KR102399755B1 - Three-layer film, method for producing three-layer film, laminated plate and printed circuit board - Google Patents

Abstract

The three-layer film includes a polyimide resin film and a liquid crystal polymer layer having hydroxycarboxylic acid as a mesogenic group laminated on both sides of the polyimide resin film, the thickness (T1) of the polyimide resin film and the The thickness T2 of the liquid crystal polymer layer having hydroxycarboxylic acid as a mesogenic group satisfies the following relational expressions (a) and (b) (provided that the two T2s are mutually independent and may be the same or different. .).
(a) 20 μm ≤ T1 ≤ 50 μm
(b) 0.3≤T2/T1≤1.5

Description

Three-layer film, manufacturing method of three-layer film, laminated board, and printed circuit board

The present invention relates to a three-layer film, a method for producing a three-layer film, a laminate and a printed circuit board.

DESCRIPTION OF RELATED ART The laminated body in which the metal layer was provided on the insulating layer is used for printed wiring boards (printed board, printed circuit board) used in electronic devices, such as a cellular phone, a personal computer, and a digital home appliance. As such a laminated body, the laminated body which laminated|stacked the layer which consists of conductors, such as metal foil, and the layer which consists of a polyimide resin film as an insulating layer, for example is known (for example, patent documents 1-2). Moreover, in patent document 3, copper foil is employ|adopted as a metal layer, and the laminated body in which the liquid crystal polyester resin layer was laminated|stacked as an insulating layer is described.

Polyimide resin has water absorbency and is inferior in moisture resistance. Moreover, since it is a non-thermoplastic resin, metal foil cannot be laminated|stacked directly. Therefore, for example, Patent Documents 4 to 5 describe that a laminate of a liquid crystal polymer film and a polyimide resin is employed as an insulating layer. Examples of the liquid crystal polymer film include those described in Patent Documents 6 to 9. Since the absorption action of the polyimide resin has a great influence on the electrical properties of the printed wiring board, the method of employing the liquid crystal polymer film is important in making the electrical properties of the printed wiring board good.

Patent Document 1: Japanese Patent Laid-Open No. 2006-008976 Patent Document 2: Japanese Patent Application Laid-Open No. 2013-032532 Patent Document 3: Japanese Patent Laid-Open No. 2007-106107 Patent Document 4: Japanese Patent Laid-Open No. 2008-290424 Patent Document 5: Japanese Patent Laid-Open No. 2008-290425 Patent Document 6: Japanese Patent Laid-Open No. 2013-189535 Patent Document 7: Japanese Patent Laid-Open No. 2004-315678 Patent Document 8: Japanese Patent Laid-Open No. 2007-238915 Patent Document 9: Japanese Patent Laid-Open No. 2013-001902

However, the characteristics required for a printed wiring board are becoming higher and higher, and there is still room for improvement in a laminate used for a printed wiring board.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a three-layer film excellent in dimensional stability and electrical properties when used in a laminate for printed wiring boards, and a method for producing the three-layer film.

In the first aspect of the present invention, a liquid crystal polymer layer having hydroxycarboxylic acid as a mesogenic group is laminated on both surfaces of a polyimide resin film, and the thickness (T1) of the polyimide resin film and the hydroxycarboxyl group A three-layer film in which the thickness T2 of the liquid crystal polymer layer having an acid as a mesogenic group satisfies the following relational expressions (a) and (b) (provided that the two T2s are mutually independent and may be the same or different. )am.

(a) 20 ㎛ ≤ T1 ≤ 50 ㎛

(b) 0.3≤T2/T1≤1.5

In the first aspect of the present invention, the liquid crystal polymer layer having hydroxycarboxylic acid as a mesogenic group preferably contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid.

In the first aspect of the present invention, the liquid crystal polymer layer having hydroxycarboxylic acid as a mesogenic group preferably further contains the following structural units (1) and (2).

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

A second aspect of the present invention is a laminate in which the three-layer film of the first aspect is used as an insulating layer, and a metal layer is formed on at least one surface of the insulating layer.

In the second aspect of the present invention, it is preferable that the maximum height (Rz) of the metal layer is formed in a range of 0.5 to 2.5 µm.

In the second aspect of the present invention, the metal layer preferably includes copper.

A 3rd aspect of this invention is a printed circuit board using the laminated board of the said 5th aspect.

A fourth aspect of the present invention is a liquid composition coating step of applying a liquid composition comprising a solvent and a liquid crystal polymer on a polyimide resin film and covering the polyimide resin film with the liquid composition, and a solvent in the liquid composition. A method for producing a three-layer film comprising a solvent removal step to remove and a heat treatment step, wherein as the liquid crystal polymer, a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structure A method for producing a three-layer film containing units (1) and (2).

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

A fifth aspect of the present invention provides an impregnating step of impregnating a polyimide resin film in a liquid composition containing a solvent and a liquid crystal polymer to cover the polyimide resin film with the liquid composition, and a solvent for removing the solvent in the liquid composition. A method for producing a three-layer film comprising a removal step and a heat treatment step, wherein, as the liquid crystal polymer, a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1 ) and (2).

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

A sixth aspect of the present invention provides a process for preparing a liquid composition comprising a solvent and a liquid crystal polymer, and a polyamic acid resin liquid composition that is a precursor of a polyimide resin, the liquid composition and the polyamic acid resin liquid composition on a support; A method for producing a three-layer film comprising a step of applying the liquid composition in three layers in this order, a solvent removal step of removing a solvent in the three-layer liquid composition, and a step of forming a three-layer film, wherein the liquid crystal polymer comprises 2- A method for producing a three-layer film comprising a structural unit derived from hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1) and (2).

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

ADVANTAGE OF THE INVENTION According to this invention, when it uses for the laminated body for printed wiring boards, the three-layer film excellent in dimensional stability and electrical characteristics, and the manufacturing method of this three-layer film can be provided.

1 is a schematic diagram for explaining a three-layer film of the present invention.
2 is a schematic view for explaining a laminate using the three-layer film of the present invention.
3 is a schematic diagram for explaining a method for manufacturing a three-layer film according to a third aspect of the present invention.

≪Three-layer film≫

First, the three-layer film which is a 1st aspect of this invention is demonstrated using FIG.

1 shows a three-layer film 20 of the present invention. In the three-layer film 20 , liquid crystal polymer layers 22a and 22b having hydroxycarboxylic acid as a mesogenic group are laminated on both surfaces of a polyimide resin film 21 . In other words, the three-layer film 20 includes liquid crystal polymer layers 22a and 22b having hydroxycarboxylic acid as a mesogenic group, and a polyimide resin film 21 sandwiched between the liquid crystal polymer layers 22a and 22b. do.

In the three-layer film 20, the thickness T1 of the polyimide resin film 21 and the thickness T2 of each of the liquid crystal polymer layers 22a and 22b having hydroxycarboxylic acid as a mesogenic group are expressed by the following relation ( a) and (b) are satisfied, and two T2 (T2a and T2b in FIG. 1) are mutually independent, and may be same or different.

(a) 20 ㎛ ≤ T1 ≤ 50 ㎛

(b) 0.3≤T2/T1≤1.5

[Polyimide Resin Film]

The polyimide resin is a condensed polyimide obtained by polycondensation using diamines and tetracarboxylic dianhydride as starting materials. There is no restriction|limiting in particular as diamines, The aromatic diamines, alicyclic diamines, aliphatic diamines, etc. which are normally used for the synthesis|combination of a polyimide can be used. Diamines may be used independently and may be used in combination of 2 or more type.

In addition, as tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, etc. can be used, and there is no restriction|limiting in particular. Tetracarboxylic dianhydride may be used independently and may be used in combination of 2 or more type.

Further, in at least one of the diamines and tetracarboxylic dianhydride, at least one functional group selected from the group consisting of a fluorine group, a trifluoromethyl group, a hydroxyl group, a sulfone group, a carbonyl group, a heterocycle, a long-chain alkyl group, etc. You may have one or more.

