JP6791131B2 - Laminated body containing a low-dielectric adhesive layer - Google Patents

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 material and a metal base material 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 abbreviated as FPC), and a coverlay film, a laminate, a copper foil with resin, and a bonding sheet containing the same.

In recent years, as the speed of transmission signals on printed wiring boards has increased, the frequency of signals has been increasing. Along with this, there is an increasing demand for FPCs to have low dielectric properties (low dielectric constant, low dielectric loss tangent) in the high frequency region. In response to such demands, as a base film used for FPC, instead of the conventional polyimide (PI) and polyethylene terephthalate film, a liquid crystal polymer (LCP) having low dielectric properties, syndiotactic polystyrene (SPS), etc. Base films such as polyphenylene sulfide (PPS) have been proposed.
However, since the base film having low dielectric properties has low polarity, the adhesive strength is weak when a conventional epoxy adhesive or acrylic adhesive is used, and FPC members such as coverlay films and laminated boards are manufactured. Was difficult. Further, epoxy adhesives and acrylic adhesives are not excellent in low dielectric properties and impair the dielectric properties of FPCs.
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 polyolefin-based copolymer containing a carboxyl group, a block copolymer of an aromatic vinyl compound polymer block and a conjugated diene-based compound polymer block, and a heat-reactive adhesive using an epoxy resin are used. Compositions have been proposed. Further, Patent Document 2 proposes an adhesive composition using a carboxyl group-containing styrene elastomer and an epoxy resin.

Japanese Patent No. 3621351 WO2014 / 147903A1 Gazette

However, Patent Document 1 describes the adhesiveness between the polyimide film and SUS and the heat resistance to solder, but does not mention the dielectric property, and the adhesiveness to the base film having low dielectric property such as LCP. Is hard to obtain. Further, Patent Document 2 describes the dielectric property and the adhesiveness between the polyimide film and the copper foil, but does not mention the adhesiveness to the base film having a low dielectric property such as LCP. Further, although the solder heat resistance after drying is stated, the solder heat resistance after humidification is not sufficient.

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

That is, the present invention has good adhesiveness to both various resin base materials such as polyimide and LCP and metal base materials, and is laminated with an adhesive layer having excellent heat resistance and low dielectric properties. The purpose is to provide the body.

A laminate (Z) in which a resin base material and a metal base material are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), and (1) the specific dielectric constant of the adhesive layer at a frequency of 1 MHz (1). ε _c ) is 3.0 or less, (2) the dielectric loss tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less, and (3) the peel strength between the resin base material and the metal base material is 0. A laminate (Z) having a temperature of .5 N / mm or more and (4) a humidified solder heat resistance of the laminate (Z) of 240 ° C. or higher.

A laminate (X) of the adhesive layer and the resin base material used for the laminate (Z) in which a resin base material and a metal base material are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A). ), And (1) the specific dielectric constant (ε _c ) of the adhesive layer at a frequency of 1 MHz is 3.0 or less, and (2) the dielectric tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less. (3) When the metal base material is laminated on the adhesive layer surface of the laminated body (X), the peel strength between the resin base material and the metal base material in the laminated body is 0.5 N / mm or more, and (3) 4) A laminated body (X) characterized in that the humidified solder heat resistance of the laminated body when a metal base material is laminated on the adhesive layer surface of the laminated body (X) is 240 ° C. or higher.

A laminate (Y) of the adhesive layer and the metal base material used for the laminate (Z) in which a resin base material and a metal base material are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A). ), And (1) the specific dielectric constant (ε _c ) of the adhesive layer at a frequency of 1 MHz is 3.0 or less, and (2) the dielectric tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less. (3) When the resin base material is laminated on the adhesive layer surface of the laminated body (Y), the peel strength between the resin base material and the metal base material in the laminated body is 0.5 N / mm or more, and (3) 4) The laminate (Y) is characterized in that the humidified solder heat resistance of the laminate (Y) when the resin base material is laminated on the adhesive layer surface of the laminate (Y) is 240 ° C. or higher.

The adhesive layer used for the laminate (Z) in which a resin base material and a metal base material are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), and (1) an adhesive layer. The specific dielectric constant (ε _c ) at a frequency of 1 MHz is 3.0 or less, (2) the dielectric tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less, and (3) one of the adhesive layers. When the resin base material is laminated on the surface of the above surface and the metal base material is laminated on the other surface, the peel strength between the resin base material and the metal base material in the laminated body is 0.5 N / mm or more, (4). An adhesive layer having a humidified solder heat resistance of 240 ° C. or higher when a resin base material is laminated on one surface of the adhesive layer and a metal base material is laminated on the other surface.

An adhesive sheet containing the above-mentioned laminate (Z), laminate (X), laminate (Y) or an adhesive layer.

A printed wiring board containing the above-mentioned adhesive sheet as a component.

The laminate in which the resin base material and the metal base material are laminated via the adhesive layer containing the carboxyl group-containing polyolefin resin (A) according to the present invention is (1) the specific dielectric constant (ε) of the adhesive layer at a frequency of 1 MHz. _c ) is 3.0 or less, (2) the dielectric tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less, and (3) the peel strength between the resin base material and the metal base material is In order to satisfy that it is 0.5 N / mm or more and (4) the humidified solder heat resistance of the laminated body is 240 ° C. or more, not only the conventional polyimide and polyester films but also LCPs that are not assumed in the prior art. It has high adhesiveness to low-polarity resin base materials such as films and metal base materials, can obtain high solder heat resistance, and has excellent low dielectric properties.

Hereinafter, embodiments of the present invention will be described in detail. The laminate (Z) according to the present invention is a laminate in which a resin base material and a metal base material are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A).

