JP4760643B2 - Aromatic liquid crystal polyester film with double-sided substrate - Google Patents

Description

  The present invention relates to an aromatic liquid crystal polyester film with a double-sided base material used for an electronic component substrate such as a printed wiring board or a module substrate, and a method for producing the same.

  In recent years, attention has been paid to a technique in which an aromatic liquid crystal polyester is formed into a film by extrusion molding such as T-die molding or inflation molding and applied to an insulating film of a circuit board such as a multilayer printed board or a flexible printed board. In particular, with the demand for high-density wiring of circuit boards on which electronic components such as IC chips and passive components are mounted, the aromatic liquid crystal polyester film also requires circuit boards having conductor layers on both sides. In order to make a simple circuit board, a method of producing an aromatic liquid crystal polyester film with a double-sided (conductor) base material in advance and forming a circuit on the (conductive) base material on both sides of the film is widely applied. Yes. For example, Patent Document 1 discloses an aromatic liquid crystal with a double-sided base material that is manufactured by extrusion molding a film made of a liquid crystal polymer, and a base material is disposed on both sides of the film, followed by thermocompression bonding under specific thermal conditions. A method for producing a polyester film is disclosed.

However, the aromatic liquid crystal polyester film obtained by extrusion molding used in Patent Document 1 has a problem that the anisotropy is large and the tear strength in the direction perpendicular to the flow direction during molding is weak.
As an aromatic liquid crystal polyester film for solving such problems, the present inventors have used an aromatic liquid crystal polyester film comprising an aromatic liquid crystal polyester solution composition containing a solvent comprising a chlorine-substituted phenol compound and an aromatic liquid crystal polyester. (Refer to Patent Document 2).

JP-A-5-42603 JP 2002-114894 A

The aromatic liquid crystal polyester film disclosed in Patent Document 2 can be suitably used for electric / electronic component applications because of its small anisotropy compared to a normal aromatic liquid crystal polyester film. However, when this aromatic liquid crystal polyester film is used as a circuit board, there is room for improvement in adhesion to a conductor (metal foil).
This invention is made | formed in view of such a condition, and it aims at providing the aromatic liquid crystal polyester film with a double-sided base material which has high adhesiveness between an aromatic liquid crystal polyester film and a base material.

（式中、Ａはハロゲン原子またはトリハロゲン化メチルを表わし、ｉは１〜５の整数を表わし、ｉが２以上の場合に複数あるＡは互いに同一でも異なっていてもよい。）
なお、前記の「実質的に融点を有さない芳香族液晶ポリエステル」とは、当該液晶ポリエステルを徐々に加熱した際に、融解を生ずることなく、該液晶ポリエステル自体が熱分解するものである。通常、芳香族液晶ポリエステルの熱分解は約５００℃程度で生じるものであるから、「実質的に融点を有さない」とは、室温から５００℃までの範囲で融点を有さないことを意味する。 That is, the present invention is as follows.
[1] Method for producing liquid crystal polyester film with double-sided substrate having steps represented by the following (i), (ii) and (iii) (i) Aromatic liquid crystal polyester solution containing aromatic liquid crystal polyester and the following solvent The process of casting the composition on a first substrate to produce a laminate 1 comprising the aromatic liquid crystal polyester film precursor containing the aromatic liquid crystal polyester and the first substrate.
(ii) The laminate 1 obtained in (i) is heat-treated, and an aromatic liquid crystal polyester film composed of an aromatic liquid crystal polyester having a melting point of 340 ° C. or higher or substantially not having a melting point, and a substrate For producing a laminate 2 made of
(iii) Process solvent for thermocompression bonding the second substrate to the surface of the laminate 2 obtained in (ii) that is not in contact with the first substrate at a temperature of 300 ° C. or higher and 360 ° C. or lower: A solvent containing 30% by weight or more of the halogen-substituted phenol compound represented by the formula (I)

(In the formula, A represents a halogen atom or trihalogenated methyl, i represents an integer of 1 to 5, and when i is 2 or more, a plurality of A may be the same or different from each other.)
The “aromatic liquid crystal polyester having substantially no melting point” means that the liquid crystal polyester itself is thermally decomposed without melting when the liquid crystal polyester is gradually heated. Usually, the thermal decomposition of aromatic liquid crystalline polyester occurs at about 500 ° C., so “substantially no melting point” means no melting point in the range from room temperature to 500 ° C. To do.

