminate, the liquid crystal polyester composition according to the present invention is applied onto a support, and then a medium is applied from the applied liquid crystal polyester composition. It may include a step of removing (drying step).
That is, in the method for producing a laminate of the embodiment, the liquid crystal polyester composition according to the present invention is applied onto a support, the medium is removed from the applied liquid crystal polyester composition, and heat treatment is performed to contain the liquid crystal polyester. By forming the liquid crystal polyester film, it may include obtaining a laminate including the support and the liquid crystal polyester film.

FIG. 1 is a schematic view showing an example of a manufacturing process of the liquid crystal polyester film and the laminate of the embodiment. The method for producing the laminate illustrated in FIG. 1 is the same as that described in the above << Manufacturing method for liquid crystal polyester film >> except that the separation step (FIG. 1 (d)) is not performed. Is omitted.

According to the method for producing a laminate of the embodiment, the laminate having the liquid crystal polyester film of the embodiment can be produced.

≪Film≫
In the above method for producing a liquid crystal polyester film or a laminate, liquid crystal polyester powder is used as a raw material, but instead of liquid crystal polyester, a thermoplastic resin having excellent dielectric properties is used as a raw material to obtain a film having excellent dielectric properties and isotropic properties. Obtainable.

FIG. 2 is a schematic view showing the configuration of the film 11 of the embodiment.

The film of the embodiment contains a thermoplastic resin, has a relative permittivity of 3 or less at a frequency of 1 GHz, a dielectric loss tangent of 0.005 or less at a frequency of 1 GHz, and has a molecular orientation (MOR) measured by a microwave orientometer. The value of is in the range of 1 to 1.1.
A film satisfying the above regulations has a quality suitable for a film for electronic components. The quality criteria are the above-mentioned relative permittivity, dielectric loss tangent, and molecular orientation (isotropic property of the film), as well as thickness and appearance (presence or absence of holes or through holes). To.
As an example, the relative permittivity and the value of the dielectric loss tangent of the film can be controlled by the type of the thermoplastic resin. Further, as an example, the degree of isotropic property of the film can be controlled by the method of manufacturing the film.

The film of the embodiment has a relative permittivity of 3 or less, preferably 2.9 or less, more preferably 2.8 or less, and further preferably 2.7 or less at a frequency of 1 GHz. It is particularly preferably 2.6 or less. Further, the relative permittivity of the film may be 2.3 or more, 2.4 or more, or 2.5 or more.
As an example of the numerical range of the relative permittivity value of the film, it may be 2.3 or more and 3 or less, 2.4 or more and 2.9 or less, and 2.5 or more and 2. It may be 8 or less, 2.5 or more and 2.7 or less, and 2.5 or more and 2.6 or less.

The film of the embodiment has a dielectric loss tangent of 0.005 or less, preferably 0.004 or less, more preferably 0.003 or less, and even more preferably 0.002 or less at a frequency of 1 GHz. , 0.001 or less is particularly preferable. The dielectric loss tangent of the liquid crystal polyester film may be 0.0003 or more, 0.0005 or more, or 0.0007 or more.
As an example of the numerical range of the value of the dielectric tangent of the film, it may be 0.0003 or more and 0.005 or less, 0.0005 or more and 0.004 or less, and 0.0007 or more and 0. It may be .003 or less, 0.0007 or more and 0.002 or less, or 0.0007 or more and 0.001 or less.
The relative permittivity and dielectric loss tangent of the film at a frequency of 1 GHz can be measured by the capacitive method using an impedance analyzer under the conditions described in the examples.

The film of the embodiment has a molecular orientation (MOR) value in the range of 1 to 1.1, preferably 1 to 1.08, preferably 1 to 1.06, as measured by a microwave orientation meter. It is more preferably in the range of 1 to 1.04, and even more preferably in the range of 1 to 1.04.

The degree of molecular orientation (MOR) is measured by a microwave molecular orientation meter (for example, MOA-5012A manufactured by Oji Measuring Instruments Co., Ltd.). The microwave molecular orientation meter is a device that utilizes the fact that the transmission intensity of microwaves differs between the orientation direction and the direction perpendicular to the orientation of the molecule. Specifically, while rotating the sample, irradiate a microwave having a constant frequency (12 GHz is used), measure the intensity of the transmitted microwave that changes depending on the orientation of the molecule, and determine the maximum / minimum value. Let the ratio be MOR. The interaction between a microwave electric field with a constant frequency and the dipoles that make up the molecule is related to the inner product of the vectors of both. Due to the anisotropy of the permittivity of the sample, the intensity of the microwave changes depending on the angle at which the sample is placed, so it is possible to know the degree of orientation.

