JPWO2018030026A1 - Laminate containing low dielectric adhesive layer - Google Patents

Abstract

Provides a laminate that has high adhesion to not only conventional polyimide and polyester films but also low polar resin substrates such as LCP and metal substrates, high solder heat resistance, and excellent low dielectric properties. Do. A laminate (Z) in which a resin substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), wherein (1) the metal substrate is removed from the laminate (Z) Dielectric loss tangent (εc) of the laminate (X) at a frequency of 1 MHz is 3.0 or less, and (2) dielectric loss tangent at a frequency of 1 MHz of the laminate (X) obtained by removing the metal base from the laminate (Z) (Tan δ) is 0.02 or less, (3) the peel strength between the resin base and the metal base is 0.5 N / mm or more, and (4) the wet solder heat resistance of the laminate (Z) is 240 A laminate (Z) characterized by having a temperature of at least ° C.

Description

  The present invention relates to a laminate containing an adhesive layer exhibiting a low dielectric constant and a low dielectric loss tangent. More specifically, the present invention relates to a laminate in which a resin base and a metal base are laminated via an adhesive layer exhibiting a low dielectric constant and a low dielectric loss tangent. In particular, the present invention relates to a laminate for a flexible printed wiring board (hereinafter referred to as an FPC), a coverlay film, a laminate, a copper foil with resin, and a bonding sheet including the laminate.

In recent years, with the speeding up of transmission signals in printed wiring boards, the frequency of signals has been increased. Along with this, the demand for low dielectric characteristics (low dielectric constant, low dielectric loss tangent) in a high frequency region is increasing for the FPC. In order to meet such requirements, conventional polyimide (PI), liquid crystal polymer (LCP) having low dielectric characteristics (LCP), syndiotactic polystyrene (SPS), and the like instead of conventional polyimide (PI) and polyethylene terephthalate film are used as substrate films for FPC. Substrate films such as polyphenylene sulfide (PPS) have been proposed.
However, since the base film having low dielectric properties has low polarity, the adhesion is weak when a conventional epoxy adhesive or acrylic adhesive is used, and a member for FPC such as a coverlay film, a laminate, etc. is produced. Was difficult. In addition, epoxy adhesives and acrylic adhesives do not have excellent low dielectric properties and impair the dielectric properties of the FPC.
On the other hand, polyolefin resins are known to have low dielectric properties. Therefore, an adhesive composition for FPC using a polyolefin resin has been proposed. For example, in Patent Document 1, a thermally reactive adhesive using a carboxyl group-containing polyolefin copolymer, a block copolymer of an aromatic vinyl compound polymer block and a conjugated diene compound polymer block, and an epoxy resin Compositions have been proposed. Further, Patent Document 2 proposes an adhesive composition using a carboxyl group-containing styrene elastomer and an epoxy resin.

Patent No. 3621351 WO 2014/147903 A1 Publication

  However, Patent Document 1 mentions the adhesion between a polyimide film and SUS, and solder heat resistance, but does not mention dielectric properties, and adhesion with a base film having low dielectric properties such as LCP. Is difficult to obtain. Moreover, in patent document 2, although the adhesiveness of a dielectric property and a polyimide film and copper foil is described, it is not mentioned about the adhesiveness with the base film which has low dielectric characteristics, such as LCP. Moreover, although the solder heat resistance after drying is described, the solder heat resistance after humidification is not sufficient.

  As a result of earnest studies to solve the above problems, the present invention finds that the adhesive layer having specific physical properties is not only a conventional polyimide film, but also a resin having low dielectric characteristics such as LCP not assumed in the prior art. It has been found that the base material and the metal base material such as copper foil are excellent in high adhesion, high solder heat resistance, and low dielectric properties, and the present invention has been completed.

  That is, the present invention is a laminate laminated with an adhesive layer having good adhesion to both of various resin substrates such as polyimide and LCP and metal substrates, and having excellent heat resistance and low dielectric characteristics. Intended to provide the body.

A laminate (Z) in which a resin substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), wherein (1) the metal substrate is removed from the laminate (Z) Dielectric constant (ε _c ) at a frequency of 1 MHz of the laminated body (X) is 3.0 or less, and (2) the dielectric at a frequency of 1 MHz of the laminated body (X) obtained by removing the metal base from the laminate (Z) The tangent (tan δ) is 0.02 or less, (3) the peel strength between the resin base and the metal base is 0.5 N / mm or more, and (4) the wet solder heat resistance of the laminate (Z) is A laminate (Z) characterized by having a temperature of 240 ° C. or more.

A laminate of the adhesive layer and the resin substrate (X) used in a laminate (Z) in which a resin substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A) (1) The dielectric constant (ε _c ) at a frequency of 1 MHz of the laminate (X) is 3.0 or less, and (2) the dielectric loss tangent (tan δ) at a frequency of 1 MHz of the laminate (X) is (3) The peel strength between the resin base and the metal base in the laminate when the metal base is laminated on the adhesive layer surface of the laminate (X) is 0.5 N / mm or more (4) A laminate (X) characterized in that the wet solder heat resistance of the laminate when the metal base is laminated on the adhesive layer side of the laminate (X) is 240 ° C. or higher.

  An adhesive sheet containing the above laminate (Z) or laminate (X).

  The printed wiring board which contains the said adhesive sheet as a component.

A laminate (Z) in which a resin substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A) according to the present invention is (1) a laminate (Z) to a metal substrate The dielectric constant (ε _c ) at a frequency of 1 MHz of the laminate (X) from which the is removed is 3.0 or less, (2) the frequency of the laminate (X) from which the metal substrate is removed from the laminate (Z) The dielectric loss tangent (tan δ) at 1 MHz is 0.02 or less, (3) the peel strength between the resin base and the metal base is 0.5 N / mm or more, (4) the laminate (Z) In order to satisfy moisture solder heat resistance of 240 ° C or higher, not only conventional polyimides and polyester films, but also low-polarity resin substrates and metal substrates such as LCP films not expected in the prior art have high adhesiveness Has high solder heat resistance And excellent in low dielectric characteristics.

  Hereinafter, embodiments of the present invention will be described in detail. The laminate (Z) according to the present invention is a laminate of a resin substrate and a metal substrate through an adhesive layer containing a carboxyl group-containing polyolefin resin (A), and the laminate (X) has a carboxyl group It is a laminated body of the adhesive bond layer containing a containing polyolefin resin (A), and a resin base material.

<Carboxyl group-containing polyolefin resin (A)>
The carboxyl group-containing polyolefin resin (A) (hereinafter also referred to simply as the component (A)) used in the present invention is not limited, but at least one of α, β-unsaturated carboxylic acid and acid anhydride thereof to the polyolefin resin. It is preferable that it is obtained by grafting. Polyolefin resins include homopolymers of olefin monomers such as ethylene, propylene, butene, butadiene, isoprene and the like, or copolymerization with other monomers, and hydrocarbons such as hydrides and halides of the obtained polymers. It refers to a polymer mainly composed of a skeleton. That is, the carboxyl group-containing polyolefin is obtained by grafting at least one of an α, β-unsaturated carboxylic acid and an acid anhydride thereof onto at least one of polyethylene, polypropylene and a propylene-α-olefin copolymer. What is obtained is preferable.

