JP2013189535A - Method of producing liquid crystal polyester film and liquid crystal polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a liquid crystal polyester film capable of easily producing a high quality liquid crystal polyester film.SOLUTION: A method of producing a liquid crystal polyester film includes processes of: applying a liquid composition including a liquid crystal polyester and an organic solvent dissolving the liquid crystal polyester to the surface of a heat resistant resin film having a contact angle of ≤50° with the liquid composition, and then, removing the organic solvent to form a laminate wherein the heat resistant resin film and a coating film including the liquid crystal polyester are layered; subjecting the laminate to heat treatment under an inert gas atmosphere in a temperature condition of 230-340°C; and peeling off the heat resistant resin film from the laminate after the heat treatment at a peeling angle within a range of 135-180°.

Description

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

  Liquid crystal polyesters are widely used in precision electronic parts such as connectors obtained by injection molding because they exhibit excellent low moisture absorption, heat resistance, insulation, mechanical strength, and the like. In recent years, liquid crystal polyester is processed into a film shape, and further application development is being studied.

  As a method for producing a liquid crystal polyester film, a liquid composition in which a liquid crystal polyester is dissolved in an organic solvent is used. After the liquid composition is applied on a substrate, the solvent is removed, and thereby a liquid crystal polyester film is formed on the substrate. A method of forming is being studied (for example, see Patent Documents 1 to 6). According to this method, unlike the case where a film is formed by melt processing, it is possible to improve the anisotropy of mechanical properties caused by the orientation of the resin in the extrusion direction.

JP 2004-203032 A JP 2006-88426 A JP 2010-142963 A JP 2011-167847 A JP 2011-62987 A JP 2004-209969 A

  However, in the above method, when the liquid crystal polyester film is peeled off from the base material, a part of the liquid crystal polyester film may be damaged and remain on the base material, which may cause a deterioration in quality. Therefore, there has been a demand for a production method that can suppress breakage during peeling.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the manufacturing method of the liquid crystalline polyester film which can manufacture a high quality liquid crystalline polyester film easily. Another object is to provide a high-quality liquid crystal polyester film manufactured by the above-described manufacturing method.

  In order to solve the above-described problems, one embodiment of the present invention provides a liquid composition containing a liquid crystal polyester and an organic solvent for dissolving the liquid crystal polyester, a heat resistant resin having a contact angle of 50 ° or less with the liquid composition. The step of forming the laminate in which the organic solvent is removed after coating on the surface of the film and the heat-resistant resin film and the coating film containing the liquid crystal polyester are laminated, and the laminate in an inert gas atmosphere A liquid crystal polyester film comprising: a step of heat-treating under a temperature condition of 230 ° C. or higher and 340 ° C. or lower; and a step of peeling the heat-resistant resin film from the laminated body after the heat treatment in a range of a peel angle of 135 ° to 180 °. A manufacturing method is provided.

  Here, the “heat resistance” of the “heat resistant resin film” means that the heat treatment performed in a temperature range of 230 ° C. or higher and 340 ° C. or lower in an inert atmosphere does not cause changes such as melting, deformation, and alteration, It refers to the property capable of maintaining physical properties. That is, if the heat treatment temperature is 230 ° C., the heat resistant resin film only needs to have heat resistance capable of withstanding the heat treatment of 230 ° C. If the heat treatment temperature is 340 ° C., the heat resistant resin film is heat treated at 340 ° C. Must be heat resistant.

  In addition, the “peeling angle” in this specification refers to the surface of the liquid crystal polyester film that is exposed by peeling the heat resistant resin film, and the direction of the force when peeling the heat resistant resin film (the pulling direction of the heat resistant resin film). ) And the angle between them.

In one aspect of the present invention, the liquid crystalline polyester comprises a repeating unit represented by the following formula (1), a repeating unit represented by the following formula (2), and a repeating unit represented by the following formula (3): It is desirable to have
(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(In the formula, Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X and Y each independently represents an oxygen atom or an imino group, and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ independently represents a halogen atom, an alkyl group or an aryl group. It may be substituted with a group.)
(4) -Ar ⁴ -Z-Ar ^5-
(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

  In one aspect of the present invention, the liquid crystalline polyester comprises 30 to 80 mol% of the repeating unit represented by the formula (1) based on the total amount of all repeating units, and the formula (2). It is desirable to have 10 to 35 mol% of repeating units represented, and 10 to 35 mol% of repeating units represented by the formula (3).

  In one aspect of the present invention, either one or both of the X and Y is preferably an imino group.