The film of the embodiment preferably has a linear expansion coefficient of 85 ppm / ° C. or less, and more preferably 50 ppm / ° C. or less, which is obtained in a temperature range of 50 to 100 ° C. under the condition of a temperature rising rate of 5 ° C./min. It is more preferably 40 ppm / ° C. or lower, and particularly preferably 30 ppm / ° C. or lower. The lower limit of the coefficient of linear expansion is not particularly limited, but is, for example, 0 ppm / ° C. or higher. Further, for example, when the copper foil and the film are laminated, the coefficient of linear expansion of the copper foil is 18 ppm / ° C., so that the coefficient of linear expansion of the film of the embodiment is preferably a value close to that. That is, the coefficient of linear expansion of the film of the embodiment is preferably 0 ppm / ° C. or higher and 50 ppm / ° C. or lower, more preferably 10 ppm / ° C. or higher and 40 ppm / ° C. or lower, and 20 ppm / ° C. or higher and 30 ppm / ° C. or lower. It is more preferable to have. If the coefficient of linear expansion differs depending on the direction or portion of the film, the higher value shall be adopted as the coefficient of linear expansion of the film. The film of the embodiment satisfying the above numerical range has a low coefficient of linear expansion and high dimensional stability.

A film having excellent isotropic properties has a small difference in linear expansion coefficient depending on the measurement direction.
In the film of the embodiment, the difference between the coefficient of linear expansion of MD and the coefficient of linear expansion of TD (MD-TD when MD> TD, TD-MD when TD> MD) is 2 ppm / The temperature is preferably 1 ppm / ° C or lower, and more preferably 1 ppm / ° C or lower. In the film formed by the casting method, MD is the coating direction of the dispersion liquid. As shown in the calculation of the difference in the coefficient of linear expansion above, in reality, it is sufficient to know the coefficient of linear expansion in different directions. Therefore, if the MD and TD of the film are unknown, the MD and TD are set to any direction of the film, and 90. ° When the intersecting direction is TD, the direction may be set so that the difference in the coefficient of linear expansion in each direction is the largest.
The film of the embodiment satisfying the above numerical range has excellent isotropic property of linear expansion and high dimensional stability in the vertical direction and the horizontal direction.

The film of the embodiment preferably has no holes or through holes as a film suitable for electronic components. If there are holes or through holes, the plating solution may seep into the holes or through holes during plating. The liquid crystal polyester film produced from the liquid crystal polyester powder of the embodiment is of high quality having a thickness suitable for a film for electronic parts and suppressing the generation of holes or through holes.

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

A film having excellent dielectric properties can be obtained by selecting a raw material resin having excellent dielectric properties from any thermoplastic resin.

The content ratio of the thermoplastic resin to 100% by mass of the total mass of the film of the embodiment may be 50 to 100% by mass or 80 to 95% by mass.

Examples of the thermoplastic resin include polypropylene, polyamide, polyester, polysulfone, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether, polyetherimide and the like.

Liquid crystal polyester is preferable as the thermoplastic resin from the viewpoint of having particularly excellent dielectric properties. As for the liquid crystal polyester, those described in << Liquid crystal polyester powder >> above can be exemplified, and the description thereof will be omitted.

When the film of the embodiment contains a liquid crystal polyester, the liquid crystal polyester of the above embodiment may be contained in an amount of more than 70% by mass and 100% by mass or less based on 100% by mass of the total amount of the liquid crystal polyester contained in the film. It may contain ~ 100% by mass. Examples of the liquid crystal polyester include those exemplified by the liquid crystal polyester powder of the above-described embodiment. For example, the liquid crystal polyesters of the above 1) to 4), the structural unit represented by the above formula (1), and the above formula (2). ), A structural unit represented by the above formula (3), a structural unit represented by the above formula (2), and a structural unit represented by the above formula (3). It is a liquid crystal polyester having.

The film of the embodiment contains a thermoplastic resin, has a relative permittivity of 3 or less at a frequency of 1 GHz, has a dielectric loss tangent of 0.005 or less at a frequency of 1 GHz, and has a molecular orientation (MOR) measured by a microwave orientometer. The value of the film is in the range of 1 to 1.1 (however, when the liquid polyester is contained as the thermoplastic resin, the content of the liquid polyester soluble in the aprotic solvent is 100% by mass of the total liquid polyester. Is less than 5% by mass).