Furthermore, the present invention provides the following [2] to [6] as preferred embodiments according to the above [1].
[2] The aromatic with double-sided base material according to [1], wherein the aromatic liquid crystal polyester solution composition is a solution composition containing 0.5 to 100 parts by weight of aromatic liquid crystal polyester with respect to 100 parts by weight of the solvent. Production method of liquid crystal polyester film [3] Double-sided substrate of method for producing aromatic liquid crystal polyester film with double-sided substrate of [1] or [2], wherein the thermocompression bonding temperature in (iii) is 320 ° C. or more and 340 ° C. or less Method for Producing Attached Aromatic Liquid Crystalline Polyester Film [4] Any of [1] to [3], wherein both the first base material and the second base material have a ten-point average roughness Rz of 4.0 μm or less [5] A process for producing an aromatic liquid crystal polyester film with a double-sided base material [5] The aromatic material with a double-sided base material according to any one of [1] to [4], wherein the first base material and the second base material are both metal foils. Manufacture of liquid crystal polyester film Method [6] The method for producing an aromatic liquid crystal polyester film with a double-sided base material according to [5], wherein the metal foil is a copper foil or a stainless steel foil.

The double-sided substrate-attached aromatic liquid crystal polyester film can be suitably applied to electronic components such as IC chips and passive components, and provides the following [7] to [9].
[7] A printed wiring using an aromatic liquid crystal polyester film with a double-sided substrate [8] [7] obtained by the production method of any one of [1] to [6] Module substrate using aromatic liquid crystal polyester film with double-sided base material of substrates [9] and [7]

  According to the present invention, there is provided an aromatic liquid crystal polyester film with a double-sided base material that has a high degree of adhesion between the aromatic liquid crystal polyester film and the base material and can be suitably used for a circuit board, and a method for producing the same. obtain.

  Hereinafter, the present invention will be described in detail.

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

Examples of the aromatic liquid crystal polyester include:
(1) What is obtained by polymerizing a combination of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic diol,
(2) those obtained by polymerizing the same or different aromatic hydroxycarboxylic acids,
(3) What is obtained by polymerizing a combination of an aromatic dicarboxylic acid and an aromatic diol,
(4) A crystalline polyester such as polyethylene terephthalate is reacted with an aromatic hydroxycarboxylic acid.
Here, the aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, and aromatic diol may have a halogen atom, an alkyl group, an aryl group, or the like in the aromatic ring as long as the ester-forming property is not inhibited. .
Examples of the alkyl group include an alkyl group having 1 to 10 carbon atoms, and a methyl group, an ethyl group, or a butyl group is more preferable. As an aryl group, a C6-C20 aryl group is mentioned, A phenyl group is more preferable.
Examples of the halogen atom include a chlorine atom and a fluorine atom.
In addition, you may use those ester-forming derivatives instead of these aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, or aromatic diol.

Examples of the ester-forming derivative of a compound having a carboxyl group include those having a highly reactive derivative such as an acid chloride or an acid anhydride, in which the carboxyl group promotes a polyester-forming reaction, However, what forms ester with alcohols, ethylene glycol, etc. which produce | generate polyester by transesterification is mentioned.
Examples of the ester-forming derivative of a compound having a phenolic hydroxyl group include those in which a phenolic hydroxyl group forms an ester with a lower carboxylic acid so that a polyester is produced by a transesterification reaction.
These ester-forming derivatives can be suitably used for producing an aromatic liquid crystal polyester, and details thereof will be described later.

  Examples of the repeating structural unit forming the aromatic liquid crystal polyester include the following, but are not limited thereto.

前記の繰り返し構造単位は、芳香環に結合している水素原子が、前記のようなハロゲン原子、アルキル基またはアリール基で置換されていてもよい。 Repeating structural units derived from aromatic hydroxycarboxylic acids:

In the repeating structural unit, a hydrogen atom bonded to an aromatic ring may be substituted with a halogen atom, an alkyl group or an aryl group as described above.

前記の繰り返し構造単位は、芳香環に結合している水素原子が、前記のようなハロゲン原子、アルキル基またはアリール基で置換されていてもよい。 Repeating structural units derived from aromatic dicarboxylic acids:

In the repeating structural unit, a hydrogen atom bonded to an aromatic ring may be substituted with a halogen atom, an alkyl group or an aryl group as described above.

前記の繰り返し構造単位は、芳香環に結合している水素原子が、前記のようなハロゲン原子、アルキル基またはアリール基で置換されていてもよい。 Repeating structural units derived from aromatic diols:

In the repeating structural unit, a hydrogen atom bonded to an aromatic ring may be substituted with a halogen atom, an alkyl group or an aryl group as described above.

In the repeating structural unit of the aromatic liquid crystal polyester, examples of preferable combinations include the following (a) to (f).
(A):
A combination of the repeating structural units (A ₁ ), (B ₂ ) and (C ₃ ),
A combination of the repeating structural units (A ₂ ), (B ₂ ) and (C ₃ ),
A combination of the repeating structural units (A ₁ ), (B ₁ ), (B ₂ ) and (C ₃ ), or the repeating structural units (A ₂ ), (B ₁ ), (B ₂ ) and (C ₃ ) ) Combination.
(B): In each of the combination of said (a), by substituting a part or all of (C ₃₎ to (C ₁₎ in combination.
(C): In each of the combination of said (a), by substituting a part or all of (C ₃₎ to (C ₂₎ combined.
(D): In each of the combination of said (a), by substituting a part or all of (C ₃₎ to (C ₄₎ combinations.
(E): In each of the combination of said (a), was replaced with a mixture of (C ₃₎ of some or all the (C ₄₎ (C ₅₎ combinations.
(F): In each of the combination of said (a), by replacing part of (A ₁₎ to (A ₂₎ in combination.