  The propylene-α-olefin copolymer is mainly composed of propylene and copolymerized with α-olefin. As the α-olefin, for example, ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate and the like can be used alone or in combination. Among these α-olefins, ethylene and 1-butene are preferred. Although the ratio of the propylene component of an propylene-alpha-olefin copolymer and an alpha-olefin component is not limited, It is preferable that a propylene component is 50 mol% or more, and it is more preferable that it is 70 mol% or more.

  Examples of at least one of the α, β-unsaturated carboxylic acids and their acid anhydrides include maleic acid, itaconic acid, citraconic acid and their acid anhydrides. Among these, acid anhydrides are preferable, and maleic anhydride is more preferable. Specifically, maleic anhydride modified polypropylene, maleic anhydride modified propylene-ethylene copolymer, maleic anhydride modified propylene-butene copolymer, maleic anhydride modified propylene-ethylene-butene copolymer, etc. may be mentioned. These acid-modified polyolefins can be used alone or in combination of two or more. Among these, maleic anhydride-modified propylene-butene copolymer is preferable. The propylene component / 1-butene component (molar ratio) of the maleic anhydride-modified propylene-butene copolymer is preferably 90 to 50/10 to 50, and more preferably 85 to 60/15 to 40. It is preferably 80 to 55/20 to 45, more preferably 75 to 60/25 to 40. By setting it as the said range, especially outstanding adhesiveness, moist solder | pewter heat resistance, and a low dielectric property can be expressed.

The lower limit of the acid value of the carboxyl group-containing polyolefin resin (A) is preferably 100 equivalents / 10 ⁶ g or more, and more preferably 200, from the viewpoint of heat resistance and adhesiveness with the resin substrate and the metal substrate. The equivalent weight / 10 ⁶ g or more, more preferably 250 equivalent / 10 ⁶ g. If it is less than the above value, the compatibility with the epoxy resin (D) and the carbodiimide resin (C) may be low, and the adhesive strength may not be expressed. In addition, the crosslink density may be low and the heat resistance may be poor. The upper limit is preferably 1000 equivalents / 10 ⁶ g or less, more preferably 700 equivalents / 10 ⁶ g or less, and still more preferably 500 equivalents / 10 ⁶ g or less. If the above value is exceeded, adhesion may be reduced. In addition, the viscosity and stability of the solution may be reduced, and the pot life may be reduced. Furthermore, it is not preferable because the production efficiency also decreases.

  The weight average molecular weight (Mw) of the carboxyl group-containing polyolefin resin (A) is preferably in the range of 10,000 to 180,000. More preferably, it is in the range of 20,000 to 160,000, more preferably in the range of 30,000 to 150,000, particularly preferably in the range of 40,000 to 140,000, and most preferably 50. The range is from 1,000 to 130,000. If it is less than the above value, the cohesion may be weak and the adhesion may be poor. On the other hand, if the value is above the above range, the flowability is low and there may be a problem in operability when bonding.

  The carboxyl group-containing polyolefin resin (A) is preferably a crystalline resin. Since the carboxyl group-containing polyolefin resin (A) is crystalline, it is advantageous because the cohesion is strong and the adhesiveness is excellent compared to the non-crystallinity. Here, the term “crystallinity” refers to one that shows a distinct melting peak in the temperature rising process by raising the temperature from −100 ° C. to 250 ° C. at 20 ° C./minute using a differential scanning calorimeter (DSC). .

  The melting point (Tm) of the carboxyl group-containing polyolefin resin (A) is preferably in the range of 50 ° C to 120 ° C. More preferably, it is in the range of 60 ° C. to 100 ° C., and most preferably in the range of 70 ° C. to 90 ° C. If it is less than the above value, the cohesion may be weak and the adhesion may be poor. On the other hand, if the value is above the above range, the flowability is low and there may be a problem in operability when bonding.

  The heat of fusion (ΔH) of the carboxyl group-containing polyolefin resin (A) is preferably in the range of 5 J / g to 60 J / g. More preferably, it is in the range of 10 J / g to 50 J / g, and still more preferably in the range of 20 J / g to 40 J / g. If it is less than the above value, the cohesion may be weak and the adhesion may be poor. On the other hand, if the value is above the above range, the flowability is low and there may be a problem in operability when bonding.

  The method for producing the carboxyl group-containing polyolefin resin (A) is not particularly limited. For example, a radical grafting reaction (that is, a radical species is generated with respect to a polymer serving as a main chain) Graft polymerization of an acid and an acid anhydride), and the like.

  The radical generator is not particularly limited, but it is preferable to use an organic peroxide. The organic peroxide is not particularly limited, and di-tert-butyl peroxy phthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy- Peroxides such as 2-ethylhexanoate, tert-butylperoxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide, etc .; azobisisobutyronitrile, azobisisopropionitrile etc. Azonitriles etc. are mentioned.

<Adhesive layer>
In the present invention, the adhesive layer (hereinafter also referred to as "Ad") refers to a layer of the adhesive composition after the adhesive composition is applied to a substrate and dried or cured. The thickness of the adhesive layer is not particularly limited, but is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more. Moreover, preferably it is 200 micrometers or less, More preferably, it is 100 micrometers or less, More preferably, it is 50 micrometers or less. If the thickness is too thin, adhesion performance may not be obtained sufficiently. If the thickness is too thick, drying is insufficient and the residual solvent tends to be large, and the printed wiring board may be swollen when pressed. There is a problem of that.

  Although it does not specifically limit as method to coat an adhesive composition on a base material, A comma coater, a reverse roll coater, etc. are mentioned. Alternatively, if necessary, the adhesive layer can be provided on the rolled copper foil or polyimide film which is a printed wiring board constituent material directly or by a transfer method. Although the drying conditions are not particularly limited, the residual solvent ratio after drying is preferably 1% by mass or less. If the amount is more than 1% by mass, there is a problem that the residual solvent is foamed at the time of pressing the printed wiring board to generate a blister.

The relative dielectric constant (ε _c ) at 1 MHz of the adhesive layer is preferably 3.0 or less, more preferably 2.6 or less, and still more preferably 2.3 or less. The lower limit is not particularly limited, but is practically 2.0. Further, the relative dielectric constant (ε _c ) in the entire region of frequencies 1 MHz to 10 GHz is preferably 3.0 or less, more preferably 2.6 or less, and still more preferably 2.3 or less.

  The dielectric loss tangent (tan δ) at 1 MHz of the adhesive layer is preferably 0.02 or less, more preferably 0.01 or less, and still more preferably 0.005 or less. The lower limit is not particularly limited, but is practically 0.0001. Further, the dielectric loss tangent (tan δ) in the entire region of frequencies 1 MHz to 10 GHz is preferably 0.02 or less, more preferably 0.01 or less, and still more preferably 0.005 or less.

The relative permittivity (ε _c ) and the dielectric loss tangent (tan δ) of the adhesive layer can be measured as follows. That is, the adhesive composition is applied to a release substrate to a dry thickness of 25 μm, and dried at about 130 ° C. for about 3 minutes. Next, the adhesive composition layer (adhesive layer) after curing is peeled off from the release film by curing by heat treatment at about 140 ° C. for about 4 hours. A metal layer is formed on both sides of the adhesive layer by vapor deposition, a thin film method such as sputtering, or application of a conductive paste to form a capacitor, and the capacitance is measured to determine the relative dielectric constant (ε from thickness and area). _c ) and the dielectric loss tangent (tan δ) can be calculated.