The film of the embodiment contains a thermoplastic resin, has a relative permittivity of 3 or less at a frequency of 1 GHz, a dielectric loss tangent of 0.005 or less at a frequency of 1 GHz, and has a molecular orientation (MOR) measured by a microwave orientometer. The film may have a value in the range of 1 to 1.1 (excluding those containing a liquid polyester soluble in an aprotic solvent).

Here, examples of the liquid crystal polyester soluble in the aprotic solvent include those exemplified by the liquid crystal polyester powder of the embodiment.

The method for producing the film of the embodiment is not particularly limited, but the film of the embodiment can be produced by the above << method for producing a crystalline polyester film >>. In the above << Method for producing a crystalline polyester film >>, liquid crystal polyester is described as a raw material, but in the method, the liquid crystal polyester is read as an arbitrary thermoplastic resin, and the embodiment containing an arbitrary thermoplastic resin. The film may be manufactured.

The film of the embodiment can be suitably used for a film application for electronic components such as a printed wiring board. The film of the embodiment can be provided as a substrate (for example, a flexible substrate), a laminated board (for example, a flexible copper-clad laminated board), a printed circuit board, a printed wiring board, a printed circuit board, etc., which are provided with the film as an insulating material. ..

≪Laminated body≫
The laminated body of the embodiment includes a metal layer and a film according to the present invention laminated on the metal layer.
FIG. 3 is a schematic view showing the configuration of the laminated body 21 according to the embodiment of the present invention. The laminated body 21 includes a metal layer 13 and a film 11 laminated on the metal layer 13.
Examples of the film included in the laminate include those exemplified above, and the description thereof will be omitted.
Examples of the metal layer provided in the laminate include those exemplified as the support in the above << Method for producing a liquid crystal polyester film >> and << Method for producing a laminate >>, and a metal foil is preferable. Copper is preferable as the metal constituting the metal layer from the viewpoint of conductivity and cost, and copper foil is preferable as the metal foil.

The thickness of the laminate of the embodiment is not particularly limited, but is preferably 5 to 130 μm, more preferably 10 to 70 μm, and even more preferably 15 to 60 μm.

The method for producing the laminated body of the embodiment is not particularly limited, but the laminated body of the embodiment can be produced by the above << manufacturing method of the laminated body >>. In the above << Manufacturing Method of Laminated Body >>, liquid crystal polyester is described as a raw material, but in the method, a film containing an arbitrary thermoplastic resin is provided by replacing the liquid crystal polyester with an arbitrary thermoplastic resin. , The laminate of the embodiment may be manufactured.

The laminate of the embodiment can be suitably used for a film application for electronic components such as a printed wiring board.

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

<Measurement method>
[Measurement of flow start temperature of liquid crystal polyester]
Using a flow tester (“CFT-500 type” manufactured by Shimadzu Corporation), about 2 g of liquid crystal polyester was filled into a cylinder equipped with a die having a nozzle with an inner diameter of 1 mm and a length of 10 mm, and 9.8 MPa (100 kg) was filled. Under a load of / cm ² ), the liquid crystal polyester was melted and extruded from a nozzle while raising the temperature at a rate of 4 ° C./min, and the temperature (FT) showing a viscosity of 4800 Pa · s (48000 P) was measured.

[Measurement of melting point of liquid crystal polyester]
Using a differential scanning calorimetry device (“DSC-50” manufactured by Shimadzu Corporation), the temperature is raised at a heating rate of 10 ° C./min, the position of the endothermic peak is confirmed, and the temperature at the apex position of the endothermic peak is confirmed. Was measured as the melting point of the liquid crystal polyester.

[Measurement of molecular weight of liquid crystal polyester contained in liquid crystal polyester fine particle powder]
Gel Penetration Chromatograph-Multi-angle Light Scattering Photometer (Differential Refractometer (Shimadzu Seisakusho: RID-20A), Multi-angle Light Scattering Detector (Wyatt Technology EOS), Column (Showa Denko: Shodex KG,) Included in liquid crystal polyester fine particle powder using K-806M (2 pieces), K-802 (1 piece) (φ8.0 mm × 30 cm)), solvent (pentafluorophenol / chloroform (weight ratio 35/65))) The number average molecular weight of the liquid crystal polyester was measured. For the sample solution for measurement, 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 a solvent (pentafluorophenol / chloroform (weight ratio 35 /)) was added. After diluting 2-fold in 65)), the sample was prepared by filtering using a filter having a pore size of 0.45 μm.