Among these polyimides, it is preferable to use aromatic tetracarboxylic dianhydride as the tetracarboxylic dianhydride from the viewpoints of mechanical strength and flexibility when the polyimide resin film 21 is formed.

Regarding diamines, aromatic diamines, alicyclic diamines, and aliphatic diamines may be used independently and may use 2 or more types together.

Moreover, from a viewpoint of the mechanical strength at the time of forming the polyimide resin film 21, and a flexibility, as diamine, aromatic diamine is preferable.

As the polyimide resin film, a commercially available polyimide resin (PI) film can be used, for example, a PI film (U-Pyrex S, U-Pyrex R) manufactured by Ube Kosan Co., Ltd., a PI film manufactured by ToleduPont ( Kapton) and SKC Colon PI's PI films (IF30, IF70, LV300) are mentioned.

In the present invention, the thickness (T1) of the polyimide resin film satisfies the formula of the following (a).

(a) 20 ㎛ ≤ T1 ≤ 50 ㎛

Here, the thickness of a polyimide resin film is the value represented by the average which measured the thickness by the contact-type thickness gauge in 5 arbitrary places of a polyimide resin film. On the other hand, when measuring the thickness of the polyimide resin film, when it is difficult to apply a direct contact thickness gauge, in a state in which other layers such as the liquid crystal polymer layers 22a and 22b are overlapped, the overall thickness is measured as described above. Thus, it may be calculated by taking the difference with the thickness of the other overlapping layers (measured in the same manner as above).

In the present invention, from the viewpoint of easy availability, the thickness of the polyimide resin film is preferably 20 µm ≤ T1 ≤ 40 µm, more preferably 20 µm ≤ T1 ≤ 30 µm.

When the thickness of the polyimide resin film is equal to or greater than the lower limit, the insulating properties and posture maintenance function of the three-layer film can be ensured, and when the thickness is equal to or less than the upper limit, appropriate flexibility can be secured.

[Liquid Crystal Polymer]

The liquid crystal polymer used for the liquid crystal polymer layer of the three-layer film of the present invention is a liquid crystal polymer having hydroxycarboxylic acid as a mesogenic group. Typical examples are those obtained by polymerizing single or multiple types of aromatic hydroxycarboxylic acids, single or multiple types of aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic hydroxylamines and aromatic diamines. What is formed by polymerizing (polycondensation) at least 1 sort(s) of compound selected from the group which consists of, and what is formed by polymerizing polyester, such as polyethylene terephthalate, and aromatic hydroxycarboxylic acid are mentioned.

Although the mesogenic group derived from hydroxycarboxylic acid is not specifically limited, It is preferable to contain the structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid. Here, the mesogenic group refers to a molecular chain having a rod-shaped or plate-shaped molecular shape contained in a liquid crystal molecule, and high rigidity along the long chain of the molecule. The mesogenic group may be present in either or both of the main chain or the side chain of the liquid crystal polymer, but if high heat resistance is required, it is preferably present in the main chain.

In the present invention, the liquid crystal polymer preferably contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid.

The liquid crystal polymer preferably has a repeating unit represented by the following (1) (hereinafter sometimes referred to as “repeating unit (1)”), and having a repeating unit (1) and a repeating unit represented by the following formula (2) It is more preferable to have a repeating unit (hereinafter, sometimes referred to as "repeating unit (2)").

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group, 2-ethylhexyl group, n- An octyl group and an n-decyl group are mentioned, The carbon number becomes like this. Preferably it is 1-10.

Examples of the aryl group include a phenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a 1-naphthyl group and a 2-naphthyl group, and the carbon number is preferably 6 to 20.

When the hydrogen atoms in the group represented by Ar ¹ to Ar ⁴ are substituted with these groups, the number is preferably 2 or less for each group represented by Ar ¹ to Ar ⁴ independently, and more preferably it is one

As an example of the said alkylidene group, a methylene group, an ethylidene group, an isopropylidene group, n-butylidene group, and 2-ethylhexylidene group are mentioned, The carbon number becomes like this. Preferably it is 1-10.

The repeating unit (1) is a repeating unit derived from a predetermined aromatic dicarboxylic acid. As the repeating unit (1), Ar ¹ is a p-phenylene group (a repeating unit derived from terephthalic acid), Ar ¹ is an m-phenylene group (a repeating unit derived from isophthalic acid), and Ar ¹ is 2,6 - a naphthylene group (a repeating unit derived from 2,6-naphthalenedicarboxylic acid) and Ar ¹ is a diphenylether-4,4'-diyl group (diphenylether-4,4'-dicarboxylic acid) repeating units derived from acids) are preferred.

The repeating unit (2) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (2), Ar ² is a p-phenylene group (a repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine) and Ar ² is a 4,4′-biphenylylene group ( A repeating unit derived from 4,4'-dihydroxybiphenyl, 4-amino-4'-hydroxybiphenyl or 4,4'-diaminobiphenyl) is preferable.

The content of the repeating unit (1) is determined by dividing the total amount of all repeating units (the mass of each repeating unit constituting the liquid crystal polymer by the food of each repeating unit) value), preferably 40 mol% or less, more preferably 10 mol% or more and 37.5 mol% or less, still more preferably 20 mol% or more and 37.5 mol% or less, still more preferably 25 mol% or more and 37.5 mol% or less.

Similarly, the content of the repeating unit (2) is preferably 40 mol% or less, more preferably 10 mol% or more and 37.5 mol% or less, still more preferably 20 mol% or more and 37.5 mol%, based on the total amount of all repeating units. % or less, and still more preferably 25 mol% or more and 37.5 mol% or less.

The content of the mesogenic group derived from hydroxycarboxylic acid is preferably 55 mol% or less, more preferably 20 mol% or more and 50 mol% or less, still more preferably 25 mol% or less with respect to the total amount of all repeating units. % or more and 45 mol% or less, more preferably 30 mol% or more and 45 mol% or less. In the liquid crystal polymer, when the content of the mesogenic group derived from hydroxycarboxylic acid is higher than 55 mol%, the obtained liquid crystal polymer tends to be difficult to dissolve in a solvent to be described later, so it is difficult to obtain a liquid crystal polymer layer. .

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

In addition, the liquid crystal polymer may have 2 or more types each independently of repeating units (1)-(2). Further, the liquid crystal polymer may have repeating units other than the repeating units (1) to (2), but the content thereof is preferably greater than 0 mol% and not more than 10 mol%, based on the total amount of all repeating units. Preferably more than 0 mol% and not more than 5 mol%.

The liquid crystal polymer has, as the repeating unit (2), one or both of X and Y being an imino group, that is, a repeating unit derived from a predetermined aromatic hydroxylamine and a repeating unit derived from an aromatic diamine. It is preferable to have either one or both because it is excellent in solubility in a solvent, and it is more preferable to have only one or both of X and Y in which one or both of X and Y are imino groups as repeating unit (2).

The liquid crystal polymer may be one in which a mesogenic group derived from hydroxycarboxylic acid and repeating units (1) to (2) are randomly bonded, or a block copolymer may be used as long as it exhibits liquid crystallinity.

It is preferable to manufacture a liquid crystal polymer by melt-polymerizing the raw material monomer corresponding to the repeating unit which comprises it, and solid-state-polymerizing the obtained polymer (prepolymer). Thereby, a high molecular weight liquid crystal polymer with high heat resistance, strength, and rigidity can be manufactured with good operability. Melt polymerization may be carried out in the presence of a catalyst. Examples of the catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, and 4-( Nitrogen-containing heterocyclic compounds, such as dimethylamino) pyridine and 1-methylimidazole, are mentioned, A nitrogen-containing heterocyclic compound is used preferably.

The liquid crystal polymer has a flow initiation temperature of preferably 250°C or higher, more preferably 250°C or higher and 350°C or lower, and still more preferably 260°C or higher and 330°C or lower. Heat resistance, strength, and rigidity tend to improve so that a flow initiation temperature is high, but when too high, solubility with respect to an organic solvent becomes low easily or the viscosity of a solution tends to become high.