  5. The method for producing a liquid crystal polyester film according to claim 1, wherein the organic solvent is an aprotic solvent.

  In one embodiment of the present invention, the aprotic solvent is preferably an aprotic solvent having no halogen atom.

  In one embodiment of the present invention, the aprotic solvent is preferably an amide solvent.

  In one aspect of the present invention, the heat-resistant resin film is preferably a polyimide film.

  In one embodiment of the present invention, it is desirable that the heat resistant resin film has a thickness of 25 μm or more and 75 μm or less.

  One aspect of the present invention provides a liquid crystal polyester film manufactured by the above-described method for manufacturing a liquid crystal polyester film.

  In one embodiment of the present invention, the thickness is desirably 5 μm or more and 50 μm or less.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the liquid crystal polyester film which can manufacture a high quality liquid crystal polyester film easily can be provided. Moreover, the high quality liquid crystal polyester film manufactured with the above-mentioned manufacturing method can be provided.

It is process drawing which shows the manufacturing method of the liquid crystalline polyester film of this embodiment.

The method for producing a liquid crystal polyester film of the present embodiment includes a liquid composition containing a liquid crystal polyester and an organic solvent for dissolving the liquid crystal polyester, and a surface of a heat resistant resin film having a contact angle of 50 ° or less with the liquid composition. The organic solvent is removed after coating, and a step of forming a laminate in which the heat-resistant resin film and the coating film containing the liquid crystalline polyester are laminated, and the laminate is 230 ° C. or higher in an inert gas atmosphere. A heat treatment under a temperature condition of 340 ° C. or less, and a step of peeling the heat-resistant resin film from the laminate after the heat treatment within a peel angle of 135 ° to 180 °.
Hereinafter, preferred embodiments of the present invention will be described in order.

(Liquid crystal polyester)
The liquid crystalline polyester used in the method for producing a liquid crystalline polyester film of the present embodiment is a liquid crystalline polyester that exhibits liquid crystallinity 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 wholly aromatic liquid crystal polyester using only an aromatic compound as a raw material monomer.

  A typical example of the liquid crystal polyester is polymerization (polycondensation) of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine, and an aromatic diamine. At least one compound selected from the group consisting of aromatic dicarboxylic acids and aromatic diols, aromatic hydroxyamines and aromatic diamines, And those obtained by polymerizing a polyester such as polyethylene terephthalate and an aromatic hydroxycarboxylic acid. Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are each independently replaced with a part or all of the polymerizable derivative. Also good.

  Examples of polymerizable derivatives of a compound having a carboxy group such as an aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid include those obtained by converting a carboxy group into an alkoxycarbonyl group or an aryloxycarbonyl group (ester), carboxy Examples 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 include those obtained by acylating a hydroxy group and converting it to an acyloxyl group (acylated product) ). Examples of polymerizable derivatives of amino group-containing compounds such as aromatic hydroxyamines and aromatic diamines include those obtained by acylating an amino group and converting it to an acylamino group (acylated product).

  The liquid crystalline polyester preferably has a repeating unit represented by the following formula (1) (hereinafter sometimes referred to as “repeating unit (1)”), and the repeating unit (1) and the following formula (2) A repeating unit represented (hereinafter sometimes referred to as “repeating unit (2)”) and a repeating unit represented by the following formula (3) (hereinafter sometimes referred to as “repeating unit (3)”). And more preferably.

(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X And Y each independently represents an oxygen atom or an imino group (—NH—), and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is independently a halogen atom or an alkyl group. Alternatively, it may be substituted with an aryl group.)
(4) -Ar ⁴ -Z-Ar ^5-
(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

  As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned.

  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, 2-ethylhexyl group, An n-octyl group and an n-decyl group are mentioned, The carbon number becomes like this. Preferably it is 1-10.

  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, and the carbon number thereof is preferably 6-20. is there.

When the hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is substituted with these groups, the number is as follows for each group represented by Ar ¹ , Ar ² or Ar ³ . Independently, it is preferably 2 or less, more preferably 1.

  Examples of the alkylidene group include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group, and a 2-ethylhexylidene group, and the carbon number thereof is preferably 1-10.

The repeating unit (1) is a repeating unit derived from a predetermined aromatic hydroxycarboxylic acid. As the repeating unit (1), Ar ¹ is a p-phenylene group (repeating unit derived from p-hydroxybenzoic acid), and Ar ¹ is a 2,6-naphthylene group (6-hydroxy-2). -Repeating units derived from naphthoic acid) are preferred.

