JP2008037982A - Liquid crystal polyester composition and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal polyester composition affording a molded product having remarkably low thermal expansion and to provide an insulating base film using the composition and suitable as a flexible printed wiring board. <P>SOLUTION: [1] The liquid crystal polyester composition comprises a liquid crystal polyester and a compound (a maleimide compound) having a plurality of maleimide groups in the molecule. [2] The liquid crystal polyester composition is as described in [1], wherein the maleimide compound is a compound having two maleimide groups in the molecule. [3] The molded product and film are obtained by heat-treating the polyester composition and a laminated film has the film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composition containing a liquid crystal polyester and a molded product obtained from the composition. More specifically, the present invention relates to a liquid crystal polyester composition that provides a molded article having suitable dimensional stability as an insulating base film of a flexible printed wiring board.

Liquid crystal polyester is excellent in molding processability, heat resistance, and low water absorption, and thus is suitably used for electrical, electronic and mechanical parts. However, when the liquid crystalline polyester is heated to about 100 to 200 ° C., thermal expansion may occur, and dimensional variation may occur due to heat generation of electronic equipment or frictional heat in mechanical parts.
By the way, various studies have been made on the use of liquid crystalline polyester as an insulating base film of a flexible wiring board (hereinafter also referred to as “FPC”) (for example, see Patent Documents 1 and 2). Is likely to cause thermal expansion, curl is likely to occur in the heat treatment process for FPC production, or wrinkles are likely to occur on the insulating base film, and a laminate comprising such an insulating base film and a conductor layer is When a FPC is manufactured by forming a fine circuit in a conductor layer, a product that can withstand practical use cannot be obtained. From such a viewpoint, a liquid crystal polyester applied to such an insulating base film for FPC is also desired to have a low thermal expansion.

JP 2005-342980 A JP 2006-96955 A

  An object of the present invention is to provide a liquid crystal polyester composition that gives a molded article having extremely low thermal expansion. Moreover, FPC provided with the insulation base film using this composition is provided.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.

That is, the present invention provides the following [1].
[1] A composition containing 3 to 30 parts by weight of a compound having a plurality of maleimide groups in the molecule with respect to 100 parts by weight of the liquid crystalline polyester.

Furthermore, the present invention provides the following [2] to [5] as preferred embodiments according to the above [1].
[2] The liquid crystal polyester composition of [1], wherein the compound having a maleimide group is a compound having two maleimide groups in the molecule. [3] The compound having a maleimide group is 4,4′-diphenylmethanebis The liquid crystal polyester composition of [1], which is maleimide and / or m-phenylenebismaleimide [4], further comprising 1 to 1000 parts by weight of an aprotic solvent with respect to 1 part by weight of the liquid crystal polyester [1] to [3] Any of the liquid crystal polyester compositions [5] The liquid crystal polyester includes structural units represented by the following formulas (1) to (3), and the total of all structural units [(1) + (2) + (3)], the structural unit represented by the formula (1) is 30 to 80 mol%, the structural unit represented by the formula (2) is 35 to 10 mol%, and the formula (3 ) The liquid crystal polyester composition according to claim 1, wherein the structural unit is 35 to 10 mol%.
(1) -O-Ar1-CO-
(2) -X-Ar2-Y-
(3) -CO-Ar3-CO-
(In the formula, Ar1 is at least one selected from the group consisting of 1,4-phenylene, 2,6-naphthylene, and 4,4′-biphenylene, and Ar2 is 1,4-phenylene, 1,3-phenylene, And at least one selected from the group consisting of phenylene and 4,4′-biphenylene, X and Y each independently represent —O— or —NH—, Ar 3 represents 1,4-phenylene, 1,3 -It is at least one selected from the group consisting of phenylene, 2,6-naphthylene and a divalent group represented by the following formula (I).

Moreover, this invention provides following [6]-[9] as an embodiment of the molded object obtained using one of the said liquid crystalline polyester compositions.
[6] When the liquid crystalline polyester composition according to any one of [1] to [5] is molded, a molded body characterized in that heat treatment is performed. [7] A film having a thickness of 1 to 500 μm. [6] Molded product [8] Production of a film, wherein the liquid crystal polyester composition of [4] or [5] is cast on a support, and then heat-treated to peel the support Method [9] Molded product of [7] obtained by the production method of [8] above

Furthermore, the present invention provides [10] and [11] using a film which is a suitable molded body as the molded body.
[10] Flexible printed wiring obtained by using the laminated film [11] [10], which has a layer made of the molded article of [7] or [9] and a layer made of a conductor. Board

  The molded body obtained from the liquid crystal polyester composition of the present invention can be obtained with a remarkably low linear expansion coefficient related to thermal expansion, that is, heat treatment. Since a laminated film using such a molded body as a film and used as an insulating base film can significantly reduce the curls and wrinkles described above, it is easy to form a fine circuit when manufacturing a wiring by processing a conductor layer. Since it can be suitably used as a flexible printed wiring board, it is industrially useful.