<Resin base material>
In the present invention, the resin base is not particularly limited as long as the adhesive composition of the present invention can be applied and dried to form an adhesive layer, but a resin base such as a film-like resin ( Hereinafter, it is also preferable to refer to a base film layer). Specifically, polyester resin, polyamide resin, polyimide resin, polyamide imide resin, liquid crystal polymer (LCP), polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, fluorine resin and the like can be exemplified. As a commercial item of LCP film, Kuraray Co., Ltd. make Vexter (registered trademark) is mentioned, for example. Moreover, as a commercial item of a polyimide film, the Apical (trademark) made from Kaneka Corporation is mentioned, for example.

The thickness of the resin substrate is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 10 μm or more. Moreover, preferably it is 50 micrometers or less, More preferably, it is 30 micrometers or less, More preferably, it is 20 micrometers or less. When the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit. On the other hand, when the thickness is too thick, the processing efficiency and the like at the time of circuit fabrication may decrease. Further, the relative dielectric constant (ε _c ) of the resin base is preferably 5.0 or less, more preferably 4.0 or less, and still more preferably 3.5 or less. The lower limit is not particularly limited, and there is no problem if it is 0.1 or more industrially.

<Metal base>
As the metal substrate, any conventionally known conductive material that can be used for a circuit board can be used. Examples of the material include various metals such as SUS, copper, aluminum, iron, steel, zinc and nickel, alloys thereof, plated products, metals treated with other metals such as zinc and chromium compounds, and the like. Preferably it is metal foil, More preferably, it is copper foil. The thickness of the metal foil is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 10 μm or more. Moreover, preferably it is 50 micrometers or less, More preferably, it is 30 micrometers or less, More preferably, it is 20 micrometers or less. When the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit. On the other hand, when the thickness is too thick, the processing efficiency and the like at the time of circuit fabrication may decrease. The metal foil is usually provided in the form of a roll. The form of the metal foil used when manufacturing the printed wiring board of this invention is not specifically limited. When using a metallic foil in the form of a ribbon, its length is not particularly limited. The width is also not particularly limited, but preferably about 250 to 500 cm.

<Laminate>
The laminate (Z) of the present invention is a laminate in which a resin substrate and a metal substrate are laminated via an adhesive layer (a three-layer laminate of resin substrate / adhesive layer / metal substrate), and a laminate (X) is a laminate of a resin base and an adhesive layer (resin base / adhesive layer). In the present invention, the laminate (X) and the laminate (Z) may be simply referred to as a laminate. The laminate (X) may be obtained by removing the metal substrate from the laminate (Z) by a method such as etching, or the adhesive composition is applied to the resin substrate according to a conventional method and dried. What is obtained by doing may be good. The laminate (Z) may be obtained by laminating a metal substrate on the laminate (X), or the adhesive composition is applied to a metal substrate according to a conventional method and dried, and then the resin substrate is What is obtained by laminating may be used. A release substrate can also be laminated on the surface of the adhesive layer of the laminate (X). In addition, an adhesive layer is further laminated on the resin base or metal base of the laminate (Z) (adhesive layer / resin base / adhesive layer / metal base, resin base / adhesive layer / metal base / Adhesive layer, adhesive layer / resin base material / adhesive layer / metal base / adhesive layer).

  The laminate of the present invention further satisfies the following requirements (1) to (4).

<Requirement (1)>
The requirement (1) will be described. In the laminate (Z) according to the present invention, it is necessary that the dielectric constant (ε _c ) at a frequency of 1 MHz of the laminate (X) obtained by removing the metal base from the laminate (Z) is 3.0 or less is there. Specifically, the relative dielectric constant (ε _c ) of the laminate (X) can be measured as follows. That is, the metal base of the laminate (Z) is cleanly removed with an etching solution to obtain a two-layer laminate (X) of the adhesive layer and the resin base. The etching solution is not particularly limited, and an aqueous solution of ferric chloride, an aqueous solution of cupric chloride, a mixed solution of sulfuric acid and hydrogen peroxide, an alkaline etchant, a nickel etchant and the like can be used. Next, a metal layer is formed on both sides of the laminate (X) by a thin film method such as evaporation, sputtering, or coating of a conductive paste to form a capacitor, and the capacitance is measured to measure the thickness and area A method of calculating the dielectric constant (ε _c ) can be exemplified.

Alternatively, the adhesive composition is applied to the resin substrate to a dry thickness of 25 μm and dried at about 130 ° C. for about 3 minutes. Then, the laminate (X) can be produced also by heat treatment at about 140 ° C. for about 4 hours to be cured. The relative dielectric constant (ε _c ) of the laminate (X) can be measured as described above. In addition, even if it is laminated body (X) produced by methods other than the said method, if the dielectric constant ((epsilon) _c ) in frequency 1 MHz is 3.0 or less, it is included by this invention.

The relative dielectric constant (ε _c ) at a frequency of 1 MHz of the laminate (X) is 3.0 or less, preferably 2.8 or less, more preferably 2.7 or less, still more preferably 2.6 or less It is. The lower limit is not particularly limited, but is practically 2.0. In addition, the relative dielectric constant (ε _c ) in the entire region of frequencies 1 MHz to 10 GHz is preferably 3.0 or less, more preferably 2.8 or less, and still more preferably 2.7 or less, It is particularly preferred that it is 2.6 or less.

<Requirement (2)>
The requirement (2) will be described. In the laminate (Z) according to the present invention, the dielectric loss tangent (tan δ) at a frequency of 1 MHz of the laminate (X) obtained by removing the metal base from the laminate (Z) needs to be 0.02 or less. Specifically, the dielectric loss tangent (tan δ) of the laminate (X) can be measured as follows. That is, the metal base of the laminate (Z) is cleanly removed with an etching solution to obtain a two-layer laminate (X) of the adhesive layer and the resin base. The etching solution is not particularly limited, and an aqueous solution of ferric chloride, an aqueous solution of cupric chloride, a mixed solution of sulfuric acid and hydrogen peroxide, an alkaline etchant, a nickel etchant and the like can be used. Next, a metal layer is formed on both sides of the laminate (X) by a method such as vapor deposition, thin film method such as sputtering method, or application of conductive paste to make a capacitor, and the capacitance is measured. A method of calculating the tangent (tan δ) can be exemplified.

  Alternatively, the adhesive composition is applied to the resin substrate to a dry thickness of 25 μm and dried at about 130 ° C. for about 3 minutes. Then, the laminate (X) can be produced also by heat treatment at about 140 ° C. for about 4 hours to be cured. The dielectric loss tangent (tan δ) of the laminate (X) can be measured as described above. In addition, even if it is laminated body (X) produced by methods other than the said method, if the dielectric loss tangent (tan-delta) in 1 MHz of frequencies is 0.02 or less, it is included by this invention.

  The dielectric loss tangent (tan δ) at a frequency of 1 MHz of the laminate (X) is 0.02 or less, preferably 0.01 or less, and more preferably 0.005 or less. The lower limit is not particularly limited, but is practically 0.0001. Further, the dielectric loss tangent (tan δ) in the entire region of frequencies 1 MHz to 10 GHz is preferably 0.02 or less, more preferably 0.01 or less, and still more preferably 0.005 or less.

<Requirement (3)>
The requirement (3) will be described. In the laminate (Z) according to the present invention, the peel strength between the resin base and the metal base needs to be 0.5 N / mm or more. Specifically, at normal temperature (about 25 ° C.), the resin base of the laminate (Z) is peeled at 90 ° at a tensile speed of 50 mm / min, and the peel strength is measured. The 90 ° peel strength needs to be 0.5 N / mm or more, preferably 0.8 N / mm or more, and more preferably 1.0 N / mm or more.

