TWI678278B - Laminated board and manufacturing method of flexible printed circuit board - Google Patents

Abstract

The present invention provides a method for stably manufacturing a laminated board with sufficiently high adhesive strength at the interface between the heat-resistant resin layer and the fluororesin layer and at the interface between the fluororesin layer and the metal foil layer.

The method for manufacturing a laminated board having a heat-resistant resin layer, a fluorine-containing resin layer, and a metal foil layer in sequence has the following steps: step (a), which is at a temperature lower than the melting point of the fluorine-containing resin (A) Next, a fluorine-containing resin film containing a fluorine-containing resin (A) and a metal foil are thermally laminated to obtain a metal foil with a fluorine-containing resin layer. The fluorine-containing resin (A) has a functional group such as a carbonyl-containing group (I ); Step (b), which is performed by thermally laminating a heat-resistant resin film containing a heat-resistant resin (B) and a metal foil with a fluororesin layer at a temperature above the melting point of the fluororesin (A) Obtain a laminate.

Description

Laminated board and manufacturing method of flexible printed circuit board Field of invention

The present invention relates to a method for manufacturing a laminated board and a flexible printed circuit board.

Background of the invention

The flexible printed board can be produced, for example, by a method in which a heat-resistant resin film (polyimide film, etc.) and a metal foil (copper foil, etc.) are bonded together through a bonding material (epoxy resin). The unnecessary part of the metal foil of the metal-clad laminated board is removed by etching to form a pattern circuit.

Recently, in order to improve the electrical reliability of flexible printed circuit boards, it has been pointed out that a fluorine-containing resin having excellent electrical characteristics is used as a bonding material for flexible metal-clad laminates.

For a flexible metal-clad laminate using a fluorine-containing resin as a bonding material, the following proposals have been made, for example.

(1) A flexible metal-clad laminate in which a heat-resistant resin film and a metal foil are bonded through a fluorine-containing resin film containing a fluorine-containing polymer having an acid anhydride group (Patent Document 1).

(2) After the surface of the heat-resistant resin film and the surface of the fluorine-containing resin film are subjected to low-temperature plasma treatment, the heat-resistant resin film and the metal foil are allowed to permeate the fluorine-containing resin. Flexible metal-clad laminated board formed by laminating films (Patent Document 2).

When manufacturing flexible metal-clad laminates industrially, those who have rolled up each of the heat-resistant resin film, fluororesin film, and metal foil into rolls are prepared to continuously send out the heat-resistant resin films and fluorine-containing films from each roll. The resin film and the metal foil are simultaneously passed through a pair of metal rollers or metal belts to be heated and pressurized to perform thermal lamination.

However, when the temperature of the metal roller or metal belt, that is, the thermal lamination temperature is higher than the melting point of the fluororesin contained in the fluororesin film, the fluororesin film is stretched in the longitudinal direction. The fluororesin film is rapidly heated, so that the fluororesin film shrinks in the width direction at the instant of being heated, and may also break. Therefore, when a fluorine-containing resin is used as an adhesive material, it is difficult to industrially produce a flexible metal-clad laminate.

On the other hand, when the thermal lamination temperature is lower than the melting point of the fluororesin contained in the fluororesin film, although the shrinkage of the fluororesin film can be suppressed, the interface between the heat-resistant resin film and the fluororesin film and the The adhesion strength at the interface between the fluororesin film and the metal foil becomes insufficient.

Prior art literature Patent literature

Patent Document 1: International Publication No. 2006/067970

Patent Document 2: Japanese Patent Laid-Open No. 2005-324511

Summary of invention

The present invention provides a method for stably manufacturing a laminated board having a sufficiently high adhesive strength at the interface between the heat-resistant resin layer and the fluororesin layer and the interface between the fluororesin layer and the metal foil layer; and a heat-resistant resin layer. A method for a laminated board and a flexible printed circuit board with sufficiently high adhesive strength at the interface with the fluororesin layer and at the interface between the fluororesin layer and the metal foil layer.

The present invention has the following aspects.

[1] A method for manufacturing a laminated board, which is used to produce a laminated board having a heat-resistant resin layer, a fluorine-containing resin layer in contact with the heat-resistant resin layer, and a metal foil layer in contact with the fluorine-containing resin layer. This manufacturing method has the following steps (a) and (b).

In step (a), a fluorine-containing resin film containing the foregoing fluorine-containing resin (A) and a metal foil are thermally laminated at a temperature lower than the melting point of the fluorine-containing resin (A) to obtain a fluorine-containing resin layer. Metal foil, the fluorine-containing resin (A) has at least one functional group selected from the group consisting of a carbonyl group-containing group, a hydroxyl group, an epoxy group, and an isocyanate group.

Step (b) is to heat-resistant the resin containing the heat-resistant resin (B) at a temperature above the melting point of the fluorine-containing resin (A) so that the heat-resistant resin film is in contact with the fluorine-containing resin layer. The flexible resin film and the metal foil with a fluorine-containing resin layer are thermally laminated to obtain the laminated board.

[2] The method for manufacturing a laminated board according to [1], wherein the melting point of the fluorine-containing resin (A) is 260 to 320 ° C, and the fluorine-containing resin (A) can be melt-molded.

[3] The method for producing a laminated board according to [1] or [2], wherein the aforementioned fluororesin (A) is a fluoropolymer having the aforementioned functional group, and the aforementioned functional group Derived from: at least one selected from the group consisting of monomers, chain transfer agents, and polymerization initiators used in the production of polymers.

[4] The method for manufacturing a laminated board according to any one of [1] to [3], wherein the thermal lamination of the foregoing step (a) and the thermal lamination of the foregoing step (b) are continuously performed by a thermal lamination device And, the thermal laminating device has more than one pair of metal rollers or more than one pair of metal belts.

[5] The method for manufacturing a laminated board according to any one of [1] to [4], wherein the fluorine-containing resin (A) has at least a carbonyl group-containing group as the foregoing functional group, and the carbonyl-containing group is selected from the group consisting of It is at least one selected from the group consisting of a carbonyl group, a carbonate group, a carboxyl group, a haloformamyl group, an alkoxycarbonyl group, and an acid anhydride group between carbon atoms of a hydrocarbon group.

[6] The method for producing a laminated board according to any one of [1] to [5], wherein the content of the functional group is 10 with respect to the main chain carbon number of the fluorine-containing resin (A) of 1 × 10 ⁶ ~ 60000.

[7] The method for manufacturing a laminated board according to any one of [1] to [6], which is in the aforementioned step (a) and at a temperature below (the melting point of the aforementioned fluororesin (A) -20 ° C) The fluororesin film and the metal foil are then thermally laminated.

[8] The method for manufacturing a laminated board according to any one of [1] to [7], wherein the thickness of the foregoing fluorine-containing resin layer is 1 to 20 μm.

[9] The method for manufacturing a laminated board according to any one of [1] to [8], wherein the melt flow rate of the fluorine-containing resin (A) under conditions of 372 ° C and a load of 49N is 0.5 to 15 g / 10 minutes .

[10] A method for manufacturing a flexible printed circuit board, which is manufactured by the manufacturing method according to any one of [1] to [9] above, and the foregoing is removed by etching. The unnecessary part of the metal foil layer of the laminated board forms a pattern circuit.

According to the manufacturing method of the laminated board of the present invention, a laminated board having sufficiently high adhesive strength at the interface between the heat-resistant resin layer and the fluororesin layer and at the interface between the fluororesin layer and the metal foil layer can be stably produced. Furthermore, the flexible printed circuit board produced by the manufacturing method of the present invention is formed of a laminated board having a sufficiently high adhesive strength at the interface between the heat-resistant resin layer and the fluororesin layer and at the interface between the fluororesin layer and the metal foil layer. Therefore, it has the characteristics of long-term high stability and high reliability.

10‧‧‧ laminated board

12‧‧‧ heat-resistant resin layer

12’‧‧‧ heat-resistant resin film

14‧‧‧ fluororesin layer

14’‧‧‧ fluororesin film

16‧‧‧ metal foil layer

16’‧‧‧metal foil

18‧‧‧ Metal foil with fluororesin layer

20, 30‧‧‧Hot-rolled laminating equipment

22, 24, 28, 32, 38‧‧‧ rollers

26, 36‧‧‧ metal roller

FIG. 1 is a schematic cross-sectional view showing an example of a laminated board according to the present invention.

FIG. 2 is a schematic cross-sectional view showing another example of the laminated board of the present invention.

Fig. 3 is a schematic configuration diagram showing an example of a hot-rolled laminating apparatus used in step (a).

Fig. 4 is a schematic configuration diagram showing an example of a hot-rolled laminating apparatus used in step (b).