（式中、Ｒ¹、Ｒ²はそれぞれ独立に水素原子または炭素数１〜４のアルキル基を表す。）
前記（II）式で表される基の中でも、Ｒ¹およびＲ²がともに水素原子であるマレイミド基であると好ましい。 The composition of the present invention contains a liquid crystal polyester and a compound having a plurality of maleimide groups in the molecule (hereinafter sometimes referred to as “maleimide compound”), and the maleimide compound is used with respect to 100 parts by weight of the liquid crystal polyester. Is 3 to 30 parts by weight. In addition, 2 or more types of liquid crystalline polyester resins may be included, and 2 or more types of maleimide compounds may be included. When a plurality of liquid crystalline polyesters or maleimide compounds are included, the total is within the above range. What is necessary is just a compounding quantity. The “maleimide group” is a group represented by the following formula (II).

(Wherein, R ^1, R ² each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
Among the groups represented by the formula (II), R ¹ and R ² are preferably maleimide groups in which both are hydrogen atoms.

  If the blending amount of the maleimide compound is too small, the effect of reducing the linear expansion coefficient related to heat treatment is small, and if it is too large, the film becomes brittle when the film is produced as a molded body, and the folding resistance, which is a required characteristic of FPC. The curvature deteriorates. More preferably, the maleimide compound is 4 to 25 parts by weight and particularly preferably 5 to 20 parts by weight with respect to 100 parts by weight of the liquid crystalline polyester.

（式中、Ｒ¹、Ｒ²は前記と同等の定義である。） Such a maleimide compound has a plurality of maleimide groups in the molecule, but is preferably a compound having 2 to 30 maleimide groups in the molecule, preferably a compound having 2 to 10 maleimide groups. Particularly preferred.
As a method for obtaining such a maleimide compound, a known method can be used. For example, in accordance with a method described in Journal of Applied Polymer Science, Vol. 73, 833-839 (1999), an amine is used. It can be easily obtained from a compound and a maleic anhydride derivative (formula (III) below).

(In the formula, R ¹ and R ² have the same definitions as above.)

  Examples of such maleimide compounds include N, N′-m-phenylene bismaleimide, N, N′-p-phenylene bismaleimide, N, N′-m-toluylene bismaleimide, and N, N′-4. , 4′-biphenylenebismaleimide, N, N′-4,4 ′-[3,3′-dimethyl-biphenylene] bismaleimide, N, N′-4,4 ′-[3,3′-dimethyldiphenylmethane] Bismaleimide, N, N′-4,4 ′-[3,3′-diethyldiphenylmethane] bismaleimide, N, N′-4,4′-diphenylmethane bismaleimide, N, N′-4,4′-diphenyl Propane bismaleimide, N, N′-4,4′-diphenyl ether bismaleimide, N, N′-3,3′-diphenylsulfone bismaleimide, N, N′-4,4′-diphenyl Le Hong bismaleimide, 4,4'-diphenylmethane bismaleimide and polyphenyl methane maleimide can be given. In particular, diamine is preferable because it is easily available, and a compound obtained from such a diamine and having two maleimide groups in the molecule is preferable. In particular, from the viewpoint of cost, 4,4'-diphenylmethane bismaleimide or m-phenylene bismaleimide is preferable.

Next, the liquid crystal polyester applied to the present invention will be described.
The liquid crystal polyester used in the present invention is a polymer called a thermotropic liquid crystal polymer, and forms a melt exhibiting optical anisotropy at a temperature of 450 ° C. or lower.

As a preferable liquid crystal polyester applied to the present invention, an aromatic liquid crystal polyester represented as type I is preferable because of excellent heat resistance.
The aromatic liquid crystal polyester has a structure derived from a compound selected from the group consisting of a structural unit derived from an aromatic hydroxycarboxylic acid (formula (1)), an aromatic diol, an aromatic diamine, and an aromatic amine having a hydroxyl group. The unit (formula (2)) and a structural unit derived from an aromatic dicarboxylic acid (formula (3)) are mainly included, but particularly from the viewpoint of liquid crystallinity, the total of all structural units [(1) + (2) + (3)] is 100 mol%, the structural unit represented by the formula (1) is 30 to 80 mol%, the structural unit represented by the formula (2) is 35 to 10 mol%, A liquid crystal polyester in which the total of the structural units represented by formula (3) is 35 to 10 mol% is preferable.
(1) -O-Ar1-CO-
(2) -X-Ar2-Y-
(3) -CO-Ar3-CO-
(In the formula, Ar1 is at least one selected from the group consisting of 1,4-phenylene, 2,6-naphthylene, and 4,4′-biphenylene, and Ar2 is 1,4-phenylene, 1,3-phenylene, And at least one selected from the group consisting of phenylene and 4,4′-biphenylene, X and Y each independently represent —O— or —NH—, Ar 3 represents 1,4-phenylene, 1,3 -It is at least one selected from the group consisting of phenylene, 2,6-naphthylene and a divalent group represented by the following formula (I).