The repeating unit (2) is a repeating unit derived from a predetermined aromatic dicarboxylic acid. As the repeating unit (2), Ar ² is a p-phenylene group (a repeating unit derived from terephthalic acid), Ar ² is an m-phenylene group (a repeating unit derived from isophthalic acid), Ar ² Is a 2,6-naphthylene group (a repeating unit derived from 2,6-naphthalenedicarboxylic acid), and Ar ² is a diphenyl ether-4,4′-diyl group (diphenyl ether- 4,4′-dicarboxylic acid-derived repeating units) are preferred.

The repeating unit (3) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (3), Ar ³ is a p-phenylene group (a repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), and Ar ³ is a 4,4′-biphenylylene group. Those (4,4′-dihydroxybiphenyl, 4-amino-4′-hydroxybiphenyl or repeating units derived from 4,4′-diaminobiphenyl) are preferred.

  The content of the repeating unit (1) is the total amount of all repeating units (the mass equivalent amount of each repeating unit (moles by dividing the mass of each repeating unit constituting the liquid crystal polyester by the formula amount of each repeating unit). ), And the total value thereof) is preferably 30 mol% or more, more preferably 30 mol% or more and 80 mol% or less, still more preferably 30 mol% or more and 60 mol% or less, and even more preferably 30 mol%. It is mol% or more and 40 mol% or less.

  Similarly, the content of the repeating unit (2) is preferably 35 mol% or less, more preferably 10 mol% or more and 35 mol% or less, further preferably 20 mol% or more 35 with respect to the total amount of all repeating units. The mol% or less, more preferably 30 mol% or more and 35 mol% or less.

  Similarly, the content of the repeating unit (3) is preferably 35 mol% or less, more preferably 10 mol% or more and 35 mol% or less, further preferably 20 mol% or more 35 with respect to the total amount of all repeating units. The mol% or less, more preferably 30 mol% or more and 35 mol% or less.

  As the content of the repeating unit (1) increases, the heat resistance, the strength and the rigidity are easily improved. However, when the content is too large, the solubility in a solvent tends to be low.

  The ratio between the content of the repeating unit (2) and the content of the repeating unit (3) is expressed as [content of repeating unit (2)] / [content of repeating unit (3)] (mol / mol). The ratio is preferably 0.9 / 1 to 1 / 0.9, more preferably 0.95 / 1 to 1 / 0.95, and still more preferably 0.98 / 1 to 1 / 0.98.

  In addition, liquid crystalline polyester may have 2 or more types of repeating units (1)-(3) each independently. The liquid crystalline polyester may have a repeating unit other than the repeating units (1) to (3), but the content thereof is preferably more than 0 mol% and 10% with respect to the total amount of all repeating units. The mol% or less, more preferably more than 0 mol% and 5 mol% or less.

  The liquid crystalline polyester has a repeating unit (3) having one or both of X and Y being imino groups, that is, a repeating unit derived from a predetermined aromatic hydroxylamine, and an aromatic diamine. It is preferable to have either one or both of the repeating unit derived from it because of excellent solubility in a solvent, and as the repeating unit (3), only one in which either one or both of X and Y is an imino group More preferably.

  The liquid crystal polyester is preferably produced by melt polymerization of raw material monomers corresponding to the repeating units constituting the liquid crystal polyester, and solid-phase polymerization of the obtained polymer (prepolymer). Thereby, high molecular weight liquid crystal polyester having high heat resistance, strength and rigidity can be produced with good operability. Melt polymerization may be carried out in the presence of a catalyst. Examples of this catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, And nitrogen-containing heterocyclic compounds such as 4- (dimethylamino) pyridine and 1-methylimidazole, and nitrogen-containing heterocyclic compounds are preferably used.

  The liquid crystal polyester has a flow initiation 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. As the flow start temperature is higher, the heat resistance, strength, and rigidity are likely to be improved. However, if the flow start temperature is too high, the solubility in a solvent tends to be low, and the viscosity of the solution tends to be high.

The flow start temperature is also called the flow temperature or flow temperature, and the liquid crystal polyester is heated at a rate of 4 ° C./min under a load of 9.8 MPa (100 kgf / cm ² ) using a capillary rheometer. Is a temperature showing a viscosity of 4800 Pa · s (48000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and is a measure of the molecular weight of the liquid crystalline polyester (Naide Koide, “ “Liquid Crystal Polymer—Synthesis / Molding / Application—”, CMC Co., Ltd., June 5, 1987, p. 95).

