TWI697532B - Laminated body including low dielectric adhesive layer - Google Patents

Abstract

The present invention provides a laminate that not only has high adhesion to conventional polyimide and polyester films, but also low-polarity resin substrates such as LCP or metal substrates, can obtain high solder heat resistance, and has low dielectric properties. Excellent electrical properties. A laminated body (Z), a resin base material and a metal base material are laminated by an adhesive layer including a polyolefin resin (A) containing carboxyl groups; the characteristics are: (1) The frequency of the adhesive layer is 1MHz The relative dielectric constant (ε _c ) is 3.0 or less, (2) the dielectric tangent (tanδ) of the adhesive layer at a frequency of 1MHz is 0.02 or less, and (3) the peel strength between the resin substrate and the metal substrate is 0.5 N/mm or more, (4) The heat resistance of the humidified solder of the laminate (Z) is 240°C or more.

Description

Laminated body containing low-dielectric adhesive layer

The present invention relates to a laminate including an adhesive layer exhibiting a low dielectric constant and a low dielectric tangent. More specifically, it relates to a laminate in which a resin substrate and a metal substrate are laminated via an adhesive that exhibits a low dielectric constant and a low dielectric tangent. In particular, it relates to laminates for flexible printed circuit boards (hereinafter referred to as FPCs), and surface coating films, laminates, copper foils with resin, and adhesive sheets containing the laminates.

In recent years, with the increase in the speed of the transmission signal in the printed circuit board, the high frequency of the signal is developing. At the same time, the requirements for low dielectric properties (low dielectric constant, low dielectric tangent) of FPC in the high-frequency region are increasing. In response to other requirements, as the base film used in FPC, some people propose to use liquid crystal polymer (LCP), parapolystyrene (SPS), polyphenylene sulfide (PPS) and other base films with low dielectric properties. Replace conventional polyimide (PI) and polyethylene terephthalate films. However, the substrate film with low dielectric properties is low in polarity, so the adhesive strength is weak when using conventional epoxy or acrylic adhesives, making it difficult to manufacture FPC components such as surface coating films and laminates. . In addition, epoxy-based adhesives or acrylic-based adhesives are not excellent in low-dielectric properties and impair the dielectric properties of FPC. On the other hand, polyolefin resins are known to have low dielectric properties. Therefore, an adhesive composition for FPC using polyolefin resin has been proposed. For example, Patent Document 1 proposes the use of a carboxyl group-containing polyolefin copolymer, a block copolymer of an aromatic vinyl compound polymer block and a conjugated diene compound polymer block, and thermal epoxy resin Reactive adhesive composition. In addition, Patent Document 2 proposes an adhesive composition using a carboxyl group-containing styrene elastomer and an epoxy resin. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent No. 3621351 [Patent Document 2] WO2014/147903A1 Publication

[Problem to be solved by the invention] However, although Patent Document 1 describes the adhesion of polyimide film to SUS and solder heat resistance, it does not mention the dielectric properties, and it is difficult to obtain low dielectric properties such as LCP. Adhesion of the characteristic substrate film. In addition, although Patent Document 2 describes the dielectric properties and the adhesion between the polyimide film and the copper foil, it does not mention the adhesion with the base film having low dielectric properties such as LCP. In addition, although the solder heat resistance after drying is described, the solder heat resistance after humidification cannot be said to be sufficient.

In order to solve the above-mentioned problems, the present invention has conducted in-depth research, and found that the adhesive layer with specific physical properties is not only compatible with the conventional polyimide film, but also with resins with low dielectric properties such as LCP which is not anticipated by the prior art. Metal substrates such as substrates and copper foils are excellent in high adhesiveness, high solder heat resistance, and low dielectric properties, and completed the present invention.

In other words, the present invention aims to provide a laminated body that has good adhesion to various resin substrates such as polyimide and LCP and metal substrates, as well as excellent heat resistance and low dielectric properties. The agent layer is laminated. [Means to solve the problem]

A laminated body (Z), a resin base material and a metal base material are laminated by an adhesive layer including a polyolefin resin (A) containing carboxyl groups; the characteristics are: (1) The frequency of the adhesive layer is 1MHz The relative dielectric constant (ε _c ) is 3.0 or less, (2) the dielectric tangent (tanδ) of the adhesive layer at a frequency of 1MHz is 0.02 or less, and (3) the peel strength between the resin substrate and the metal substrate is 0.5 N/mm or more, (4) The heat resistance of the humidified solder of the laminate (Z) is 240°C or more.