  The structural units represented by the formula (1), the formula (2) and the formula (3) are structural units derived from the above compounds, respectively, and the compounds that derive these structural units are condensed by a known method. An aromatic liquid crystal polyester can be obtained. Further, instead of the compound that derives the structural unit, an ester-forming derivative or an amide-forming derivative of these compounds may be used.

  Examples of ester-forming derivatives of carboxylic acids include those in which the carboxyl group is a derivative having a high reaction activity such as an acid chloride or an acid anhydride that promotes the reaction to form a polyester. And those that form esters with alcohols, ethylene glycol, or the like that form polyesters by transesterification.

  Examples of the ester-forming derivative of a phenolic hydroxyl group include those in which a phenolic hydroxyl group forms an ester with a carboxylic acid so that a polyester is produced by a transesterification reaction.

  Examples of the amide-forming derivative of an amino group include those in which an amino group forms an amide with a carboxylic acid so that a polyamide is formed by an amide exchange reaction.

Examples of the repeating structural unit of the aromatic liquid crystal polyester applied to the present invention include the following, but are not limited thereto.
Examples of the structural unit represented by the formula (1) include structural units derived from p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4′-biphenylcarboxylic acid, and the like. Two or more structural units represented by (1) may be contained in the aromatic liquid crystal polyester. Among these structural units, an aromatic liquid crystal polyester containing a structural unit derived from 2-hydroxy-6-naphthoic acid is preferable.

  The structural unit represented by the formula (1) is preferably 30 to 80% by mole, more preferably 35 to 65% by mole, and 40 to 55% by mole based on the total of all the structural units. Is more preferable. When the structural unit represented by the formula (1) is in the above range, the solubility in a solvent becomes good, and therefore the aromatic liquid crystal polyester can be easily converted into a film form by using a solution casting method described later. The liquid crystallinity is also maintained.

  Examples of the structural unit represented by the formula (2) include resorcin, hydroquinone, 3-aminophenol, 4-aminophenol, 1,4-phenylenediamine, 1,3-phenylenediamine, 4,4′-diaminodiphenyl ether, Examples thereof include structural units derived from 4-hydroxy-4′-biphenyl alcohol, and two or more structural units represented by the formula (2) may be contained in the aromatic liquid crystal polyester. Among these structural units, an aromatic liquid crystal polyester containing a structural unit derived from 4-aminophenol is preferable from the viewpoint of reactivity.

  The structural unit represented by the formula (2) is preferably 10 to 35 mol%, more preferably 17.5 to 32.5 mol%, and more preferably 22.5 mol based on the total of all structural units. More preferably, it is ˜30.0 mol%. When the structural unit represented by the formula (2) is in the above range, liquid crystallinity is maintained, and the solubility in a solvent tends to be good.

  Examples of the structural unit represented by the formula (3) include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, or Examples include structural units derived from benzophenone-4,4′-dicarboxylic acid and the like, and two or more structural units represented by the formula (3) may be included in all the structural units. Among these structural units, an aromatic liquid crystal polyester containing a structural unit derived from isophthalic acid is preferable from the viewpoint of solubility in a solvent.

  The structural unit represented by the formula (3) is more preferably 10 to 35 mol%, more preferably 17.5 to 32.5 mol%, based on the total of all structural units, and 22. More preferably, it is 5 to 30.0 mol%.

  In addition, the aromatic liquid crystal polyester in which Ar3 in the formula (3) is a divalent group selected from the group represented by the above (I) is contained in an amount of 1 to 35 mol% based on the total of all the structural units. When it is, the solubility to a solvent can be improved more. When such a structural unit is included, it is more preferable that it is contained in an amount of 10 to 30 mol%, and more preferably 15 to 25 mol%.

  The structural unit represented by the formula (2) is preferably contained in an equimolar equivalent with respect to the structural unit represented by the formula (3), but [the copolymerization ratio of the structural unit represented by the formula (2) ] / [Copolymerization ratio of the structural unit represented by the formula (3)], and by setting it to 0.85 to 1.25, the degree of polymerization of the obtained aromatic liquid crystal polyester can be controlled.

  The aromatic liquid crystal polyester applied to the present invention is a compound (monomer) for deriving each structural unit, that is, aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic amine, aromatic amine having a hydroxyl group, aromatic diol. Alternatively, these ester-forming derivatives and amide-forming derivatives can be produced by polymerizing in accordance with ordinary methods (for example, methods described in JP-A Nos. 2002-220444 and 2002-146003). .