Forms used to implement the invention

The following definitions of terms apply to the scope of this specification and patent applications.

"Heat-resistant resin" means a polymer compound with a melting point of 280 ° C or higher, or a polymer compound with a maximum continuous use temperature of 121 ° C or higher according to JIS C 4003: 2010 (IEC 60085: 2007).

`` Fluorine-containing resin '' means a polymer compound with a fluorine atom in the molecule Thing.

"Melting point" means the temperature corresponding to the maximum value of the melting peak measured by differential scanning calorimetry (DSC).

"Thermal lamination" means that two or more members are bonded together by heating.

By "melt-moldable" is meant that it exhibits melt fluidity.

"Showing melt fluidity" means a temperature at which the melt flow rate becomes 0.1 to 1000 g / 10 minutes at a temperature of 20 ° C or more higher than the melting point of the resin under a load of 49N.

The "melt flow rate" means the melt mass flow rate (MFR) specified in JIS K 7210: 1999 (ISO 1133: 1997).

The "carbonyl-containing group" means a group having a carbonyl group (-C (= O)-) in the structure.

"Anhydride group" means a group represented by -C (= O) -O-C (= O)-.

"Unit" means a unit derived from a monomer formed by polymerization of the monomer. The unit may be a unit formed directly by a polymerization reaction, or may be a unit in which a part of the unit is converted into another structure by treating a polymer.

"Monomer" means a compound having a polymerizable carbon-carbon double bond.

<Laminate board>

The "laminated sheet of the present invention" refers to a product produced by a method for producing a laminated sheet of the present invention described later. The laminated board of the present invention may be a so-called flexible metal-clad laminated board that can be used as a material for a flexible printed circuit board.

The laminated board of the present invention includes a heat-resistant resin layer, a fluorine-containing resin layer in contact with the heat-resistant resin layer, and a metal foil layer in contact with the fluorine-containing resin layer.

FIG. 1 is a schematic cross-sectional view showing an example of a laminated board according to the present invention. The laminated board 10 includes a heat-resistant resin layer 12, a fluorine-containing resin layer 14 laminated on the first surface of the heat-resistant resin layer 12, and a metal foil laminated on the surface of the fluorine-containing resin layer 14 on the side opposite to the heat-resistant resin layer 12. Layer 16.

Fig. 2 is a schematic cross-sectional view showing another example of a laminated board according to the present invention. The laminated board 10 includes a heat-resistant resin layer 12, two fluorine-containing resin layers 14 laminated on the first and second faces of the heat-resistant resin layer 12, and a heat-resistant resin layer 12 laminated on each of the fluorine-containing resin layers 14. Two metal foil layers 16 on the opposite surface.

The thickness of the laminated board of the present invention is usually 10 to 2500 μm. From the viewpoint of being used for a flexible printed circuit board, it is preferably 12 to 300 μm, more preferably 18 to 150 μm, and even more preferably 20 to 100 μm.

(Heat-resistant resin layer)

The heat-resistant resin layer is a layer composed of a heat-resistant resin film described later, and contains a heat-resistant resin (B) (except for a fluorine-containing resin (A)). The heat-resistant resin layer may contain additives and the like described below within a range that does not impair the effects of the present invention.

The heat-resistant resin layer may have a single-layer structure or a laminated structure of two or more layers.

The thickness of the heat-resistant resin layer is preferably 3 to 500 μm, more preferably 5 to 200 μm, and even more preferably 6 to 50 μm. As long as the thickness of the heat-resistant resin layer is greater than or equal to the aforementioned lower limit value, electrical insulation is excellent. As long as the thickness of the heat-resistant resin layer is below the aforementioned upper limit value, the thickness of the entire laminated board can be reduced.

The heat-resistant resin (B) contained in the heat-resistant resin layer may be one type or two or more types. Heat-resistant resin layer based on heat-resistant resin layer The content of the heat-resistant resin (B) in the heat-resistant resin layer is preferably 50% by mass or more, and more preferably 80% by mass or more. The upper limit of the content is not particularly limited, and may be 100% by mass.

Examples of the heat-resistant resin (B) include polyimide (such as aromatic polyimide), polyarylate, polyfluorene, polyallyl fluorene (such as polyether fluorene), aromatic polyfluorene, and aromatic polyimide. Etheramine, polyphenylene sulfide, polyallyl ether ketone, polyamine imine, liquid crystal polyester, and the like.

The heat-resistant resin (B) is preferably polyimide. The polyimide may be a thermosetting polyimide or a thermoplastic polyimide. The polyimide is preferably an aromatic polyimide. The aromatic polyfluorene imide is preferably a wholly aromatic polyfluorene imide produced by condensation polymerization of an aromatic polycarboxylic acid dianhydride and an aromatic diamine.

Polyfluorene imine is generally obtained by the reaction (polycondensation) of a polycarboxylic dianhydride (or a derivative thereof) with a diamine through a polyamic acid (polyimide precursor).

Polyfluorene imine, especially aromatic polyfluorene, is insoluble in solvents and the like due to its rigid main chain structure, and has insoluble properties. Therefore, a polyimide precursor (polyamic acid or polyamide acid) that is soluble in organic solvents is first synthesized by the reaction of a polycarboxylic dianhydride and a diamine. The forming process is performed in various stages. Thereafter, the polyfluorenic acid is heated or chemically dehydrated and cyclized (fluorinated) to form a polyfluorinated imine.

Specific examples of the aromatic polycarboxylic dianhydride include those described in paragraph [0055] of Japanese Patent Laid-Open No. 2012-145676. Also, you can make Ethylene tetracarboxylic dianhydride and cyclopentane tetracarboxylic dianhydride, which are non-aromatic polycarboxylic dianhydrides, are not inferior to those of aromatic systems.

The polycarboxylic dianhydride may be used alone or in combination of two or more.

Specific examples of the aromatic diamine include those described in paragraph [0057] of Japanese Patent Laid-Open No. 2012-145676. The aromatic diamine may be used singly or in combination of two or more kinds.

An additive may be contained in the heat-resistant resin layer. The additive is preferably an inorganic filler having a low dielectric constant and a low dielectric tangent.

Examples of the inorganic filler include silica, clay, talc, calcium carbonate, mica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, calcium hydroxide, and hydroxide Magnesium, aluminum hydroxide, basic magnesium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, sodalumite, hydrotalcite, calcium sulfate, barium sulfate, calcium silicate, montmorillonite, bentonite, activated clay, sea foam Stone, filiform alumina, sericite, glass fiber, glass beads, silicon oxide hollow spheres, carbon black, carbon nanotubes, carbon nanohorns, graphite, carbon fibers, glass hollow spheres, carbon burn , Wood flour, zinc borate, etc. The inorganic filler may be used singly or in combination of two or more kinds.

The inorganic filler may be porous or non-porous, but from the viewpoint of lower dielectric constant and lower dielectric tangent, porous is preferred. From the viewpoint of improving the dispersibility of the resin, the inorganic filler may also be surface-treated with a surface-treating agent such as a silane coupling agent or a titanate coupling agent.

Relative to 100 parts by mass of the heat-resistant resin (B), the content of additives such as inorganic fillers in the heat-resistant resin layer is preferably from 0.1 to 100 parts by mass, and from 0.1 to 60 Mass parts are better.

(Fluorine resin layer)

The fluorine-containing resin layer is a layer composed of a fluorine-containing resin film described later, and contains a specific fluorine-containing resin (A). The fluorine-containing resin layer may contain other resins, additives, and the like as long as the effects of the present invention are not impaired. The fluorine-containing resin layer may have a single-layer structure or a laminated structure of two or more layers.

The thickness of the fluororesin layer is usually 1 to 1000 μm. From the viewpoint of heat resistance to a soldering iron, it is preferably 1 to 20 μm, more preferably 3 to 20 μm, and more preferably 3 to 15 μm. As long as the thickness of the fluororesin layer is below the aforementioned upper limit value, the thickness of the entire laminated board can be reduced. As long as the thickness of the fluororesin layer is above the aforementioned lower limit, when the heat-resistant resin layer is exposed to a gas environment corresponding to solder reflow at high temperatures, the fluororesin layer is less likely to expand (foam) due to heat and is electrically insulated. Good sex.

The fluorine-containing resin layer may be laminated only on the first surface of the heat-resistant resin layer, or may be laminated on the first surface and the second surface of the heat-resistant resin layer. From the standpoint of obtaining a double-sided metal-clad laminated board which suppresses warpage of the laminated board and is excellent in electrical reliability, it is preferable to use a fluorine-containing resin layer on the first surface and the second area of the heat-resistant resin layer.