<Carboxylic group-containing polyolefin resin (A)>
The carboxyl group-containing polyolefin resin (A) used in the present invention (hereinafter, also simply referred to as the component (A)) is not limited, but the polyolefin resin contains at least one α, β-unsaturated carboxylic acid and an acid anhydride thereof. It is preferably obtained by grafting. The polyolefin resin is a hydrocarbon such as homopolymerization of an olefin monomer exemplified by ethylene, propylene, butene, butadiene, isoprene, or copolymerization with other monomers, and hydrides and halides of the obtained polymer. Refers to a polymer whose main component is the skeleton. That is, the carboxyl group-containing polyolefin is obtained by grafting at least one of α, β-unsaturated carboxylic acid and its acid anhydride on at least one of polyethylene, polypropylene and a propylene-α-olefin copolymer. What is obtained is preferable.

The propylene-α-olefin copolymer is obtained by copolymerizing propylene as a main component with α-olefin. As the α-olefin, for example, one or several kinds of ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate and the like can be used. Among these α-olefins, ethylene and 1-butene are preferable. The ratio of the propylene component to the α-olefin component of the propylene-α-olefin copolymer is not limited, but the propylene component is preferably 50 mol% or more, and more preferably 70 mol% or more.

Examples of at least one of α, β-unsaturated carboxylic acid and its acid anhydride include maleic acid, itaconic acid, citraconic acid and their acid anhydrides. Among these, acid anhydride is preferable, and maleic anhydride is more preferable. Specific examples thereof include maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, maleic anhydride-modified propylene-ethylene-butene copolymer and the like. These acid-modified polyolefins can be used alone or in combination of two or more.

The acid value of the carboxyl group-containing polyolefin resin (A), in view of adhesion to the heat resistance and the resin base material or metal substrate, preferably the lower limit is 100 eq / 10 6 ^g or more, more preferably 200 Equivalent / 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) is low, and the adhesive strength may not be exhibited. 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 even more preferably 500 equivalents / 10 ⁶ g or less. If it exceeds the above value, the adhesiveness may decrease. In addition, the viscosity and stability of the solution may decrease, and the pot life property may decrease. Further, the production efficiency is lowered, which is not preferable.

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. It is more preferably in the range of 20,000 to 160,000, further preferably in the range of 30,000 to 150,000, particularly preferably in the range of 40,000 to 140,000, and most preferably in the range of 50. It ranges from 000 to 130,000. If it is less than the above value, the cohesive force may be weakened and the adhesiveness may be poor. On the other hand, if it exceeds the above value, the fluidity is low and there may be a problem in operability at the time of bonding.

The method for producing the carboxyl group-containing polyolefin resin (A) is not particularly limited, and for example, a radical graft reaction (that is, a radical species is generated for a polymer serving as a main chain, and the radical species is used as a polymerization initiation point to form an unsaturated carboxylic acid. (Reaction of graft polymerization of acid and 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, but is di-tert-butylperoxyphthalate, tert-butylhydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxy-. Peroxides such as 2-ethylhexanoate, tert-butylperoxypivalate, methylethylketone peroxide, di-tert-butyl peroxide, lauroyl peroxide; azobisisobutyronitrile, azobisisopropionitrile, etc. Examples include azonitriles.

<Adhesive layer>
In the present invention, the adhesive layer refers to a layer of an adhesive composition after the adhesive composition is applied to a base material and dried. The thickness of the adhesive layer is not particularly limited, but is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more. Further, it is preferably 200 μm or less, more preferably 100 μm or less, and further preferably 50 μm or less. If the thickness is too thin, sufficient adhesive performance may not be obtained, and if it is too thick, drying will be insufficient and residual solvent will tend to increase, causing blister during pressing for manufacturing printed wiring boards. There is a problem.

The method for coating the adhesive composition on the substrate is not particularly limited, and examples thereof include a comma coater and a reverse roll coater. Alternatively, if necessary, the adhesive layer may be provided directly or by a transfer method on the rolled copper foil or the polyimide film which is the constituent material of the printed wiring board. The drying conditions are not particularly limited, but the residual solvent ratio after drying is preferably 1% by mass or less. If it exceeds 1% by mass, there is a problem that the residual solvent foams when the printed wiring board is pressed, causing blisters.

<Resin base material>
In the present invention, the resin base material 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 the resin base material such as a film-like resin ( Hereinafter, it is also referred to as a base film layer). Specifically, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer (LCP), polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, fluorine resin and the like can be exemplified. Examples of commercially available LCP films include Vecstar (registered trademark) manufactured by Kuraray Co., Ltd. Examples of commercially available polyimide films include Apical (registered trademark) manufactured by Kaneka Corporation.

The thickness of the resin base material is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 10 μm or more. Further, it is preferably 50 μm or less, more preferably 30 μm or less, and further preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit, while if the thickness is too thick, the processing efficiency at the time of manufacturing the circuit may decrease. The relative permittivity (ε _c ) of the resin base material is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.5 or less. The lower limit is not particularly limited, and industrially, there is no problem if it is 0.1 or more.

<Metal base material>
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, as well as alloys, plated products, and metals treated with other metals such as zinc and chromium compounds. A metal foil is preferable, and a copper foil is more preferable. The thickness of the metal foil is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 10 μm or more. Further, it is preferably 50 μm or less, more preferably 30 μm or less, and further preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit, while if the thickness is too thick, the processing efficiency at the time of manufacturing the circuit may decrease. The metal foil is usually provided in roll form. The form of the metal foil used in manufacturing the printed wiring board of the present invention is not particularly limited. When a ribbon-shaped metal foil is used, its length is not particularly limited. The width thereof is also not particularly limited, but is preferably about 250 to 500 cm.