On the other hand, the flow initiation temperature is also called the flow temperature or flow temperature, and using a capillary rheometer, under a load of 9.8 MPa (100 kgf/cm 2 ), while raising the temperature at a rate of 4° C./min, the liquid crystal polymer is melted It is the temperature at which a viscosity of 4800 Pa·s (48000 poise) is exhibited when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and serves as a standard for molecular weight of liquid crystal polymers (Koide Naoyuki, "Liquid Crystal Polymer - Synthesis, Molding, and Application", CMC, Ltd., June 5, 1987, see p.95).

In the present invention, the liquid crystal polymer layer can be formed of a liquid composition including the above liquid crystal polymer and a solvent. As the solvent, an organic solvent is preferable, and the organic solvent is one in which the liquid crystal polymer to be used is soluble, specifically, one that is soluble in a concentration of 1 mass% or more at 50 ° C ([liquid crystal polymer]/[liquid crystal polymer + organic solvent]); Appropriately selected and used.

Examples of the organic solvent include halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane and o-dichlorobenzene; halogenated phenols such as p-chlorophenol, pentachlorophenol and pentafluorophenol; ethers such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; ketones such as acetone and cyclohexanone; esters such as ethyl acetate and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; amines such as triethylamine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; nitriles such as acetonitrile and succinonitrile; amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone (organic solvents having an amide bond in the molecule); urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and sulfolane; and phosphorus compounds such as hexamethylphosphoric acid amide and trin-butyl phosphoric acid. Moreover, you may use combining 2 or more types of organic solvents among these organic solvents.

As the organic solvent, since it has low corrosiveness and is easy to handle, a solvent containing an aprotic compound as a main component (aprotic solvent), particularly a solvent containing an aprotic compound having no halogen atom as a main component, is preferable. As this aprotic compound, since it is easy to melt|dissolve a liquid crystal polymer, it is preferable to use amide solvents, such as N,N- dimethylformamide, N,N- dimethylacetamide, and N-methylpyrrolidone. Moreover, the ratio of the aprotic compound to the whole organic solvent becomes like this. Preferably it is 50 mass % or more and 100 mass % or less, More preferably, it is 70 mass % or more and 100 mass % or less, More preferably, it is 90 mass % or more and 100 mass %. % or less.

In addition, as the organic solvent, since it is easy to dissolve the liquid crystal polymer, a solvent containing a compound having a dipole moment of 3 to 5 (unit: diby) as a main component is preferable. It is more preferable to use a phosphorus compound.

Further, the ratio of the compound having a dipole moment of 3 to 5 in the entire organic solvent is preferably 50 mass% or more and 100 mass% or less, more preferably 70 mass% or more and 100 mass% or less, still more preferably 90 mass% % or more and 100 mass% or less.

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

In addition, as the organic solvent, since it is easy to remove, a solvent containing as a main component a compound having a boiling point of 220°C or lower at 1 atm is preferable. more preferably. Further, the ratio of the compound having a boiling point of 220° C. or less at 1 atm to the entire organic solvent is preferably 50 mass% or more and 100 mass% or less, more preferably 70 mass% or more and 100 mass% or less, still more preferably 90 mass % or more and 100 mass % or less.

Examples of the aprotic compound and the compound having a boiling point of 220°C or lower at 1 atm include N,N-dimethylacetamide (boiling point: 160°C), N,N-dimethylformamide (boiling point: 153°C), and N-methylpyrroly Don (boiling point: 202°C) can be exemplified.

(liquid composition)

The content of the liquid crystal polymer in the liquid composition is preferably 5 mass % or more and 60 mass % or less, more preferably 10 mass % or more and 50 mass % or less, still more preferably 15 mass % or more with respect to the total amount of the liquid crystal polymer and the organic solvent. % or more and 45 mass% or less, and is appropriately adjusted so as to obtain a liquid composition having a desired viscosity.

Moreover, the liquid composition may contain 1 or more types of components, such as a resin other than a filler, an additive, and a liquid-crystal polymer, in the range which does not impair the effect of the three-layer film of this invention.

Examples of the filler include inorganic fillers such as silica, alumina, titanium oxide, barium titanate, strontium titanate, aluminum hydroxide, and calcium carbonate; and organic fillers such as a leveling agent, a cured epoxy resin, a crosslinked benzoguanamine resin, and a crosslinked acrylic resin, and the content thereof is preferably 0 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the liquid crystal polymer. .

Examples of the additive include a leveling agent, an antifoaming agent, an antioxidant, a ultraviolet absorber, a flame retardant, and a colorant, and the content thereof is preferably 0 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the liquid crystal polymer.

Examples of the resin other than the liquid crystal polymer include polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenylene ether and modified products thereof, and liquid crystal polymers such as polyetherimide of thermoplastics; Elastomers, such as a copolymer of glycidyl methacrylate and polyethylene; and thermosetting resins such as a phenol resin, an epoxy resin, and a cyanate resin, and the content thereof is preferably 0 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the liquid crystal polymer.

A liquid composition can be prepared by mixing a liquid crystal polymer, an organic solvent, and other components used as needed collectively or in an appropriate order. When using a filler as another component, after dissolving a liquid crystal polymer in an organic solvent and obtaining a liquid composition, it is preferable to prepare by dispersing a filler in this liquid composition.

In the present invention, the thickness (T2) of the liquid crystal polymer layer satisfies the following formula (b) in relation to the thickness (T1) of the polyimide resin film.

(b) 0.3≤T2/T1≤1.5

In the present invention, the "thickness of the liquid crystal polymer layer" means each thickness of the liquid crystal polymer layer laminated on both surfaces of the polyimide resin film. Specifically, each of T2a and T2b in FIG. 1 satisfies the above formula (b).

Here, the thickness of the liquid crystal polymer layer is a value expressed as an average of thicknesses measured with a contact thickness gauge at five arbitrary locations of the liquid crystal polymer layer. On the other hand, when measuring the thickness of the liquid crystal polymer layer, when it is difficult to apply a direct contact thickness gauge, in a state in which other layers such as polyimide resin film are overlapped, the overall thickness is measured as described above, You may calculate by taking the difference with the thickness of another layer (measured by the same method as above).

In the present invention, the thickness (T2) of the liquid crystal polymer layer preferably has a relationship with the thickness (T1) of the polyimide resin film in the range of 0.35≤T2/T1≤1.4, and 0.4≤T2/T1≤1.3 It is particularly preferred.

In the three-layer film of the present invention, for example, when a polyimide resin film having a thickness of 25 µm is employed, the thickness of the liquid crystal polymer layer is preferably 7.5 µm to 50 µm, more preferably 8 µm to 40 µm, 9 It is especially preferable that it is micrometer - 35 micrometers.

In the three-layer film of the present invention, the thicknesses of the liquid crystal polymer layers (T2a and T2b in Fig. 1) are mutually independent and may be the same or different. Although the same thing is preferable in this invention, if it is a range which exhibits the effect of this invention, and does not produce a warp in a three-layer film, it can adjust and change suitably.

For example, when the polyimide resin film has a hardness enough to prevent warpage, the thickness of the liquid crystal polymer layer (T2a and T2b in FIG. 1) may be different.

When the thickness of the liquid crystal polymer layer (T2a and T2b in Fig. 1) is different, for example, the difference between the thickness of T2a and the thickness of T2b is preferably within ±10%, more preferably within ±5%, and ± It is especially preferable to set it as 3 % or less.

Since the liquid crystal polymer has excellent low hygroscopicity, insulation, mechanical strength, etc., by laminating the liquid crystal polymer layer on both surfaces of the polyimide resin film, the moisture absorption of the hygroscopic polyimide resin film can be highly suppressed. For this reason, even when a printed circuit board on which a metal is laminated on the three-layer film of the present invention is placed in a humid environment or immersed in water, deterioration of electrical properties due to the hygroscopicity of the polyimide resin film can be highly suppressed. can

In addition, in the case where the metal is laminated on the three-layer film of the present invention by setting the thickness (T2) of the liquid crystal polymer layer to be less than or equal to the predetermined upper limit in relation to the thickness (T1) of the polyimide resin film, the metal lamination The dimensional stability of the sieve can be made favorable.