A laminated body (X), a resin base material and a metal base material laminated with an adhesive layer including a polyolefin resin (A) containing a carboxyl group. The adhesive layer and the laminated body (Z) used The laminated body of the resin base material is characterized by: (1) the relative permittivity (ε _c ) of the adhesive layer at a frequency of 1MHz is 3.0 or less, (2) the dielectric tangent of the adhesive layer at a frequency of 1MHz (tanδ) is 0.02 or less, (3) When the metal substrate is laminated on the adhesive layer of the laminate (X), the peel strength between the resin substrate and the metal substrate in the laminate is 0.5N/mm Above, (4) When the metal base material is laminated on the adhesive layer of the laminate (X), the heat resistance of the humidified solder of the laminate is 240° C. or more.

A laminate (Y) comprising a resin substrate and a metal substrate via an adhesive layer including a polyolefin resin (A) containing a carboxyl group. The adhesive layer and the laminate (Z) used The laminated body of the metal substrate; it is characterized in that: (1) the relative dielectric constant (ε _c ) of the adhesive layer at a frequency of 1MHz is 3.0 or less, (2) the dielectric tangent of the adhesive layer at a frequency of 1MHz (tanδ) is 0.02 or less, (3) When the resin substrate is laminated on the adhesive layer of the laminate (Y), the peel strength between the resin substrate and the metal substrate in the laminate is 0.5N/mm Above, (4) When the resin base material is laminated on the adhesive layer of the laminate (Y), the heat resistance of the humidified solder of the laminate is 240° C. or more.

An adhesive layer, which is used in a laminate (Z) in which a resin base material and a metal base material are laminated via an adhesive layer including a polyolefin resin (A) containing a carboxyl group; the characteristic is : (1) The relative dielectric constant (ε _c ) of the adhesive layer at a frequency of 1MHz is 3.0 or less, (2) the dielectric tangent (tanδ) of the adhesive layer at a frequency of 1MHz is 0.02 or less, (3) When the resin substrate is laminated on one side of the agent layer, and the metal substrate is laminated on the other side, the peel strength between the resin substrate and the metal substrate in the laminate is 0.5N/mm or more. (4) When a resin substrate is laminated on one side of the agent layer and a metal substrate is laminated on the other side, the heat resistance of the humidified solder of the laminated body is 240°C or higher.

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

A printed circuit board includes the aforementioned adhesive sheet as a constituent element. [Effects of Invention]

The resin base material and the metal base material of the present invention are laminated with an adhesive layer including a polyolefin resin (A) containing a carboxyl group. Since it satisfies (1) the relative medium of the adhesive layer at a frequency of 1 MHz The electrical constant (ε _c ) is 3.0 or less, (2) the dielectric tangent (tanδ) of the adhesive layer at a frequency of 1MHz is 0.02 or less, (3) the peel strength between the resin substrate and the metal substrate is 0.5N/mm Above, (4) The heat resistance of the humidified solder of the laminate is 240°C or higher, so it is not only compatible with conventional polyimide and polyester film, but also with low-polarity resin substrates such as LCP film that was not anticipated by the prior art. Or the metal substrate also has high adhesion, 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) of the present invention is formed by laminating a resin base material and a metal base material via an adhesive layer including a carboxyl group-containing polyolefin resin (A).

<Carboxyl group-containing polyolefin resin (A)> The carboxyl group-containing polyolefin resin (A) used in the present invention (hereinafter also referred to as (A) component) is not limited, but it is preferable to use α,β-unsaturated Preferably, at least one of carboxylic acid and its anhydride is grafted onto a polyolefin resin. Polyolefin resin means homopolymers of olefin monomers such as ethylene, propylene, butene, butadiene, isoprene, etc., or copolymers with other monomers, and hydrogenated products of the obtained polymers Or halides and other polymers with a hydrocarbon skeleton as the main body. That is, the polyolefin containing carboxyl group is preferably obtained by grafting at least one of α, β-unsaturated carboxylic acid and its anhydride to at least one of polyethylene, polypropylene, and propylene-α-olefin copolymer. The kind that is obtained is better.