The laminate (Z) can be produced as follows. Specifically, the adhesive composition is applied to a resin substrate to a dry thickness of about 25 μm, and dried at about 130 ° C. for about 3 minutes. Next, a metal substrate is bonded to the surface of the adhesive composition layer (adhesive layer). Bonding is carried out by vacuum pressing for about 30 seconds under a pressure of about 40 kgf / cm ² at about 160 ° C. so that the shiny side of the metal substrate is in contact with the adhesive composition layer. Then, heat treatment and curing are carried out at about 140 ° C. for about 4 hours to produce a resin base / adhesive layer / metal base three-layer laminate (Z). In addition, even if it is a laminated body (Z) produced by methods other than the said method, if 90 degree peel strength is 0.5 N / mm or more, it is included by this invention.

From the laminate (X), the laminate (Z) of the present invention can be obtained by laminating a metal base on the surface of the adhesive composition layer (adhesive layer) of the laminate (X). Bonding is carried out by vacuum pressing for about 30 seconds under a pressure of about 40 kgf / cm ² at about 160 ° C. so that the shiny side of the metal substrate is in contact with the adhesive composition layer. Then, heat treatment and curing are carried out at about 140 ° C. for about 4 hours to produce a resin base / adhesive layer / metal base three-layer laminate (Z). At normal temperature (about 25 ° C.), the resin base of the laminate (Z) is peeled at 90 ° at a tensile speed of 50 mm / min, and the peel strength is measured. The 90 ° peel strength needs to be 0.5 N / mm or more, preferably 0.8 N / mm or more, and more preferably 1.0 N / mm or more.

<Requirement (4)>
The requirement (4) will be described. The layered product (Z) according to the present invention is required to have a humidified solder heat resistance of 240 ° C. or higher. Specifically, the laminate (Z) is treated for about 72 hours under conditions of about 40 ° C. and about 80 RH%, and flows for 1 minute into the molten solder bath at each temperature, causing no appearance change such as blistering. Measure the temperature. Humidified solder heat resistance needs to be 240 ° C. or higher, preferably 250 ° C. or higher, and more preferably 260 ° C. or higher.

The laminate (Z) can be produced as follows. Specifically, the adhesive composition is applied to a resin base so that the thickness after drying is 25 μm, and dried at about 130 ° C. for about 3 minutes. Next, a metal substrate is bonded to the surface of the adhesive composition layer (adhesive layer). Bonding is performed by vacuum pressing for about 30 seconds under a pressure of about 40 kgf / cm ² at about 160 ° C. so that the shiny side of the metal substrate is in contact with the adhesive composition layer. Then, heat treatment and curing are carried out at about 140 ° C. for about 4 hours to produce a resin base / adhesive layer / metal base three-layer laminate (Z). In addition, even if it is a laminated body (Z) produced by methods other than the said method, if humidified solder heat resistance is 240 degreeC or more, it is included in this invention.

From the laminate (X), the laminate (Z) of the present invention can be obtained by laminating a metal base on the surface of the adhesive composition layer (adhesive layer) of the laminate (X). Bonding is carried out by vacuum pressing for about 30 seconds under a pressure of about 40 kgf / cm ² at about 160 ° C. so that the shiny side of the metal substrate is in contact with the adhesive composition layer. Then, heat treatment and curing are carried out at about 140 ° C. for about 4 hours to produce a resin base / adhesive layer / metal base three-layer laminate (Z). The laminate (Z) is treated for about 72 hours under conditions of about 40 ° C. and about 80 RH%, and flows for 1 minute into the molten solder bath at each temperature, and a temperature not causing appearance change such as blistering is measured. . Humidified solder heat resistance needs to be 240 ° C. or higher, preferably 250 ° C. or higher, and more preferably 260 ° C. or higher.

<Adhesive composition>
The adhesive composition used in the present invention contains at least a carboxyl group-containing polyolefin resin (A). By containing a carboxyl group-containing polyolefin resin (A), a laminate having an adhesive layer formed of the adhesive composition can exhibit the excellent performances of the above (1) to (4).

  The adhesive composition of the present invention comprises, in addition to the component (A), a carboxyl group-containing styrene resin (B) (hereinafter, also simply referred to as component (B)), a carbodiimide resin (C) (hereinafter, simply (C). And / or epoxy resin (D) (hereinafter, also simply referred to as component (D)). Not only conventional polyimides and polyester films but also low-polarity resin substrates such as LCP films not expected in the prior art by containing the four types of resins of the components (A) to (D) It also has high adhesion to a metal substrate, can obtain high solder heat resistance, and is excellent in low dielectric characteristics.

<Carboxyl group-containing styrene resin (B)>
The carboxyl group-containing styrene resin (B) which can be used in the present invention is not limited, but a vinyl aromatic compound alone or a copolymer of an aromatic vinyl compound and a conjugated diene compound mainly composed of a block and / or a random structure. It is preferable that the polymer and its hydrogenated substance be modified with an unsaturated carboxylic acid. The aromatic vinyl compound is not particularly limited, and examples thereof include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethyl Styrene, vinyl toluene, p-tert-butyl styrene and the like can be mentioned. Moreover, as a conjugated diene compound, butadiene, isoprene, a 1, 3- pentadiene, a 2, 3- dimethyl- 1, 3- butadiene etc. are mentioned, for example. Specific examples of the copolymer of the aromatic vinyl compound and the conjugated diene compound are styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), Styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS) etc. are mentioned.

  The modification of the carboxyl group-containing styrene resin (B) can be performed, for example, by copolymerizing an unsaturated carboxylic acid at the time of polymerization of the styrene resin. It can also be carried out by heating and kneading a styrene resin and an unsaturated carboxylic acid in the presence of an organic peroxide. The unsaturated carboxylic acid is not particularly limited and includes acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, maleic anhydride, itaconic anhydride, fumaric anhydride and the like.

The lower limit of the acid value of the carboxyl group-containing styrene resin (B) is preferably 10 equivalents / 10 ⁶ g or more, more preferably 100, from the viewpoint of heat resistance and adhesion to the resin substrate and metal substrate. The equivalent weight / 10 ⁶ g or more, more preferably 150 equivalent / 10 ⁶ g. If it is less than the above value, the compatibility with the epoxy resin (D) and the carbodiimide resin (C) may be low, and the adhesive strength may not be expressed. In addition, the crosslink density may be low and the heat resistance may be poor. The upper limit is preferably 1000 equivalents / 10 ⁶ g or less, more preferably 700 equivalents / 10 ⁶ g or less, and still more preferably 500 equivalents / 10 ⁶ g or less. If the above values are exceeded, adhesion and low dielectric properties may be reduced.

  In the adhesive composition used in the present invention, the content of the carboxyl group-containing styrene resin (B) is 95 to 150 parts by mass of the carboxyl group-containing styrene resin (B) based on 5 to 95 parts by mass of the carboxyl group-containing polyolefin resin (A). It is preferable that it is the range of 5 mass parts, ie, (A) component / (B) component = 5-95 / 95-5 (mass ratio). More preferably, (A) component / (B) component 10 to 90/90 to 10 (mass ratio), and most preferably (A) component / (B) component = 15 to 85/85 to 15 (mass ratio) Range. When the amount of the component (A) is less than the above value, the crosslinking density may be reduced, and the moisture resistance to humidified solder may be reduced. When the amount of the component (A) exceeds the above value, the wettability to the substrate may be reduced, and the adhesive strength may be reduced.