  More specifically, the method for producing the liquid crystalline polyester of the present invention includes, for example, an aromatic hydroxycarboxylic acid corresponding to the structural unit represented by the formula (1) and a hydroxyl group corresponding to the structural unit represented by the formula (2). The acylated product is obtained by acylating the hydroxyl group or amino group of an aromatic amine, aromatic diol, or aromatic diamine with an excess amount of fatty acid anhydride, and the resulting acylated product and the structure represented by the formula (3) Examples thereof include a method in which a unit and an aromatic dicarboxylic acid corresponding to the structural unit represented by the formula (4) are subjected to melt polymerization by transesterification / amide exchange (polycondensation).

  In the acylation reaction, the amount of fatty acid anhydride added is preferably 1.0 to 1.2 times equivalent to the total of the phenolic hydroxyl group and amino group, more preferably 1.05 to 1. 1 equivalent. If the addition amount of the fatty acid anhydride is within this range, it is possible to avoid the problem that the acylated product and the raw material monomer are not easily sublimated during transesterification / amide exchange (polycondensation), and the reaction system is blocked. There is a tendency that coloring of the obtained liquid crystal polyester is remarkably reduced.

  The acylation reaction is preferably performed at 130 to 180 ° C. for 5 minutes to 10 hours, 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 examples thereof include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, anhydrous 2-ethylhexanoic acid, and monochloroacetic anhydride. , Dichloroacetic anhydride, trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, β- Examples thereof include bromopropionic acid, and two or more of these may be used in combination. From the viewpoint of price and handleability, acetic anhydride, propionic anhydride, butyric anhydride or isobutyric anhydride is preferable, and acetic anhydride is more preferable.

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

  The transesterification / amide exchange (polycondensation) is preferably carried out while raising the temperature up to 400 ° C. at a rate of 0.1 to 50 ° C./min. More preferably.

  When transesterification and amide exchange (polycondensation) of acylated products and carboxylic acids are performed, the equilibrium is shifted so that by-product fatty acids and unreacted fatty acid anhydrides are distilled out of the system, such as by evaporation. Is preferred.

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

Polycondensation by transesterification / 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 phase polymerization method after the polymer is extracted from the melt polymerization step and then pulverized into powder or flakes. Specifically, for example, a method of heat treatment in a solid state at 20 to 350 ° C. for 1 to 30 hours under an inert atmosphere such as nitrogen can be used. Solid phase polymerization may be carried out while stirring or in a state of standing without stirring. In addition, by providing an appropriate stirring mechanism, the melt polymerization tank and the solid phase polymerization tank can be made the same reaction tank. After the solid state polymerization, the obtained aromatic liquid crystal polyester may be pelletized and molded by a known method.
Manufacture of liquid crystalline polyester can be performed using a batch apparatus, a continuous apparatus, etc., for example.

  The composition containing the liquid crystalline polyester and the maleimide compound obtained as described above can be used to obtain a molded product by various known molding methods, and the obtained molded product has a remarkably low linear expansion coefficient related to heat treatment. It can be. In particular, the composition of the present invention is suitable for use as a film form. Moreover, the composition of this invention may contain a well-known filler or additive other than said liquid crystalline polyester and a maleimide compound.

  When a molded body is obtained from the composition of the present invention, when the maleimide compound contained in the composition is subjected to heat treatment at a temperature higher than the temperature at which the maleimide compound undergoes a thermal reaction, the resulting molded body has a thermal expansion. This can be further reduced. The temperature at which the maleimide compound undergoes a thermal reaction can be usually determined by using differential thermal analysis (DSC). In the case of 4,4′-diphenylmethane bismaleimide or m-phenylene bismaleimide exemplified as a preferred maleimide compound, What is necessary is just 200 degreeC or more.

A method for obtaining a molded body in the form of a film using the composition of the present invention will be described.
For example, JP-A-52-1095787 and JP-A-58-317187 disclose a film containing a liquid crystal polyester obtained by extrusion molding, and also from such a composition by such extrusion molding. A film can be obtained.

On the other hand, a film forming method by inflation molding can also be applied. Inflation film formation means that a resin melted and kneaded in an extruder is extruded into a cylindrical melt using a die having an annular slit, and a certain amount of air is fed into it to expand it. A method of making a cylindrical film while cooling the periphery. Examples thereof include, for example, the methods described in JP-A-63-173620, JP-A-3-288623, JP-A-4-4126, JP-A-4-50233, or JP-A-4-49026. Is mentioned.