In addition, when the thickness T2 of the liquid crystal polymer layer, in relation to the thickness T1 of the polyimide resin film, is greater than or equal to the predetermined lower limit, the moisture absorption action of the polyimide resin film can be highly suppressed. For this reason, when a metal is laminated|stacked on the three-layer film of this invention, the effect|action which reduces the transmission loss of the said metal laminated body can be expressed highly. The three-layer film of the present invention can exhibit particularly high dimensional stability and transmission loss reducing action when metal layers are laminated on both surfaces of the three-layer film. Accordingly, the three-layer film of the present invention is preferably used for a laminate obtained by laminating metal layers on both surfaces of the three-layer film.

As a laminate in which the three-layer film of the present invention can be suitably used, for example, as shown in FIG. 2 , there may be mentioned those in which metal layers 30a and 30b are laminated on both surfaces of the three-layer film 20 of the present invention. That is, the laminate includes the metal layers 30a and 30b and the three-layer film 20 sandwiched between the metal layers 30a and 30b.

As a metal layer, the alloy containing copper, aluminum, silver, or 1 or more types of metals chosen from these is preferable. Among them, copper or a copper alloy is preferable from the viewpoint of having more excellent conductivity. In addition, the metal layer is preferably formed of metal foil, and more preferably formed of copper foil, from the viewpoint of easy material handling, simple formation, and excellent economic efficiency. When the metal layers are provided on both surfaces of the three-layer film, the materials of these metal layers may be the same or different.

The thickness of the metal layer is preferably 1 to 50 µm, more preferably 3 to 35 µm, still more preferably 5 to 20 µm.

Here, the thickness of a metal layer is a value represented by the average which measured the thickness by the contact-type thickness gauge in 5 arbitrary places of a metal layer. On the other hand, when measuring the thickness of a metal layer, when it is difficult to apply a direct contact thickness gauge, in a state in which other layers such as a liquid crystal polymer layer are overlapped, the overall thickness is measured as described above, and the You may calculate by taking the difference with the thickness (measured by the same method as above).

«Manufacturing method 1 of a three-layer film»

A second aspect of the present invention provides a liquid composition coating step of applying a liquid composition comprising a solvent and a liquid crystal polymer on a polyimide resin film, and covering the polyimide resin film with the liquid composition, and a solvent in the liquid composition. A method for producing a three-layer film of the first aspect of the present invention comprising a solvent removal step to remove and a heat treatment step, wherein the liquid crystal polymer is derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid. It is a manufacturing method of the three-layer film of the 1st aspect of this invention containing a structural unit and the following structural units (1)-(2).

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

[Liquid composition application process]

The method for producing a three-layer film of the present invention includes a liquid composition application step of applying a liquid composition containing a solvent and a liquid crystal polymer on a polyimide resin film, and covering the polyimide resin film with the liquid composition.

The description of the liquid composition containing the solvent and the liquid crystal polymer and the polyimide resin film is the same as the description of the three-layer film of the present invention.

As a method of applying the liquid composition described above on the polyimide resin film, various means such as a roller coat method, a dip coater method, a spray coater method, a curtain coat method, a slot coat method, and a screen printing method are mentioned, for example. It is preferable that the temperature at the time of application|coating is 10-40 degreeC.

In this invention, a liquid composition is apply|coated to both surfaces of a polyimide resin film by the said application|coating method. At this time, the application amount of the liquid composition is adjusted so that the liquid crystal polymer layer has the predetermined thickness.

[Solvent Removal Process]

After the [liquid composition application step], the solvent in the liquid composition is removed.

Here, although the method of removing a solvent is not specifically limited, It is preferable to carry out by evaporation of a solvent. As a method of evaporating the solvent, methods such as heating, reduced pressure, ventilation, etc. are mentioned. Among them, it is preferable to evaporate by heating from the viewpoint of production efficiency and handleability, and more preferably to evaporate by heating while ventilating.

The heat treatment in the solvent removal step may be appropriately selected depending on the solvent applied to the solution composition, may be heat treated at 60 to 200°C for 60 to 600 seconds, and is preferably from 120 to 600 seconds. By setting it as more than a lower limit, a solvent is fully removed and blocking is suppressed in the obtained three-layer film.

In addition, the removal of the solvent in the [solvent removal step] does not have to be complete, and the residual solvent may be removed in the next [heat treatment step]. From the viewpoint of preventing the surface roughening of the liquid crystal polymer layer, it is preferable to remove the solvent by this [solvent removal step].

[Heat treatment process]

After the above [solvent removal step], heat treatment is performed. For the heat treatment, for example, a method of heating the three-layer film by applying heat under an inert gas atmosphere can be employed. The heat treatment conditions may be appropriately adjusted according to the employed liquid composition, for example, in the range of 250°C to 400°C for 1 minute to 4 hours.

In the manufacturing method of the three-layer film of the 2nd aspect of this invention, first, a liquid composition is apply|coated to one side of a polyimide resin film, and the solvent in the said liquid composition is removed. Next, this operation is repeated also on the other side, and finally, the three-layer film of the 1st aspect of this invention can be obtained by heat-processing.

«Manufacturing method 2 of three-layer film»

A third aspect of the present invention provides an impregnation step of impregnating a polyimide resin film in a liquid composition containing a solvent and a liquid crystal polymer to cover the polyimide resin film with the liquid composition, and a solvent for removing the solvent in the liquid composition. The present invention comprising a removal step and a heat treatment step, wherein the liquid crystal polymer contains, as the liquid crystal polymer, a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units A method for producing a three-layer film of the first aspect.

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

[Impregnation process]

In the impregnation step, the polyimide resin film is impregnated in a liquid composition containing a solvent and a liquid crystal polymer. The impregnation time is preferably 30 seconds to 5 minutes. It is preferable that the temperature at the time of impregnation is 10-40 degreeC.

The description of the liquid composition containing the solvent and the liquid crystal polymer and the polyimide resin film is the same as the description of the three-layer film of the present invention.

After the impregnation step, the polyimide resin film impregnated with the liquid composition is passed between a pair of rolls having an interval smaller than the thickness thereof. According to this process, the liquid composition which adhered excessively to the surface of a polyimide resin film can be removed.

It is a schematic for demonstrating the method of continuously implementing an impregnation process and a roll passing process using a long polyimide resin film. However, what is shown here is an example, and the impregnation process in this invention is not limited to what is described here.

The polyimide resin film 10 is guided by the guide roller 4 and the guide roller G ₁ to move in the direction of the arrow, immersed in the liquid composition W in the immersion tank 3, and then the liquid composition The polyimide resin film 11 immediately after impregnation is pulled up from the immersion tank 3 and sent to the squeeze roll 5 provided with a pair of rolls 5A and 5B. The pair of rolls 5A and 5B are arranged to face each other so as to sandwich the polyimide resin film 11, and the distance between them is at least the thickness of the polyimide resin film 11 (polyimide resin film ( 10) and the total thickness including the liquid composition (W) impregnated therein). The polyimide resin film 11 is tightened by passing between such a pair of rolls 5A and 5B, so that the excess liquid composition is removed and the liquid composition impregnated polyimide resin in which the liquid composition is sufficiently impregnated therein. It becomes the film (12).

The pair of rolls 5A and 5B may rotate by themselves (self-rotation), or may rotate according to the running of the polyimide resin film 11 immediately after impregnation with the liquid composition. When the pair of rolls 5A and 5B are self-rotating, the adhesion amount of the liquid composition on the liquid composition-impregnated polyimide resin film 12 can be easily adjusted, and the target liquid composition-impregnated polyimide The surface of the mid resin film is also sufficiently tamed, and the smoothness of the surface is improved.

The film thickness of the liquid crystal polymer layer is a three-layer film adjusted to a predetermined film thickness by adjusting the pulling speed from the immersion tank 3 or the spacing between the pair of rolls 5A and 5B in the squeeze roll 5 . can be obtained

The description regarding the [solvent removal step] and the [heating step] in the third aspect of the present invention is the same as the description in the second aspect of the present invention.