<Carbodiimide resin (C)>
The carbodiimide resin (C) is not particularly limited as long as it has a carbodiimide group in the molecule. Preferred is a polycarbodiimide having two or more carbodiimide groups in the molecule. By using the carbodiimide resin (C), the carboxyl group of the carboxyl group-containing polyolefin resin (A) or the carboxyl group-containing styrene resin (B) reacts with the carbodiimide to interact the adhesive composition with the substrate. The adhesion can be enhanced.

  In the adhesive composition used in the present invention, the content of the carbodiimide resin (C) is 0.1 to 0.1 parts by mass with respect to a total of 100 parts by mass of the carboxyl group-containing polyolefin resin (A) and the carboxyl group-containing styrene resin (B). It is preferably in the range of 30 parts by mass. More preferably, it is in the range of 1 to 25 parts by mass, and most preferably in the range of 2 to 20 parts by mass. If it is less than the above-mentioned value, there is a problem that the interaction with the substrate is not expressed, and the adhesiveness is lowered. If the above value is exceeded, there is a problem that the pot life of the adhesive is lowered and the low dielectric property is lowered.

<Epoxy resin (D)>
The epoxy resin (D) is not particularly limited as long as it has a glycidyl group in its molecule, but preferably it has two or more glycidyl groups in its molecule. Specifically, although not particularly limited, biphenyl type epoxy resin, naphthalene type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, alicyclic epoxy resin, dicyclopentadiene type epoxy resin, At least one selected from the group consisting of tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, tetraglycidylbisaminomethylcyclohexanone, and N, N, N ′, N′-tetraglycidyl-m-xylenediamine can be used. Preferably, it is a bisphenol A epoxy resin, a novolak epoxy resin or a dicyclopentadiene epoxy resin.

  In the adhesive composition used in the present invention, the content of the epoxy resin (D) is 1 to 30 parts by mass with respect to a total of 100 parts by mass of the carboxyl group-containing polyolefin resin (A) and the carboxyl group-containing styrene resin (B). It is preferably in the range of parts, more preferably in the range of 2 to 15 parts by mass, and most preferably in the range of 3 to 10 parts by mass. If the amount is less than the above range, a sufficient curing effect can not be obtained, and adhesion and heat resistance may be reduced. Further, in the above range, there is a problem that the pot life of the adhesive is lowered and the low dielectric property is lowered.

  The adhesive composition used in the present invention may further contain an organic solvent. The organic solvent used in the present invention is not particularly limited as long as it dissolves a carboxyl group-containing polyolefin resin (A), a carboxyl group-containing styrene resin (B), a carbodiimide resin (C) and an epoxy resin (D). Specifically, for example, aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as hexane, heptane, octane and decane, and alicyclic carbonized compounds such as cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane Hydrogen, halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, chloroform, etc., methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, alcohol solvents such as phenol, acetone, methyl isobutyl ketone, Ketone solvents such as methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, acetophenone, cell solves such as methyl cell sorb, ethyl cell sorb, methyl acetate, ethyl acetate, vinegar Ester solvents such as methyl propionate, butyl formate, etc., ethylene glycol mono n-butyl ether, ethylene glycol mono iso-butyl ether, ethylene glycol mono tert-butyl ether, diethylene glycol mono n-butyl ether, diethylene glycol mono iso-butyl ether, triethylene glycol Glycol ether solvents such as mono n-butyl ether and tetraethylene glycol mono n-butyl ether can be used, and one or more of these can be used in combination.

  The organic solvent is preferably in the range of 100 to 1000 parts by mass, and in the range of 200 to 900 parts by mass with respect to a total of 100 parts by mass of the carboxyl group-containing polyolefin resin (A) and the carboxyl group-containing styrene resin (B). Is more preferable, and most preferably in the range of 300 to 800 parts by mass. Below the range, the liquid and pot life may be reduced. Moreover, when the said range is exceeded, there exists a problem which becomes disadvantageous from the surface of manufacturing cost and transportation cost.

  In addition, the adhesive composition used in the present invention may further contain other components as necessary. Specific examples of such components include flame retardants, tackifiers, fillers, and silane coupling agents.

<Flame retardant>
A flame retardant may be added to the adhesive composition used in the present invention as required. Examples of the flame retardant include bromine-based, phosphorus-based, nitrogen-based and metal hydroxide compounds. Among them, phosphorus-based flame retardants are preferable, and phosphate esters such as trimethyl phosphate, triphenyl phosphate, tricresyl phosphate and the like, phosphates such as aluminum phosphinate and the like, and known phosphorus flame retardants such as phosphazene etc. can be used. . These may be used alone or in any combination of two or more. When the flame retardant is contained, the flame retardant is preferably contained in a range of 1 to 200 parts by mass, more preferably 5 to 150 parts by mass with respect to a total of 100 parts by mass of the components (A) to (D). The range of 10 to 100 parts by mass is most preferable. Below the range, the flame retardance may be low. If the above range is exceeded, there is a problem that the adhesion, heat resistance, electrical properties and the like deteriorate.

<Tackifier>
A tackifier may be added to the adhesive composition used in the present invention as required. The tackifier includes polyterpene resin, rosin resin, aliphatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, styrene resin, hydrogenated petroleum resin, etc., and improves adhesion strength. It is used for the purpose. These may be used alone or in any combination of two or more.

<Filler>
The adhesive composition used in the present invention may optionally contain a filler such as silica. It is very preferable to blend silica because the heat resistance property is improved. Generally, hydrophobic silica and hydrophilic silica are known as the silica, but here, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane or the like to impart moisture resistance is known. Is good. It is preferable that the compounding quantity of a silica is a compounding quantity of 0.05-30 mass parts with respect to a total of 100 mass parts of (A)-(D) component. If the amount is less than 0.05 parts by mass, the effect of improving the heat resistance may not be exhibited. On the other hand, if it exceeds 30 parts by mass, dispersion failure of the silica may occur, the solution viscosity may become too high, and the workability may be impaired or the adhesiveness may be lowered.

<Silane coupling agent>
A silane coupling agent may be blended into the adhesive composition used in the present invention as required. It is very preferable to blend a silane coupling agent because the adhesion to metals and the heat resistance property are improved. The silane coupling agent is not particularly limited, and examples thereof include those having an unsaturated group, those having a glycidyl group, and those having an amino group. Among them, glycidyl such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltriethoxysilane from the viewpoint of heat resistance Further preferred is a silane coupling agent having a group. It is preferable that the compounding quantity of a silane coupling agent is a compounding quantity of 0.5-20 mass parts with respect to a total of 100 mass parts of (A)-(D) component. If the amount is less than 0.5 parts by mass, heat resistance may be impaired. On the other hand, if it exceeds 20 parts by mass, heat resistance may be poor and adhesiveness may be lowered.