From the viewpoint of heat resistance, the aromatic liquid crystal polyester is selected from the group consisting of p-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acids when the total number of repeating structural units constituting the aromatic liquid crystal polyester is 100 mol%. 30 to 80 mol% of repeating structural units derived from at least one selected compound, that is, repeating structural units derived from at least one compound selected from the group consisting of (A ₁ ) and (A ₂ ), hydroquinone and A repeating structural unit derived from at least one compound selected from the group consisting of 4,4′-dihydroxybiphenyls, that is, at least one repeating structural unit selected from the group consisting of (C ₁ ) and (C ₃ ) 10-35 mol%, at least one selected from the group consisting of terephthalic acids and isophthalic acids The repeating structural unit derived from the compound, that is, the repeating structural unit selected from the group consisting of (B ₁ ) and (B ₂ ) is preferably composed of 10 to 35 mol%.
In addition, from the viewpoint of balance between heat resistance and mechanical properties, the aromatic liquid crystal polyester has a repeating unit represented by the above (A ₁ ) when the total number of repeating structural units constituting the aromatic liquid crystal polyester is 100 mol%. It is preferable that 30 mol% or more is included.

  Although the manufacturing method of the aromatic liquid crystal polyester used in the present invention is not particularly limited, it is preferable to use an ester-forming derivative as described above. For example, at least one selected from the group consisting of aromatic hydroxycarboxylic acids and aromatic diols is acylated with an excess amount of fatty acid anhydride to obtain an acylated product, and the resulting acylated product, aromatic hydroxycarboxylic acid and aromatic diol And a method of melt polymerization by transesterification with at least one selected from the group consisting of group dicarboxylic acids.

  In the acylation reaction, the addition amount of the fatty acid anhydride is preferably 1.0 to 1.2 times equivalent, more preferably 1.05 to 1.1 times equivalent to the phenolic hydroxyl group. If the amount of fatty acid anhydride added is small, acylated products, aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, etc. will sublimate during the transesterification polymerization, and the reaction system tends to be clogged. There is a tendency that coloring of the group liquid crystal polyester becomes remarkable.

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

  The fatty acid anhydride used in the acylation reaction is not particularly limited. For example, acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, 2-ethylhexanoic anhydride, 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 these may be used in combination of two or more. From the viewpoint of price and handleability, acetic anhydride, propionic anhydride, butyric anhydride, or isobutyric anhydride is preferably used, and acetic anhydride is more preferably used.

  In the transesterification, the acyl group of the acylated product is preferably 0.8 to 1.2 times the carboxyl group.

  The transesterification is preferably performed while increasing the temperature up to 400 ° C. at a rate of 0.1 to 50 ° C./min, and more preferably performed while increasing the temperature up to 350 ° C. at a rate of 0.3 to 5 ° C./min. .

  When transesterifying the fatty acid ester and the carboxylic acid obtained by acylation, the by-product fatty acid and the unreacted fatty acid anhydride are preferably distilled out of the system by evaporating or the like in order to move the equilibrium. .

  The acylation reaction and transesterification 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. The catalyst is usually added together with the monomer, 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.

The polymerization by transesterification is usually carried out by melt polymerization, but it is preferable to use both melt polymerization and solid phase polymerization. The solid phase polymerization can be 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. Specific examples include a method of heat treatment in a solid state at 250 to 350 ° C. for 1 to 30 hours under an inert atmosphere such as nitrogen. Solid phase polymerization is stirred even while stirring. You may carry out in the state left still. 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 phase polymerization, the obtained aromatic liquid crystal polyester may be pelletized by a known method, and the aromatic liquid crystal polyester excellent in operability can be obtained by such pelletization.
In addition, such an aromatic liquid crystal polyester may be produced using either a batch device or a continuous device.

  The aromatic liquid crystal polyester obtained by the production method exemplified above has sufficient solubility in the solvent when obtaining an aromatic liquid crystal polyester solution composition described later, and has a melting point of 340 on the first substrate. It is suitable for forming an aromatic liquid crystal polyester film having a temperature of not lower than ° C. or having substantially no melting point, and is preferable because the effects of the present invention are easily exhibited.