<Laminated body>
The laminate (Z) of the present invention is a laminate in which a resin base material and a metal base material are laminated via an adhesive layer (a three-layer laminate of a resin base material / an adhesive layer / a metal base material). (X) is a laminated resin base material and an adhesive layer (resin base material / adhesive layer), and (Y) is a laminated metal base material and an adhesive layer (metal base material / adhesive layer). Agent layer). In the present invention, the laminated body (X), the laminated body (Y), and the laminated body (Z) may be collectively referred to as a laminated body. The laminate (X) is obtained by applying the adhesive composition to a resin base material and drying it according to a conventional method. Further, the laminate (Y) is obtained by applying the adhesive composition to a metal base material and drying it according to a conventional method. The laminated body (Z) can be obtained by laminating a metal base material or a resin base material on the laminated body (X) or the laminated body (Y), respectively. The release base material can also be laminated on the surface of the adhesive layer of the laminate (X) or the laminate (Y). Further, an adhesive layer is further laminated on the resin base material or the metal base material of the laminated body (Z) (adhesive layer / resin base material / adhesive layer / metal base material, resin base material / adhesive layer / metal base material). / Adhesive layer, adhesive layer / resin base material / adhesive layer / metal base material / adhesive layer) may be used.

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

<Requirement (1)>
The requirement (1) will be described. The laminate (Z) according to the present invention needs to have a relative permittivity (ε _c ) of 3.0 or less at a frequency of 1 MHz for the adhesive layer. Specifically, the adhesive composition is applied to a release base material so that the thickness after drying is 25 μm, and dried at about 130 ° C. for about 3 minutes. Then, it is heat-treated at about 140 ° C. for about 4 hours to be cured, and the cured adhesive composition layer (adhesive layer) is peeled off from the release film. The relative permittivity (ε _c ) of the adhesive composition layer after peeling at a frequency of 1 MHz is measured. The relative permittivity (ε _c ) is 3.0 or less, preferably 2.6 or less, and more preferably 2.3 or less. The lower limit is not particularly limited, but is 2.0 in practice. The relative permittivity (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 even more preferably 2.3 or less.

The relative permittivity (ε _c ) of the adhesive layer in the laminated body (Z) can be measured as follows. That is, the metal base material of the laminated body (Z) is cleanly removed with an etching solution to obtain a two-layer laminated body (X) of an adhesive layer and a resin base material. The etching solution is not particularly limited, and an aqueous solution of ferric chloride, an aqueous solution of cupric chloride, a mixed solution of hydrogen peroxide solution, an alkaline etchant, a nickel etchant and the like can be used. Next, the resin base material of the laminate (X) is cleanly peeled off (removed), and a metal layer is formed on both sides of the remaining adhesive layer by a thin film method such as vapor deposition or a sputtering method, or a method such as coating a conductive paste. A method of calculating the relative permittivity (ε _c ) from the thickness and area by measuring the capacitance can be exemplified. Alternatively, a metal layer is formed on the surface of the resin base material of the laminate (X) by the method described above to form a capacitor, and the combined capacitance relative permittivity (ε _c ) of the resin base material and the adhesive layer is measured. After that, the metal layer and the adhesive layer are cleanly peeled off (removed) from the laminate (X), and the relative permittivity (ε _c ) of the remaining resin base material is similarly made into a capacitor to measure the capacitance. To do. Since the dielectric layer of the capacitor obtained from the laminate (X) can be regarded as a multi-layer dielectric of the resin base material and the adhesive layer, the relative permittivity (ε _c ) of the adhesive layer should be calculated from the difference between the two. Can be done.

<Requirement (2)>
The requirement (2) will be described. The laminate (Z) according to the present invention needs to have a dielectric loss tangent (tan δ) of the adhesive layer at a frequency of 1 MHz of 0.02 or less. Specifically, the adhesive composition is applied to a release base material so that the thickness after drying is 25 μm, and dried at about 130 ° C. for about 3 minutes. Then, it is heat-treated at about 140 ° C. for about 4 hours to be cured, and the cured adhesive composition layer (adhesive layer) is peeled off from the release film. The dielectric loss tangent (tan δ) of the adhesive composition after peeling at a frequency of 1 MHz is measured. The dielectric loss tangent (tan δ) 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 0.0001 in practice. Further, the dielectric loss tangent (tan δ) in the entire region of a frequency of 1 MHz to 10 GHz is preferably 0.02 or less, more preferably 0.01 or less, and further preferably 0.005 or less.

The dielectric loss tangent (tan δ) of the adhesive layer in the laminated body (Z) can also be measured by the same operation as the dielectric constant.

<Requirement (3)>
The requirement (3) will be described. The laminate (Z) according to the present invention needs to have a peel strength of 0.5 N / mm or more between the resin base material and the metal base material. Specifically, the adhesive composition is applied to a resin base material so that the thickness after drying is about 25 μm, and dried at about 130 ° C. for about 3 minutes. Next, a metal base material is attached to the surface of the adhesive composition layer (adhesive layer). The bonding is performed by vacuum pressing at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds so that the glossy surface of the metal substrate is in contact with the adhesive composition layer. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. At room temperature (about 25 ° C.), the resin base material of the laminate (Z) is peeled by 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. Even a laminated body (Z) produced by a method other than the above method is included in the present invention as long as the 90 ° peel strength is 0.5 N / mm or more.

From the laminate (X), the laminate (Z) of the present invention can be obtained by laminating a metal base material on the surface of the adhesive composition layer (adhesive layer) of the laminate (X). The bonding is performed by vacuum pressing at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds so that the glossy surface of the metal substrate is in contact with the adhesive composition layer. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. At room temperature (about 25 ° C.), the resin base material of the laminate (Z) is peeled by 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.

From the laminate (Y), the laminate (Z) of the present invention can be obtained by laminating a resin base material on the surface of the adhesive composition layer (adhesive layer) of the laminate (Y). The bonding is performed by vacuum pressing at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds so that the resin base material is in contact with the adhesive composition layer. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. At room temperature (about 25 ° C.), the resin base material of the laminate (Z) is peeled by 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.