<Adhesive sheet>
In the present invention, the adhesive sheet refers to a laminate of the laminate (Z) and a release substrate through an adhesive composition, or a release substrate laminated on the adhesive layer surface of the laminate (X). Or a release substrate laminated on at least one surface of the adhesive layer. Specific configuration modes are: release substrate / adhesive layer, release substrate / adhesive layer / release substrate, resin substrate / adhesive layer / release substrate, metal substrate / adhesive Layers / release substrates, laminates / adhesive layers / release substrates, or release substrates / adhesive layers / laminates / adhesive layers / release substrates may be mentioned. By laminating a release substrate, it functions as a protective layer of the substrate. Moreover, by using a release substrate, the release substrate can be released from the adhesive sheet, and the adhesive layer can be transferred to another substrate.

  The adhesive sheet of the present invention can be obtained by applying and drying the adhesive composition used in the present invention on various laminates according to a conventional method. In addition, when the release substrate is attached to the adhesive layer after drying, it can be taken up without causing offset to the substrate, and the operation property is excellent, and the adhesive layer is protected. And easy to use. In addition, if another release substrate is applied to the release substrate after drying and if necessary, the adhesive layer itself can be transferred to the other substrate.

<Release Material>
The release substrate is not particularly limited. For example, a coating agent of an adhesive such as clay, polyethylene, polypropylene, etc. is applied to both sides of a paper such as high-quality paper, kraft paper, roll paper, glassine paper, etc. Further, there may be mentioned those in which silicone, fluorine or alkyd release agents are applied on the respective coated layers. Further, various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer alone, and those obtained by applying the above-mentioned release agent on a film such as polyethylene terephthalate may also be mentioned. For both sides of wood free paper, polypropylene sealing is applied to both sides of wood free paper and an alkyd release agent is applied on the both sides, for the reasons such as the mold release force between the mold release substrate and the adhesive layer, and silicone adversely affects electrical properties. Or what used the alkyd type mold release agent on polyethylene terephthalate is preferable.

<Printed wiring board>
The “printed wiring board” in the present invention includes, as a component, a laminate formed of a metal foil forming a conductor circuit and a resin base. The printed wiring board is manufactured, for example, by a conventionally known method such as a subtractive method using a metal-clad laminate. If necessary, a so-called flexible circuit board (FPC), flat cable, or tape automated bonding (cover circuit, screen printing ink, etc.) partially or entirely covered with a conductor circuit formed of metal foil. It is a generic term for circuit boards for TAB.

  The printed wiring board of the present invention can be of any laminated configuration that can be employed as a printed wiring board. For example, it can be set as the printed wiring board comprised from four layers, a base film layer, a metal foil layer, an adhesive bond layer, and a cover film layer. For example, it can be set as the printed wiring board comprised from five layers, a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

  Furthermore, as required, two or three or more of the above printed wiring boards can be stacked.

  The adhesive composition used in the present invention can be suitably used for each adhesive layer of a printed wiring board. In particular, when the adhesive composition used in the present invention is used as an adhesive, it has high adhesiveness with a low polar resin base material such as LCP as well as the conventional polyimide, polyester film and copper foil constituting a printed wiring board. The solder reflow resistance can be obtained, and the adhesive layer itself is excellent in low dielectric characteristics. Therefore, it is suitable as an adhesive composition used for a coverlay film, a laminated board, copper foil with resin, and a bonding sheet.

  In the printed wiring board of the present invention, any resin film conventionally used as a base material of printed wiring boards can be used as the base film. As resin of a base film, polyester resin, polyamide resin, polyimide resin, polyamide imide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, fluorine resin, etc. can be illustrated. In particular, it has excellent adhesion to low polar substrates such as liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resins.

<Cover film>
As the cover film, any insulating film conventionally known as an insulating film for a printed wiring board can be used. For example, manufactured from various polymers such as polyimide, polyester, polyphenylene sulfide, polyether sulfone, polyether ether ketone, aramid, polycarbonate, polyarylate, polyimide, polyamide imide, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, etc. Films are available. More preferably, it is a polyimide film or a liquid crystal polymer film.

  The printed wiring board of the present invention can be manufactured using any conventionally known process except that the materials of the respective layers described above are used.

  In a preferred embodiment, a semi-finished product (hereinafter referred to as a "cover film side semi-finished product") in which an adhesive layer is laminated on a cover film layer is produced. On the other hand, a metal foil layer is laminated on the base film layer to form a desired circuit pattern (hereinafter, referred to as “base film side two-layer semi-finished product”) or an adhesive layer is laminated on the base film layer To manufacture a semi-finished product (hereinafter referred to as "three base film side semi-finished products") having a desired circuit pattern formed by laminating a metal foil layer thereon (hereinafter referred to as "two base film side semi-finished products" Together with the base film side three-layer semi-finished product, it is called "base film side semi-finished product"). By laminating the cover film side semi-finished product thus obtained and the base film side semi-finished product together, a 4-layer or 5-layer printed wiring board can be obtained.

  The base film side semi-finished product applies the solution of resin used as a base film to (A) the above-mentioned metal foil, and carries out initial drying of a coating film, and the metal foil and initial stage obtained by (A) It can be obtained by a manufacturing method including a step of heat treating and drying a laminate with a dried coating (hereinafter, referred to as "heat treatment and solvent removal step").

  A conventionally known method can be used to form a circuit in the metal foil layer. The active method may be used or the subtractive method may be used. Preferably, it is a subtractive method.

  The obtained base film side semi-finished product may be used as it is for bonding with the cover film side semi-finished product, or after bonding and releasing a release film, for bonding with the cover film side semi-finished product You may use it.

  The cover film side semifinished product is manufactured, for example, by applying an adhesive to the cover film. If necessary, a crosslinking reaction can be carried out in the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

  The obtained cover film side semi-finished product may be used as it is for bonding with the base material side semi-finished product, or after bonding and releasing the release film for bonding with the base film side semi-finished product You may use it.

  The base film side semi-finished product and the cover film side semi-finished product are respectively stored, for example, in the form of a roll and then laminated to produce a printed wiring board. As a method of bonding, any method can be used, and for example, bonding can be performed using a press or a roll. Moreover, both can also be bonded together, performing heating by methods, such as a heating press or using a heating roll apparatus.

  For example, in the case of a soft and windable reinforcing material such as a polyimide film, the reinforcing material-side semifinished product is preferably produced by applying an adhesive to the reinforcing material. Also, for example, in the case of a reinforcing plate which can not be wound up as hard as a metal plate such as SUS, aluminum or the like, a plate obtained by curing glass fiber with an epoxy resin, etc., an adhesive coated in advance on a release substrate is transferred and applied. It is preferred to be manufactured. Moreover, the crosslinking reaction in the apply | coated adhesive agent can be performed as needed. In a preferred embodiment, the adhesive layer is semi-cured.

  The obtained semi-finished product on the reinforcing material side may be used as it is for bonding to the back surface of the printed wiring board, or it may be used for bonding to the semi-finished product on the base film side after storing the release film. You may

  The base film side semifinished product, the cover film side semifinished product, and the reinforcing agent side semifinished product are all the laminates for a printed wiring board in the present invention.

<Example>
Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples. The term "parts" in the examples and comparative examples indicates parts by mass.