Specifically, as the [solvent removal step], the liquid composition-impregnated polyimide resin film passed between the rolls 5A and 5B may be heat-treated at 60 to 200° C. for 60 to 600 seconds, and for 120 to 600 seconds. it is preferable

By this heat treatment, the solvent of the liquid composition impregnated in the liquid composition-impregnated polyimide resin film is evaporated and removed, and a target three-layer film can be obtained.

Then, as the [heating step], heat treatment may be performed in the range of, for example, 250°C to 400°C for 1 minute to 4 hours. By setting the temperature and time of the heat treatment in this way, a three-layer film with reduced voids can be stably obtained.

«Manufacturing method 3 of three-layer film»

A fourth aspect of the present invention provides a process for preparing a liquid composition comprising a solvent and a liquid crystal polymer, and a polyamic acid resin liquid composition that is a precursor of a polyimide resin, the liquid composition and the polyamic acid resin liquid composition on a support; A manufacturing method comprising a step of applying the liquid composition in three layers in this order, a solvent removal step of removing a solvent in the three layers of the liquid composition, and a heat treatment step, wherein as the liquid crystal polymer, 2-hydroxybenzoic acid or A method for producing a three-layer film according to the first aspect of the present invention, comprising a structural unit derived from 2-hydroxy-6-naphthoic acid and the following structural units.

(1) -CO-Ar ¹ -CO-

(2) -X-Ar ² -Y-

(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)

(3) -Ar ³ -Z-Ar ⁴ -

(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

[Polyamic acid resin liquid composition]

Polyimide resin is obtained by the dehydration conversion reaction from the precursor of a polyimide, ie, a polyamic acid. As a method of performing this conversion reaction, two methods are known: a thermosetting method performed only by heat, and a chemical curing method using a chemical dehydrating agent.

A polyamic acid can be obtained by polymerizing tetracarboxylic dianhydride and diamine to a raw material, as described in patent document 1, for example. By processing (chemical hardening method) a polyamic acid by heating 200 degreeC or more (thermal curing method) or a chemical ring closure agent (chemical hardening method), dehydration and cyclization reaction can advance and a polyimide resin can be obtained.

[Step of applying a liquid composition containing a solvent and a liquid crystal polymer on a support, a liquid composition of a polyamic acid resin, and a liquid composition containing a solvent and a liquid crystal polymer in this order in three layers]

In this process, although glass etc. are used normally as a support body, a conductor can also be used. As such a conductor, metal plates or metal foil, such as gold|metal|money, silver, copper, aluminum, nickel, and stainless steel, are mentioned.

As a method of casting a liquid composition containing a solvent and a liquid crystal polymer and a liquid polyamic acid resin composition on a support, a liquid composition containing the solvent and a liquid crystal polymer or a liquid polyamic acid resin composition, if necessary, After filtering with a filter or the like to remove foreign substances contained in the liquid composition containing the solvent and the liquid crystal polymer and the liquid polyamic acid resin composition, the roller coating method, dip coating method, spray coating method, spinner coating method, and curtain coating method on the support It can be obtained by smoothing the surface and uniformly flexible by various means such as a method, slot coating method, and screen printing method, and then removing the solvent.

On the support, a liquid composition containing a solvent and a liquid crystal polymer, a liquid polyamic acid resin composition, and a liquid composition containing a solvent and a liquid crystal polymer are applied in this order in three layers. At this time, the application amount of the liquid composition containing the solvent and the liquid crystal polymer is adjusted so that the liquid crystal polymer layer has the predetermined thickness.

The description regarding the [solvent removal step] in the fourth aspect of the present invention is the same as the description in the second aspect of the present invention.

[Three-layer film forming process]

Then, it heat-processes, and the support body can be peeled off, and a three-layer film can be obtained. Here, instead of heat processing, it is good also as processing with a chemical ring closing agent. As a chemical ring closure agent in this case, what is used for obtaining a polyimide from polyamic acid can be used, For example, pyridine, acetic anhydride, benzoic acid etc. are used. When heat-processing, it is good to set it as the temperature range of 250-400 degreeC in nitrogen atmosphere.

In the method for producing a three-layer film according to the fourth aspect of the present invention, a liquid composition containing a solvent and a liquid crystal polymer is first applied on a support, and the solvent in the liquid composition is removed. Next, the polyamic acid resin liquid composition is applied, and the solvent of the polyamic acid resin liquid composition is removed. Further, a liquid composition containing a solvent and a liquid crystal polymer is applied, and the solvent in the liquid composition is removed. Finally, a three-layer film can be obtained by processing by heat treatment or a chemical ring closure agent and peeling from the support.

Further, in the method for producing a three-layer film according to the fourth aspect of the present invention, a liquid composition containing a solvent and a liquid crystal polymer, a liquid composition containing a polyamic acid resin, and a liquid composition containing a solvent and a liquid crystal polymer are applied in this order on a support. and remove the solvent in the liquid composition. Finally, a three-layer film may be obtained by treating with a heat treatment or chemical closure agent and peeling from the support.

≪Laminate Board≫

A 5th aspect of this invention is a laminated board in which the three-layer film obtained by said 2nd - 4th aspect is used as an insulating layer, and the metal layer is formed in at least one surface of this insulating layer.

In the laminate of the present invention, a metal layer may be formed on at least one surface of the three-layer film, but it is preferable that the metal layer is laminated on both surfaces. That is, it is preferable that the laminated board contains the 1st and 2nd metal layers, and the three-layer film pinched|interposed between the 1st and 2nd metal layers. A laminate in which a metal layer is laminated on both sides of the three-layer film. More specifically, the laminate shown in FIG. 2 is a laminate in which 30a and 30b in FIG. 2 are metal layers.

The metal layer laminated|stacked on the said three-layer film is demonstrated.

The metal layer in the laminate of the present invention is a copper foil having a tensile modulus of 60 GPa or less and a stress at break of 150 MPa or less after heat treatment at 300°C. As a lower limit regarding this tensile modulus, it is 10 GPa or more in a practical range, and it is preferable in it being 20 GPa or more. The lower limit regarding the stress at break is preferably 20 MPa or more in a practical range, and particularly preferably 30 MPa or more. The type of the metal layer used in the present invention may be either a layer formed by electrolysis or a layer formed by rolling. From a high-temperature high elongation copper foil (hereinafter abbreviated as "HTE copper foil") or a copper foil commercially available as a rolled copper foil, the tensile modulus and stress at break can be obtained and selected by the method specified in JIS C2151.

The thickness of the metal layer used for the laminated board of this invention becomes like this. Preferably it exceeds 5 micrometers and is the range of 35 micrometers or less. In particular, it is preferable to exist in the range of 9-28 micrometers. When the thickness of the metal layer is within the above range, adjustment of the tension of the metal layer is easy at the time of manufacture of the laminate, and since the flexibility of the laminated sheet obtained improves more, it is preferable.

Here, the thickness of a metal layer is a value represented by the average which measured the thickness by the contact-type thickness gauge in 5 arbitrary places of a metal layer. On the other hand, when measuring the thickness of a metal layer, when it is difficult to apply a direct contact thickness gauge, in a state in which other layers such as a three-layer film are overlapped, the overall thickness is measured as described above, and the thickness of the other layer that has been superimposed You may calculate by taking the difference with (measured by the same method as above).

Moreover, it is preferable to exist in the range of 0.5-2.5 micrometers, as for the maximum height Rz of the metal layer in a laminated board, the inside of the range of 0.6-2.4 micrometers is more preferable, The inside of the range of 0.6-2.2 micrometers is especially preferable.