From the adhesive layer, the laminate (Z) of the present invention can be obtained by laminating a resin base material on one surface of the adhesive layer and laminating a glossy surface of a metal base material on the other surface. For bonding, the release base material / adhesive layer and the resin base material are bonded together by rolling laminating about 1 m / min under a pressure of about 3 kgf / cm ² at about 100 ° C., and then the release base material is peeled off. The glossy surface of the metal base material is brought into contact with the adhesive layer, and the adhesive is bonded by vacuum pressing at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. At room temperature (about 25 ° C.), the resin base material of the laminate (Z) is peeled by 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 laminate (Z) according to the present invention needs to have a humidifying solder heat resistance of 240 ° C. or higher. Specifically, the adhesive composition is applied to a resin base material so that the thickness after drying is 25 μm, and dried at about 130 ° C. for about 3 minutes. Next, a metal base material is attached to the surface of the adhesive composition layer (adhesive layer). The bonding is performed by vacuum pressing at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds so that the glossy surface of the metal substrate is in contact with the adhesive composition layer. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. The laminate (Z) is treated under the conditions of about 40 ° C. and about 80 RH% for about 72 hours, flowed into a solder bath melted at each temperature for 1 minute, and the temperature at which the appearance does not change such as swelling is measured. .. The heat resistance of the humidified solder needs to be 240 ° C. or higher, preferably 250 ° C. or higher, and more preferably 260 ° C. or higher. Even a laminated body (Z) produced by a method other than the above method is included in the present invention as long as the humidifying solder heat resistance is 240 ° C. or higher.

From the laminate (X), the laminate (Z) of the present invention can be obtained by laminating a metal base material on the surface of the adhesive composition layer (adhesive layer) of the laminate (X). The bonding is performed by vacuum pressing at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds so that the glossy surface of the metal substrate is in contact with the adhesive composition layer. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. The laminate (Z) is treated under the conditions of about 40 ° C. and about 80 RH% for about 72 hours, flowed into a solder bath melted at each temperature for 1 minute, and the temperature at which the appearance does not change such as swelling is measured. .. The heat resistance of the humidified solder needs to be 240 ° C. or higher, preferably 250 ° C. or higher, and more preferably 260 ° C. or higher.

From the laminate (Y), the laminate (Z) of the present invention can be obtained by laminating a resin base material on the surface of the adhesive composition layer (adhesive layer) of the laminate (Y). The bonding is performed by vacuum pressing at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds so that the resin base material is in contact with the adhesive composition layer. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. The laminate (Z) is treated under the conditions of about 40 ° C. and about 80 RH% for about 72 hours, flowed into a solder bath melted at each temperature for 1 minute, and the temperature at which the appearance does not change such as swelling is measured. .. The heat resistance of the humidified solder needs to be 240 ° C. or higher, preferably 250 ° C. or higher, and more preferably 260 ° C. or higher.

Further, from the adhesive layer, the laminate (Z) of the present invention can be obtained by laminating a resin base material on one surface of the adhesive layer and laminating a glossy surface of a metal base material on the other surface. it can. For bonding, after bonding the adhesive layer and the resin base material, the glossy surface of the metal base material is in contact with the adhesive layer, and vacuum is applied at about 160 ° C. under a pressure of about 40 kgf / cm ² for about 30 seconds. Press and glue. Next, it is heat-treated at about 140 ° C. for about 4 hours to be cured to prepare a three-layer laminate (Z) of a resin base material / adhesive layer / metal base material. The laminate (Z) is treated under the conditions of about 40 ° C. and about 80 RH% for about 72 hours, flowed into a solder bath melted at each temperature for 1 minute, and the temperature at which the appearance does not change such as swelling is measured. .. The heat resistance of the humidified solder 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 the carboxyl group-containing polyolefin resin (A), the laminate via the adhesive layer made of the adhesive composition can exhibit the excellent performances of the above (1) to (4).

In addition to the component (A), the adhesive composition of the present invention includes a carboxyl group-containing styrene resin (B) (hereinafter, also simply referred to as a component (B)) and a carbodiimide resin (C) (hereinafter, simply (C). ) And / or the epoxy resin (D) (hereinafter, also simply referred to as the component (D)) is preferably contained. By containing the four types of resins (A) to (D), it is not only a conventional polyimide and polyester film, but also a low-polarity resin base material such as an LCP film that is not assumed in the prior art. However, it has high adhesiveness to a metal base material, can obtain high solder heat resistance, and is excellent in low dielectric property.

<Carboxylic group-containing styrene resin (B)>
The carboxyl group-containing styrene resin (B) that can be used in the present invention is not limited, but is mainly composed of a block and / or a random structure of an aromatic vinyl compound alone or an aromatic vinyl compound and a conjugated diene compound. The polymer and its hydrogenated product are preferably modified with an unsaturated carboxylic acid. The aromatic vinyl compound is not particularly limited, and is, for example, styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethyl. Examples thereof include styrene, vinyltoluene, p-third butylstyrene and the like. Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like. Specific examples of the copolymer of these aromatic vinyl compounds and the conjugated diene compound include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and so on. Examples thereof include styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS).

The modification of the carboxyl group-containing styrene resin (B) can be performed, for example, by copolymerizing an unsaturated carboxylic acid during the 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 examples thereof include 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 adhesiveness to the resin base material and the metal base material. Equivalent / 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) is low, and the adhesive strength may not be exhibited. 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 even more preferably 500 equivalents / 10 ⁶ g or less. If it exceeds the above value, the adhesiveness and low dielectric property may be deteriorated.

In the adhesive composition used in the present invention, the content of the carboxyl group-containing styrene resin (B) is 95 to 95 parts by mass of the carboxyl group-containing polyolefin resin (A) with respect to 5 to 95 parts by mass. It is preferably in the range of 5 parts by mass, that is, the component (A) / component (B) = 5 to 95/95 to 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). Is the range of. If the amount of the component (A) is less than the above value, the crosslink density may decrease and the heat resistance of the humidified solder may decrease. If the amount of the component (A) exceeds the above value, the wettability to the substrate may decrease and the adhesive strength may decrease.