[Analysis of the amount of residual acetic acid contained in the liquid crystal polyester fine particle powder]
Using a headspace gas chromatograph device (manufactured by Shimadzu Corporation: GC-2014), the amount of residual acetic acid in the liquid crystal polyester fine particle powder was analyzed under extraction conditions of 120 ° C. and 20 h and analytical conditions of 200 ° C. and 1 h.

[Relative permittivity and dielectric loss tangent measurement of liquid crystal polyester fine particle powder]
The liquid crystal polyester fine particle powder is melted at a temperature 5 ° C. higher than the melting point measured using a flow tester (“CFT-500 type” manufactured by Shimadzu Corporation), and then cooled and solidified to have a diameter of 1 cm and a thickness. A 0.5 cm tablet was made. Relative permittivity and dielectric loss tangent at 1 GHz were measured for the obtained tablets under the following conditions.
-Measurement method: Capacitive method (Device: Impedance analyzer (Agilent model: E4991A))
-Electrode model: 16453A
-Measurement environment: 23 ° C, 50% RH
・ Applied voltage: 1V

[Measurement of average particle size of liquid crystal polyester fine particle powder]
0.01 g of the liquid crystal polyester fine particle powder was weighed and dispersed in about 10 g of pure water. The prepared dispersion of the liquid crystal polyester fine particle powder was dispersed by ultrasonic waves for 5 minutes. Using a scattering type particle size distribution measuring device (“LA-950V2” of HORIBA Co., Ltd.), the refractive index of pure water was set to 1.333, and the volume-based cumulative particle size distribution of liquid crystal polyester fine particle powder was measured and averaged. The particle size (D ₅₀ ) was calculated.

[Relative permittivity and dielectric loss tangent measurement of liquid crystal polyester film]
A liquid crystal polyester film was melted at 350 ° C. using a flow tester (“CFT-500 type” manufactured by Shimadzu Corporation) and then cooled and solidified to prepare tablets having a diameter of 1 cm and a thickness of 0.5 cm. .. Relative permittivity and dielectric loss tangent at 1 GHz were measured for the obtained tablets under the following conditions.
-Measurement method: Capacitive method (Device: Impedance analyzer (Agilent model: E4991A))
-Electrode model: 16453A
-Measurement environment: 23 ° C, 50% RH
・ Applied voltage: 1V

[Measurement of molecular orientation of liquid crystal polyester film]
Cut the film into a 5 cm square, place it in a holder, and measure the degree of molecular orientation using a molecular orientation meter (manufactured by Oji Measuring Instruments Co., Ltd., model: MOA-5012A) under the conditions of frequency 12 GHz and rotation speed 1 rpm. went.

[Measurement of coefficient of linear expansion of liquid crystal polyester film]
The coefficient of linear expansion from 50 ° C. to 100 ° C. was measured at a heating rate of 5 ° C./min using a thermomechanical analyzer (manufactured by Rigaku Co., Ltd., model: TMA8310). The measurement was performed in the flow direction (MD) of the liquid crystal polyester film and the direction perpendicular to the flow direction (TD). In the liquid crystal polyester film of each Example or Comparative Example formed by the casting method, the flow direction (MD) was defined as the coating direction of the dispersion liquid.

<Manufacturing of liquid crystal polyester fine particle powder>
[Example 1]
-Manufacture of liquid crystal polyester (A) In a reactor equipped with a stirrer, torque meter, nitrogen gas introduction tube, thermometer and reflux cooler, 1034.99 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, Of 2,6-naphthalenedicarboxylic acid 378.33 g (1.75 mol), terephthalic acid 83.07 g (0.5 mol), hydroquinone 272.52 g (2.475 mol, 2,6-naphthalenedicarboxylic acid and terephthalic acid) 0.225 mol excess with respect to the total molar amount), 1226.87 g (12 mol) of anhydrous acetic acid, and 0.17 g of 1-methylimidazole as a catalyst. After replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature to 145 ° C. over 15 minutes while stirring under a nitrogen gas stream, and the mixture was refluxed at 145 ° C. for 1 hour.
Then, while distilling off the by-produced acetic acid and unreacted acetic anhydride, the temperature was raised from 145 ° C. to 310 ° C. over 3 hours and 30 minutes, held at 310 ° C. for 3 hours, and then the solid liquid crystal polyester was taken out. The liquid crystal polyester was cooled to room temperature to obtain a liquid crystal polyester (A). The flow start temperature of the liquid crystal polyester (A) was 268 ° C. This liquid crystal polyester (A) was pulverized with a cutter mill VM-16 manufactured by Orient Crusher Co., Ltd. to obtain a powder of the liquid crystal polyester (A) having an average particle size of 394 μm.