As a concrete example of a preferable metal layer applied to the present invention, copper foil is preferable, and among them, as HTE copper foil, for example, SQ-HTE copper foil (manufactured by Mitsui Industries, Ltd.), 3EC-M3S-HTE copper foil (Mitsui Industries, Ltd.) Co., Ltd.), NS-HTE copper foil (manufactured by Mitsui Ginzoku Kogyo Co., Ltd.), 3EC-HTE copper foil (manufactured by Mitsui Ginzoku Kogyo Co., Ltd.), F2-WS copper foil (manufactured by Furukawa Denko Co., Ltd.), HLB (manufactured by Nippon Denkai Co., Ltd.), CF-T4X-DS-SVR (manufactured by Fukuda Kinzoku Hakuhoon Co., Ltd.) and the like, and examples of the rolled copper foil include RCF-T5B-HPC (manufactured by Fukuda Kinzoku Hakuhoun Co., Ltd.), BHY-22B-T (JX Nikko Niseki Kinjo Co., Ltd.). Co., Ltd.), BHY-22B-HA (manufactured by JX Nikko Nippon Industries, Ltd.), BHYA-T (manufactured by JX Nikko Nisseki Kinzoku Co., Ltd.), BHYA-HA (manufactured by JX Nikko Nisseki Kinzoku Co., Ltd.), etc. are mentioned. These copper foils are readily available in the market.

By using the copper foil which has the above-mentioned characteristic for the laminated board of this invention, it is excellent also in the adhesiveness of a metal layer and a resin layer, and can implement|achieve a laminated board with favorable flexibility and bending resistance.

As a method of integrating the said three-layer film and a metal layer, the method of hot-pressing a metal layer and a three-layer film is used suitably. For example, using a commercial press machine, 200-350 degreeC, the method of hold|maintaining for 10 minutes - 60 minutes at the pressure of 3-10 MPa, and performing hot press is mentioned.

The liquid crystal polymer laminate of the present invention obtained in this way has excellent properties such as dimensional stability and low hygroscopicity. It is suitably used for a film for automatic tape bonding and the like.

<Printed circuit board>

A sixth aspect of the present invention is a printed circuit board using the three-layer film as an insulating layer. The printed circuit board of this invention can be set as the structure similar to a well-known printed circuit board except using the said three-layer film as an insulating layer, and can be manufactured by the same method. That is, the printed circuit board includes an insulating layer including a three-layer film, and a circuit pattern positioned on the three-layer film. In other words, the printed circuit board includes an insulating layer including at least one three-layer film, and a circuit pattern formed on at least one of the first side and the second side of the insulating layer. The insulating layer may consist of one three-layer film, and a plurality of three-layer films may be laminated. The circuit pattern may be located only on the first surface, the first circuit pattern may be located on the first surface, and the second circuit pattern may be located on the second surface.

For the printed circuit board of the present invention, for example, an insulating layer formed of one sheet of the three-layer film, or an insulating layer formed by laminating several sheets of the three-layer film, a laminate in which a metal layer is provided on one or both sides is prepared, It can manufacture by forming a predetermined circuit pattern in the metal layer of a laminated body by etching etc., and laminating|stacking two or more sheets of the laminated body in which this circuit pattern was formed as it is or as needed. As for the printed circuit board of this invention, it is preferable that the metal layer is laminated|stacked on both surfaces of a three-layer film. That is, the printed circuit board preferably includes a three-layer film, a first circuit pattern positioned on the first surface of the three-layer film, and a second circuit pattern positioned on the second surface of the three-layer film.

In the case of an insulating layer in which several sheets of the three-layer film are laminated, all of these three-layer films may be the same, only some may be the same, or all may be different. In addition, if the number of sheets is two or more, it will not specifically limit. Such an insulating layer can be produced by, for example, superimposing a plurality of three-layer films in the thickness direction, hot-pressing them, fusion-bonding them, and integrating them.

The material of the metal layer is preferably copper, aluminum, silver, or an alloy containing at least one metal selected from these. Especially, copper or a copper alloy is preferable at the point which has more outstanding electroconductivity. In addition, the metal layer is preferably formed of metal foil, more preferably formed of copper foil, from the viewpoint of easy material handling, simple formation, and excellent economic feasibility. When the metal layers are provided on both surfaces of the insulating layer, the materials of these metal layers may be the same or different.

The thickness of the metal layer is preferably 1 to 50 µm, more preferably 3 to 35 µm, still more preferably 5 to 20 µm.

Here, the thickness of a metal layer is a value represented by the average which measured the thickness by the contact-type thickness gauge in 5 arbitrary places of a metal layer. On the other hand, when measuring the thickness of a metal layer, when it is difficult to apply a direct contact thickness gauge, in a state in which other layers such as a three-layer film are overlapped, the overall thickness is measured as described above, and the thickness of the other layer that has been superimposed You may calculate by taking the difference with (measured by the same method as above).

As a method of providing the metal layer, a method of fusion bonding a metal foil to the surface of the insulating layer, a method of bonding a metal foil to the surface of the insulating layer with an adhesive, a method of plating the surface of the insulating layer, a screen printing method or a sputtering method, A method of coating with powder or metal particles can be exemplified.

When the insulating layer is formed by laminating several sheets of the three-layer film, these three-layer films are overlapped in the thickness direction, and a metal foil is further overlapped on the surface of one or both three-layer films located at the outermost side, When forming an insulating layer by hot-pressing metal foil and several sheets of three-layer film, a metal layer can also be provided simultaneously on one side or both surfaces of an insulating layer.

A circuit pattern is formed by patterning the metal layer. Etching etc. can be illustrated as a method of forming a circuit pattern. Etching (processing) will be briefly described. First, the metal layer is masked so that the metal layer has a predetermined circuit pattern, and in the masked metal layer portion and the unmasked metal layer portion, the latter metal layer portion is subjected to an etching process called a wet method (chemical treatment). It can be carried out by removing it. As a chemical|medical agent used for this etching process, a ferric chloride aqueous solution is mentioned, for example. In addition, as said masking, what is necessary is just to use a commercially available etching resist or a dry film.

Then, the etching resist or dry film is removed from the masked metal layer portion with acetone or aqueous sodium hydroxide solution. By patterning the metal layer in this way, a predetermined circuit pattern (wiring) can be formed.

Example

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited by the examples.

<Production Example 1>

677.4 g (3.6 mol) of 2-hydroxy-6-naphthoic acid (hereinafter referred to as "HNA"), 4-hydroxy acetanilide (hereinafter referred to as "APAP") 332.6 g (2.2 moles), isophthalic acid (hereinafter referred to as "IPA") 99.7 g (0.6 moles), diphenyl ether-4,4'-dicarboxyl 413.2 g (1.6 mol) of an acid (hereinafter referred to as "DEDA") and 673.8 g (6.6 mol) of acetic anhydride were added.

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.

After that, the temperature was raised to 320° C. over 170 minutes while distilling off by-product acetic acid and unreacted acetic anhydride, and the time when a torque increase was confirmed was regarded as the completion of the reaction, and the contents were removed. pulled out The obtained solid content was cooled to room temperature, pulverized with a coarse grinder, and observed with a polarizing microscope (ECLIPSE LV100POV manufactured by NIKON) at 230°C to confirm that it exhibits a schlieren shape peculiar to a liquid crystal phase. In addition, the liquid crystal polymer in powder form was maintained at 250° C. for 3 hours under a nitrogen atmosphere to advance the polymerization reaction to a solid phase. 100 g of the obtained liquid crystal polymer powder was added to 900 g of N-methyl-2-pyrrolidone, and it was heated to 120° C. to completely dissolve it to obtain a brown transparent liquid crystal polymer solution composition (1).

<Preparation Example 2>

332.6 g (2.2 moles) of 4-hydroxyacetanilide (hereinafter referred to as "APAP"), isophthalic acid (hereinafter "IPA" ') 99.7 g (0.6 mol), diphenyl ether-4,4'-dicarboxylic acid (hereinafter referred to as "DEDA") 413.2 g (1.6 mol) and acetic anhydride 269.5 g (2.6 mol) put in 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 by-product acetic acid and unreacted acetic anhydride, and the time when a torque increase was confirmed was regarded as the completion of the reaction, and the contents were taken out. After the obtained solid content was cooled to room temperature and pulverized with a coarse grinder, polarization microscope observation was performed while raising the temperature from room temperature to 400°C, but the schlieren pattern peculiar to the liquid crystal phase was not observed.