<Carbodiimide resin (C)>
The carbodiimide resin (C) is not particularly limited as long as it has a carbodiimide group in the molecule. It is preferably 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, and the interaction between the adhesive composition and the substrate is observed. It can be enhanced and the adhesiveness can be improved.

In the adhesive composition used in the present invention, the content of the carbodiimide resin (C) is 0.1 to 0 to 100 parts by mass of the total 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. It is more preferably 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 value, there is a problem that the interaction with the base material is not exhibited and the adhesiveness is lowered. If it exceeds the above value, 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 the molecule, but is preferably one having two or more glycidyl groups in the 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 tetraglycidyl diaminodiphenylmethane, triglycidyl paraaminophenol, tetraglycidyl bisaminomethylcyclohexanone, N, N, N', N'-tetraglycidyl-m-xylene diamine can be used. A bisphenol A type epoxy resin, a novolak type epoxy resin or a dicyclopentadiene type epoxy resin is preferable.

In the adhesive composition used in the present invention, the content of the epoxy resin (D) is 1 to 30 mass by mass with respect to 100 parts by mass in total of the carboxyl group-containing polyolefin resin (A) and the carboxyl group-containing styrene resin (B). The range 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 it is less than the above range, a sufficient curing effect may not be obtained and the adhesiveness and heat resistance may be lowered. Further, above 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 can further contain an organic solvent. The organic solvent used in the present invention is not particularly limited as long as it dissolves the carboxyl group-containing polyolefin resin (A), the carboxyl group-containing styrene resin (B), the carbodiimide resin (C), and the 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 hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane. Halogenized hydrocarbons such as hydrogen, trichloroethylene, dichloroethylene, chlorobenzene, chloroform, alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, phenol, acetone, methylisobutylketone, Ketone solvents such as methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, acetophenone, cell solves such as methyl cellsolve and ethyl cell solve, ester solvents such as methyl acetate, ethyl acetate, butyl acetate, 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 mono n-butyl ether, tetraethylene glycol mono n-butylate, etc. Glycol ether-based solvents and the like 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, preferably 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 the range is most preferably in the range of 300 to 800 parts by mass. If it is less than the above range, the liquid and pot life properties may decrease. Further, if it exceeds the above range, there is a problem that it is disadvantageous in terms of manufacturing cost and transportation cost.

Further, the adhesive composition used in the present invention may further contain other components as required. 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, if necessary. Examples of the flame retardant include bromine-based, phosphorus-based, nitrogen-based, and metal hydroxide compounds. Among them, a phosphorus-based flame retardant is preferable, and a known phosphorus-based flame retardant such as a phosphate ester such as trimethyl phosphate, triphenyl phosphate, tricresyl phosphate or the like, a phosphate such as aluminum phosphinate or phosphazene can be used. .. These may be used alone or in any combination of two or more. When the flame retardant is contained, it is preferable to contain the flame retardant in the range of 1 to 200 parts by mass, and more preferably in the range of 5 to 150 parts by mass with respect to a total of 100 parts by mass of the components (A) to (D). , 10 to 100 parts by mass is most preferable. If it is less than the above range, the flame retardancy may be low. If it exceeds the above range, there is a problem that adhesiveness, heat resistance, electrical characteristics and the like are deteriorated.

<Adhesive imparting agent>
A tackifier may be added to the adhesive composition used in the present invention, if necessary. Examples of the tackifier include polyterpene resin, rosin resin, aliphatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, styrene resin, hydrogenated petroleum resin, and the like to improve the adhesive strength. Used for purposes. These may be used alone or in any combination of two or more.

<Filler>
If necessary, a filler such as silica may be added to the adhesive composition used in the present invention. It is very preferable to add silica because the heat resistance property is improved. Hydrophobic silica and hydrophilic silica are generally known as silica, but here, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, etc. in order to impart moisture absorption resistance is used. Is good. The amount of silica blended is preferably 0.05 to 30 parts by mass with respect to 100 parts by mass of the total of the components (A) to (D). If it is less than 0.05 parts by mass, the effect of improving heat resistance may not be exhibited. On the other hand, if it exceeds 30 parts by mass, poor dispersion of silica may occur, the viscosity of the solution may become too high, which may cause a problem in workability or a decrease in adhesiveness.

<Silane coupling agent>
A silane coupling agent may be added to the adhesive composition used in the present invention, if necessary. It is very preferable to add a silane coupling agent because the properties of adhesion to metal and heat resistance 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. Of these, glycidyls such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxidecyclohexyl) ethyltrimethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltriethoxysilane from the viewpoint of heat resistance. A silane coupling agent having a group is more preferable. The blending amount of the silane coupling agent is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the total of the components (A) to (D). If it is less than 0.5 parts by mass, heat resistance may be poor. 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 is a product obtained by laminating the laminate (Z) and a release base material via an adhesive composition, or on the adhesive layer surface of the laminate (X) or the laminate (Y). The release base material is laminated, or the release base material is laminated on at least one surface of the adhesive layer. Specific configurations include a release base material / adhesive layer, a release base material / adhesive layer / release base material, a resin base material / adhesive layer / release base material, and a metal base material / adhesive. Examples include a layer / release base material, a laminate / adhesive layer / release base material, or a release base material / adhesive layer / laminate / adhesive layer / release base material. By laminating the release base material, it functions as a protective layer of the base material. Further, by using the release base material, the release base material can be released from the adhesive sheet and the adhesive layer can be transferred to another base material.