When the fluororesin layer is formed on the first surface and the second area of the heat-resistant resin layer, the composition of each fluororesin layer (the type of the fluororesin (A), the types of other resins and additives, and the content thereof) ) Or thickness can be the same or different. From the viewpoint of suppressing warpage of the laminated board, it is preferable that the composition and thickness of each fluororesin layer be the same.

The fluorine-containing resin (A) contained in the fluorine-containing resin layer may be one kind or two More than that.

From the viewpoint of the adhesive strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer, the content of the fluororesin (A) in the fluororesin layer is 100% by mass of the fluororesin layer. It is preferably 50% by mass or more, and more preferably 80% by mass or more. The upper limit of the content of the fluororesin (A) is not particularly limited, and may be 100% by mass.

The fluorine-containing resin (A) is a fluorine-containing resin having at least one functional group (hereinafter referred to as a functional group (I)) selected from the group consisting of a carbonyl-containing group, a hydroxyl group, an epoxy group, and an isocyanate group. . By having a functional group (I), the adhesion strength at the interface between the fluorine-containing resin layer containing the fluorine-containing resin (A) and the heat-resistant resin layer or the fluorine-containing resin layer containing the fluorine-containing resin (A) and the metal foil layer can be improved. .

From the point of view of the adhesion strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer, the functional group (I) includes the end groups of the main chain of the fluororesin (A) and the main chain. Either or both of the side groups are preferred.

The functional group (I) may be one type or two or more types.

From the viewpoint of the adhesion strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer, the fluororesin (A) preferably has at least a carbonyl group-containing group as the functional group (I). Examples of the carbonyl-containing group include a group having a carbonyl group between carbon atoms of a hydrocarbon group, a carbonate group, a carboxyl group, a haloformyl group, an alkoxycarbonyl group, an acid anhydride group, and the like.

Examples of the hydrocarbon group having a carbonyl group between the carbon atoms of the hydrocarbon group include an alkylene group having 2 to 8 carbon atoms. The carbon number of the alkylene group is free of carbonyl groups. The carbon number in the state. The alkylene group may be linear or branched. Haloformamyl is represented by -C (= O) -X (where X is a halogen atom).

Examples of the halogen atom of the haloformamyl group include a fluorine atom and a chlorine atom, and a fluorine atom is preferred. That is, the haloformamyl group is preferably a fluoroformamyl group (also referred to as a fluorinated carbonyl group).

The alkoxy group of the alkoxycarbonyl group may be linear or branched. An alkoxy group having 1 to 8 carbon atoms is preferred, and a methoxy or ethoxy group is particularly preferred.

Relative to the number of carbons in the main chain of the fluorine-containing resin (A) 1 × 10 ⁶ ; the content of the functional group (I) in the fluorine-containing resin (A) should preferably be 10 to 60,000, preferably 100 to 50,000, and 100 to 10,000 More preferably, 300 ~ 5000 are even better. As long as the content of the functional group (I) is at least the aforementioned lower limit value, the adhesion strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer is higher. As long as the content of the functional group (I) is below the aforementioned upper limit value, the adhesion strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer can be improved even if the temperature of the thermal lamination is reduced.

The content of the functional group (I) can be measured by methods such as nuclear magnetic resonance (NMR) analysis and infrared absorption spectrum analysis. For example, as described in Japanese Patent Application Laid-Open No. 2007-314720, the ratio of units having a functional group (I) in the total units constituting the fluororesin (A) can be determined using a method such as infrared absorption spectroscopy (mol%) Then, the content of the functional group (I) was calculated from the ratio.

The melting point of the fluorine-containing resin (A) is preferably 260 to 320 ° C, more preferably 295 to 315 ° C, and even more preferably 295 to 310 ° C. As long as the melting point of the fluorine-containing resin (A) is at least the aforementioned lower limit value, the heat resistance of the fluorine-containing resin layer is good. As long as the melting point of the fluororesin (A) is below the aforementioned upper limit, the moldability of the fluororesin (A) is good.

The melting point of the fluororesin (A) can be adjusted by the type or ratio of the units constituting the fluororesin (A), the molecular weight of the fluororesin (A), and the like. For example, as the proportion of the unit (u1) described later increases, the melting point tends to increase.

From the viewpoint of easily producing a fluorine-containing resin film described later, the fluorine-containing resin (A) is preferably one that can be melt-molded.

Examples of the melt-moldable fluororesin (A) include known melt-moldable fluororesins (tetrafluoroethylene / fluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoro Ethylene copolymers, polydifluoroethylene, polychlorotrifluoroethylene, ethylene / chlorotrifluoroethylene copolymers, etc.) fluorine-containing resins having functional groups (I) introduced therein; and fluorine-containing polymers (α1) described later, etc. .

As a fluororesin (A), it is suitable to have a melt flow rate of 0.1 ~ 1000g / 10 minutes (with 0.5 ~) at a temperature of 20 ° C or higher than the melting point of the fluororesin (A) under a load of 49N. 100g / 10 minutes is better, 1-30g / 10 minutes is better, 5-20g / 10 minutes is better). As long as the melt flow rate is above the aforementioned lower limit value, the moldability of the fluorine-containing resin (A) is good, and the surface smoothness and appearance of the fluorine-containing resin layer are good. As long as the melt flow rate is below the aforementioned upper limit, the mechanical strength of the fluorine-containing resin layer is good.

The melt flow rate of the fluorine-containing resin (A) under the conditions of 372 ° C and a load of 49N is preferably 0.5 to 15 g / 10 minutes, more preferably 1 to 15 g / 10 minutes, and more preferably 1 to 12 g / 10 minutes. As long as the melt flow rate is below the aforementioned upper limit value, the heat resistance of the soldering iron tends to be improved. As long as the melt flow rate is at least the aforementioned lower limit value, the moldability of the fluororesin (A) is good.

The melt flow rate is a measure of the molecular weight of the fluororesin (A), which means that when the melt flow rate is large, the molecular weight is small, and when the melt flow rate is small, the molecular weight is Big. The molecular weight and even the melt flow rate of the fluororesin (A) can be adjusted by the manufacturing conditions of the fluororesin (A). For example, if the polymerization time is shortened during monomer polymerization, the melt flow rate tends to increase. In order to reduce the melt flow rate, the following methods can be cited: a method of heat-treating the fluororesin (A) to form a crosslinked structure to increase the molecular weight; and reducing the use of a radical polymerization initiator in the production of the fluororesin (A) Method of measurement, etc.

As a fluorine-containing resin (A), the following are mentioned according to the manufacturing method.

Fluoropolymer (α), which has a functional group (I), and the functional group (I) is derived from the group consisting of a monomer, a chain transfer agent, and a polymerization initiator used in the production of the polymer At least one of the group.

The fluorine-containing resin (β) is one in which a functional group (I) is introduced into a fluorine-containing resin having no functional group (I) by surface treatment such as corona discharge treatment and plasma treatment.

The fluorine-containing resin (γ) is obtained by graft-polymerizing a monomer having a functional group (I) with a fluorine-containing resin having no functional group (I).

For the following reasons, the fluororesin (A) is preferably a fluoropolymer (α).

In the fluoropolymer (α), a functional group (I) exists in either or both of the end group and the side group of the main chain of the fluoropolymer (α). The adhesive strength at the interface between the flexible resin layer or the fluororesin layer and the metal foil layer becomes higher.

The functional group (I) of the fluororesin (β) is formed by surface treatment, so it is unstable and easily disappears with time.

The functional group (I) of the fluoropolymer (α) is derived from When the polymer (α) is a monomer, the fluoropolymer (α) can be produced by the following method (1). At this time, the functional group (I) is present in a unit derived from the monomer formed by polymerization of the monomer during production.

Method (1): When a fluoropolymer (α) is produced by monomer polymerization, a monomer having a functional group (I) is used.

When the functional group (I) of the fluoropolymer (α) is derived from a chain transfer agent used to produce the fluoropolymer (α), the fluoropolymer (α) can be produced by the following method (2). At this time, the functional group (I) exists as a terminal group of the main chain of the fluoropolymer (α).

Method (2): A fluoropolymer (α) is produced by polymerizing a monomer in the presence of a chain transfer agent having a functional group (I).

Examples of the chain transfer agent having a functional group (I) include acetic acid, acetic anhydride, methyl acetate, ethylene glycol, and propylene glycol.

When the functional group (I) of the fluorinated polymer (α) is derived from a polymerization initiator used to produce the fluorinated polymer (α), the fluorinated polymer (α) can be produced by the following method (3). At this time, the functional group (I) exists as a terminal group of the main chain of the fluoropolymer (α).

Method (3): A fluoropolymer (α) is produced by polymerizing a monomer in the presence of a polymerization initiator such as a radical polymerization initiator having a functional group (I).