In the above extrusion molding and inflation molding, since the liquid crystalline polyester is melted, the composition of the present invention is usually heat-treated at 280 ° C. or higher. In these molding methods, heat treatment can be performed in a cylinder. Moreover, although the upper limit of the temperature in this heat processing can be set in the range in which the liquid crystalline polyester to be used is not thermally deteriorated, it is usually 350 ° C. or less, preferably 340 ° C. or less, and particularly preferably 330 ° C. or less.
The thickness of the film made of liquid crystal polyester thus obtained is not particularly limited, but is preferably about 1 to 500 μm from the viewpoint of film forming properties and mechanical properties, and from the viewpoint of handleability. It is more preferable that it is 1-350 micrometers.
The film containing liquid crystal polyester obtained by the above extrusion molding or inflation molding can obtain a laminated film suitable for producing an FPC by laminating a metal layer as a conductor layer on the film. For example, the metal layer can be formed by a known method such as a laminating method, a plating method, a sputtering method, or a CVD method.

On the other hand, as a method for obtaining a laminated film suitable for FPC, a solution composition containing a solvent in addition to the liquid crystal polyester and the maleimide compound is used, and the solution composition is cast and applied to a metal foil, A laminated film can also be obtained by forming an insulating base film on a metal foil by removing the solvent.
The solvent applied to the solution composition is preferably an aprotic solvent.

  Next, a method for producing a solution composition containing an aromatic liquid crystal polyester will be described. The solution composition is preferably prepared by dissolving the aromatic liquid crystal polyester and maleimide compound obtained as described above in a solvent containing an aprotic solvent (preferably a solvent comprising an aprotic solvent). It can be manufactured by mixing.

In the solution composition, the aprotic solvent is preferably 1 to 1000 parts by weight with respect to 1 part by weight of the aromatic liquid crystal polyester. When the mixing amount of the aromatic liquid crystal polyester is within the above range, it is preferable because the solution viscosity enables a uniform coating when applied to the metal foil.
Furthermore, from the viewpoint of workability and economy, the aprotic solvent is more preferably 1 to 99 parts by weight, and further preferably 3 to 98 parts by weight with respect to 1 part by weight of the aromatic liquid crystal polyester. .

  Examples of the aprotic solvent include halogen solvents such as 1-chlorobutane, chlorobenzene, 1,1-dichloroethane, 1,2-dichloroethane, chloroform, 1,1,2,2-tetrachloroethane, diethyl ether, tetrahydrofuran, Ether solvents such as 1,4-dioxane, ketone solvents such as acetone and cyclohexanone, ester solvents such as ethyl acetate, lactone solvents such as γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, Amine solvents such as triethylamine and pyridine, nitrile solvents such as acetonitrile and succinonitrile, amide solvents such as N, N′-dimethylformamide, N, N′-dimethylacetamide, tetramethylurea and N-methylpyrrolidone , Nitromethane, nitro-based solvents such as nitrobenzene, dimethyl sulfoxide, sulfide-based solvent such as sulfolane, hexamethylphosphoramide, and phosphoric acid-based solvent such as tri-n- butyl phosphate and the like.

Among these, a solvent containing no halogen atom is preferable from the viewpoint of influence on the environment, and a solvent having a dipole moment of 3 to 5 is preferable from the viewpoint of solubility. Specifically, an amide solvent such as N, N′-dimethylformamide, N, N′-dimethylacetamide, tetramethylurea, N-methylpyrrolidone, or a lactone solvent such as γ-butyrolactone is more preferable. '-Dimethylformamide, N, N'-dimethylacetamide or N-methylpyrrolidone is more preferably used.
The solution composition may contain a solvent other than the aprotic solvent as long as the production of the laminated film is not impaired.

  An inorganic filler or an additive may be added to the obtained solution composition within a range in which the film obtained by coating and solvent removal does not become brittle. It is preferable that the compounding quantity of this inorganic filler is 10-50 weight part with respect to 100 weight of liquid crystalline polyester. It is preferable that the blending amount of the inorganic filler is in such a range because the effect of reducing the linear expansion coefficient is more excellent and the flexure of the resulting laminate is excellent. More preferably, the blending amount is 20 to 40 parts by weight of the inorganic filler with respect to 100 parts by weight of the liquid crystalline polyester.

  Examples of the inorganic filler include commonly used inorganic fillers such as silica, alumina, mica, glass, calcium carbonate, titanium oxide, aluminum borate, potassium titanate, barium titanate, and strontium titanate. It is preferable to use a fibrous or plate-like inorganic filler that can further reduce the linear expansion coefficient of the film made of liquid crystal polyester even if the addition of is added.

Examples of the fibrous inorganic filler include alumina whisker, titanium oxide whisker, aluminum borate whisker, potassium titanate whisker, barium titanate whisker, basic magnesium sulfate whisker, zinc oxide whisker, and silicon carbide whisker. Of these, alumina whiskers or aluminum borate whiskers are particularly preferred.
The shape of the fibrous inorganic filler is preferably an average fiber length of 0.1 to 100 μm, more preferably an average fiber length of 0.1 to 10 μm, and most preferably an average fiber length of 0.2 to 1 μm. The aspect ratio (ratio of average fiber length to average fiber diameter) is preferably 3 or more, and more preferably 10 or more.