(Organic solvent)
The liquid composition used in the method for producing a liquid crystal polyester film of the present embodiment includes the liquid crystal polyester as described above and an organic solvent. As the organic solvent, one that can dissolve the liquid crystal polyester to be used, specifically, one that can be dissolved at a concentration of 1% by mass or more at 50 ° C. ([liquid crystal polyester] / [liquid crystal polyester + solvent]) is appropriately selected. Used.

  Examples of organic solvents include halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, o-dichlorobenzene; p-chlorophenol, pentachlorophenol, pentafluoro Halogenated phenols such as phenol; Ethers such as diethyl ether, tetrahydrofuran and 1,4-dioxane; Ketones such as acetone and cyclohexanone; Esters such as ethyl acetate and γ-butyrolactone; Carbonates such as ethylene carbonate and propylene carbonate; Triethylamine and the like Amines; Nitrogen-containing heterocyclic aromatic compounds such as pyridine; Nitriles such as acetonitrile and succinonitrile; Ami such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone System solvents (organic solvents having an amide bond in the molecule); urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethylsulfoxide and sulfolane; and hexamethylphosphoric acid amide and tri-n-butylphosphorus Examples thereof include phosphorus compounds such as acids. Of these organic solvents, two or more organic solvents may be used in combination.

  As the organic solvent, a solvent having an aprotic compound as a main component (aprotic solvent), particularly a solvent having an aprotic compound having no halogen atom as a main component is preferable because it is low in corrosivity and easy to handle. . As this aprotic compound, it is preferable to use an amide solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and the like because the liquid crystalline polyester is easily dissolved. The proportion of the aprotic compound in the whole organic solvent is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and further preferably 90% by mass to 100% by mass. is there.

  The organic solvent is preferably a solvent mainly composed of a compound having a dipole moment of 3 to 5 (unit: Debye) because it easily dissolves the liquid crystalline polyester, and is an aprotic compound described above, It is more preferable to use a compound having a dipole moment of 3 to 5. The proportion of the compound having a dipole moment of 3 to 5 in the entire organic solvent is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and still more preferably 90% by mass. It is 100 mass% or less.

  Examples of the aprotic compound having a dipole moment of 3 to 5 include dimethyl sulfoxide (dipole moment: 4.1 debye), N, N-dimethylacetamide (3.7 debye), N, N -Dimethylformamide (3.9 debye) and N-methylpyrrolidone (4.1 debye) can be exemplified.

  The organic solvent is preferably a solvent mainly composed of a compound having a boiling point of 220 ° C. or less at 1 atm because it is easy to remove, and is the above-mentioned aprotic compound having a boiling point of 220 at 1 atm. It is more preferable to use a compound having a temperature of 0 ° C or lower. The proportion of the compound having a boiling point of 220 ° C. or less at 1 atm in the entire organic solvent is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and still more preferably 90% by mass. % Or more and 100% by mass or less.

  N, N-dimethylacetamide (boiling point: 160 ° C.) N, N-dimethylformamide (153 ° C.) can be exemplified as a compound that is an aprotic compound and has a boiling point of 220 ° C. or less at 1 atm. .

(Liquid composition)
The content of the liquid crystal polyester in the liquid composition is preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and still more preferably with respect to the total amount of the liquid crystal polyester and the organic solvent. It is 15 mass% or more and 45 mass% or less, and is adjusted suitably so that the liquid composition of desired viscosity may be obtained.

  Further, the liquid composition may contain one or more components such as a filler, an additive, and a resin other than the liquid crystal polyester as long as the production method of the present invention is not impaired.

  Examples of fillers include inorganic fillers such as silica, alumina, titanium oxide, barium titanate, strontium titanate, aluminum hydroxide, calcium carbonate; and leveling agents, cured epoxy resins, crosslinked benzoguanamine resins, crosslinked acrylic resins, etc. The content thereof is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the liquid crystalline polyester.

  Examples of the additive include a leveling agent, an antifoaming agent, an antioxidant, an ultraviolet absorber, a flame retardant, and a colorant, and the content thereof is preferably 0 part by mass with respect to 100 parts by mass of the liquid crystalline polyester. The amount is 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 modified products thereof, and heat other than liquid crystal polyester such as polyether imide. Examples 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 100 parts by mass of the liquid crystalline polyester. Preferably, it is 0 to 20 parts by mass.

  The liquid composition can be prepared by mixing the liquid crystal polyester, the organic solvent, and other components used as necessary, all at once or in an appropriate order. When using a filler as another component, it is preferable to prepare by dissolving liquid crystal polyester in an organic solvent to obtain a liquid composition, and then dispersing the filler in the liquid composition.

  In the method for producing a liquid crystal polyester film of the present embodiment, a heat resistant resin film having a contact angle with the above-described liquid composition of 50 ° or less is used.