Examples of the radical polymerization initiator having a functional group (I) include di-n-propylperoxydicarbonate, diisopropylperoxycarbonate, tertiary butylperoxyisopropylcarbonate, and bis (4- Tertiary butylcyclohexyl) peroxydicarbonate, di-2-ethylhexylperoxydicarbonate, and the like.

The functional group (I) of the fluoropolymer (α) is derived from When two or more of the monomer (α), chain transfer agent, and polymerization initiator of the polymer (α) are used, the fluoropolymer (α) can be produced by using two or more of the methods (1) to (3) in combination.

From the viewpoint that the content of the functional group (I) can be easily controlled and the adhesion strength with the metal foil layer is easily adjusted, the fluorine-containing polymer (α) is produced by the method (1) and has a functional group derived from a monomer ( The fluoropolymer (α) of I) is preferred.

From the viewpoint that the adhesion strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer is higher, the fluoropolymer (α) having the functional group (I) derived from the monomer is as follows A fluoropolymer (α1) is particularly preferred.

A fluoropolymer (α1) is a unit (u1) derived from tetrafluoroethylene (hereinafter also referred to as "TFE"), a unit (u2) derived from a cyclic hydrocarbon monomer having an acid anhydride group, and a unit derived from Unit (u3) of fluorine monomer (except TFE). Here, the acid anhydride group which the unit (u2) has corresponds to a functional group (I).

烯-2,3-二羧酸酐(以下亦記為「NAH」)、馬來酸酐等。該單體可單獨使用1種亦可將2種以上併用。 Examples of the monomer constituting the unit (u2) include iconic anhydride (hereinafter also referred to as "IAH"), citraconic anhydride (hereinafter also referred to as "CAH"), 5-nor

Ene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), maleic anhydride and the like. This monomer may be used individually by 1 type, and may use 2 or more types together.

The monomer constituting the unit (u2) is preferably one or more selected from the group consisting of IAH, CAH, and NAH. In this case, the fluorine-containing polymer (α1) having an acid anhydride group can be easily produced without using a special polymerization method necessary when using maleic anhydride (see Japanese Patent Application Laid-Open No. 11-193312). From the viewpoint of higher adhesion strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer, NAH is preferred as the monomer constituting the unit (u2).

The fluorine-containing monomer constituting the unit (u3) is preferably a fluorine-containing compound having one polymerizable carbon-carbon double bond, and examples thereof include fluoroolefins (fluoroethylene, difluoroethylene (hereinafter also referred to as "VdF") , Trifluoroethylene, chlorotrifluoroethylene (hereinafter also referred to as "CTFE"), hexafluoropropylene (hereinafter also referred to as "HFP"), etc., except TFE), CF ₂ = CFOR ^f1 (however, R ^f1 is Perfluoroalkyl group having 1 to 10 carbon atoms and containing an oxygen atom between carbon atoms), CF ₂ = CFOR ^f2 SO ₂ X ¹ (However, R ^f2 is 1 to 10 carbon atoms and may contain an oxygen atom between carbon atoms. X ¹ is a halogen atom or a hydroxyl group), CF ₂ = CFOR ^f3 CO ₂ X ² (however, R ^f3 is a perfluoroalkylene having 1 to 10 carbon atoms and containing an oxygen atom between carbon atoms) X ² is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), CF ₂ = CF (CF ₂ ) _p OCF = CF ₂ (however, p is 1 or 2), and CH ₂ = CX ³ (CF ₂ ) _q X ⁴ (however, X ³ is a hydrogen atom or a fluorine atom, q is an integer from 2 to 10, X ⁴ is a hydrogen atom or a fluorine atom), perfluoro (2-methylene-4-methyl-1,3 -Dioxetane) and the like.

The fluorine-containing monomer constituting the unit (u3) is preferably at least one selected from the group consisting of VdF, CTFE, HFP, CF ₂ = CFOR ^f1, and CH ₂ = CX ³ (CF ₂ ) _q X ⁴ , And CF ₂ = CFOR ^f1 and HFP are preferred.

CF ₂ = CFOR ^f1 includes CF ₂ = CFOCF ₂ CF ₃ , CF ₂ = CFOCF ₂ CF ₂ CF ₃ , CF ₂ = CFOCF ₂ CF ₂ CF ₂ CF ₃ , CF ₂ = CFO (CF ₂ ) ₈ F, etc. CF ₂ = CFOCF ₂ CF ₂ CF ₃ (hereinafter also referred to as “PPVE”) is preferred.

CH ₂ = CX ³ (CF ₂ ) _q X ^{4 can} be listed as CH ₂ = CH (CF ₂ ) ₂ F, CH ₂ = CH (CF ₂ ) ₃ F, CH ₂ = CH (CF ₂ ) ₄ F, CH ₂ = CF (CF ₂ ) ₃ H, CH ₂ = CF (CF ₂ ) ₄ H, and the like are preferably CH ₂ = CH (CF ₂ ) ₄ F or CH ₂ = CH (CF ₂ ) ₂ F.

Of the total unit (u1), unit (u2) and unit (u3) of 100 mol%, the unit (u1) is preferably 50 to 99.89 mol%, 50 to 99.4 mol% is better, 50 ~ 98.9 mole% is more preferred.

Of the total unit (u1), unit (u2) and unit (u3) of 100 mol%, the unit (u2) is preferably 0.01 to 5 mol%, 0.1 to 3 mol% is better, 0.1 to 2 mole% is better.

In the unit (u1), unit (u2), and unit (u3) of 100 mol% in total, the unit (u3) is preferably 0.1 to 49.99 mol%, 0.5 to 49.9 mol% is better, 1 ~ 49.9 mole% is more preferred.

As long as the proportion of each unit is within the aforementioned range, the heat resistance, chemical resistance, and elastic modulus at high temperature of the fluororesin layer are preferred. As long as the ratio of the unit (u2) is within the foregoing range, the amount of the acid anhydride group of the fluoropolymer (α1) is appropriate, and the adhesion strength at the interface between the fluororesin layer and the heat-resistant resin layer or the fluororesin layer and the metal foil layer Will get higher. As long as the proportion of the unit (u3) is within the aforementioned range, the moldability of the fluoropolymer (α1) is good, and the fluororesin layer is excellent in bending resistance and the like. The proportion of each unit can be calculated by melt NMR analysis, fluorine content analysis, infrared absorption spectrum analysis, and the like of the fluoropolymer (α1).

When the fluoropolymer (α1) is composed of a unit (u1), a unit (u2), and a unit (u3), the ratio of the unit (u2) to 0.01 mol% is equivalent to that of the fluoropolymer (α1). The number of carbon atoms in the main chain is 1 × 10 ⁶ and the content of acid anhydride groups in the fluoropolymer (α1) is 100. The proportion of the unit (u2) of 5 mole% is equivalent to 1 × 10 ⁶ carbon atoms in the main chain of the fluoropolymer (α1), and the content of acid anhydride groups in the fluoropolymer (α1) is 50,000.

烯-2,3-二羧酸、馬來酸等)的單元。含有源自該二羧酸之單元時，該單元的比例係含在單元(u2)的比例中。 The fluorinated polymer (α1) may contain dicarboxylic acid (Iconic acid, citraconic acid, 5 -drop

Ene-2,3-dicarboxylic acid, maleic acid, etc.). When the unit derived from the dicarboxylic acid is contained, the proportion of the unit is included in the proportion of the unit (u2).

The fluoropolymer (α1) may contain units (u4) derived from non-fluorine-containing monomers (except for cyclic hydrocarbon monomers containing acid anhydride groups) in addition to the units (u1) to (u3).

The non-fluorinated monomer is preferably a non-fluorinated compound having one polymerizable carbon-carbon double bond, and examples thereof include olefins (ethylene, propylene, etc.) having a carbon number of 3 or less, and vinyl esters (such as vinyl acetate). The non-fluorine-containing monomer may be used alone or in combination of two or more.

Non-fluorinated monomers are preferably ethylene, propylene or vinyl acetate, and especially ethylene.

When the fluorinated polymer (α1) has a unit (u4), the ratio of the unit (u4) is preferably 5 to 90 mol% relative to the total of the unit (u1), the unit (u2), and the unit (u3). 5 ~ 80 mole% is better, 10 ~ 65 mole% is better.

When the total unit of the fluoropolymer (α1) is 100 mol%, the total of the unit (u1), the unit (u2), and the unit (u3) is preferably 60 mol% or more, and 65 mol% or more Good, more preferably above 68 mol%. The ideal upper limit is 100 mole%.