Further, the aromatic liquid crystal polyester is not limited as long as it has a melting point of 340 ° C. or higher or can be converted into an aromatic liquid crystal polyester having substantially no melting point. It is preferable for the temperature to be 260 ° C. or higher because higher adhesion can be obtained between the resulting aromatic liquid crystal polyester film and the substrate.
Here, the “flow start temperature” refers to a temperature at which the melt viscosity of the aromatic polyester becomes 4800 Pa · s or less under a pressure of 9.8 MPa in the evaluation of the melt viscosity by a flow tester.
According to the book “Liquid Crystal Polymer -Synthesis / Molding / Application-” published in 1987 (Naide Koide, pp. 95-105, CMC, published on June 5, 1987), liquid crystal polyester resin in the 1970s. Has been developed, the flow temperature (synonymous with the flow start temperature) has been used as a measure of the molecular weight of the liquid crystal polyester resin.

  The aromatic liquid crystal polyester applied to the present invention preferably has a flow start temperature of 260 ° C. or higher, more preferably 280 ° C. or higher and 340 ° C. or lower. Thus, when the first base material or the second base material is a metal foil, the higher the flow start temperature, the more the adhesion between the metal foil and the aromatic liquid crystal polyester film tends to be improved. If the flow start temperature is 340 ° C. or lower, the solubility in a solvent tends to be further improved in the aromatic liquid crystal polyester solution composition described later. More preferably, the flow starting temperature is 300 ° C. or higher and 330 ° C. or lower, and a particularly preferable range is the flow starting temperature of 315 ° C. or higher and 325 ° C. or lower.

Here, as a method for controlling the flow start temperature of the aromatic liquid crystal polyester, the flow start temperature can be adjusted according to the polymerization conditions according to the solid phase polymerization method.
More specifically, in the polyester comprising a combination of the above preferred repeating structural units, as the polymerization conditions for solid phase polymerization, in a state of standing at a temperature of 255 ° C. to 350 ° C. for 1 to 10 hours in a nitrogen atmosphere. By performing solid phase polymerization, the flow initiation temperature can be set within a suitable range.

（式中、Ａはハロゲン原子またはトリハロゲン化メチル基を表わし、ｉはＡの個数であって１〜５の整数を表わす。ｉが２以上の場合、複数あるＡは互いに同一でも異なっていてもよい）
なお、前記溶媒には、芳香族液晶ポリエステル溶液組成物の保存時または後述の流延時に芳香族液晶ポリエステル析出を防止できる範囲で、前記ハロゲン置換フェノール化合物以外に他の成分を含有していてもよい。このような他の成分としては、例えば、クロロホルム、塩化メチレン、テトラクロロエタン等の塩素系化合物が挙げられる。 The solvent used for the preparation of the aromatic liquid crystal polyester solution composition used in the present invention is a solvent containing 30% by weight or more of a halogen-substituted phenol compound represented by the following general formula (I). Furthermore, the solvent is preferably a solvent containing 60% by weight or more of the halogen-substituted phenol compound, and the halogen-substituted phenol compound as it is is preferably used as the solvent. Thus, the higher the content ratio of the halogen-substituted phenol as the solvent, the more sufficient the solubility in the preferred aromatic liquid crystal polyesters exemplified above is ensured, and the dissolved aromatic liquid crystal polyesters become more stable over time. Since it can also prevent precipitation, it becomes a solution composition excellent in storage stability, and is preferable.
Formula (I)

(In the formula, A represents a halogen atom or a trihalogenated methyl group, i represents the number of A and represents an integer of 1 to 5. When i is 2 or more, a plurality of A's are the same or different from each other. Also good)
The solvent may contain other components in addition to the halogen-substituted phenolic compound as long as aromatic liquid crystal polyester precipitation can be prevented when the aromatic liquid crystal polyester solution composition is stored or casted later. Good. Examples of such other components include chlorine compounds such as chloroform, methylene chloride, and tetrachloroethane.

In the general formula (I), i is preferably 1 to 3, more preferably 1 or 2. When i is 1, the substitution position of A is preferably the 4-position, and when i is 2 or more, the substitution position of at least one A is preferably the 4-position (the hydroxyl substitution position is the 1-position). .
When a plurality of A are present, A may be the same as or different from each other, and is preferably the same.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. A fluorine atom or a chlorine atom is preferable, and a chlorine atom is particularly preferable.
Examples of the halogen-substituted phenol compound represented by the general formula (I) in which the halogen atom is a fluorine atom include pentafluorophenol and tetrafluorophenol.
Examples of the halogen-substituted phenol compound represented by the general formula (I) in which the halogen atom is a chlorine atom include p-chlorophenol.

Examples of the halogen atom of the trihalogenated methyl group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the halogen-substituted phenol compound represented by the general formula (I) in which the halogen atom of the trihalogenated methyl group is a fluorine atom include 3,5-bistrifluoromethylphenol.