-Manufacture of liquid crystal polyester fine particle powder Next, using a jet mill ("KJ-200" manufactured by Kurimoto Iron Works, crushing nozzle diameter: 4.5 mm), classification rotor rotation speed 10000 rpm, crushing nozzle pressure 0.64 MPa, processing speed Was set to 2.1 kg / hour, and the powder of the liquid crystal polyester (A) was pulverized to obtain the liquid crystal polyester fine particle powder of Example 1. The average particle size of the liquid crystal polyester fine particle powder was 8 μm. Further, the melting point of the liquid crystal polyester fine powder of Example 1 was measured using a differential scanning calorimeter and found to be 290 ° C.

[Example 2]
Liquid crystal polyester powder was crushed by setting the processing conditions of a jet mill (“KJ-200” manufactured by Kurimoto Iron Works) to a classification rotor rotation speed of 10000 rpm, a crushing nozzle pressure of 0.63 MPa, and a processing speed of 2.6 kg / hour. Except for the above, the liquid crystal polyester fine particle powder of Example 2 was obtained in the same manner as in the production of the liquid crystal polyester fine particle powder of Example 1. The average particle size of the liquid crystal polyester fine particle powder was 10 μm.

[Example 3]
Liquid crystal polyester powder was crushed by setting the processing conditions of a jet mill (“KJ-200” manufactured by Kurimoto Iron Works) to a classification rotor rotation speed of 10000 rpm, a crushing nozzle pressure of 0.60 MPa, and a processing speed of 4.0 kg / hour. Except for the above, the liquid crystal polyester fine particle powder of Example 3 was obtained in the same manner as in the production of the liquid crystal polyester fine particle powder of Example 1. The average particle size of the liquid crystal polyester fine particle powder was 15 μm.

[Comparative Example 1]
The liquid crystal polyester fine particle powder of Example 1 was used in place of the jet mill, except that the liquid crystal polyester powder was crushed by using a freezing / impact crusher (Linlex mill manufactured by Hosokawa Micron) at a processing speed of 10 kg / hour. The liquid crystal polyester fine particle powder of Comparative Example 1 was obtained in the same manner as in the production. The average particle size of the liquid crystal polyester fine particle powder was 27 μm.

[Comparative Example 2]
-Production of liquid crystal polyester (D) The powder of the liquid crystal polyester (A) obtained in Example 1 was filled in a SUS tray and heat-treated at 290 ° C. for 6 hours to obtain a liquid crystal polyester (D).

-Manufacture of liquid crystal polyester fine particle powder Then, using a jet mill ("KJ-200" manufactured by Kurimoto Iron Works), the classification rotor rotation speed was set to 10000 rpm, the crushing nozzle pressure was set to 0.60 MPa, and the processing speed was set to 0.1 kg / hour. The liquid crystal polyester fine particle powder of Comparative Example 2 was obtained in the same manner as in the production of the liquid crystal polyester fine particle powder of Example 1 except that the powder of the liquid crystal polyester (D) of the lever was pulverized. The average particle size of the liquid crystal polyester fine particle powder was 7 μm.

Relative permittivity and dielectric loss tangent were measured for each of the obtained liquid crystal polyester fine particle powders.

Table 1 shows each of the above items and their measurement results.

<Manufacturing of liquid crystal polyester film>
[Examples 1-1 to 3-1 and Comparative Examples 1-1 to 2-1]
Preparation of dispersion 8 parts by weight of each of the above liquid crystal polyester fine particle powders of Examples 1 to 2 and Comparative Examples 1 and 2 was added to 92 parts by weight of N-methyl2-pyrrolidone (boiling point (1 atm) 204 ° C.). In addition, each dispersion was obtained by stirring using a stirring defoamer AR-500 manufactured by Shinky Co., Ltd.

-Manufacture of liquid crystal polyester film A film applicator with a micrometer (3EC-VLP 18 μm manufactured by Mitsui Mining & Smelting Co., Ltd.) was applied to the roughened surface of each of the above dispersions so that the thickness of the cast film was 300 μm. After casting using SHEEN's "SA204") and an automatic coating device (Tester Sangyo Co., Ltd.'s "I type"), it is dried at 40 ° C. and normal pressure (1 atm) for 4 hours. Removed the solvent from the casting film. In Comparative Example 2-1 the dispersion liquid became a gel and could not be cast, and could not be formed into a film.