The adhesive sheet of the present invention can be obtained by applying the adhesive composition used in the present invention to various laminates and drying them according to a conventional method. In addition, if a release base material is attached to the adhesive layer after drying, it can be wound up without causing set-off to the base material, which is excellent in operability and protects the adhesive layer for storage stability. It is excellent and easy to use. Further, if the release base material is coated and dried, and then another release base material is attached as needed, the adhesive layer itself can be transferred to another base material.

<Release base material>
The release base material is not particularly limited, but for example, a coating layer of a sealant such as clay, polyethylene, or polypropylene is applied to both sides of paper such as high-quality paper, kraft paper, roll paper, and glassine paper. Examples thereof include those in which a silicone-based, fluorine-based, or alkyd-based mold release agent is coated on each of the coating layers. In addition, various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, propylene-α-olefin copolymer, etc., and films such as polyethylene terephthalate coated with the above-mentioned release agent can also be mentioned. For reasons such as the release force between the release base material and the adhesive layer, and the fact that silicone adversely affects the electrical properties, polypropylene sealing treatment is applied to both sides of high-quality paper, and an alkyd-based release agent is used on top of it. Alternatively, one using an alkyd-based mold release agent on polyethylene terephthalate is preferable.

<Printed circuit board>
The "printed wiring board" in the present invention includes a laminate formed of a metal foil forming a conductor circuit and a resin base material as a component. The printed wiring board is manufactured by a conventionally known method such as a subtractive method using a metal-clad laminate, for example. So-called flexible circuit board (FPC), flat cable, tape automated bonding (FPC), flat cable, tape automated bonding (FPC), flat cable, tape automated bonding (FPC), flat cable, tape automated bonding, etc. It is a general term for circuit boards for TAB).

The printed wiring board of the present invention may have an arbitrary laminated structure that can be adopted as the printed wiring board. For example, it can be a printed wiring board composed of four layers, a base film layer, a metal foil layer, an adhesive layer, and a cover film layer. Further, for example, the printed wiring board may be composed of five layers of a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

Further, if necessary, two or three or more of the above-mentioned printed wiring boards may be laminated.

The adhesive composition used in the present invention can be suitably used for each adhesive layer of the printed wiring board. In particular, when the adhesive composition used in the present invention is used as an adhesive, it has high adhesiveness not only to the conventional polyimide, polyester film, and copper foil constituting the printed wiring board, but also to a low-polarity resin base material such as LCP. However, solder reflow resistance can be obtained, and the adhesive layer confidence is excellent in low dielectric properties. Therefore, it is suitable as an adhesive composition used for coverlay films, laminated boards, copper foils with resins, and bonding sheets.

In the printed wiring board of the present invention, as the base film, any resin film conventionally used as the base material of the printed wiring board can be used. Examples of the resin of the base film include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluorine resin. In particular, it has excellent adhesiveness to low-polarity substrates such as liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resins.

<Cover film>
As the cover film, any conventionally known insulating film as an insulating film for a printed wiring board can be used. For example, manufactured from various polymers such as polyimide, polyester, polyphenylene sulfide, polyethersulfone, polyetheretherketone, aramid, polycarbonate, polyarylate, polyimide, polyamideimide, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resin. The film to be used is 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 by any conventionally known process other than using the above-mentioned materials for each layer.

In a preferred embodiment, a semi-finished product in which an adhesive layer is laminated on a cover film layer (hereinafter, referred to as “cover film side semi-finished product”) is manufactured. On the other hand, a semi-finished product (hereinafter referred to as "base film side two-layer semi-finished product") in which a metal foil layer is laminated on a base film layer to form a desired circuit pattern, or an adhesive layer is laminated on a base film layer. , A semi-finished product (hereinafter referred to as "base film side three-layer semi-finished product") in which a metal foil layer is laminated on the metal foil layer to form a desired circuit pattern (hereinafter referred to as a base film-side two-layer semi-finished product). 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, a four-layer or five-layer printed wiring board can be obtained.

The base film side semi-finished product is, for example, the metal foil obtained in the steps (A) of applying a resin solution to be a base film to the metal foil and initial drying the coating film (B) and the initial stage. It is obtained by a production method including a step of heat-treating / drying the laminate with the dry coating film (hereinafter, referred to as “heat treatment / solvent removal step”).

A conventionally known method can be used for forming the circuit in the metal foil layer. The active method may be used, or the subtractive method may be used. The subtractive method is preferable.

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 for bonding with the cover film side semi-finished product after the release film is bonded and stored. You may use it.

The cover film side semi-finished product is manufactured, for example, by applying an adhesive to the cover film. If necessary, a cross-linking reaction can be carried out on 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 film side semi-finished product, or for bonding with the base film side semi-finished product after the release film is bonded and stored. You may use it.

The base film side semi-finished product and the cover film side semi-finished product are, for example, stored in the form of rolls and then bonded to each other to manufacture a printed wiring board. Any method can be used as the bonding method, and for example, the bonding can be performed using a press or a roll. It is also possible to bond the two together while heating by a method such as using a heating press or a heating roll device.

In the case of a reinforcing material that can be wound up softly, for example, a polyimide film, the reinforcing material side semi-finished product is preferably manufactured by applying an adhesive to the reinforcing material. Further, in the case of a reinforcing plate that is hard and cannot be wound up, such as a metal plate such as SUS or aluminum, or a plate obtained by curing glass fiber with epoxy resin, the adhesive previously applied to the release base material is transferred and applied. It is preferable to be manufactured. In addition, if necessary, a cross-linking reaction can be carried out on the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

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

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

<Example>
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples. In the examples and comparative examples, simply "parts" indicates parts by mass.