(Physical property evaluation method)

Acid Value (A) Component: Carboxyl Group-Containing Polyolefin Resin The acid value (equivalent weight / 10 ⁶ g) in the present invention is the carbonyl of maleic anhydride (FT-IR (manufactured by Shimadzu Corporation, FT-IR 8200 PC). Absorbance (I) of stretching peak (1780 cm ^-1 ) of C = O) bond, absorbance (II) of isotactic characteristic peak (840 cm ^-1 ) and chloroform solution of maleic anhydride (manufactured by Tokyo Kasei Co., Ltd.) The value calculated by the following equation using a factor (f) obtained from the calibration curve was expressed as an equivalent (equivalent weight / 10 ⁶ g) in 1 ton of resin.
Acid value = [Absorbance (I) / Absorbance (II) × (f) / Molecular weight of maleic anhydride × 2 × 10 ⁴ ]
Molecular weight of maleic anhydride: 98.06

Acid value (B) component: Carboxyl group-containing styrene resin The acid number (equivalent weight / 10 ⁶ g) in the present invention is obtained by dissolving a carboxyl group-containing styrene resin in toluene and using phenolphthalein as an indicator in a methanol solution of sodium methoxide. Titrated. It was expressed as equivalent weight (equivalent weight / 10 ⁶ g) in 1 ton of resin.

Weight average molecular weight (Mw)
The weight average molecular weight in the present invention is a value measured by gel permeation chromatography (hereinafter, GPC, standard substance: polystyrene resin, mobile phase: tetrahydrofuran).

Measurement of melting point and heat of fusion The melting point and heat of fusion in the present invention are raised at a rate of 20 ° C./minute using a differential scanning calorimeter (hereinafter, DSC, manufactured by TA Instruments Japan, Q-2000) It is a value measured from the top temperature and the area of the melting peak at the time of heat melting, cooling resinification, and temperature rising melting again.

(1) Peeling strength (adhesiveness)
The adhesive composition to be described later becomes 25 μm in thickness after drying to a 12.5 μm thick polyimide film (Kaneka Co., Ltd., Apical) or a 25 μm thick LCP film (Kuraray Co., Ltd., Vecter) The solution was applied and dried at 130 ° C. for 3 minutes. The adhesive film (B-stage product) obtained in this manner was bonded to a 18 μm rolled copper foil. The lamination was performed by pressing for 30 seconds under a pressure of 40 kgf / cm ² at 160 ° C. so that the shiny side of the rolled copper foil was in contact with the adhesive. Next, the sample was heat treated at 140 ° C. for 4 hours to be cured to obtain a sample for evaluation of peel strength. The peel strength was determined by film drawing at 25 ° C., and a 90 ° peel test at a tensile rate of 50 mm / min to measure the peel strength. This test shows the adhesive strength at normal temperature.
<Evaluation criteria>
:: 1.0 N / mm or more ○: 0.8 N / mm or more and 1.0 N / mm or less Δ: 0.5 N / mm or more and 0.8 N / mm or less ×: 0.5 N / mm or less

(2) Dry solder heat resistance A sample is prepared by the same method as described above, and a 2.0 cm × 2.0 cm sample piece is subjected to a drying treatment at 120 ° C. for 30 minutes, and is allowed to flow for 1 minute in molten solder bath at each temperature. The temperature which does not cause the appearance change such as blistering was measured.
<Evaluation criteria>
◎: 310 ° C. or more ○: 300 ° C. or more and less than 310 ° C. Δ: 290 ° C. or more and less than 300 ° C. ×: less than 290 ° C.

(3) Humidified solder heat resistance A sample is produced by the same method as the above, and a 2.0 cm × 2.0 cm sample piece is treated at 40 ° C. × 80 RH% × 72 hours, and melted for 1 minute in a solder bath melted at each temperature. The temperature which does not cause the appearance change such as flow and swelling was measured.
<Evaluation criteria>
◎: 260 ° C. or more ○: 250 ° C. or more and less than 260 ° C. Δ: 240 ° C. or more and less than 250 ° C. ×: less than 240 ° C.

(4) Relative permittivity (ε _c ) and dielectric loss tangent (tan δ)
The adhesive composition to be described later is a polyimide film of 12.5 μm thickness (Apical NPI (dielectric constant 3.28 at 1 MHz, dielectric loss tangent 0.0101 at 1 MHz) manufactured by Kaneka Co., Ltd.) or LCP of 25 μm thickness Apply a film (manufactured by Kuraray Co., Ltd., Bexter CTZ-50 (dielectric constant 3.03 at 1 MHz, dielectric loss tangent at 1 MHz 0.0186)) to a dry thickness of 25 μm, 3 at 130 ° C. Dried for a minute. Next, the laminate was heat treated at 140 ° C. for 4 hours to be cured to obtain a laminate (X) for test. Conductive silver paste of evaporation-to-dry type is applied by screen printing in a circle of 50 mm in diameter on both sides of the obtained laminate (X) for test, dried and cured at 120 ° C. for 30 minutes, and further conductive silver paste A lead wire of 30 mm in length was adhered to the center of the circle with a conductive adhesive to obtain a parallel plate capacitor. The capacitance Cap and loss coefficient D (dielectric loss tangent) of the obtained parallel plate capacitor are measured under conditions of a frequency of 1 MHz at 22 ° C. using a PRECISION LCR meter HP-4284A. The ε _c ) was calculated.
ε _c = (Cap × d) / (S × ε ₀ )
Here Cap: Capacitance [F]
d: Dielectric layer thickness = 25 × 10 ^-6 [m]
S: dielectric area to be measured = π × (25 × 10 ⁻³ ) ²
ε ₀ : permittivity of vacuum 8.854 × 10 ^-12
It is.
The obtained relative dielectric constant and dielectric loss tangent were evaluated as follows.
<Evaluation criteria for relative permittivity>
:: 2.6 or less ○: more than 2.6 and 2.8 or less :: more than 2.8 and 3.0 or less ×: more than 3.0 <evaluation criteria of dielectric loss tangent>
:: 0.005 or less ○: more than 0.005 and 0.01 or less Δ: more than 0.01 and 0.02 or less ×: more than 0.02

(Carboxyl group-containing polyolefin resin)
Production Example 1
In a 1 L autoclave, 100 parts by mass of propylene-butene copolymer ("Tafmer (registered trademark) XM 7080" manufactured by Mitsui Chemicals, Inc.), 150 parts by mass of toluene and 19 parts by mass of maleic anhydride, 6 parts by mass of di-tert-butyl peroxide Were added, and the temperature was raised to 140.degree. C., followed by stirring for 3 hours. Then, after cooling the obtained reaction liquid, it poured in the container containing a large amount of methyl ethyl ketone, and deposited resin. Thereafter, the solution containing the resin is centrifuged to separate and purify the acid-modified propylene-butene copolymer graft-polymerized with maleic anhydride, (poly) maleic anhydride and low molecular weight substances. Then, by drying under reduced pressure at 70 ° C. for 5 hours, maleic anhydride-modified propylene-butene copolymer (CO-1, acid value 410 equivalent / 10 ⁶ g, weight average molecular weight 60,000, Tm 80 ° C., ΔH 35 J / G).

Production Example 2
Maleic anhydride-modified propylene-butene copolymer (CO-2, acid value 290 equivalents / 10 ⁶ g, weight) as in Production Example 1 except that the preparation amount of maleic anhydride is changed to 13 parts by mass An average molecular weight of 68,000, Tm 79 ° C., ΔH 32 J / g) was obtained.

Production Example 3
Maleic anhydride-modified propylene-butene copolymer (CO-3, acid value: 220 equivalents / 10 ⁶ g, weight) as in Production Example 1 except that the amount of maleic anhydride charged is changed to 8 parts by mass An average molecular weight of 74,000, Tm 78 ° C., ΔH 29 J / g) was obtained.