  The contact angle includes (i) the surface energy (surface tension) of the surface to which the liquid composition of the heat resistant resin film is applied (application surface), (ii) the surface tension of the liquid composition, and (iii) the heat resistant resin film. Based on the interfacial tension between the coated surface and the liquid composition, it can be expressed by the Young equation. Therefore, when there is a heat-resistant film having a contact angle exceeding 50 ° in relation to a certain liquid composition, (a) surface treatment is performed on the heat-resistant resin film to reduce the surface energy, and (b) the liquid composition is diluted. The contact angle is appropriately adjusted to 50 ° or less by various operations such as lowering the viscosity and (c) adding a polar solvent to the liquid composition to increase the interfacial tension between the heat-resistant resin film and the liquid composition. be able to.

  The contact angle is preferably 5 ° or more and 50 ° or less, and more preferably 7 ° or more and 30 ° or less. When the contact angle is 5 ° or more, the adhesive force at the interface between the heat-resistant resin film and the liquid crystal polyester film is small, and breakage is difficult to occur when the liquid crystal polyester film is peeled off.

  Examples of the surface treatment method for the heat resistant resin film include corona discharge treatment, flame treatment, solvent treatment, UV treatment, and plasma treatment.

  As the heat-resistant resin film, it is preferable that the surface has polyimide as a forming material because it has releasability, heat resistance, and coatability. A commercially available polyimide (PI) film can be used as the heat-resistant resin film, for example, Ube Industries, Ltd. PI film (U-Pyrex S, U-Pyrex R), Toray DuPont film (Kapton), SKC Kolon Examples include films manufactured by PI (IF30, IF70, LV300).

  The film thickness of the heat resistant resin film is preferably 25 μm or more and 75 μm or less, and more preferably 50 μm or more and 75 μm or less. When the film thickness of the heat resistant resin film is 25 μm or more, handling becomes easier than a thin film having a thickness of less than 25 μm. Further, when the film thickness of the heat resistant resin film is 75 μm or less, the operation of peeling at a desired angle is easier in the manufacturing method described later than that having a thickness greater than 75 μm.

(Production method of liquid crystal polyester film)
FIG. 2 is a process diagram showing a method for producing a liquid crystal polyester film of the present embodiment. In the manufacturing method of the liquid crystalline polyester film of this embodiment, a liquid crystalline polyester film is formed on the heat resistant resin film described above by the method shown in the drawing.

(Application)
First, as shown in FIG. 2A, the liquid composition 12S described above is applied on a support (heat resistant resin film) 10.

  Examples of the method for applying the liquid composition 12S onto the support 10 include 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 die coating method, and a screen printing method. It is done. In FIG. 2A, the liquid composition S is illustrated as being applied from the die 50.

(Solvent removal)
Next, as shown in FIG. 2B, the solvent S is removed from the liquid composition 12 </ b> S applied on the support 10 and preliminarily dried to form a coating film 12 </ b> A containing liquid crystal polyester on the support 10. A laminated body 14 is obtained.

  The removal of the solvent S is preferably performed by evaporation of the solvent S because the operation is simple. Examples of the method include heating, decompression and ventilation, and these may be combined. Among these, from the viewpoint of productivity and operability, it is preferably performed by heating, and more preferably by heating while ventilating. The removal temperature of the solvent S is preferably 60 ° C. or more and 200 ° C. or less, and the removal time of the solvent S is preferably 10 minutes or more and 2 hours or less. When the removal temperature of the solvent S is 60 ° C. or higher, the removal of the solvent is completed in a short time, which is economical. When the temperature is 200 ° C. or lower, the solvent S does not evaporate all at once, and the surface is not roughened and is good. Appearance is good.

  It is desirable that the removal temperature of the solvent S is less than the boiling point of the solvent used. If the boiling point of the solvent S is higher than the boiling point of the solvent S, the surface of the coating film becomes rough due to the volatilization of the solvent S, and it is difficult to obtain a uniform coating film 12A.

  Further, the removal of the solvent S here is not necessarily complete, and the remaining solvent may be removed by the next heat treatment. If a large amount of the solvent S evaporates in the heat treatment described later, the surface of the coating film 12A may be roughened. Therefore, it is preferable to remove the solvent S as much as possible before the heat treatment. In this operation, the organic solvent may be removed from 1 part by mass to 25 parts by mass with respect to 100 parts by mass of the liquid crystalline polyester.

  Further, the operations from the application of the liquid composition 12S to the removal of the solvent S described above may be performed in a continuous manner or in a single wafer manner.