(Physical property evaluation method)

Acid value (A) component: acid value of the carboxyl group-containing polyolefin resin present invention (equivalents / ¹⁰ 6 g) is, FT-IR (manufactured by Shimadzu Corporation, FT-IR8200PC) using, carbonyl maleic anhydride ( It was prepared by the absorbance (I) of the expansion and contraction peak (1780 cm ^-1 ) of the C = O) bond, the absorbance (II) of the peak (840 cm ^-1 ) peculiar to isotactics, and the chloroform solution of maleic anhydride (manufactured by Tokyo Kasei). It represents the value calculated by the following equation using the factor (f) obtained from the calibration curve as the equivalent amount of the resin 1 ton (equivalents / 10 6 ^g).
Acid value = [absorbance (I) / absorbance (II) x (f) / molecular weight of maleic anhydride x 2 x 10 ⁴ ]
Molecular weight of maleic anhydride: 98.06

Acid value (B) component: acid value of the carboxyl group-containing styrene resin present invention (equivalents / 10 6 ^g) is a carboxyl group-containing styrene resin was dissolved in toluene, using phenolphthalein as an indicator of methanol solution of sodium methoxide Titrated. Equivalents in the resin 1ton expressed as (equivalents / ¹⁰ 6 g).

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).

(1) Peeling strength (adhesiveness)
The adhesive composition described later is applied to a polyimide film (manufactured by Kaneka Corporation, Apical) having a thickness of 12.5 μm or an LCP film (manufactured by Kuraray Co., Ltd., Vecstar) having a thickness of 25 μm, and the thickness after drying is 25 μm. And dried at 130 ° C. for 3 minutes. The adhesive film (B stage product) thus obtained was bonded to an 18 μm rolled copper foil. The bonding was performed by pressing the rolled copper foil under pressure of 40 kgf / cm ² at 160 ° C. for 30 seconds so that the glossy surface of the rolled copper foil was in contact with the adhesive. Then, it 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 measured by conducting a 90 ° peel test at a film pulling rate of 50 mm / min at 25 ° C. This test shows the adhesive strength at room temperature.
<Evaluation criteria>
⊚: 1.0 N / mm or more ○: 0.8 N / mm or more and less than 1.0 N / mm Δ: 0.5 N / mm or more and less than 0.8 N / mm ×: 0.5 N / mm or less

(2) Dry solder heat resistance A sample is prepared by the same method as above, a sample piece of 2.0 cm × 2.0 cm is dried at 120 ° C. for 30 minutes, and flowed into a solder bath melted at each temperature for 1 minute. , The temperature at which the appearance did not change such as swelling was measured.
<Evaluation criteria>
⊚: 310 ° C or higher ○: 300 ° C or higher and lower than 310 ° C Δ: 290 ° C or higher and lower than 300 ° C ×: less than 290 ° C

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

(4) Relative permittivity (ε _c ) and dielectric loss tangent (tan δ)
The adhesive composition described below was applied to the glossy surface of an electrolytic copper foil having a thickness of 35 μm so that the thickness after drying and curing was 25 μm, and dried at 130 ° C. for 3 minutes. Then, it was heat-treated at 140 ° C. for 4 hours and cured to obtain a copper-clad laminate for testing. On the cured adhesive composition surface of the obtained copper-clad laminate for testing, a dry-evaporated conductive silver paste was applied by screen printing to a circle having a diameter of 50 mm, dried and cured at 120 ° C. for 30 minutes, and further. A lead wire having a length of 30 mm was bonded to the center of a circle made of conductive silver paste with a conductive adhesive to obtain a parallel flat plate capacitor. The capacitance Cap and loss coefficient D (dielectric loss tangent) of the obtained parallel plate capacitor were measured using PRECISION LCR meter HP-4284A under the condition of 22 ° C. and frequency 1 MHz, and the relative permittivity (dielectric constant) was calculated from the following equation. 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
Is.
The obtained relative permittivity and dielectric loss tangent were evaluated as follows.
<Evaluation criteria for relative permittivity>
⊚: 2.3 or less ○: More than 2.3 and 2.6 or less Δ: More than 2.6 and 3.0 or less ×: More than 3.0 <Evaluation criteria for dielectric loss tangent>
⊚: 0.005 or less ○: 0.005 or more and 0.01 or less Δ: 0.01 or more and 0.02 or less ×: 0.02 or more

(Carboxylic group-containing polyolefin resin)
Manufacturing example 1
100 parts by mass of propylene-butene copolymer (“Toughmer (registered trademark) XM7080” manufactured by Mitsui Chemicals, Inc.), 150 parts by mass of toluene, 19 parts by mass of maleic anhydride, and 6 parts by mass of di-tert-butyl peroxide in a 1 L autoclave. Was added, the temperature was raised to 140 ° C., and the mixture was further stirred for 3 hours. Then, the obtained reaction solution was cooled and then poured into a container containing a large amount of methyl ethyl ketone to precipitate a resin. Then, the liquid containing the resin was centrifuged to separate and purify the acid-modified propylene-butene copolymer graft-polymerized with maleic anhydride, (poly) maleic anhydride and a low molecular weight substance. Thereafter, by drying under vacuum for 5 hours 70 ° C., maleic acid-modified propylene anhydride - butene copolymer (CO-1, acid value 410 equivalent / ¹⁰ 6 g, weight average molecular weight 60,000, Tm80 ℃, △ H35J / G) was obtained.

Manufacturing example 2
By except that the charged amount of maleic anhydride was changed to 11 parts by weight is in the same manner as in Production Example 1, maleic anhydride-modified propylene anhydride - butene copolymer (CO-2, acid value 220 equivalent / 10 6 ^g, the weight An average molecular weight of 65,000, Tm78 ° C., ΔH25J / g) was obtained.

Example 1
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 were placed in a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer. (Tough Tech (registered trademark) M1943) was charged in an amount of 20 parts by mass and toluene was added in an amount of 500 parts by mass, the temperature was raised to 80 ° C. with stirring, and the mixture was dissolved by continuing stirring for 1 hour. 5 parts by mass of carbodiimide resin V-05 and 10 parts by mass of epoxy resin HP-7200 were added to the solution obtained by cooling to obtain an adhesive composition. Table 1 shows the blending amount, adhesive strength, solder heat resistance, and electrical characteristics.