  As the halogen-substituted phenol compound represented by the general formula (I), a chlorine-substituted phenol compound such as p-chlorophenol is preferable from the viewpoint of price and availability.

  The aromatic liquid crystal polyester solution composition used in the present invention is obtained by dissolving the aromatic liquid crystal polyester in the solvent.

In the aromatic liquid crystal polyester solution composition, the aromatic liquid crystal polyester is usually 0.5 to 100 parts by weight, preferably 1 to 50 parts by weight, more preferably 3 to 20 parts by weight with respect to 100 parts by weight of the solvent. Contained.
If the total amount of the aromatic liquid crystal polyester is 0.5 parts by weight or more, the production efficiency of the aromatic liquid crystal polyester film tends to be further improved, and if it is 100 parts by weight or less, the solubility in the solvent tends to be further improved. There is.
Thereafter, the solution composition may be further filtered through a filter or the like, if necessary, to remove fine foreign matters contained in the solution composition.

The aromatic liquid crystal polyester solution composition used in the present invention may contain an inorganic filler. Examples of the inorganic filler include silica, aluminum hydroxide, calcium carbonate, alumina, mica, mica, aluminum borate, potassium titanate, barium titanate, strontium titanate, and titanate titanate. Some are replaced with other metals, or barium oxide (BaO), bismuth oxide (Bi ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), neodymium oxide (Nd ₂ O ₃ ), samarium oxide (Sm _A combination of at least two selected from ₂ O ₃ ) and aluminum oxide (Al ₂ O ₃ ) and titanium oxide (TiO ₂ ) can be used. The shape of the inorganic filler may be any shape such as a spherical shape, a crushed shape, a plate shape, and a needle shape.

When using an inorganic filler, the content thereof is usually 10 to 100 parts by weight with respect to 100 parts by weight of the aromatic liquid crystal polyester.
If content of an inorganic filler is this range, there exists a tendency which can express the function by this inorganic filler, without reducing adhesiveness with a base material. However, when the obtained double-sided substrate-attached aromatic polyester film is used for applications requiring high flexibility, such as a flexible substrate, the inorganic filler is 10 to 50 parts by weight with respect to 100 parts by weight of the aromatic liquid crystal polyester. The range of is preferable.

  Further, the aromatic liquid crystal polyester solution composition includes polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenyl ether and modified products thereof, polyetherimide, and other thermoplastic resins, phenol resins, and epoxy. Various additives such as thermosetting resins such as resins, polyimide resins and cyanate resins, silane coupling agents, antioxidants and ultraviolet absorbers may be contained.

Next, a method for producing an aromatic liquid crystal polyester film with a double-sided substrate will be described. The production method includes the following steps (i) to (iii).
(I) A laminate 1 comprising the aromatic liquid crystal polyester film precursor containing the aromatic liquid crystal polyester and the first base material is cast by casting the aromatic liquid crystal polyester solution composition on a first base material. Manufacturing process
(ii) The laminate 1 obtained in (i) is heat-treated, and an aromatic liquid crystal polyester film composed of an aromatic liquid crystal polyester having a melting point of 340 ° C. or higher or substantially not having a melting point, and a substrate For producing a laminate 2 made of
(iii) A step of thermocompression bonding the second base material to a surface of the laminate 2 obtained in (ii) that is not in close contact with the first base material at a temperature of 300 ° C. or higher and 360 ° C. or lower.

  The step (i) is a step of casting the aromatic liquid crystal polyester solution composition on a first substrate in a film form. In (i), it is preferable to remove the solvent used in the aromatic liquid crystal polyester solution composition from the cast aromatic liquid crystal polyester film precursor.

The method of casting the aromatic liquid crystal polyester solution composition includes roller coating, dip coating, spray coating, spinner coating, curtain coating, slot coating, screen printing, die coating, and knife coating. Various means such as law can be used.
The method for removing the solvent 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, heat treatment is preferable from the viewpoint of production efficiency and handleability, that is, the melting point of the aromatic liquid crystal polyester of (ii) is increased. It is preferable to perform a pre-heating treatment for removing the solvent before performing the heat treatment at 340 ° C. or higher or denature until the melting point is substantially eliminated. The temperature condition for the preheating treatment is in the range of 60 to 200 ° C., and the treatment time in the range of 10 minutes to 2 hours is sufficient. Further, it is more preferable that the preheating treatment is performed while ventilating.