Specific examples of the fluoropolymer (α1) include TFE / PPVE / NAH copolymer, TFE / PPVE / IAH copolymer, TFE / PPVE / CAH copolymer, TFE / HFP / IAH copolymer, and TFE / HFP / CAH copolymer, TFE / VdF / IAH copolymer, TFE / VdF / CAH copolymer, TFE / CH ₂ = CH (CF ₂ ) ₄ F / IAH / ethylene copolymer, TFE / CH ₂ = CH (CF ₂ ) ₄ F / CAH / ethylene copolymer, TFE / CH ₂ = CH (CF ₂ ) ₂ F / IAH / ethylene copolymer, TFE / CH ₂ = CH (CF ₂ ) ₂ F / CAH / ethylene copolymer, and the like.

Manufacturing method of fluororesin (A):

The fluororesin (A) can be produced by a conventional method. When the fluororesin (A) is produced by monomer polymerization, the polymerization method is preferably a method using a radical polymerization initiator.

Examples of the polymerization method include a block polymerization method, a solution polymerization method using an organic solvent (fluorinated hydrocarbon, chlorinated hydrocarbon, chlorofluorocarbon, alcohol, hydrocarbon, etc.), a suspension polymerization using an aqueous medium, and an appropriate organic solvent as required. Method, an emulsion polymerization method using an aqueous medium and an emulsifier, and a solution polymerization method is preferred.

The free radical polymerization initiator is preferably an initiator having a half-life of 10 hours and a temperature of 0 to 100 ° C, and an initiator of 20 to 90 ° C is preferred.

Examples of the radical polymerization initiator include azo compounds (such as azobisisobutyronitrile, etc.), non-fluorine-based dioxoperyl peroxide (isobutylamyl peroxide, octyl peroxide, benzoylperoxide, and lauryl peroxide). Group, etc.), peroxydicarbonate (diisopropylperoxydicarbonate, etc.), peroxyester (tertiary butyl peroxy trimethyl acetate, tertiary butyl peroxy isobutyrate, Tertiary butyl peroxyacetate, etc.), fluorinated difluorenyl peroxide ((Z (CF ₂ ) _r COO) ₂ (However, Z is a hydrogen atom, a fluorine atom or a chlorine atom, and r is 1 to 10 (Integer), compounds shown), inorganic peroxides (potassium persulfate, sodium persulfate, ammonium persulfate, etc.) and the like.

A chain transfer agent can also be used during monomer polymerization to control the fluorine-containing tree. Melt viscosity of grease (A). Examples of the chain transfer agent include alcohols (methanol, ethanol, etc.), chlorofluorocarbons (1,3-dichloro-1,1,2,2,3-pentafluoropropane, 1,1-dichloro-1-fluoroethyl) Alkanes, etc.), hydrocarbons (pentane, hexane, cyclohexane, etc.).

Examples of the organic solvent used in the solution polymerization method include perfluorocarbon, hydrofluorocarbon, chlorohydrofluorocarbon, and hydrofluoroether. The carbon number is preferably from 4 to 12.

Specific examples of the perfluorocarbon include perfluorocyclobutane, perfluoropentane, perfluorohexane, perfluorocyclopentane, and perfluorocyclohexane.

Specific examples of the hydrofluorocarbon include 1-hydroperfluorohexane and the like.

Specific examples of chlorohydrofluorocarbons include 1,3-dichloro-1,1,2,2,3-pentafluoropropane and the like.

Specific examples of the hydrofluoroether include methyl perfluorobutyl ether, 2,2,2-trifluoroethyl 2,2,1,1-tetrafluoroethyl ether, and the like.

The polymerization temperature is preferably 0 to 100 ° C, and more preferably 20 to 90 ° C. The polymerization pressure is preferably from 0.1 to 10 MPa, and more preferably from 0.5 to 3 MPa. The polymerization time is preferably 1 to 30 hours.

When manufacturing the fluoropolymer (α1), the concentration of the monomers constituting the unit (u2) in the polymerization is preferably 0.01 to 5 mole%, more preferably 0.1 to 3 mole%, and 0.1 to 2 Molar% is better. As long as the monomer concentration is within the aforementioned range, the polymerization rate is appropriate. When the monomer concentration is too high, the polymerization rate tends to decrease.

As the monomer constituting the unit (u2) is consumed in the polymerization, it is desirable to continuously or intermittently supply the consumed amount into the polymerization tank so as to maintain the monomer concentration within the aforementioned range.

As long as other resins contained in the heat-resistant resin layer do not damage the electricity The characteristics of reliability are not particularly limited. Examples of other resins include fluorine-containing resins other than the fluorine-containing resin (A), aromatic polyesters, polyamidoimine, and thermoplastic polyimide. Among them, a fluorine-containing copolymer other than the fluorine-containing resin (A) is preferred based on electrical reliability.

Examples of the fluorine-containing resin other than the fluorine-containing resin (A) include a tetrafluoroethylene / fluoroalkyl vinyl ether copolymer, a tetrafluoroethylene / hexafluoropropylene copolymer, and an ethylene / tetrafluoroethylene copolymer.

The melting point of the fluorine-containing resin other than the fluorine-containing resin (A) is preferably 280 to 320 ° C. As long as the melting point is within the aforementioned range, the fluororesin layer is less likely to expand (foam) due to heat when exposed to an ambient gas equivalent to solder reflow.

Examples of the additives contained in the heat-resistant resin layer include the same as those contained in the heat-resistant resin layer, and ideal forms are also the same.

(Metal foil layer)

The metal foil layer is a layer composed of a metal foil. The metal foil is not particularly limited, and may be appropriately selected according to the use of the laminated board. For example, when the laminated board is used in electronic equipment and electrical equipment, the material of the metal foil may be copper or copper alloy, stainless steel or its alloy, nickel or nickel alloy (including 42 alloy), aluminum or aluminum alloy. For general laminated boards used in electronic equipment and electrical equipment, copper foils such as rolled copper foil and electrolytic copper foil are often used, and copper foil is also suitably used in the present invention.

A rust-proof layer (such as an oxide film such as chromate) or a heat-resistant layer may be formed on the surface of the metal foil. Further, in order to improve the adhesive strength with the fluororesin layer, a surface of the metal foil may be subjected to a coupling agent treatment or the like.

The thickness of the metal foil is not particularly limited, and it can be used according to the purpose of the laminated board A fully functional thickness is sufficient.

In the laminated board of the present invention, since the fluorine-containing resin layer contains a fluorine-containing resin (A) having a functional group (I), the interface between the heat-resistant resin layer and the fluorine-containing resin layer and the interface between the fluorine-containing resin layer and the metal foil layer Adhesive strength is sufficiently high. The functional group (I) is at least one selected from the group consisting of a carbonyl group-containing group, a hydroxyl group, an epoxy group, and an isocyanate group.

<Manufacturing method of laminated board>

The method for manufacturing a laminated board of the present invention has the following steps (a) and (b), and further has steps (x), (y), and (z) which can be implemented according to requirements.

Step (a) is a method of thermally laminating a fluorine-containing resin film containing a fluorine-containing resin (A) and a metal foil at a temperature lower than the melting point of the fluorine-containing resin (A) to obtain a metal with a fluorine-containing resin layer. Foil.

Step (x) is to correct the warpage of the metal foil with a fluorine-containing resin layer.

In step (b), the heat-resistant resin film containing the heat-resistant resin (B) and the heat-resistant resin film are attached to the fluorine-containing resin layer at a temperature above the melting point of the fluororesin (A), and The metal foil of the fluorine-containing resin layer is thermally laminated to obtain a laminated board.

Step (y) is to correct the warpage of the laminated board.

In step (z), the laminated board is subjected to heat treatment.

(Hot Lamination Device)

Based on manufacturing efficiency, the thermal lamination in step (a) and the thermal lamination in step (b) should be performed continuously using a thermal lamination device with a thermal lamination mechanism, and the thermal lamination mechanism is composed of a pair of metal rollers or one It is composed of the above metal strips.

Examples of the hot lamination device having a pair of metal rolls include a hot-rolled lamination device. Examples of the thermal lamination device having a pair of metal strips include a double-belts press.

From the viewpoint of simple device configuration and favorable maintenance cost, the hot lamination device is preferably a hot-rolled lamination device.

The hot-rolled lamination device is only required to have a device capable of simultaneously heating and pressing two members of one or more pairs of metal rolls, and the specific device configuration is not particularly limited.

The heating method of the thermal lamination mechanism is not particularly limited, and a known method capable of heating at a predetermined temperature may be adopted, such as a thermal cycle method, a hot air heating method, an induction heating method, and the like.

The pressurizing method of the thermal lamination mechanism is not particularly limited, and a known method that can apply a predetermined pressure can be used, such as an oil pressure method, an air pressure method, and a gap pressure method.