After the above drying, the temperature was further raised from room temperature to 310 ° C. at 7 ° C./min in a hot air oven under a nitrogen atmosphere, and heat treatment was performed to maintain the temperature at that temperature for 6 hours to obtain a liquid crystal polyester film with a copper foil.

The obtained liquid crystal polyester film with a copper foil was immersed in an aqueous solution of ferric chloride, and the copper foil was removed by etching to obtain a single-layer film.
The appearance of each film was confirmed. The liquid crystal polyester film of Comparative Example 1-1 had a large number of holes on the surface and had a poor appearance, and was of a quality unsuitable as a film for electronic components.

Table 1 shows each of the above items and their measurement results.

In Comparative Example 2-1 using the liquid crystal polyester fine particle powder of Comparative Example 2 containing the liquid crystal polyester whose number average molecular weight does not satisfy the range of 10,000 or less, the liquid crystal polyester film could not be produced. On the other hand, the liquid crystal polyester film of Examples 1-1 to 3-1 can be produced by using the liquid crystal polyester fine particle powder of Examples 1 to 3 containing the liquid crystal polyester having a number average molecular weight in the range of 10,000 or less as a raw material. Met.
Further, the liquid crystal polyester film of Comparative Example 1-1 produced from the liquid crystal polyester fine particle powder of Comparative Example 1 whose average particle size does not satisfy the range of 0.5 to 20 μm has many holes on the surface. The appearance was poor. On the other hand, the liquid crystal polyester films of Examples 1-1 to 3-1 produced from the liquid crystal polyester fine particle powders of Examples 1 to 3 having an average particle size in the range of 0.5 to 20 μm have a thickness. It was thin and had an excellent appearance. The results of the appearance evaluation of the liquid crystal polyester films of Examples 1-1 to 3-1 and Comparative Example 1-1 were "G" for those having excellent appearance without any holes, and the appearance with many holes. Those with a defect are listed in Table 1 as "F".

<Manufacturing of liquid crystal polyester film>
Using the liquid crystal polyester fine particle powder of the liquid crystal polyester (A) obtained in Example 1 as a raw material, the liquid crystal polyester films of Examples 1-1 to 1-5 were produced by changing the heat treatment conditions. The liquid crystal polyester film of Example 1-1 was obtained by the same production method as that of Example 1-1.

[Example 1-1]
-Preparation of dispersion liquid 8 parts by weight of the liquid crystal polyester fine particle powder of the liquid crystal polyester (A) produced in Example 1 above was put into 92 parts by weight of N-methyl-2-pyrrolidone, and stirred and removed by Shinky Co., Ltd. The mixture was stirred using a foamer AR-500 to obtain a dispersion liquid.

-Manufacture of liquid crystal polyester film A film applicator with a micrometer (3EC-VLP 18 μm manufactured by Mitsui Mining & Smelting Co., Ltd.) was applied to the roughened surface of each of the above dispersions so that the thickness of the cast film was 300 μm. After casting using SHEEN's "SA204") and an automatic coating device (Tester Sangyo Co., Ltd.'s "I type"), it is dried at 40 ° C. and normal pressure (1 atm) for 4 hours. Removed the solvent from the casting film.
After the above drying, the temperature is further raised from room temperature to 310 ° C. in a hot air oven under a nitrogen atmosphere at 7 ° C./min, and heat treatment is performed to maintain the temperature at that temperature for 6 hours. The liquid crystal polyester film with copper foil of Example 1-1 is subjected to heat treatment. Got

[Example 1-2]
The heat treatment conditions were raised from room temperature to 330 ° C. at 7 ° C./min, but with the copper foil of Example 1-2 in the same manner as in the production of the liquid crystal polyester film with copper foil of Example 1-1. A liquid crystal polyester film was obtained.

[Example 1-3]
The heat treatment conditions were raised from room temperature to 310 ° C. at 4 ° C./min, but with the copper foil of Example 1-3 in the same manner as in the production of the liquid crystal polyester film with copper foil of Example 1-1. A liquid crystal polyester film was obtained.

[Example 1-4]
The heat treatment conditions were raised from room temperature to 300 ° C. at 7 ° C./min, but with the copper foil of Example 1-4 in the same manner as in the production of the liquid crystal polyester film with copper foil of Example 1-1. A liquid crystal polyester film was obtained.