Subsequently, by performing the heat treatment in (ii), the melting point of the aromatic liquid crystal polyester in the aromatic liquid crystal polyester film precursor is set to 340 ° C. or higher, or is modified to have substantially no melting point. .
As temperature conditions for the heat treatment, the temperature is preferably 310 ° C. or higher, more preferably 310 ° C. or higher and 360 ° C. or lower, and particularly preferably 320 ° C. or higher and 350 ° C. or lower. In addition, as processing time, the range of 10 minutes-10 hours is preferable, and 10 minutes or more and 60 minutes or less are preferable. In such heat treatment, when the temperature condition is within the above range, the decomposition of the aromatic liquid crystal polyester itself is suppressed, and the modification of the aromatic liquid crystal polyester can be efficiently caused. In addition, the treatment time is preferably a short time because productivity is improved, but the treatment time can be appropriately optimized depending on the applied temperature condition. Note that the heat treatment is preferably performed in an inert gas atmosphere such as nitrogen or argon or under reduced pressure.

By the heat treatment, a laminate 1 composed of an aromatic liquid crystal polyester film containing an aromatic liquid crystal polyester having a melting point of 340 ° C. or higher or substantially not having a melting point and a first substrate can be obtained. Here, in order to obtain the melting point of the aromatic liquid crystal polyester film in the laminate 1, when the laminate 1 is analyzed by a differential scanning calorimetry (DSC) at a heating rate of 10 ° C./min, 340 It can be carried out by confirming that the melting peak temperature is shown in the range of 0 ° C. or higher, or that the melting point peak is substantially absent. In addition, when the 1st base material in the laminated body 1 is metal foil, when measuring DSC, this metal foil is removed by an etching process etc., and an aromatic liquid-crystal polyester film is obtained, and thus metal The aromatic liquid crystal polyester film from which the foil has been removed may be subjected to measurement.
In addition, it is more preferable that melting | fusing point of this aromatic liquid crystalline polyester is 360 degreeC or more, and it is especially preferable in it that an aromatic liquid crystalline polyester film does not have melting | fusing point substantially.

Next, (iii) will be described.
(Iii) is a temperature of 300 ° C. or more and 360 ° C. or less of the second substrate on the surface of the aromatic liquid crystal polyester film in the laminate 1 obtained through (ii) that is not in contact with the first substrate. This is a step of thermocompression bonding to obtain an aromatic liquid crystal polyester film with a double-sided substrate.
Here, as thermocompression bonding, the laminate 1 and the second substrate are bonded while heating, and a press molding method, a roll laminating method, or the like can be used. The temperature of thermocompression bonding is a control temperature in a press molding machine and a roll laminating machine widely used in the industry, and means a temperature measured at almost the center of a thermocompression bonding plate or a heating roll. Is.

  The temperature condition for the thermocompression bonding is 300 ° C. or higher and 360 ° C. or lower, and within this temperature range, a high degree of adhesion is exhibited between the second substrate and the aromatic liquid crystal polyester film, and the aromatic liquid crystal polyester. Therefore, an aromatic liquid crystal polyester film with a double-sided substrate having sufficient mechanical strength can be obtained. A more preferable temperature condition for thermocompression bonding is 320 ° C. or higher and 340 ° C. or lower.

  Moreover, as pressure conditions for thermocompression bonding, the range of 0.1 to 10 MPa is practical, and when the first base material and the second base material are metal foils, 2 MPa or more is the metal foil and the aromatic liquid crystal. It is preferable because a high degree of adhesion can be obtained between the polyester film and the range of 4 MPa or more and 8 MPa or less is particularly preferable.

  Moreover, as atmospheric conditions at the time of performing thermocompression bonding, it is preferable to carry out under an inert gas atmosphere such as nitrogen or argon, or under reduced pressure or vacuum.

The base material (first base material, second base material) applied to the present invention is preferably a metal foil in order to function as a conductor layer according to the electronic component. As the metal foil, a copper foil, a silver foil, Gold foil, aluminum foil or stainless steel foil is preferred. More preferable metal foil includes copper foil and stainless steel foil, and copper foil is particularly preferable. As the copper foil, any of an electrolytic copper foil, a rolled copper foil or a special electrolytic copper foil can be used. However, when the obtained aromatic liquid crystal polyester film with a double-sided substrate is used for a flexible substrate, its flexibility is required. From the viewpoint, a rolled copper foil having high flexibility is more preferable.
Thus, although the base material is preferably a metal foil, the first base material and the second base material may be the same as or different from each other.

In addition, the “second base material” in (iii) can be replaced with “laminated body 1 ′ composed of the second base material and an aromatic liquid crystal polyester film”. That is, even if the laminated body 1 and the laminated body 1 ′ are brought into contact with each other so that the aromatic liquid crystal polyester films are overlapped with each other and thermocompression-bonded under the above-described processing conditions, the laminate 1 and the laminated body 1 ′ are An aromatic liquid crystal polyester film with a double-sided substrate having a level of adhesion can be produced.
In this case, the substrate 1 and the substrate 2 may be the same or different from each other, and the aromatic liquid crystal polyester films in the laminate 1 and the laminate 1 ′ may be the same or different. It is necessary that the aromatic liquid crystalline polyester constituting the material has a melting point of 340 or higher or substantially has no melting point, and both the laminated body 1 and the aromatic liquid crystalline polyester film in the laminated body 1 ′ However, it is preferable that the melting point is not less than 340, or it is made of an aromatic liquid crystal polyester having substantially no melting point.