Examples 2-10
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 in Example 1, Table 1 Examples 2 to 14 were carried out after changing the blending amounts to those shown in 1. Table 1 shows the adhesive strength, solder heat resistance, and electrical characteristics.

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) were changed to those shown in Table 2, and the same method as in Example 1 was applied to Table 2. Comparative Examples 1 to 7 were carried out by changing the blending amounts shown in 1. Table 2 shows the blending amount, adhesive strength, solder heat resistance, and electrical characteristics.

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.
Carboxylic acid-containing styrene resin: Tough Tech (registered trademark) M1911 (manufactured by Asahi Kasei Chemicals)
Carboxylic acid-containing styrene resin: Tough Tech (registered trademark) M1913 (manufactured by Asahi Kasei Chemicals)
Carboxylic group-containing styrene resin: Tough Tech (registered trademark) M1943 (manufactured by Asahi Kasei Chemicals)
Polyolefin resin: Toughmer (registered trademark) XM7080 (manufactured by Mitsui Chemicals, Inc.)
Styrene resin: Tough Tech (registered trademark) H1052 (manufactured by Asahi Kasei Chemicals)
Carboxylic acid-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 type epoxy resin: YDCN-700-10 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Dicyclopentadiene type epoxy resin: HP-7200 (manufactured by DIC Corporation)

As is clear from Table 1, in Examples 1 to 14, the liquid crystal polymer (LCP) and the copper foil have excellent adhesiveness while having excellent adhesiveness between the polyimide (PI) and the copper foil and solder heat resistance. Has solder heat resistance. Further, the electrical characteristics of the adhesive composition are both low and good in both dielectric constant and dielectric loss tangent. On the other hand, as is clear from Table 2, in Comparative Example 1, since the carboxyl group-containing styrene resin is not blended, the heat resistance of the humidified solder and the adhesive strength are inferior. In Comparative Example 2, since the carboxyl group-containing polyolefin resin is not blended, the crosslink density is low and the humidifying solder heat resistance is inferior. In Comparative Example 3, since the polyolefin resin does not contain a carboxyl group, the crosslink density is low and the humidifying solder heat resistance is inferior. In Comparative Example 4, since the styrene resin does not contain a carboxyl group, the crosslink density is low and the heat resistance of the humidified solder is inferior. 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 property of the adhesive composition is 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 obtain a laminate having excellent low dielectric properties. Due to the above characteristics, it is useful for flexible printed wiring board applications, especially for FPC applications where low dielectric properties (low dielectric constant, low dielectric loss tangent) in a high frequency region are required.

Claims (6)

A laminate in which an LCP base material and a metal base material are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), a carboxyl group-containing styrene resin (B), a carbodiimide resin (C), and an epoxy resin (D). (Z)
(1) The relative permittivity (εc) of the adhesive layer at a frequency of 1 MHz is 3.0 or less.
(2) The dielectric loss tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less.
(3) The peel strength between the LCP base material and the metal base material is 0.8 N / mm or more.
(4) The laminated body (Z) characterized in that the humidifying solder heat resistance of the laminated body (Z) is 240 ° C. or higher. A laminate in which an LCP substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), a carboxyl group-containing styrene resin (B), a carbodiimide resin (C), and an epoxy resin (D). The laminate (X) of the adhesive layer and the LCP base material used in (Z).
(1) The relative permittivity (εc) of the adhesive layer at a frequency of 1 MHz is 3.0 or less.
(2) The dielectric loss tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less.
(3) When the metal base material is laminated on the adhesive layer surface of the laminated body (X), the peel strength between the LCP base material and the metal base material in the laminated body is 0.8 N / mm or more.
(4) A laminated body (X) characterized in that the humidifying solder heat resistance of the laminated body when a metal base material is laminated on the adhesive layer surface of the laminated body (X) is 240 ° C. or higher. A laminate in which an LCP substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), a carboxyl group-containing styrene resin (B), a carbodiimide resin (C), and an epoxy resin (D). The laminate (Y) of the adhesive layer and the metal base material used in (Z).
(1) The relative permittivity (εc) of the adhesive layer at a frequency of 1 MHz is 3.0 or less.
(2) The dielectric loss tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less.
(3) When the LCP base material is laminated on the adhesive layer surface of the laminated body (Y), the peel strength between the LCP base material and the metal base material in the laminated body is 0.8 N / mm or more.
(4) The laminate (Y) is characterized in that the humidifying solder heat resistance of the laminate (Y) when the resin base material is laminated on the adhesive layer surface of the laminate (Y) is 240 ° C. or higher. A laminate in which an LCP substrate and a metal substrate are laminated via an adhesive layer containing a carboxyl group-containing polyolefin resin (A), a carboxyl group-containing styrene resin (B), a carbodiimide resin (C), and an epoxy resin (D). The adhesive layer used in (Z).
(1) The relative permittivity (εc) of the adhesive layer at a frequency of 1 MHz is 3.0 or less.
(2) The dielectric loss tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less.
(3) When the LCP base material is laminated on one surface of the adhesive layer and the metal base material is laminated on the other surface, the peel strength between the LCP base material and the metal base material in the laminated body is 0.8 N. / Mm or more,
(4) Adhesion characterized in that the humidified solder heat resistance of the laminated body when the resin base material is laminated on one surface of the adhesive layer and the metal base material is laminated on the other surface is 240 ° C. or higher. Agent layer. An adhesive sheet containing the laminate (Z) according to claim 1, the laminate (X) according to claim 2, the laminate (Y) according to claim 3, or the adhesive layer according to claim 4. .. A printed wiring board including the adhesive sheet according to claim 5 as a component.