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

As at least one of α,β-unsaturated carboxylic acids and anhydrides thereof, for example, maleic acid, itaconic acid, citraconic acid, and these acid anhydrides can be cited. Of these, acid anhydrides are preferred, and maleic anhydride is even more preferred. 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., one kind or a combination of two or more kinds of these acid-modified polyolefins can be used.

The acid value of the carboxyl group-containing polyolefin resin (A), from the viewpoint of heat resistance and adhesion to the resin substrate or metal substrate, the lower limit is preferably 100 equivalent/10 ⁶ g or more, preferably 200 equivalent/10 More than ⁶ g is more preferable, 250 equivalent/10 ⁶ g is particularly preferable. If the value 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 expressed. In addition, the crosslinking density may be low and heat resistance may be insufficient. The upper limit is preferably 1000 equivalents/10 ⁶ g or less, more preferably 700 equivalents/10 ⁶ g or less, and particularly preferably 500 equivalents/10 ⁶ g or less. If the above value is exceeded, the adhesion may be reduced. In addition, the viscosity and stability of the solution decrease, and the pot life may be shortened. Further manufacturing efficiency is also reduced, so it is not good.

The weight average molecular weight (Mw) of the polyolefin resin (A) containing carboxyl groups is preferably in the range of 10,000 to 180,000. The range of 20,000-160,000 is more preferable, the range of 30,000-150,000 is especially preferable, the range of 40,000-140,000 is particularly preferable, and the range of 50,000-130,000 is the best. If it does not reach the above value, the cohesion will be weakened and the adhesion will be poor. On the other hand, if the above value is exceeded, the fluidity will be low, and there may be problems with the operability during bonding.

The production method of the carboxyl group-containing polyolefin resin (A) is not particularly limited. For example, a radical grafting reaction (that is, a radical species is generated for the polymer that becomes the main chain, and the radical species is used as the polymerization starter). Point and graft polymerization reaction of unsaturated carboxylic acid and acid anhydride) and so on.

The radical generator is not particularly limited, and organic peroxides are preferably used. The organic peroxide is not particularly limited. Examples include di-tert-butyl peroxyphthalate, tertiary butyl hydroperoxide, dicumyl peroxide, benzyl peroxide, and tertiary benzoic acid. Peroxides such as butyl ester, tert-butyl peroxy-2-ethylhexanoate, tertiary butyl peroxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, laurel peroxide, etc.; Azonitriles such as azobisisobutyronitrile and azobisisopropionitrile.

<Adhesive layer> In the present invention, the adhesive layer refers to a layer of the adhesive composition after the adhesive composition is applied to the substrate and dried. The thickness of the adhesive layer is not particularly limited, but it is preferably 5 μm or more, more preferably 10 μm or more, and particularly preferably 15 μm or more. Moreover, it is preferably 200 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less. When the thickness is too thin, it may be difficult to obtain sufficient adhesive performance. When the thickness is too thick, there may be problems such as insufficient drying, which tends to increase residual solvent, and swelling during pressing during the manufacture of the printed circuit board.

The method of applying the adhesive composition to the substrate is not particularly limited, and examples include a comma coater, a reverse roll coater, and the like. Or, if necessary, an adhesive layer can be provided directly or by a transfer method on the rolled copper foil or the polyimide film that is the constituent material of the printed circuit board. The drying conditions are not particularly limited, and the residual solvent rate after drying is preferably 1% by mass or less. If it exceeds 1% by mass, the residual solvent foams during the pressing of the printed circuit board, causing swelling.

<Resin substrate> The resin substrate in the present invention is not particularly limited as long as it can be coated with the adhesive composition of the present invention and dried to form an adhesive layer. It is preferably a resin substrate such as a film resin ( Hereinafter, it is also referred to as a base film layer). Specifically, polyester resins, polyamide resins, polyimide resins, polyimide resins, liquid crystal polymers (LCP), polyphenylene sulfide, parallel polystyrene, and polyolefin resins can be exemplified Resin, fluorine-based resin, etc. As a commercially available product of the LCP film, for example, Vecstar (registered trademark) manufactured by Kuraray Co., Ltd. can be cited. In addition, as a commercial product of the polyimide film, for example, Apical (registered trademark) manufactured by Kaneka Co., Ltd. can be cited.