(Heat treatment)
Next, as shown in FIG. 2C, the laminate 14 is heated by adding heat H in an inert gas atmosphere, and heat-treated in a temperature range of 230 ° C. or higher and 320 ° C. or lower. The temperature range of the heat treatment is more preferably 250 ° C. or more and 320 ° C. or less, and further preferably 270 ° C. or more and 300 ° C. or less.
The heat treatment time is preferably 30 minutes or more and 5 hours or less.

  Next, as shown in FIG. 2D, the target liquid crystal polyester film 12 can be obtained by peeling the support 10. In the drawing, the surface of the liquid crystal polyester film 12 exposed by peeling the support 10 is indicated by reference numeral 12x, and the state in which the support 10 is pulled in the direction of force F and peeled from the liquid crystal polyester film 12 is shown. The angle formed between the surface 12 and the force F is the peeling angle θ. When the support 10 is peeled at the peeling angle θ, the liquid crystal polyester film 12 is not damaged.

  The peeling angle is from 135 ° to 180 °, preferably from 150 ° to 180 °, and more preferably from 165 ° to 180 °.

  In the present embodiment, a support having a film thickness of 25 μm or more and 75 μm or less may be used as the support 10. When the film thickness of the support 10 is 25 μm or more, handling becomes easier than a thin film having a thickness of less than 25 μm. Further, when the film thickness of the support 10 is 75 μm or less, the support 10 is easily bent in the operation of peeling at the above-described angle, and is more easily peeled than a film thicker than 75 μm.

  The obtained liquid crystal polyester film 12 is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 50 μm or less because it is easy to handle. The film thickness of the liquid crystal polyester film 12 can be appropriately controlled by controlling the concentration of the liquid composition to be applied, the speed of application, and the number of times of application to adjust the film thickness of the coating film.

  According to the method for producing a liquid crystal polyester film as described above, a high quality liquid crystal polyester film can be easily produced.

  Moreover, according to the above liquid crystal polyester film, it becomes a high quality thing, without an external appearance being impaired by damage.

  The liquid crystal polyester film of the present embodiment can be applied to uses such as a heat-resistant tape substrate, a printed wiring board substrate, a coverlay film, a speaker diaphragm, and a seamless belt.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. The above-described example is an example, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

(Measurement of flow start temperature of liquid crystal polyester)
The flow start temperature of the liquid crystal polyester is about 2 g of liquid crystal polyester filled in a cylinder equipped with a die having an inner diameter of 1 mm and a length of 10 mm using a flow tester (manufactured by Shimadzu Corporation, CFT-500 type). The liquid crystal polyester was melted while being heated at a rate of 4 ° C./min under a load of 9.8 MPa (100 kgf / cm ² ), extruded from a nozzle, and a temperature showing a viscosity of 4800 Pa · s (48000 poise). Obtained by measuring.

(Contact angle)
The contact angle of the support was measured using a wafer cleaning / processing evaluation apparatus (Kyowa Interface Chemical Co., Ltd., CA-X200, temperature 23 ° C., humidity 50% RH) for the liquid composition described later.

(Measurement of surface roughness (10-point average height))
The surface roughness of the support was measured as follows.
First, using a scanning probe microscope SPM-9500 manufactured by Shimadzu Corporation, measurement was performed under conditions of a temperature of 23 ° C. and a relative humidity of 50%. The measurement area was 10 μm ² .
Using the analysis software built in the device, in the roughness curve obtained by measurement, select 5 points from the highest peak of the curve and 5 points from the lowest of the bottom of the curve, and calculate the arithmetic average of the height values of 10 points in total The value obtained in this manner was adopted as the surface roughness value.

(Synthesis of liquid crystal polyester)
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 941 g (5.0 mol) of 2-hydroxy-6-naphthoic acid and 273 g (2.5 mol) of 4-aminophenol were added. ), 415.3 g (2.5 mol) of isophthalic acid and 1123 g (11 mol) of acetic anhydride. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to 150 ° C. over 15 minutes under a nitrogen gas stream, and the temperature was maintained and refluxed for 3 hours.
Next, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150 ° C. to 290 ° C. over 4 hours and 15 minutes, held at 290 ° C. for 30 minutes, and then the contents were taken out of the reactor, Until cooled. The obtained solid was pulverized with a pulverizer to obtain a powdery prepolymer. The flow initiation temperature of this prepolymer was 181 ° C.
Next, the prepolymer was heated from room temperature to 250 ° C. in a nitrogen atmosphere over 6 hours, and held at 250 ° C. for 10 hours to cause solid-phase polymerization, and then cooled to obtain a solid liquid crystal polyester. Got. The obtained solid was pulverized with a pulverizer to obtain a liquid crystalline polyester. The flow starting temperature of the liquid crystal polyester was 240 ° C.
The liquid crystal polyester was heated from room temperature to 255 ° C. over 6 hours under a nitrogen atmosphere and held at 255 ° C. for 3 hours to solid-phase polymerize and then cooled to obtain a powdered liquid crystal polyester. . The flow starting temperature of the liquid crystal polyester was 325 ° C.