  Further, the surface roughness (ten-point average roughness Rz) of the first base material and the second base material is preferably low roughness of 4.0 μm or less from the viewpoint of transmission characteristics. When the first base material and the second base material are suitable metal foils, the surface roughness of the metal foil is more preferably 2.5 μm or less, and particularly preferably 2.2 μm or less. preferable. Such surface roughness can be determined by using a known surface roughness meter.

The thus obtained aromatic liquid crystal polyester film with a double-sided base material of the present invention maintains a high degree of adhesion between the base material and the aromatic liquid crystal polyester film, and the aromatic liquid crystal polyester film has mechanical properties and the like. Because of its excellent characteristics, it is a rigid printed circuit board, flexible printed circuit board (flexible printed circuit board for mobile phone hinges, flexible printed circuit board for notebook computer hinges, flexible printed circuit boards for optical pickups and hard disk magnetic head drive units, liquid crystal displays and plasma displays, It is suitably used for printed wiring boards such as organic EL displays and other printed circuit boards such as flexible printed circuit boards for mounting ICs or the like. Moreover, since it is excellent also in the high frequency transmission characteristic as a circuit board, it is utilized suitably also as a high frequency circuit board.
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 using an Example, this invention is not limited by an Example.

[Synthesis example of aromatic liquid crystal polyester]
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 128 g (0.68 mol) of 2-hydroxy-6-naphthoic acid and 63.3 g of 4,4′-dihydroxybiphenyl were added. (0.34 mol), isophthalic acid 56.5 g (0.34 mol) and acetic anhydride 152.7 g (1.50 mol) were charged. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to an internal temperature of 140 ° C. under a nitrogen gas stream, and the temperature was maintained and refluxed for 3 hours. Thereafter, while distilling off distilling by-product acetic acid and unreacted acetic anhydride, the temperature was raised to 300 ° C. at the internal temperature. The time point at which an increase in torque was observed was regarded as completion of the reaction, and the contents were taken out. The obtained solid content was cooled to room temperature and pulverized with a coarse pulverizer.

Furthermore, solid phase polymerization reaction was advanced in nitrogen atmosphere using the obtained aromatic liquid crystalline polyester powder, and aromatic liquid crystalline polyester powder was obtained.
In this solid phase polymerization, polyester A is obtained by reacting the aromatic liquid crystal polyester powder at 264 ° C. for 3 hours, and polyester B is obtained by polymerizing the aromatic liquid crystal polyester powder at 276 ° C. for 3 hours. When the flow start temperature of the aromatic liquid crystal polyester powder after solid-phase polymerization was evaluated by a flow tester CFT-500 manufactured by Shimadzu Corporation, the flow start temperature of polyester A was 300 ° C, and the flow start temperature of polyester B was 321 ° C. there were.

[Preparation of Aromatic Liquid Crystalline Polyester Solution Composition]
As a result of adding 10 g of polyester A or polyester B obtained by the above synthesis example to 90 g of p-chlorophenol (hereinafter sometimes abbreviated as PCP), and then heating to 120 ° C. and holding for 8 hours, aromatic liquid crystal polyester solution A composition was obtained. The solution composition for polyester A is referred to as composition A, and the solution composition for polyester B is referred to as composition B.

Examples 1-8
[Manufacture of Laminate 1]
The composition A or the composition B is an electrolytic copper foil F2WS manufactured by Furukawa Electric as a first base material (thickness = 18 μm, ten-point average roughness Rz = 2.1 μm: base material 1). ) After casting for 20 minutes at a set temperature of 100 ° C. with a hot air dryer and evaporating the solvent, heat treatment was performed in a nitrogen atmosphere with a hot air dryer, and a copper foil was laminated on one side. Body 1 (aromatic liquid crystal polyester film with single-sided copper foil) was obtained. In addition, the thickness of the aromatic liquid crystal polyester film with a single-sided copper foil after the heat treatment was 43 μm. The conditions for such heat treatment are summarized in Tables 1 and 2.

[Evaluation of melting point]
The copper foil is removed from the laminate 1 obtained as described above to obtain a single-layer aromatic liquid crystal polyester film, and the aromatic liquid crystal polyester film is obtained at 10 ° C./min using a differential thermal balance DSC-50 manufactured by Shimadzu Corporation. The melting peak temperature was evaluated by heating at a rate of temperature rise of, and the melting peak temperature was determined as the melting point. In addition, when the melting peak temperature was not observed and the resin decomposition temperature was reached, it was defined as “no melting point”. The results are summarized in Tables 1 and 2.