[Example 1]

Liquid crystal polymer solution composition (1) was applied on one side of a commercially available polyimide resin film, Kapton H (manufactured by Toledu Pont) having a film thickness of 25 µm, on one side using a film applicator (coating thickness of 100 µm), and 100 µm with a hot air dryer. The solvent was removed by heating at °C, and this operation was repeated on the other side, and heat-treated at 300 °C with a high-temperature hot air dryer to make a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer=10 µm/25 µm/ 10 μm) was obtained.

The three-layer film obtained above was used as an insulating layer, and copper foil (“BHY-22B-T” manufactured by JX Nikko Nisseki Kinzoku Co., Ltd. (thickness 18 µm, Rz=0.7 µm)) was laminated on both surfaces thereof. By hot pressing this with a high-temperature vacuum press machine ("KVHC-PRESS" manufactured by Kitagawa Seiki Co., Ltd., 300 mm long, 300 mm wide) under the conditions of a temperature of 340 ° C. and a pressure of 5 MPa for 20 minutes to integrate, A double-sided copper clad laminate was obtained.

About the double-sided copper clad laminated board obtained above, TDR measurement was performed and the printed circuit board was produced so that it might become 50 Ω. As a result, a circuit pattern having a ground layer having a wiring width of 110 µm and a length of 100 mm was formed.

<Measurement of transmission loss>

About the printed circuit pattern in which the circuit pattern was formed, the transmission loss (S21 parameter) was measured using the measurement probe "E8363B" manufactured by Agilent Technologies. Transmission losses at frequencies of 5 GHz, 10 GHz, 20 GHz, and 40 GHz were measured before and after immersion in water at 23°C for 48 hours.

Tables 3 and 4 show the transmission losses at 5 GHz, 10 GHz, 20 GHz, and 40 GHz before immersion in water. In addition, the rate of change of the transmission loss (frequency 5 GHz) before and after 23 degreeC x 48h immersion is described in Tables 3 and 4.

<Dimensional stability evaluation>

Using a ferric chloride solution (manufactured by Gida Co., Ltd., 40° Baume), the copper foil was completely removed from the double-sided copper-clad laminate, and in accordance with JIS C6481 "Test method for copper-clad laminates for printed wiring boards", a thermomechanical analyzer (Rigaku Corporation) Using the manufactured "Thermo plus TMA8310"), while applying a load of 2.5 g to a 20 mm x 50 mm test piece (insulating layer), the in-plane temperature was raised to 250 °C at 5 °C/min under nitrogen stream The coefficient of thermal expansion was measured (temperature range 50-250° C.: 1St scan). The results are shown in Tables 1 and 2.

[Example 2]

A copper clad laminate was prepared in the same manner except in Example 1, except that the thickness of the film applicator was changed to 200 µm to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer = 20 µm/25 µm/20 µm). . About the obtained copper clad laminated board, when TDR measurement was carried out and the printed circuit board was produced so that it might be set to 50 (ohm), the wiring width was set to 142 micrometers and length was set to 100 mm.

[Example 3]

A copper clad laminate was produced in the same manner as in Example 1, except that Upirex S (manufactured by Ube Kosan Co., Ltd.) having a film thickness of 25 µm, which is a commercially available polyimide resin film, was used. About the obtained copper clad laminated board, when TDR measurement was performed and the printed circuit board was produced so that it might become 50 (ohm), wiring width was 110 micrometers and length was 100 mm.

[Example 4]

In Example 1, except having laminated|stacked copper foil ("F2-WS" by Furukawa Denko Co., Ltd. (18 micrometers, Rz = 2.1 micrometers)), the same operation was performed and the copper-clad laminated board was produced. About the obtained copper clad laminated board, when TDR measurement was performed and the printed circuit board was produced so that it might be set to 50 (ohm), wiring width was set to 110 micrometers and length was set to 100 mm.

[Example 5]

A copper clad laminate was prepared in the same manner except in Example 1, except that the thickness of the film applicator was changed to 250 µm to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer = 25 µm/25 µm/25 µm). .

[Example 6]

A copper clad laminate was prepared in the same manner except in Example 1, except that the thickness of the film applicator was changed to 335 µm to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer=33.5 µm/25 µm/33.5 µm) .

[Comparative Example 1]

A copper clad laminate was prepared in the same manner except that in Example 1, the application thickness of the film applicator was changed to 50 µm to obtain a three-layer film (liquid crystal polymer/polyimide/liquid crystal polymer = 5 µm/25 µm/5 µm). . About the obtained copper clad laminated board, when TDR measurement was carried out and the printed circuit board was produced so that it might become 50 (ohm), wiring width became 95 micrometers and length became 100 mm. It was found that the change in transmission loss before and after water immersion was 23% as large.

[Comparative Example 2]

TDR measurement was performed using a commercially available copper clad laminate using a commercially available polyimide resin film, Espanex MB (manufactured by Nippon Steel Chemicals, Inc., polyimide film thickness of 50 µm), and the printed circuit board was fabricated so as to be 50 Ω. As a result, the wiring The width was 110 μm and the length was 100 mm.

Next, about the model sample, the transmission loss (S21 parameter) of the printed circuit board was measured using the measurement probe "E8363B" manufactured by Agilent Technologies.

It was found that the change in transmission loss before and after immersion in water was as large as 35%.

[Comparative Example 3]

Liquid-crystal polymer solution composition (1) on copper foil ("BHY-22B-T" (thickness 18 µm, Rz = 0.7 µm) manufactured by JX Nikko Nisseki Kinzoku Co., Ltd.) Using a film applicator (coating thickness 500 µm) One side was coated, and the solvent was removed by heating at 100 ° C. using a hot air dryer, and heat treatment at 300 ° C. with a high temperature hot air dryer to obtain a one-sided copper clad laminate (50 μm).

Copper foil ("BHY-22B-T" (thickness 18 µm, Rz = 0.7 µm) manufactured by JX Nikko Nisseki Kinzoku Co., Ltd.) was further laminated on the liquid crystal polymer of the single-sided copper clad laminate obtained above, and high-temperature vacuum Double-sided copper clad laminate by heat-pressing for 20 minutes under conditions of a temperature of 340° C. and a pressure of 5 MPa with a press machine (“KVHC-PRESS” manufactured by Kitagawa Seiki Co., Ltd., 300 mm long, 300 mm wide) to integrate got

All copper foils were removed from the double-sided copper-clad laminate using a ferric chloride solution (manufactured by Gida Co., Ltd., 40° Baume), and in accordance with JIS C6481 "Test method for copper-clad laminates for printed wiring", a thermomechanical analyzer (manufactured by Rigaku Corporation) In-plane thermal expansion when the temperature is raised to 250°C at 5°C/min under a nitrogen stream while applying a load of 2.5 g to a 20 mm×50 mm test piece (insulating layer) using 「Thermo plus TMA8310」) Coefficients were measured (temperature range 50-250° C., 1St scan). Compared with the three-layer film, it expanded significantly, and it was found that the dimensional change was large.

[Comparative Example 4]

A commercially available liquid crystal polymer film (Kurare Co., Ltd., Bexstar 50 µm) was used as an insulating layer, and copper foil (“BHY-22B-T” manufactured by JX Nikko Nisseki Kinzoku Co., Ltd. (thickness 18 µm, Rz=0.7) on both surfaces μm)) was laminated. By hot pressing this with a high-temperature vacuum press machine ("KVHC-PRESS" manufactured by Kitagawa Seiki Co., Ltd., 300 mm long, 300 mm wide) under the conditions of a temperature of 340 ° C. and a pressure of 5 MPa for 20 minutes to integrate, A double-sided copper clad laminate was obtained.