The heat lamination device can be provided with a feeding mechanism for sending out the components in front of the heat lamination mechanism (a pair of metal rollers, etc.), or it can be installed in the back of the heat lamination mechanism for winding the bonded components. Take-up mechanism. By providing a feeding mechanism and a winding mechanism for each component, productivity can be further improved. The specific structure of the sending-out mechanism and the winding mechanism of each component is not particularly limited, and examples thereof include a known winding machine that can wind each component into a roll shape.

In order to make the appearance of the metal foil layer good, a hot-laminating device may be provided with a sending-out mechanism for sending out the protective material and a winding-up mechanism for winding the protective material, which are arranged between the hot-laminating mechanism and the metal foil. By providing a protective material sending-out mechanism and a winding mechanism, the protective material that has been used can be rolled up. Take it again on the delivery side to reuse the protective material. In addition, in order to align both ends of the protective material when the protective material is wound, an end position detection mechanism and a winding position correction mechanism may be provided. Thereby, the ends of the winding protection material can be aligned with high accuracy, and the reuse efficiency can be improved. The specific structures of the protective material feeding mechanism, the winding mechanism, the end position detection mechanism, and the winding position correction mechanism are not particularly limited, and various known devices can be mentioned.

The protective material is not particularly limited as long as it can withstand the heating temperature during thermal lamination. Examples include heat-resistant plastic films (non-thermoplastic polyimide films), metal foils (copper foil, aluminum foil, SUS foil, etc.), etc. . From the viewpoint of a good balance of heat resistance and recyclability, a non-thermoplastic polyimide film is preferred.

The thickness of the non-thermoplastic polyimide film is preferably 75 μm or more. The thickness of the non-thermoplastic polyfluorene imide film is thin, and it is impossible to fully exert the buffering and protection effects during thermal lamination. The protective material may have a single-layer structure or a multilayer structure with two or more layers.

(Step (a))

Fluorine-containing resin film and metal foil are thermally laminated to obtain fluorine-containing Metal foil for resin layer.

The fluorine-containing resin film may be one containing a fluorine-containing resin (A). The fluorine-containing resin film may be a single-layer film or a laminated film. The thickness of the fluorine-containing resin film is usually 1 to 1000 μm, and preferably 1 to 20 μm, more preferably 3 to 20 μm, and more preferably 3 to 15 μm.

The fluorine-containing resin film can be produced, for example, by the following method.

A method for molding the fluororesin (A) itself or the resin composition containing the fluororesin (A) into a film shape by a known molding method (extrusion molding method, inflation molding method, etc.).

A method of introducing a functional group (I) by applying a known surface treatment such as a corona discharge treatment or a plasma treatment to a fluorine-containing resin film containing a fluorine-containing resin having no functional group (I).

The fluorine-containing resin film may be subjected to heat treatment in advance, and the temperature should be 100 to 250 ° C, more preferably 150 to 250 ° C, more preferably 180 to 250 ° C, and particularly preferably above the temperature of the thermal lamination and below 250 ° C. The heat treatment in advance can reduce the shrinkage of the fluororesin film in step (a), and as a result, the warpage of the metal foil with the fluororesin layer can be reduced.

Fig. 3 is a schematic configuration diagram showing an example of a hot-rolled laminating apparatus used in step (a). In the hot-rolled laminating apparatus 20, the long fluororesin film 14 'continuously sent from the roller 22 and the long metal foil 16' continuously sent from the roller 24 are overlapped between a pair of metal rollers 26. The state is heated and pressurized while continuously passing between a pair of metal rollers 26 to be thermally laminated to become a metal foil 18 with a fluororesin layer. The metal foil 18 with a fluorine-containing resin layer passing between a pair of metal rollers 26 is continuously wound by a roller member 28.

The temperature of the metal roll or metal belt, that is, the thermal lamination temperature, is lower than the melting point of the fluororesin (A), preferably below (melting point -20 ° C), and more preferably (melting point -50 ° C). As long as the thermal lamination temperature is below the aforementioned upper limit value, the instant the fluororesin film is heated, it is not easy to shrink in the width direction, and it is not easy to break. In addition, the fluororesin film does not easily adhere to a metal roller or a metal belt.

The thermal lamination temperature is preferably at least (the melting point of the fluororesin (A) -200 ° C), It is more preferably (melting point-180 ° C) or more, and more preferably (melting point-150 ° C) or more. As long as the thermal lamination temperature is above the aforementioned lower limit value, the fluororesin film and the metal foil will be in a pre-adhered state, and the fluororesin layer and the metal foil will not be easily peeled in the subsequent step.

The pressure between a pair of metal rollers or the pressure between a pair of metal belts, that is, the pressure of thermal lamination is preferably 49 ~ 1764N / cm, and more preferably 98 ~ 1470N / cm. If the pressure of the thermal lamination is within the aforementioned range, the three conditions of the thermal lamination temperature, the thermal lamination speed, and the thermal lamination pressure can be made good, and the productivity can be further improved.

The thermal lamination speed is preferably 0.5 m / min or more, and more preferably 1.0 m / min or more. If the thermal lamination speed is 0.5 m / min or more, sufficient thermal lamination can be achieved. If the thermal lamination speed is above 1.0 m / min, productivity can be further improved.

The interfacial adhesion strength between the fluororesin layer and the metal foil of the metal foil with a fluorine resin layer is preferably 0.1 N / cm or more, more preferably 0.2 N / cm or more, and even more preferably 0.3 N / cm or more. If the adhesive strength is above the aforementioned lower limit value, it is difficult for the fluororesin layer and the metal foil to peel off at a later step.

(Step (x))

By reducing the thickness of the fluororesin film or reducing the thermal lamination temperature in the step (a), the warping of the metal foil with the fluororesin layer can be suppressed.

Even so, when the metal foil with a fluororesin layer is warped in step (a), the warpage of the metal foil with a fluororesin layer can be corrected by performing step (x) before step (b).

The warpage correction of the metal foil with a fluororesin layer in step (x) can be performed by applying heat treatment to the metal foil with a fluororesin layer at the following temperature: preferably 100 to 250 ° C, more preferably 150 ~ 250 ℃, more preferably 180 ~ 250 ℃, especially suitable for thermal lamination above 250 ℃.

(Step (b))

The heat-resistant resin film and the fluororesin layer-attached metal foil were thermally laminated so that the heat-resistant resin film was in contact with the fluororesin layer to obtain a laminated board. When thermal lamination is performed, the metal foil with a fluorine-containing resin layer may be disposed only on the first surface of the heat-resistant resin film, or may be disposed on the first surface and the second surface of the heat-resistant resin film.

The heat-resistant resin film may be any one containing a heat-resistant resin (B), and may be a single-layer film or a laminated film.

The thickness of the heat-resistant resin film is preferably 3 to 500 μm, more preferably 5 to 200 μm, and even more preferably 6 to 50 μm.

The heat-resistant resin film can be formed into a film shape, for example, by a known molding method (extrusion molding method, inflation molding method, etc.) or the resin composition containing the heat-resistant resin (B). Method.

Fig. 4 is a schematic configuration diagram showing an example of a hot-rolled laminating apparatus used in step (b). In the hot-rolled laminating apparatus 30, a strip-shaped heat-resistant resin film 12 'continuously fed from the roll member 32 and a strip-shaped metal foil 18 with a fluororesin layer continuously fed from the roll member 28 are placed on a pair of metals. The rollers 36 are laminated in a state of being heated and pressed while continuously passing between a pair of metal rollers 36 to form a laminated board 10, and the roller member 28 is wound and attached in step (a). 18 metal foils of the fluororesin layer. The laminated plate 10 passing between a pair of metal rollers 36 is continuously taken up by a roller member 38.

The temperature of the metal roll or metal belt, that is, the thermal lamination temperature, is above the melting point of the fluororesin (A), preferably above (melting point + 10 ° C), and at (melting point + 20 ° C) The above is better. As long as the thermal lamination temperature is below the aforementioned upper limit value, the heat-resistant resin film and the metal foil with a fluorine-containing resin layer can be thermally laminated well. If the thermal lamination temperature is above (melting point + 20 ° C), the thermal lamination speed can be increased, and the productivity can be further improved.

The thermal lamination temperature is preferably below 420 ° C, and more preferably below 400 ° C.

The pressure between a pair of metal rollers or the pressure between a pair of metal belts, that is, the thermal lamination pressure is preferably 49 to 1764 N / cm, and more preferably 98 to 1600 N / cm. If the thermal lamination pressure is within the aforementioned range, the three conditions of the thermal lamination temperature, the thermal lamination speed, and the thermal lamination pressure can be made good, and the productivity can be further improved.