(Preparation of liquid composition)
8 g of the liquid crystal polyester obtained by the above method was added to 92 g of N-methylpyrrolidone and stirred at 140 ° C. for 4 hours in a nitrogen atmosphere to prepare a liquid composition.

[Example 1]
A commercially available polyimide film (manufactured by Ube Industries, Upilex S, film thickness 75 μm, contact angle 14 °) is installed on the automatic coating apparatus I type (manufactured by Tester Sangyo) as a support, and a film applicator with a micrometer (manufactured by SHEEN) ) Was set to “500 μm”, the liquid composition was applied to the set film thickness, and then dried at 150 ° C. to prepare a laminate. In the laminated body after drying, the amount of solvent contained in the coating film formed by drying the liquid composition was 19.8%. The obtained laminate was treated at 270 ° C. for 2 hours under a nitrogen atmosphere. Thereby, the laminated body in which the liquid crystal polyester film was formed on the polyimide film was obtained.

  The obtained laminate is cut into a strip of 25 mm × 300 mm to create a test piece, and an adhesive is applied to the liquid crystal polyester film side of the test piece and fixed to a jig, and the polyimide film of the test piece is oriented in a 135 ° direction. The film was peeled off in the direction parallel to the long side of the test piece at a speed of 50 mm / min.

[Example 2]
The same operation as in Example 1 was performed except that the peeling angle was changed from 135 to 180 °.

[Example 3]
The same operation as in Example 2 was performed except that the heat treatment temperature was changed from 270 to 250 ° C.

[Example 4]
The same operation as in Example 2 was performed except that the heat treatment temperature was changed from 270 to 290 ° C.

[Example 5]
The same operation as in Example 1 was performed except that the heat treatment temperature was changed from 270 to 320 ° C.

[Example 6]
The same operation as in Example 1 was performed except that the heat treatment temperature was changed from 270 to 340 ° C.

[Example 7]
The same operation as in Example 1 was performed except that the support was changed to a different polyimide film (Toray DuPont, Kapton H, film thickness 25 μm, contact angle 7 °).

[Example 8]
The same operation as in Example 2 was performed except that the heat treatment temperature was changed from 270 to 230 ° C.

[Comparative Example 1]
The same operation as in Example 1 was performed except that the peeling angle was changed from 135 to 45 °. The peel strength was 0.24 N / cm, the liquid crystal polyester film was partially broken, and it was confirmed that it remained on the support.

[Comparative Example 2]
The same operation as in Example 1 was performed except that the peeling angle was changed from 135 to 90 °. The peel strength was 0.12 N / cm, the liquid crystal polyester film was partially broken, and it was confirmed that it remained on the support.

[Comparative Example 3]
The same operation as in Example 4 was performed except that the peel angle was changed from 180 to 90 °. The peel strength was 0.16 N / cm, the liquid crystal polyester film was partially broken, and it was confirmed that it remained on the support.

[Comparative Example 4]
The same operation as in Example 5 was performed except that the peeling angle was changed from 180 to 90 °.

[Comparative Example 5]
The same operation as in Example 6 was performed except that the peeling angle was changed from 180 to 90 °.

[Comparative Example 6]
The same operation as in Example 1 was performed except that the support was changed from PI to SUS foil (manufactured by Nikko Metal, SUS304HT, film thickness 25 μm, contact angle 21 °).

[Comparative Example 7]
The same operation as in Example 1 was performed except that the support was changed from PI to copper foil (manufactured by Mitsui Mining & Smelting, 3EC-VLP, film thickness 18 μm, contact angle 40 °).

[Comparative Example 8]
The same operation as in Example 1 was performed except that the support was changed from PI to PTFE (Freon Industries, F-8034-34, film thickness 100 μm, contact angle 82 °).

[Evaluation method]
(Peel strength)
The peel strength was measured at a width of 25 mm using a tester (Instron, Model 5566) under conditions of 23 ° C. and 50% RH based on JIS K6854. The test piece fixed the liquid crystal polyester film side on the 2 mm-thick stainless steel plate with the double-sided adhesive tape, and calculated | required the intensity | strength at the time of peeling by peeling a support body by the designated angle.