[Example 1-5]
The heat treatment conditions were raised from room temperature to 310 ° C. at 3 ° C./min, but with the copper foil of Example 1-5 in the same manner as in the production of the liquid crystal polyester film with copper foil of Example 1-1. A liquid crystal polyester film was obtained.

[Comparative Example 3]
A liquid crystal polyester soluble in an organic solvent was produced, and the liquid crystal polyester film of Comparative Example 3 was produced using the liquid crystal polyester as a raw material as follows.

-Manufacture of liquid crystal polyester (B) For reactors equipped with a stirrer, torque meter, nitrogen gas introduction pipe, thermometer and reflux condenser
6-Hydroxy-2-naphthoic acid 940.9 g (5.0 mol), 4-hydroxyacetaminophen 377.9 g (2.5 mol), isophthalic acid 415.3 g (2.5 mol) and acetic anhydride 867. After adding 8 g (8.4 mol) and replacing the gas in the reactor with nitrogen gas, the temperature was raised from room temperature to 140 ° C. over 60 minutes with stirring under a nitrogen gas stream for 3 hours at 140 ° C. It was refluxed.
Then, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150 ° C. to 300 ° C. over 5 hours, held at 300 ° C. for 30 minutes, and then the contents were taken out from the reactor and brought to room temperature. Cooled. The obtained solid matter was pulverized with a pulverizer to obtain a powdery liquid crystal polyester (B1). The flow start temperature of this liquid crystal polyester (B1) was 193.3 ° C.

The liquid crystal polyester (B1) obtained above is heated in a nitrogen atmosphere from room temperature to 160 ° C. over 2 hours and 20 minutes, then from 160 ° C. to 180 ° C. over 3 hours and 20 minutes, and at 180 ° C. By holding for 5 hours, it was subjected to solid phase polymerization, cooled, and then pulverized with a pulverizer to obtain a powdery liquid crystal polyester (B2). The flow start temperature of this liquid crystal polyester (B2) was 220 ° C.

The liquid crystal polyester (B2) obtained above is heated from room temperature to 180 ° C. over 1 hour and 25 minutes in a nitrogen atmosphere, and then from 180 ° C. to 255 ° C. over 6 hours and 40 minutes at 255 ° C. By holding for 5 hours, solid-phase polymerization was carried out and then cooled to obtain a powdery liquid crystal polyester (B). The flow start temperature of the liquid crystal polyester (B) was 302 ° C. The melting point of this liquid crystal polyester (B) was measured using a differential scanning calorimetry device and found to be 311 ° C.

-Preparation of liquid crystal polyester solution 8 parts by mass of liquid crystal polyester (B) is added to 92 parts by mass of N-methylpyrrolidone (boiling point (1 atm) 204 ° C.) and stirred at 140 ° C. for 4 hours under a nitrogen atmosphere to obtain liquid crystal polyester. A solution was prepared. The viscosity of this liquid crystal polyester solution was 955 mPa · s.

-Manufacture of liquid crystal polyester film A film applicator with a micrometer (SHEEN) so that the liquid crystal polyester solution is applied to the roughened surface of a copper foil (3EC-VLP 18 μm manufactured by Mitsui Mining & Smelting Co., Ltd.) so that the thickness of the cast film is 300 μm. "SA204") and an automatic coating device ("I type" of Tester Sangyo Co., Ltd.), and then dried at 40 ° C. and normal pressure (1 atm) for 4 hours. The solvent was removed from the casting film. Further, a second casting was performed on the surface of the dried liquid crystal polyester (B) so that the thickness of the casting film was 300 μm, and the dried liquid crystal polyester (B) was dried at 40 ° C. and normal pressure (1 atm) for 4 hours. , The solvent was removed from the casting film.

After the above drying, the temperature is further raised from room temperature to 270 ° C. at 1 ° C./min in a hot air oven under a nitrogen atmosphere, and heat treatment is performed to maintain the temperature at that temperature for 2 hours to obtain a liquid crystal polyester film with a copper foil of Comparative Example 3. It was.

[Comparative Example 4]
-Production of liquid crystal polyester (C) The powder of the liquid crystal polyester (A) obtained in Example 1 above was filled in a SUS tray and heat-treated at 280 ° C. for 6 hours to obtain a liquid crystal polyester (C). The flow start temperature of the obtained liquid crystal polyester (C) was 306 ° C.

-Manufacture of liquid crystal polyester film 100 parts by weight of the obtained liquid crystal polyester (C) is granulated at 325 ° C. using a twin-screw extruder ("PCM-30" manufactured by Ikekai Iron Works Co., Ltd.) to obtain pellets. It was. The melting point of this pellet was measured using a differential scanning calorimetry device and found to be 319 ° C.