Production Example 4
Production Example 1 and Production Example 1 except that the propylene-butene copolymer ("Tafmer (registered trademark) XM 7080" manufactured by Mitsui Chemicals, Inc.) is changed to a propylene-butene copolymer ("Tafmer (registered trademark) XM 7070" manufactured by Mitsui Chemicals) By doing the same, a maleic anhydride modified propylene-butene copolymer (CO-4, acid value 400 equivalent / 10 ⁶ g, weight average molecular weight 57,000, Tm 68 ° C., ΔH 15 J / g) was obtained.

Production Example 5
Maleic anhydride-modified propylene-butene copolymer (CO-5, acid value: 300 equivalents / 10 ⁶ g, weight) as in Production Example 1 except that the amount of maleic anhydride charged is changed to 15 parts by mass Average molecular weight 65,000, Tm 70 ° C., ΔH 21 J / g) was obtained.

Example 1
In a 500 ml four-necked flask equipped with a water cooled reflux condenser and a stirrer, 80 parts by mass of the maleic anhydride-modified propylene-butene copolymer (CO-1) obtained in Production Example 1 and a carboxyl group-containing styrene resin 20 parts by mass of (Tuftec (registered trademark) M1943) and 500 parts by mass of toluene were charged, the temperature was raised to 80 ° C. while stirring, and the solution was dissolved by continuing stirring for 1 hour. In the solution obtained by cooling, 5 parts by mass of carbodiimide resin V-05 and 10 parts by mass of epoxy resin HP-7200 were blended to obtain an adhesive composition. The compounding amount, adhesive strength, solder heat resistance, and electrical properties are shown in Table 1. The relative dielectric constant of the adhesive layer is 2.27, the dielectric loss tangent is 0.0031, the relative dielectric constant of the laminate 1 (adhesive layer / polyimide film) is 2.51, and the dielectric loss tangent is 0.0042. The dielectric constant of laminate 2 (adhesive layer / LCP film) was 2.68, and the dielectric loss tangent was 0.0122.

Examples 2 to 17
The carboxyl group-containing polyolefin resin (A), the carboxyl group-containing styrene resin (B), the carbodiimide resin (C) and the epoxy resin (D) were changed to those shown in Table 1, and in the same manner as Example 1, Table 1 It changed so that it might become each compounding quantity shown to, and Examples 2-17 were performed. The adhesive strength, solder heat resistance and electrical properties are shown in Table 1.

Comparative Examples 1 to 7
The carboxyl group-containing polyolefin resin (A), the carboxyl group-containing styrene resin (B), the carbodiimide resin (C) and the epoxy resin (D) are changed to those shown in Table 2, and in the same manner as Example 1, Table 2 It changed so that it might become each compounding quantity shown to, and carried out Comparative Examples 1-7. The compounding amount, adhesive strength, solder heat resistance and electrical properties are shown in Table 2.

The polyolefin resin, carboxyl group-containing styrene resin (B), carbodiimide resin (C) and epoxy resin (D) used in Tables 1 and 2 are as follows.
Carboxyl group-containing styrene resin: Tuftec (registered trademark) M1911 (manufactured by Asahi Kasei Chemicals Corporation)
Carboxyl group-containing styrene resin: Tuftec (registered trademark) M1913 (manufactured by Asahi Kasei Chemicals Corporation)
Carboxyl group-containing styrene resin: Tuftec (registered trademark) M1943 (manufactured by Asahi Kasei Chemicals Corporation)
Polyolefin resin: Tafmer (registered trademark) XM 7080 (manufactured by Mitsui Chemicals, Inc.)
Styrene resin: Tuftec (registered trademark) H1052 (manufactured by Asahi Kasei Chemicals Corporation)
Carboxyl group-containing acrylonitrile butadiene rubber NBR (manufactured by JSR Corporation)
Carbodiimide resin: V-05 (manufactured by Nisshinbo Chemical Co., Ltd.)
Carbodiimide resin: V-03 (manufactured by Nisshinbo Chemical Co., Ltd.)
o-Cresol novolac epoxy resin: YDCN-700-10 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Dicyclopentadiene type epoxy resin: HP-7200 (manufactured by DIC)

  As is clear from Table 1, in Examples 1 to 17, while having excellent adhesion with a polyimide (PI) and a copper foil and solder heat resistance, excellent adhesion with both a liquid crystal polymer (LCP) and a copper foil, It has solder heat resistance. In addition, the electrical properties of the laminate are low both in dielectric constant and dielectric loss tangent and good. On the other hand, as is clear from Table 2, in Comparative Example 1, the carboxyl group-containing styrene resin is not blended, so that the moisture resistance and the heat resistance of the wet solder are inferior. In Comparative Example 2, since the carboxyl group-containing polyolefin resin is not blended, the crosslink density is low, and the wet solder heat resistance is poor. In Comparative Example 3, since the polyolefin resin does not contain a carboxyl group, the crosslink density is low, and the wet solder heat resistance is poor. In Comparative Example 4, since the styrene resin does not contain a carboxyl group, the crosslink density is low, and the wet solder heat resistance is poor. In Comparative Example 5, since the carbodiimide resin is not blended, the interaction with the LCP interface is small, and the adhesive strength is low. In Comparative Example 6, since the epoxy resin is not blended, the crosslink density is low and the solder heat resistance is inferior. In Comparative Example 7, since the polyolefin resin and the styrene resin are not blended, the low dielectric characteristics of the adhesive composition are inferior.

  According to the present invention, not only conventional polyimide and polyethylene terephthalate films but also resin substrates having low dielectric properties such as LCP, and metal substrates such as copper foil have high adhesiveness and high solder heat resistance. It is possible to provide a laminate that can be obtained and that is excellent in low dielectric properties. The above characteristics are useful in flexible printed wiring board applications, particularly in FPC applications where low dielectric characteristics (low dielectric constant, low dielectric loss tangent) in high frequency regions are required. Furthermore, the laminate of the present invention can be suitably used for electromagnetic wave shielding applications.

Claims (4)

A laminate (Z) in which a resin base and a metal base are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A),
(1) The dielectric constant (ε _c ) at a frequency of 1 MHz of the laminate (X) obtained by removing the metal base from the laminate (Z) is 3.0 or less,
(2) The dielectric loss tangent (tan δ) at a frequency of 1 MHz of the laminate (X) obtained by removing the metal base from the laminate (Z) is 0.02 or less,
(3) The peel strength between the resin base and the metal base is 0.5 N / mm or more,
(4) A laminate (Z) characterized in that the wet solder heat resistance of the laminate (Z) is 240 ° C. or higher. A laminate of the adhesive layer and the resin substrate (X) used in a laminate (Z) in which a resin substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A) ) And
(1) The dielectric constant (ε _c ) at a frequency of 1 MHz of the laminate (X) is 3.0 or less,
(2) The dielectric loss tangent (tan δ) at a frequency of 1 MHz of the laminate (X) is 0.02 or less,
(3) The peel strength between the resin substrate and the metal substrate in the laminate when the metal substrate is laminated on the adhesive layer surface of the laminate (X) is 0.5 N / mm or more,
(4) A laminate (X) characterized in that the wet solder heat resistance of the laminate when the metal base is laminated on the adhesive layer surface of the laminate (X) is 240 ° C. or higher.   The adhesive sheet containing the laminated body (Z) of Claim 1, or the laminated body (X) of Claim 2.   A printed wiring board comprising the adhesive sheet according to claim 3 as a component.