The thermal lamination speed is preferably 0.5 m / min or more, and more preferably 1.0 m / min or more. If the thermal lamination speed is 0.5 m / min or more, sufficient thermal lamination can be achieved. If the thermal lamination speed is above 1.0 m / min, productivity can be further improved.

The interface adhesion strength between the heat-resistant resin layer and the fluororesin layer of the laminated board is preferably 5N / cm or more, more preferably 6N / cm or more, and even more preferably 7N / cm or more.

The interface adhesion strength between the fluororesin layer and the metal foil of the laminated board is preferably 7N / cm or more, more preferably 8N / cm or more, and more preferably 10N / cm or more.

(Step (y))

When the laminated board is warped in step (b), the warpage of the laminated board can be corrected by implementing step (y).

The warpage correction of the laminated board in step (y) can be performed by applying heat treatment to the laminated board at the following temperature: preferably 100 to 250 ° C, more preferably 150 to 250 ° C, and more preferably 180 to 250 ° C. Above thermal lamination temperature And below 250 ° C.

(Step (z))

Step (z) is performed in order to improve the heat resistance of the iron of the laminated board or the adhesion strength between the layers of the laminated board. The melt flow rate of the fluororesin (A) can also be reduced by applying heat treatment to the laminated board. The heat treatment in step (z) can be performed using, for example, the above-mentioned thermal laminating apparatus. The heat treatment temperature is preferably 370 ° C or higher, and more preferably 380 ° C or higher. In this case, the upper limit is usually below 420 ° C, and preferably below 400 ° C.

In addition, by applying heat treatment to the laminated board at a temperature higher than the melting point of the fluororesin (A) in an environment with a low oxygen concentration under an inert gas environment such as nitrogen or argon, the flexible printing described later can be improved. Dimensional stability when the substrate is subjected to a solder reflow step or other heat treatment steps (installation of a cover layer, etc.). The heat treatment conditions are preferably performed at a temperature of (the melting point of the fluororesin (A) + 10 ° C to 120 ° C) for 5 seconds to 48 hours, and more preferably (the melting point of the fluororesin (A) + 30 ° C to 100 ° C ℃ or less) for 30 seconds to 36 hours, more preferably at a temperature of (melting point of fluororesin (A) + 40 ° C or more and 80 ° C or less) for 1 minute to 24 hours.

In addition, the adhesion between the metal foil and the fluorine-containing resin layer, and the fluorine-containing resin layer and the heat-resistant resin film can be improved by this heat treatment. When this heat treatment is performed, even if the thermal lamination pressure in steps (a) and (b) is adjusted down, a laminated board with sufficiently high adhesive strength at the interface can still be obtained. In addition, once the thermal lamination pressure is increased, the dimensional stability of the laminated board and even the flexible printed circuit board described later tends to deteriorate. However, the thermal lamination pressure is reduced when the heat treatment is performed, so that the dimensional stability can be improved.

In the method for manufacturing a laminated board of the present invention, in step (a), the fluororesin film and the metal foil are thermally laminated to each other at a temperature lower than the melting point of the fluororesin (A), so the fluororesin film is not easily broken. Off. In addition, in step (b), the heat-resistant resin film and the metal foil with a fluororesin layer are thermally laminated to each other at a temperature higher than the melting point of the fluororesin (A), so the heat-resistant resin film and the fluororesin film The adhesion strength at the interface and the interface between the fluororesin film and the metal foil will be sufficiently improved. In addition, during the thermal lamination in step (b), the fluororesin film is pre-adhered to the metal foil and supported by the metal foil. Therefore, the thermal lamination is performed even at a temperature above the melting point of the fluororesin (A) The fluororesin film is also not easy to thermally shrink in the width direction and is not easy to break.

Based on the above method, a laminated board having sufficiently high adhesive strength at the interface between the heat-resistant resin layer and the fluororesin layer and at the interface between the fluororesin layer and the metal foil layer can be stably produced.

<Flexible printed circuit board>

The flexible printed circuit board of the present invention includes a pattern circuit formed by etching and removing unnecessary portions of the metal foil layer of the laminated board of the present invention.

The flexible printed circuit board of the present invention can also be mounted with various miniaturized and high-density components.

In the flexible printed circuit board of the present invention, since the fluorine-containing resin layer contains the fluorine-containing resin (A) having a functional group (I), the interface between the heat-resistant resin layer and the fluorine-containing resin layer, and the fluorine-containing resin layer and the metal foil layer The adhesion strength at the interface is sufficiently high. The functional group (I) is selected from the group consisting of a carbonyl group, a hydroxyl group, and a ring. At least one of the group consisting of an oxy group and an isocyanate group.

Examples

Hereinafter, the present invention will be described in detail with examples, but the present invention is not limited thereto. In addition, Examples 1, 2 and 3 are examples, and Examples 4 and 5 are comparative examples.

(Copolymer composition)

The copolymerization composition of the fluorine-containing resin (A) was determined by melt NMR analysis, fluorine content analysis, and infrared absorption spectrum analysis.

(Functional group (I) content)

The ratio of units derived from NAH having a functional group (I) in the fluororesin (A) was determined by the following infrared absorption spectrum analysis.

The fluororesin (A) was pressure-molded to obtain a 200 μm film. In the infrared absorption spectrum, the absorption peak of the unit derived from NAH in the fluorine-containing resin (A) appeared at 1778 cm ^-1 . The absorbance of the absorption peak was measured, and the Mohr absorption coefficient of NAH was 20810 mol ^-1 ‧ l‧ cm ^{-1 to} determine the proportion of units derived from NAH (Molar%).

If so the ratio of a (mole%), the number of the main chain 1 × 10 ⁶ carbon atoms, a functional group (I) (acid anhydride groups) is calculated as the sum [a × 10 ^6/100] a.

(Melting point)

Using a differential scanning calorimeter (DSC device, manufactured by Seiko Instruments Inc.), the melting peak of the fluororesin (A) at a temperature rise of 10 ° C / min was recorded, and the temperature (° C) corresponding to the maximum value was taken as Melting point.

(Melt flow rate)

Using Melt Indexer (TECHNOL SEVEN (Manufactured by CO., LTD.) The mass (g) of the fluororesin (A) flowing out from a nozzle having a diameter of 2 mm and a length of 8 mm for 10 minutes was measured at a temperature of 372 ° C higher than the melting point and a load of 49N.

(Adhesive strength)

Interface between fluororesin layer and metal foil layer:

A metal foil or a laminated board with a fluororesin layer was cut to a length of 150 mm and a width of 10 mm to prepare an evaluation sample. Using the one end in the longitudinal direction of the evaluation sample as a starting point, the fluororesin layer and the metal foil were peeled to a position of 50 mm. Next, using a tensile tester, it was peeled to 90 degrees at a tensile speed of 50 mm / min, and the maximum load was the adhesive strength (N / cm).

Interface between heat-resistant resin layer and fluorine-containing resin layer:

The laminated board was cut to a length of 150 mm and a width of 10 mm to prepare an evaluation sample. Using the one end in the longitudinal direction of the evaluation sample as a starting point, the heat-resistant resin layer and the fluororesin layer were peeled to a position of 50 mm. Next, using a tensile tester, it was peeled to 90 degrees at a tensile speed of 50 mm / min, and the maximum load was the adhesive strength (N / cm).

(Fluorine resin (A-1))

NAH (nadic acid anhydride, manufactured by Hitachi Chemical Co., Ltd.) was prepared as a monomer for forming the unit (u2), and PPVE (CF ₂ = CFO (CF ₂ ) ₃ F, perfluoropropyl vinyl ether was used as the forming unit ( u3).

(Perfluorobutylfluorenyl) peroxide is dissolved in 1,3-dichloro-1,1,2,2,3-pentafluoropropane (hereinafter also referred to as AK225cb; manufactured by Asahi Glass Co., Ltd.) at a concentration of 0.36 mass%, A polymerization initiator solution was prepared.

It is prepared by dissolving NAH in AK225cb at a concentration of 0.3% by mass Out of NAH solution.

369kg of AK225cb and 30kg of PPVE were fed into a polymerization tank with a stirrer with a volume of 430L which had been degassed in advance. After the temperature in the polymerization tank was increased to 50 ° C. and 50 kg of TFE was further fed, the pressure in the polymerization tank was increased to 0.89 MPa [gauge pressure].

A polymerization initiator solution of 3 liters (L) was continuously added to the polymerization tank at a rate of 6.25 mL / min to perform polymerization. The TFE was continuously fed while the pressure in the polymerization tank during the polymerization reaction was maintained at 0.89 MPa [gauge pressure]. In addition, the NAH solution was continuously fed in an amount equivalent to 0.1 mole% of the TFE mole number fed during the relative polymerization.