All copper foils were removed from the double-sided copper-clad laminate using a ferric chloride solution (manufactured by Gida Co., Ltd., 40° Baume), and in accordance with JIS C6481 "Test method for copper-clad laminates for printed wiring", a thermomechanical analyzer (manufactured by Rigaku Corporation) In-plane thermal expansion when the temperature was raised to 250°C at 5°C/min under a nitrogen stream while applying a load of 2.5 g to a 20 mm × 50 mm test piece (insulating layer) using 「Thermo plus TMA8310」) Coefficients were measured (temperature range 50-250° C., 1St scan). It was found that the dimensional change was large due to the large shrinkage compared to the three-layer film.

As described in the above results, the double-sided copper clad laminates of Examples 1 to 4 using the three-layer film of the present invention have a lower rate of change in transmission loss before and after immersion in water than the double-sided copper clad laminate of Comparative Example 1, and the dimensions Stability was also good.

Further, even when the liquid crystal polymer layer was thickened as in Examples 5 to 6, dimensional stability was good. Since the three-layer film of Examples 5-6 has a thick liquid crystal polymer layer, when a printed circuit board is produced using the three-layer film of Examples 5-6, the rate of change of the transmission loss of the printed circuit board is, The effect of being lower than or equal to 4 can be fully exhibited.

On the other hand, since Comparative Examples 3-4 had a large dimensional change compared with the three-layer film of this invention, the measurement of transmission loss was not carried out.

As described above, in the examples of the present specification, a three-layer film was prepared by applying a liquid composition including a solvent and a liquid crystal polymer on a polyimide resin film. The three-layer film, in addition to the above method, can also be prepared in the following <Method for producing a three-layer film by impregnation> or <Method for producing a three-layer film by sequential application>, and the three-layer film produced by the method and prepared in the above Examples One three-layer film is to exert the same effect.

<Method for producing three-layer film by impregnation>

A commercially available polyimide resin film, Kapton 200H (manufactured by Toledu Pont; 50 µm), is immersed in the liquid crystal polymer solution composition (1) for 1 minute at room temperature, and then pulled up, in order to drop the liquid crystal polymer excessively adhering to the surface. After passing between a pair of rolls, a three-layer film can be produced by evaporating a solvent with a hot-air dryer, and also heat-processing using a high temperature hot-air dryer.

At this time, the film thickness of the liquid crystal polymer can also be adjusted by adjusting the pulling rate.

<Method for manufacturing three-layer film by sequential application>

As a support, the liquid crystal polymer solution composition (1), the polyamic acid resin liquid composition, and the liquid crystal polymer solution composition (1) are applied in this order on the SUS foil, heated at 100° C. using a hot air dryer to remove the solvent, and then A three-layer film can be produced by heat-processing at 330 degreeC and peeling from a support body.

ADVANTAGE OF THE INVENTION According to this invention, when it uses for the laminated body for printed wiring boards, the three-layer film excellent in dimensional stability and electrical characteristics, and the manufacturing method of this three-layer film can be provided.

20: three-layer film, 21: polyimide resin film, 22a, 22b: liquid crystal polymer layer, 30a, 30b: metal layer, 3: immersion tank, 4: guide roller, 5: squeeze roll, 5A, 5B: roll, 10: polyy Mid resin film, 11: polyimide resin film immediately after impregnation with liquid composition, 12: polyimide resin film impregnated with liquid composition, W: liquid composition, G ₁ : guide roller

Claims (14)

A liquid crystal polymer layer having hydroxycarboxylic acid as a mesogenic group is laminated on both surfaces of a polyimide resin film, and the thickness (T1) of the polyimide resin film and a liquid crystal polymer having the above hydroxycarboxylic acid as a mesogenic group A three-layer film in which the thickness T2 of the layer satisfies the following relational expressions (a) and (b) (however, the two T2s are mutually independent and may be the same or different).
(a) 20 μm ≤ T1 ≤ 50 μm
(b) 0.3≤T2/T1≤0.8 The three-layer film according to claim 1, wherein the liquid crystal polymer layer having hydroxycarboxylic acid as a mesogenic group contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid. The three-layer film according to claim 1 or 2, wherein the liquid crystal polymer layer having the hydroxycarboxylic acid as a mesogenic group further contains the following structural units (1) and (2).
(1) -CO-Ar ¹ -CO-
(2) -X-Ar ² -Y-
(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)
(3) -Ar ³ -Z-Ar ⁴ -
(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.) A laminate in which the three-layer film according to claim 1 or 2 is used as an insulating layer, and a metal layer is formed on at least one surface of the insulating layer. The laminate according to claim 4, wherein the maximum height (Rz) of the metal layer is 0.5 to 2.5 μm. The laminate according to claim 4, wherein the metal layer comprises copper. The laminate according to claim 5, wherein the metal layer comprises copper. A printed circuit board using the laminate according to claim 4. A printed circuit board using the laminate according to claim 5. A printed circuit board using the laminate according to claim 6. A printed circuit board using the laminate according to claim 7. A liquid composition application step of applying a liquid composition containing a solvent and a liquid crystal polymer on a polyimide resin film to cover the polyimide resin film with the liquid composition;
a solvent removal step of removing the solvent in the liquid composition;
heat treatment process
As a method for producing a three-layer film containing this,
The liquid crystal polymer contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid and the following structural units,
(1) -CO-Ar ¹ -CO-
(2) -X-Ar ² -Y-
(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)
(3) -Ar ³ -Z-Ar ⁴ -
(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)
In the step of applying the liquid composition, the thickness (T1) of the polyimide resin film and the thickness (T2) of the liquid crystal polymer layer are three layers in which the amount of the liquid composition is adjusted so that the following relational expressions (a) and (b) are obtained. Method of making the film:
(a) 20 μm≤T1≤50 μm
(b) 0.3≤T2/T1≤0.8
(However, the two T2s are mutually independent and may be the same or different.). An impregnation step of impregnating a polyimide resin film in a liquid composition containing a solvent and a liquid crystal polymer, and covering the polyimide resin film with the liquid composition;
a solvent removal step of removing the solvent in the liquid composition;
heat treatment process
As a method for producing a three-layer film containing this,
The liquid crystal polymer contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1) and (2);
(1) -CO-Ar ¹ -CO-
(2) -X-Ar ² -Y-
(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)
(3) -Ar ³ -Z-Ar ⁴ -
(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)
In the impregnation step, the liquid composition in the polyimide resin film so that the thickness (T1) of the polyimide resin film and the thickness (T2) of the liquid crystal polymer layer are the following relational expressions (a) and (b). Method for producing a three-layer film to adjust the adhesion amount of:
(a) 20 μm ≤ T1 ≤ 50 μm
(b) 0.3≤T2/T1≤0.8
(However, the two T2s are mutually independent and may be the same or different.). A step of preparing a liquid composition containing a solvent and a liquid crystal polymer, and a polyamic acid resin liquid composition that is a precursor of a polyimide resin;
A step of applying the liquid composition, the polyamic acid resin liquid composition, and the liquid composition in this order in three layers on a support;
A solvent removal step of removing the solvent in the three-layer liquid composition;
Three-layer film forming process
As a method for producing a three-layer film containing this,
The liquid crystal polymer contains a structural unit derived from 2-hydroxybenzoic acid or 2-hydroxy-6-naphthoic acid, and the following structural units (1) and (2);
(1) -CO-Ar ¹ -CO-
(2) -X-Ar ² -Y-
(Wherein, Ar ¹ and Ar ² each independently represent a phenylene group, a naphthylene group, a biphenylene group, or a group represented by the following formula (3). X and Y each independently represent an oxygen atom or an imino group. Ar Each hydrogen atom in the group represented by ¹ or Ar ² may be independently substituted with a halogen atom, an alkyl group or an aryl group.)
(3) -Ar ³ -Z-Ar ⁴ -
(Ar ³ and Ar ⁴ each independently represents a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)
In the applying step, the liquid composition containing the solvent and the liquid crystal polymer so that the thickness (T1) of the polyimide resin film and the thickness (T2) of the liquid crystal polymer layer are the following relational formulas (a) and (b) Method for producing a three-layer film to adjust the amount of application:
(a) 20 μm≤T1≤50 μm
(b) 0.3≤T2/T1≤0.8
(However, the two T2s are mutually independent and may be the same or different.).

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