Examples of the plate-like inorganic filler include mica (mica), talc, plate-like alumina, and glass flakes.
The plate-like inorganic filler preferably has an average particle size of 0.1 to 100 μm, more preferably an average particle size of 0.1 to 10 μm. The aspect ratio (ratio of average particle diameter to average thickness) is preferably 3 or more, and more preferably 10 or more.

The above fibrous and plate-like inorganic fillers may be used in combination, and other spherical inorganic fillers such as silica, alumina, glass, calcium carbonate, titanium oxide, barium titanate, and strontium titanate may be further added. It doesn't matter.
Such an inorganic filler can be applied to the solution composition, and can also be suitably used for a composition applied to the above-described extrusion molding or inflation molding.

  The inorganic filler may be subjected to a surface treatment with a known coupling agent, anti-settling agent or the like.

  If necessary, the solution composition may be filtered with a filter or the like to remove fine foreign matters contained in the solution composition.

Next, a preferred embodiment relating to a method for producing a laminated film suitable for an FPC obtained using the solution composition will be described.
First, the solution composition is applied to a metal foil. Examples of the coating method include various means such as a roller coating method, a dip coater method, a spray coater method, a spin coating method, a curtain coating method, a slot coating method, and a screen printing method.

Next, the remaining solvent is removed from the coating film applied on the metal foil. The method for removing the solvent is not particularly limited, but it is preferably performed by evaporation of the solvent. Examples of the method for evaporating the solvent include methods such as heating, reduced pressure, and ventilation. Among them, it is preferable to evaporate by heating from the viewpoint of production efficiency and handleability, and it is possible to evaporate by heating while ventilating. More preferred.
Drying is performed so that the amount of the solvent remaining in the film is 18% by weight or less in the coating film. Although drying temperature and time are arbitrary, in this invention, it is 160 degrees C or less, Preferably it is 150 degrees C or less, More preferably, it is 140 degrees C or less. If the drying temperature is too high, defects tend to occur on the coating film surface. Further, if the drying temperature is too low, it takes a time necessary for drying, and the productivity is lowered. Pre-drying is performed so that the residual solvent amount in the coating film is 18% by weight or less, preferably 15% by weight or less.

After pre-drying as described above, the maleimide compound in the film is thermally reacted by further heat treatment at 200 ° C. or more, and the adhesion between the liquid crystal polyester-containing layer and the metal foil is improved. Can be made. In the heat treatment, the treatment temperature is preferably in the range of 200 ° C. to 350 ° C., and the lower limit of the treatment temperature is more preferably 250 ° C. or more, and particularly preferably 280 ° C. or more. On the other hand, the upper limit of the treatment temperature is more preferably 340 ° C. or less, and particularly preferably 330 ° C. or less. The processing time is in the range of 10 minutes to 15 hours. The lower limit of the treatment time is more preferably 20 minutes or more, and particularly preferably 40 minutes or more. On the other hand, the upper limit of the treatment time is more preferably 12 hours or less, and particularly preferably 10 hours or less.
From the viewpoint of preventing oxidative deterioration of the metal foil, it is preferable to replace the processing environment with an inert gas such as nitrogen, argon or neon, or to perform processing in a vacuum.

  Examples of the metal foil to which the liquid crystal polyester solution composition is applied include metal foil made of gold, silver, copper, aluminum, nickel, and the like, and preferably copper foil is used.

  The thickness of the insulating base film containing the liquid crystal polyester obtained by such a method is not particularly limited, but is preferably about 1 to 500 μm from the viewpoint of film forming properties and mechanical properties, and handleability. From the viewpoint of the above, it is more preferably 1 to 350 μm. When particularly high insulation is required, the thickness may be increased to 350 μm or more. The surface of the insulating base film may be subjected to a treatment such as polishing, a chemical solution such as an acid or an oxidizing agent, ultraviolet rays, or plasma irradiation, as necessary.

  As described above, the method for producing a laminate suitable as an FPC using the solution composition of the present invention has been described. In such a method, after replacing the metal foil with an appropriate support and producing a laminate, the laminate is produced. A film containing liquid crystal polyester can also be obtained by peeling the support. Since the film thus obtained also has a remarkably low linear expansion coefficient related to heat treatment, it can be applied to various applications. As the support, the metal foil as described above can be used, but a support made of glass or the like can also be applied, and a support that is not damaged by the solvent used in the solution composition is selected. be able to.