After more than 8 hours from the start of polymerization and at the time point of feeding 32 kg of TFE, the temperature in the polymerization tank was lowered to room temperature while the pressure was exhausted to normal pressure. The obtained slurry was separated from AK225cb solid-liquid, and then dried at 150 ° C. for 15 hours to obtain 33 kg of a fluororesin (A-1).

The specific gravity of the fluororesin (A-1) is 2.15, and the copolymer composition is: TFE-derived units / NAH-derived units / PPVE-derived units = 97.9 / 0.1 / 2.0 (mole%).

The melting point of the fluororesin (A-1) was 305 ° C, and the melt flow rate was 11.0 g / 10 minutes.

The main chain carbon number of fluorine-containing resin (A-1) of 1 × 10 ⁶ th, a fluorine-containing resin having a functional group (A-1) in the (I) (acid anhydride group) content of 1,000.

(Other fluororesin)

PFA: TFE / perfluoro (alkyl vinyl ether) copolymer (manufactured by Asahi Glass Co., Fluon (registered trademark) PFA 73PT, melting point: 305 ° C, melt flow rate 13.6g / 10 points).

(Fluorine resin film 1)

Using a 30 mmφ uniaxial extruder having a coat hanger die with a width of 750 mm, the fluororesin (A-1) was extruded at a mold temperature of 340 ° C. to obtain a fluororesin film 1 having a thickness of 25 μm.

(Fluorine resin film 2)

A fluororesin film 2 having a thickness of 12.5 μm was obtained in the same manner as the fluororesin film 1 except that the pulling speed was changed.

(Fluorine resin film 3)

Using a 30 mmφ uniaxial extruder having a 750 mm wide hanger-type mold, PFA was extruded at a mold temperature of 340 ° C. to obtain a fluororesin film 3 having a thickness of 25 μm.

(Heat-resistant resin film)

A 25 μm-thick polyimide film (manufactured by Toray DuPont, Kapton (registered trademark) 100EN) was prepared.

(Metal foil)

An electrolytic copper foil (manufactured by Fukuda Metal Foil, CF-T4X-SVR-12, Rz: 1.2 μm) having a thickness of 12 μm was prepared.

(example 1)

Step (a):

Using a hot-rolled lamination device with a pair of metal rolls, the fluorine-containing resin film 1 and the metal foil were thermally laminated at a temperature of 230 ° C., a pressure of 784 N / cm, and a speed of 4 m / min to produce a fluorine-containing resin. Layer of metal foil 1. The interface adhesion strength between the fluororesin layer and the metal foil layer was 0.3 N / cm.

Step (b):

Using a hot-rolled laminating device with a pair of metal rolls, a polyimide film and a metal foil 1 with a fluororesin layer were thermally laminated at a temperature of 400 ° C, a pressure of 1470 N / cm, and a speed of 1 m / min. To produce a laminated board 1. The interface adhesion strength between the fluorine-containing resin layer and the metal foil layer was 11 N / cm, and the interface adhesion strength between the heat-resistant resin layer and the fluorine-containing resin layer was 8 N / cm.

(Example 2)

Step (a):

A metal foil 2 with a fluorine-containing resin layer was produced in the same manner as in Example 1 except that the fluorine-containing resin film 2 was used instead of the fluorine-containing resin film 1. The interface adhesion strength between the fluororesin layer and the metal foil layer was 0.3 N / cm.

Step (b):

A laminated plate 2 was produced in the same manner as in Example 1 except that the metal foil 2 with a fluororesin layer was used instead of the metal foil 1 with a fluororesin layer. The interface adhesion strength between the fluorine-containing resin layer and the metal foil layer was 10 N / cm, and the interface adhesion strength between the heat-resistant resin layer and the fluorine-containing resin layer was 7 N / cm.

(Example 3)

Step (z):

The laminated board 2 obtained in Example 2 was heat-treated to produce a laminated board 3. The heat treatment was performed using a thermal laminator under conditions of a temperature of 380 ° C, a pressure of 1470 N / cm, and a speed of 1 m / min. The interface adhesion strength between the fluororesin layer and the metal foil layer of the laminated board 3 was 12 N / cm, and the interface adhesion strength between the heat-resistant resin layer and the fluororesin layer was 10 N / cm.

(Example 4)

Except that the fluororesin film 3 was used instead of the fluororesin film 1, although a metal foil with a fluororesin layer was intended to be produced in the same manner as in Example 1, the interface adhesive strength between the fluororesin layer and the metal foil layer was not sufficient. When the metal foil with a fluororesin layer was wound up, separation occurred between the fluororesin film 3 and the metal foil.

(Example 5)

Originally, a hot-rolled lamination device with a pair of metal rollers was used to thermally laminate a fluororesin film 1, a metal foil, and a polyimide film at a temperature of 400 ° C, a pressure of 784 N / cm, and a speed of 4 m / min. However, since the thermal shrinkage of the fluororesin film 1 near the metal roller is large and the fluororesin film 1 is broken, it is not possible to continuously manufacture a laminated board.

Industrial availability

The laminated board produced by the manufacturing method of the laminated board of the present invention can effectively manufacture a flexible printed substrate requiring high electrical reliability.

In addition, here are the descriptions and patent applications of Japanese Patent Application No. 2014-264875 filed on December 26, 2014 and Japanese Patent Application No. 2015-121143 filed on June 16, 2015. The entire contents of the scope, drawings, and abstract are incorporated as a disclosure of the specification of the present invention.

Claims (10)

A laminated board manufacturing method is used for manufacturing a laminated board having a heat-resistant resin layer, a fluorine-containing resin layer in contact with the heat-resistant resin layer, and a metal foil layer in contact with the fluorine-containing resin layer. The method has the following steps (a) and (b); step (a) is a method of forming a fluorine-containing resin film containing the foregoing fluorine-containing resin (A) at a temperature lower than the melting point of the fluorine-containing resin (A). Thermally laminated with a metal foil to obtain a metal foil with a fluorine-containing resin layer, the fluorine-containing resin (A) having at least one selected from the group consisting of a carbonyl-containing group, a hydroxyl group, an epoxy group, and an isocyanate group. 1 type of functional group; step (b), the heat-resistant resin film (the heat-resistant resin film and the fluorine-containing resin layer is contacted with the heat-resistant resin ( B) The heat-resistant resin film and the metal foil with a fluorine-containing resin layer are thermally laminated to obtain the laminated board. For example, the method for manufacturing a laminated board according to claim 1, wherein the melting point of the fluorine-containing resin (A) is 260 to 320 ° C, and the fluorine-containing resin (A) can be melt-molded. The method for manufacturing a laminated board according to claim 1, wherein the aforementioned fluororesin (A) is a fluoropolymer having the aforementioned functional group, and the aforementioned functional group is derived from a monomer selected from the group consisting of At least one of the group consisting of a polymer, a chain transfer agent, and a polymerization initiator. The method for manufacturing a laminated board according to any one of claims 1 to 3, wherein the thermal lamination of the foregoing step (a) and the thermal lamination of the foregoing step (b) are continuously performed by a thermal lamination device, and the thermal layer The closing device has more than one pair of metal rollers or more than one pair of metal belts. The method for manufacturing a laminated board according to any one of claims 1 to 3, wherein the fluorine-containing resin (A) has at least a carbonyl-containing group as the aforementioned functional group, and the aforementioned carbonyl-containing group is selected from the group consisting of At least one of the group consisting of a carbonyl group, a carbonate group, a carboxyl group, a haloformamyl group, an alkoxycarbonyl group, and an acid anhydride group between carbon atoms. A method for producing a laminate according to any one of the requested item, such as the 3, wherein with respect to the fluorine-containing resin main chain carbon atoms (A) of 1 × 10 ⁶ th, the functional groups content of 10 to 60,000. The method for manufacturing a laminated board according to any one of claims 1 to 3, which is in the aforementioned step (a) and the aforementioned fluorine-containing resin film is at a temperature of -20 ° C or lower of the melting point of the fluorine-containing resin (A). It is thermally laminated with the aforementioned metal foil. The method for manufacturing a laminated board according to any one of claims 1 to 3, wherein the thickness of the foregoing fluororesin layer is 1 to 20 μm. The method for manufacturing a laminated board according to any one of claims 1 to 3, wherein the melt flow rate of the fluororesin (A) under the conditions of 372 ° C and a load of 49N is 0.5 to 15 g / 10 minutes. A method of manufacturing a flexible printed circuit board is to form a pattern circuit by etching and removing unnecessary portions of the metal foil layer of the aforementioned laminated board after the laminated board is manufactured by the manufacturing method according to any one of claims 1 to 9.