The obtained pellets were melt-extruded with a single-screw extruder, and then inflation film formation was performed using an annular inflation die having a die diameter of 30 mm and a slit spacing of 0.25 mm. At that time, a film was formed while filtering the dissolved liquid crystal polyester using a filtration device (leaf disc type filter, manufactured by Nippon Seisen Co., Ltd.) connected to the inlet of the annular inflation die. As the filtration device, 16 Naslon filters LF4-0 NF2M-05D2 (manufactured by Nippon Seisen Co., Ltd., filtration accuracy 5.0 μm, leaf disc type) were laminated and used.

The liquid crystal polyester film of Comparative Example 4 was obtained by extruding the draw ratio of TD with respect to the draw ratio of MD from the annular inflation die heated to 340 ° C. under the condition of 4.3.

The liquid crystal polyester films with copper foils obtained in Examples 1-1 to 1-5 and Comparative Examples 3 to 4 were immersed in an aqueous solution of ferric chloride, and the copper foil was removed by etching to obtain a single-layer film.

Table 2 shows each of the above items and their measurement results.

The liquid crystal polyester film of Examples 1-1 to 1-5 was obtained by casting a dispersion liquid of liquid crystal polyester fine particle powder on a copper foil and then heat-treating it (abbreviated as "dispersion liquid cast" in the table). Therefore, it has excellent dielectric properties, low molecular orientation (MOR), and excellent properties.
The liquid crystal polyester film of Comparative Example 3 was obtained by casting a solution of the liquid crystal polyester fine powder on a copper foil (abbreviated as "solution cast" in the table), and thus is non-oriented, but solution cast. The method tends to be inferior in dielectric properties due to the limitation of using liquid crystal polyester that is soluble in a solvent as a raw material.
Since the liquid crystal polyester film of Comparative Example 4 was obtained by the inflation method, it tended to have a high degree of molecular orientation (MOR), and there was a difference in linear expansion between MD and TD.

Each configuration and a combination thereof in each embodiment is an example, and the configuration can be added, omitted, replaced, and other changes are possible without departing from the spirit of the present invention. Moreover, the present invention is not limited to each embodiment, but is limited only to the scope of claims.

1 ... Liquid crystal polyester powder, 3 ... Medium, 30 ... Liquid crystal polyester composition, 10 ... Liquid crystal polyester film, 11 ... Film, 12 ... Support, 13 ... Metal layer, 20, 21 ... Laminate, 22 ... Laminate precursor , 40 ... Liquid crystal polyester film precursor

Claims (8)

A liquid crystal polyester powder containing a liquid crystal polyester having a number average molecular weight of 10,000 or less and having an average particle size of 0.5 to 20 μm. The liquid crystal polyester powder according to claim 1, wherein the relative permittivity at a frequency of 1 GHz is 3 or less, and the dielectric loss tangent at a frequency of 1 GHz is 0.005 or less. The liquid crystal polyester powder according to claim 1 or 2, wherein the liquid crystal polyester has a structural unit containing a naphthalene structure. The liquid crystal polyester powder according to claim 3, wherein the content of the structural unit containing the naphthalene structure is 40 mol% or more with respect to 100 mol% of the total amount of all the structural units in the liquid crystal polyester. According to claim 3 or 4, the liquid crystal polyester has a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3). The liquid crystal polyester powder described.
(1) -O-Ar ^1- CO-
(2) -CO-Ar ^2- CO-
(3) -O-Ar ^3- O-
(Ar ¹ represents a 2,6-naphthalenedyl group, a 1,4-phenylene group, or a 4,4'-biphenylylene group.
Ar ² and Ar ³ independently have a 2,6-naphthalenedyl group, a 2,7-naphthalenedyl group, a 1,4-phenylene group, a 1,3-phenylene group, or a 4,4'-biphenylylene group. Represent.
The hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is 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. May be good. ) A liquid crystal polyester composition containing a medium and the liquid crystal polyester powder according to any one of claims 1 to 5. A method for producing a liquid crystal polyester film, which comprises applying the liquid crystal polyester composition according to claim 6 on a support and heat-treating it to obtain a liquid crystal polyester film containing the liquid crystal polyester. The liquid crystal polyester composition according to claim 6 is applied onto the support and heat-treated to form a liquid crystal polyester film containing the liquid crystal polyester, thereby forming a laminate having the support and the liquid crystal polyester film. A method for producing a laminate, including obtaining.

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