The laminated film thus obtained is excellent in flexibility, dimensional stability, and curl reduction. Therefore, in addition to the insulating base film of FPC, the film for multilayer printed circuit boards for semiconductor packages and motherboards by the build-up method, It can be suitably used for a film for flexible printed wiring boards, a film for tape automated bonding, a film for tag tape, a packaging film for heating a microwave oven, a film for electromagnetic wave shielding, and the like.
In addition, the film containing the liquid crystalline polyester provided by the present invention is excellent in high-frequency characteristics, low water absorption, and the like, and therefore can be suitably used for a high-frequency printed wiring board, a high-frequency cable, a communication device circuit, a package substrate, and the like.
In addition, although the said range has the preferable thickness of the insulating base film which concerns on a laminated | multilayer film, when especially high insulation is requested | required as a FPC use, it is preferable to set it as 350 micrometers or more.
Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is defined by the terms of the claims, and further includes meanings equivalent to the description of the claims and all modifications within the scope.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example, this invention is not limited by an Example.
Moreover, about the copper clad laminated film obtained by the following example and the comparative example, the curl property was measured with the following method. The results are shown in Table 1.
(Curlability of copper-clad laminated film)
The liquid crystal polyester laminated film was cut out to 150 mm × 150 mm, placed on a surface plate with the copper foil side of the copper clad laminated film facing down, and the distance D (unit: mm) between both ends of the copper foil in the liquid crystal polyester laminated film was measured. .
When the degree of curling of the copper-clad laminate film was small, the curl amount (unit: mm) of the copper-clad laminate film was determined by the following formula (see FIG. 1. In FIG. 1, both ends of the copper foil of the copper-clad laminate film It is indicated by a distance D (unit: mm). The curl amount is in the range of 0 to 1.0 mm.
Curling amount of copper clad laminated film = (150−D) / 150
When the degree of curling of the copper-clad laminated film is large and rounds, it is said that the curl amount exceeds 1. Such a case is shown in FIG.
The smaller the curling amount, the smaller the curling property and the better.

(Linear expansion coefficient of liquid crystal polyester film)
Using a thermomechanical analyzer TMA manufactured by Seiko Electronics Co., Ltd., the temperature was increased at 5 ° C./min under a nitrogen stream, and the linear expansion coefficient of a liquid crystal polyester film at 50 to 100 ° C. was measured. When the take-up direction was MD and the perpendicular direction was TD, the respective linear expansion coefficients were measured.

(Synthesis Example 1)
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.
Thereafter, the temperature was raised to 320 ° C. over 170 minutes while distilling off the by-product acetic acid and unreacted acetic anhydride, and the time when an increase in torque was observed was regarded as the completion of the reaction, and the contents were taken out. The obtained solid content was cooled to room temperature, pulverized with a coarse pulverizer, held at 250 ° C. for 10 hours in a nitrogen atmosphere, and the polymerization reaction proceeded in a solid phase. After completion of the polymerization, the content was taken out by cooling and pulverized to obtain a liquid crystal polyester powder.

(Example 1)
32 g of the liquid crystal polyester powder obtained in Synthesis Example 1 was added to 368 g of N-methyl-2-pyrrolidone, heated to 140 ° C. and completely dissolved to obtain a brown transparent liquid crystal polyester solution composition. 8.4 g of a solution obtained by dissolving 16 g of a thermosetting organic compound 4,4′-diphenylmethane bismaleimide (Aldrich) in 64 g of N-methyl-2-pyrrolidone is added to the solution composition to obtain a liquid crystal polyester solution composition. 1 was obtained. Next, this solution composition was cast on an electrolytic copper foil (3EC-VLP, thickness 18 μm, manufactured by Mitsui Kinzoku Co., Ltd.) using a film applicator so that the resin layer thickness after heat treatment was 25 μm, and then hot hot air After removing the solvent by heating at 120 ° C. in a dryer so that the amount of residual solvent in the resin layer is 18% by weight or less, heat treatment is performed at 320 ° C. in a nitrogen atmosphere, so that a copper-clad laminated film with less curling was gotten.

(Example 2)
32 g of the liquid crystal polyester powder obtained in Synthesis Example 1 was added to 368 g of N-methyl-2-pyrrolidone, heated to 140 ° C. and completely dissolved to obtain a brown transparent liquid crystal polyester solution composition. 17.8 g of a solution obtained by dissolving 16 g of a thermosetting organic compound 4,4′-diphenylmethane bismaleimide (Aldrich) in 64 g of N-methyl-2-pyrrolidone is added to the solution composition to obtain a liquid crystal polyester solution composition. 2 was obtained. Next, this solution composition was cast on an electrolytic copper foil (3EC-VLP, thickness 18 μm, manufactured by Mitsui Kinzoku Co., Ltd.) using a film applicator so that the resin layer thickness after heat treatment was 25 μm, and then hot hot air After removing the solvent by heating at 120 ° C. in a dryer so that the amount of residual solvent in the resin layer is 18% by weight or less, heat treatment is performed at 320 ° C. in a nitrogen atmosphere, so that a copper-clad laminated film with less curling was gotten.