[Manufacture of Laminate 2]
Cut an aromatic liquid crystal polyester film with single-sided copper foil into 150 x 150 mm size, and the same Furukawa Electric electrolytic copper foil F2WS (thickness = 18 μm, 10-point average roughness) on the aromatic liquid crystal polyester resin surface Rz = 2.1 μm: base material 2) was laminated and thermocompression bonded with a vacuum press machine VH1-1765 (manufactured by Kitagawa Seiki) to obtain an aromatic liquid crystal polyester film with double-sided copper foil. This time, copper foil was used as the metal foil, but other metal foils such as stainless steel foil can also be suitably used. The processing conditions for such thermocompression bonding are summarized in Tables 1 and 2.

[Evaluation of adhesion]
The adhesion of the obtained aromatic liquid crystal polyester film with double-sided copper foil was evaluated by Autograph AG-IS (manufactured by Shimadzu Corporation) (90-degree direction tension, tensile speed 50 mm / min). This measurement was performed for each of the base material 1 (casting side) and the base material 2 (compression bonding side) to determine adhesion. The results are summarized in Tables 1 and 2.

Comparative Example 1
Using composition B, the heat treatment was performed at 300 ° C. for 20 minutes, and the aromatic liquid crystal polyester film obtained was subjected to the same experiment as in Example 3 except that the melting point was 327 ° C. A group liquid crystal polyester film was obtained and the adhesion was measured. The results are shown in Table 3.

Comparative Example 2
Using composition A, except that the thermocompression bonding conditions were changed to 280 ° C. and 20 minutes, the same experiment as in Example 5 was performed to obtain an aromatic liquid crystal polyester film with a double-sided substrate, and the adhesion was measured. The results are shown in Table 3.

  From the results of Examples 1 to 8, the aromatic liquid crystal polyester film with a double-sided substrate provided by the present invention has an adhesion between the film and the substrate 1 and an adhesion between the film and the substrate 2 of 5 N / cm or more. It has been found that it exhibits a high degree of adhesion. On the other hand, in Comparative Example 1 in which the melting point of the aromatic liquid crystal polyester is less than 340 ° C. and Comparative Example 2 in which the thermocompression bonding conditions are 280 ° C. and 300 ° C. or less, the adhesion between the film and the substrate 2 or the film and the base Either or both of the adhesiveness of the material 1 is reduced as compared with Examples 1-8.

Claims (9)

The manufacturing method of the liquid crystal polyester film with a double-sided base material which has the process represented by following (i), (ii) and (iii).
(I) An aromatic liquid crystal polyester solution containing an aromatic liquid crystal polyester and the following solvent is cast on a first substrate, the aromatic liquid crystal polyester film precursor containing the aromatic liquid crystal polyester and the first The process of manufacturing the laminated body 1 which consists of a base material
(ii) The laminated body 1 obtained in (i) is subjected to a heat treatment, and an aromatic liquid crystal polyester film composed of an aromatic liquid crystal polyester having a melting point of 340 ° C. or higher or substantially not having a melting point and the first The process of manufacturing the laminated body 2 which consists of a base material
(iii) Process solvent for thermocompression bonding the second substrate to the surface not in contact with the first substrate of the laminate 2 obtained in (ii) at a temperature of 300 ° C. or higher and 360 ° C. or lower: A solvent containing 30% by weight or more of the halogen-substituted phenol compound represented by (I).

(In the formula, A represents a halogen atom or a trihalogenated methyl group, i represents an integer of 1 to 5, and when i is 2 or more, a plurality of A may be the same or different from each other.) The aromatic liquid crystal polyester with double-sided substrate according to claim 1, wherein the aromatic liquid crystal polyester solution composition is a solution composition containing 0.5 to 100 parts by weight of aromatic liquid crystal polyester with respect to 100 parts by weight of the solvent. A method for producing a film. The method for producing an aromatic liquid crystal polyester film with a double-sided substrate according to claim 1 or 2, wherein the thermocompression bonding temperature in (iii) is 320 ° C or higher and 340 ° C or lower. The ten-point average roughness Rz of both the first substrate and the second substrate is 4.0 µm or less. Production of an aromatic liquid crystal polyester film with a double-sided substrate according to any one of claims 1 to 3 Method. Both the 1st base material and the 2nd base material are metal foil, The manufacturing method of the aromatic liquid crystal polyester film with a double-sided base material in any one of Claims 1-4. The method for producing an aromatic liquid crystal polyester film with a double-sided base material according to claim 5, wherein the metal foil is a copper foil or a stainless steel foil. The aromatic liquid-crystal polyester film with a double-sided base material obtained by the manufacturing method in any one of Claims 1-6. A printed wiring board comprising the aromatic liquid crystal polyester film with double-sided base material according to claim 7. A module substrate comprising the aromatic liquid crystal polyester film with a double-sided base material according to claim 7.