(Peelability evaluation)
About the test piece after peel strength evaluation, the surface which was in contact with the liquid-crystal polyester film of a support body was confirmed and evaluated. The case where the liquid crystal polyester film could be peeled without remaining on the support was designated as “◯”, and the case where the liquid crystal polyester film was broken and partly remained on the support was designated as “x”.

  The results are shown in Table 1 for Examples 1-8 and Comparative Examples 1-8.

  As a result of the evaluation, Examples 1 to 8 were able to be peeled well, and a high-quality liquid crystal polyester film without breakage could be obtained. Moreover, in Examples 1-6, the polyimide film which is a support body is a smooth thing whose surface roughness is 0.06 micrometer, and in Example 7, the polyimide film which is a support body is surface roughness. Was 0.2 μm, and the resulting liquid crystal polyester film was glossy and high quality on both the front and back.

  On the other hand, in each of Comparative Examples 1 to 7, the liquid crystal polyester film partially remained on the support. Moreover, it turned out that peel strength is high compared with Examples 1-8, and requires more energy than an Example for peeling operation.

  In Comparative Example 8, when the liquid composition was applied, the desired shape was not exhibited at the end of the region where the liquid composition was applied, and a liquid crystal polyester film having the intended shape could not be obtained. Moreover, the surface roughness of the used PTFE film was 0.9 μm, and the films had different appearances on the front and back sides.

  From these results, it was found that when the method for producing a liquid crystal polyester film of the present invention was used, a high-quality liquid crystal polyester film could be easily produced. Moreover, the liquid crystalline polyester of the present invention was of high quality without damaging the appearance due to breakage.

DESCRIPTION OF SYMBOLS 10 ... Support body (heat resistant porous film), 12 ... Liquid crystal polyester film, 12A ... Coating film, 12S ... Liquid composition, 14 ... Laminated body, 50 ... Die, F ... Power, H ... Heat, S ... Solvent, θ ... Peeling angle

Claims (11)

A liquid composition containing a liquid crystal polyester and an organic solvent for dissolving the liquid crystal polyester is applied to the surface of the heat-resistant resin film having a contact angle with the liquid composition of 50 ° or less, and then the organic solvent is removed. Forming a laminate in which a heat-resistant resin film and a coating film containing the liquid crystalline polyester are laminated;
Heat-treating the laminate in a temperature condition of 230 ° C. or higher and 340 ° C. or lower in an inert gas atmosphere;
A step of peeling the heat-resistant resin film from the laminate after the heat treatment in a range of a peel angle of 135 ° or more and 180 ° or less. 2. The liquid crystal polyester according to claim 1, wherein the liquid crystal polyester has a repeating unit represented by the following formula (1), a repeating unit represented by the following formula (2), and a repeating unit represented by the following formula (3). A method for producing a liquid crystal polyester film.
(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(In the formula, Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X and Y each independently represents an oxygen atom or an imino group, and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ independently represents a halogen atom, an alkyl group or an aryl group. It may be substituted with a group.)
(4) -Ar ⁴ -Z-Ar ^5-
(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)   The liquid crystalline polyester has a repeating unit represented by the formula (1) of 30 mol% or more and 80 mol% or less and a repeating unit represented by the formula (2) of 10 mol based on the total amount of all repeating units. The method for producing a liquid crystal polyester film according to claim 2, wherein the repeating unit represented by the formula (3) is 10 mol% or more and 35 mol% or less.   The method for producing a liquid crystal polyester film according to claim 2 or 3, wherein one or both of X and Y are imino groups.   The method for producing a liquid crystal polyester film according to claim 1, wherein the organic solvent is an aprotic solvent.   The method for producing a liquid crystal polyester film according to claim 5, wherein the aprotic solvent is an aprotic solvent having no halogen atom.   The method for producing a liquid crystal polyester film according to claim 5 or 6, wherein the aprotic solvent is an amide solvent.   The method for producing a liquid crystal polyester film according to claim 1, wherein the heat resistant resin film is a polyimide film.   The method for producing a liquid crystal polyester film according to any one of claims 1 to 8, wherein a film thickness of the heat resistant resin film is 25 µm or more and 75 µm or less.   The liquid crystal polyester film manufactured with the manufacturing method of the liquid-crystal polyester film of any one of Claim 1 to 9.   The liquid crystal polyester film according to claim 10, wherein the film thickness is 5 μm or more and 50 μm or less.

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