(Example 3)
32 g of the liquid crystal polyester powder obtained in Synthesis Example 1 was added to 368 g of N-methyl-2-pyrrolidone, heated to 140 ° C. and completely dissolved to obtain a brown transparent liquid crystal polyester solution composition. 40 g of a solution obtained by dissolving 16 g of a thermosetting organic compound 4,4′-diphenylmethane bismaleimide (Aldrich) in 64 g of N-methyl-2-pyrrolidone was added to the solution composition to obtain a liquid crystal polyester solution composition 3. Obtained. Next, this solution composition was cast on an electrolytic copper foil (3EC-VLP, thickness 18 μm, manufactured by Mitsui Kinzoku Co., Ltd.) using a film applicator so that the resin layer thickness after heat treatment was 25 μm, and then hot hot air After removing the solvent by heating at 120 ° C. in a dryer so that the amount of residual solvent in the resin layer is 18% by weight or less, heat treatment is performed at 320 ° C. in a nitrogen atmosphere, so that a copper-clad laminated film with less curling was gotten.

(Comparative Example 1)
32 g of the liquid crystal polyester powder obtained in Synthesis Example 1 was added to 368 g of N-methyl-2-pyrrolidone, heated to 140 ° C. and completely dissolved to obtain a brown transparent liquid crystal polyester solution composition 4. Next, this solution composition was cast on an electrolytic copper foil (3EC-VLP, thickness 18 μm, manufactured by Mitsui Kinzoku Co., Ltd.) using a film applicator so that the resin layer thickness after heat treatment was 25 μm, and then hot hot air The resulting laminated film heated at 120 ° C. in a dryer to remove the solvent so that the residual solvent amount in the resin layer is 18% by weight or less and then heat-treated at 320 ° C. in a nitrogen atmosphere has extremely large curl. It was a thing.

It is a schematic diagram (when a curl amount is 1 or less) which measures the curling property of a copper clad laminated film. It is a schematic diagram (when a curl amount exceeds 1) which measures the curl property of a copper clad laminated film.

Explanation of symbols

1 ... Metal foil (copper foil) of liquid crystal polyester laminated film
2 ... Resin layer of liquid crystal polyester laminated film

Claims (11)

  A liquid crystal polyester composition containing 3 to 30 parts by weight of a compound having a plurality of maleimide groups in the molecule with respect to 100 parts by weight of the liquid crystal polyester.   The liquid crystal polyester composition according to claim 1, wherein the compound having a maleimide group is a compound having two maleimide groups in the molecule.   The liquid crystal polyester composition according to claim 1, wherein the compound having a maleimide group is 4,4'-diphenylmethane bismaleimide and / or m-phenylene bismaleimide.   Furthermore, 1-1000 weight part of aprotic solvents are contained with respect to 1 weight part of liquid crystal polyester, The liquid crystal polyester composition in any one of Claims 1-3 characterized by the above-mentioned. The liquid crystal polyester includes structural units represented by the following formulas (1) to (3), and the total [(1) + (2) + (3)] of all structural units is represented by the formula (1). The structural unit shown is 30 to 80 mol%, the structural unit represented by the formula (2) is 35 to 10 mol%, and the structural unit represented by the formula (3) is 35 to 10 mol%. Liquid crystal polyester composition in any one of -4.
(1) -O-Ar1-CO-
(2) -X-Ar2-Y-
(3) -CO-Ar3-CO-
(In the formula, Ar1 is at least one selected from the group consisting of 1,4-phenylene, 2,6-naphthylene, and 4,4′-biphenylene, and Ar2 is 1,4-phenylene, 1,3-phenylene, And at least one selected from the group consisting of phenylene and 4,4′-biphenylene, X and Y each independently represent —O— or —NH—, Ar 3 represents 1,4-phenylene, 1,3 -It is at least one selected from the group consisting of phenylene, 2,6-naphthylene and a divalent group represented by the following formula (I).

  A molded article, wherein a heat treatment is performed when the liquid crystal polyester composition according to any one of claims 1 to 5 is molded.   The molded body according to claim 6, which is in the form of a film having a thickness of 1 to 500 µm.   A method for producing a film, comprising casting the liquid crystal polyester composition according to claim 4 or 5 on a support, then heat-treating the support, and peeling the support.   The molded body according to claim 7, which is obtained by the production method according to claim 8.   A laminated film comprising a layer made of the molded product according to claim 7 and a layer made of a conductor. The flexible printed wiring board obtained using the laminated | multilayer film of Claim 10.

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