The thickness of the resin substrate is not particularly limited, and it is preferably 1 μm or more, more preferably 3 μm or more, and particularly preferably 10 μm or more. Furthermore, it is preferably 50 μm or less, more preferably 30 μm or less, and particularly preferably 20 μm or less. When the thickness is too thin, it may be difficult for the circuit to obtain sufficient electrical performance. On the other hand, when the thickness is too thick, the processing efficiency during circuit production may decrease. In addition, the relative dielectric constant (ε _c ) of the resin substrate is preferably 5.0 or less, more preferably 4.0 or less, and particularly preferably 3.5 or less. The lower limit is not particularly limited, and there is no problem as long as it is 0.1 or more industrially.

<Metal base material> For the metal base material, any conventionally known conductive materials that can be used for circuit boards can be used. Examples of materials include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, and respective alloys, plating materials, and metals processed with other metals such as zinc or chromium compounds. Metal foil is preferable, and copper foil is more preferable. The thickness of the metal foil is not particularly limited, and is preferably 1 μm or more, more preferably 3 μm or more, and particularly preferably 10 μm or more. Furthermore, it is preferably 50 μm or less, more preferably 30 μm or less, and particularly preferably 20 μm or less. When the thickness is too thin, it may be difficult for the circuit to obtain sufficient electrical performance. On the other hand, when the thickness is too thick, the processing efficiency during circuit production may decrease. Metal foil is usually provided in the form of a reel. The form of the metal foil used when manufacturing the printed circuit board of this invention is not specifically limited. When the metal foil in the form of a strip is used, its length is not particularly limited. Moreover, the width is not particularly limited, but it is preferably about 250 to 500 cm.

<Laminate> The laminate (Z) of the present invention is formed by laminating a resin base material and a metal base material via an adhesive (a 3-layer laminate of resin base material/adhesive layer/metal base material), A laminate (X)-based resin base material and an adhesive layer are laminated (resin base material/adhesive layer), and a laminate (Y)-based metal base material and adhesive are laminated (metal base material) /Adhesive layer). In the present invention, the laminate (X), the laminate (Y), and the laminate (Z) may be collectively referred to as the laminate. The laminate (X) can be obtained by applying the adhesive composition to a resin substrate in a conventional method and drying. In addition, the laminate (Y) can be obtained by applying the adhesive composition to a metal substrate according to a conventional method and drying. The laminate (Z) can be obtained by laminating a metal base material or a resin base material, respectively, due to the laminate (X) or the laminate (Y). A release base material can also be laminated on the surface of the adhesive layer of the laminate (X) or the laminate (Y). Furthermore, an adhesive layer (adhesive layer/resin base material/adhesive layer/metal base material, resin base material/adhesive layer/metal base material) is further laminated on the resin base material or metal base material of the laminate (Z). The base material/adhesive layer, adhesive layer/resin base material/adhesive layer/metal base material/adhesive layer) are also acceptable.

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

<Requirement (1)> The requirement (1) is explained. Regarding the laminate (Z) of the present invention, the relative permittivity (ε _c ) of the adhesive layer at a frequency of 1 MHz is required to be 3.0 or less. Specifically, the adhesive composition was applied to the release substrate so that the thickness after drying became 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 harden, and the cured adhesive composition layer (adhesive layer) is peeled from the release film. The relative dielectric constant (ε _c ) of the adhesive composition layer after peeling at a frequency of 1 MHz was measured. The relative dielectric constant (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 practically it is 2.0. In addition, the relative permittivity (ε _c ) in the entire frequency range of 1 MHz to 10 GHz is preferably 3.0 or less, more preferably 2.6 or less, and particularly preferably 2.3 or less.

The relative dielectric constant (ε _c ) of the adhesive layer in the laminate (Z) can be measured as follows. That is, a method can be exemplified by removing the metal substrate of the laminate (Z) with an etching solution to obtain a two-layer laminate (X) of the adhesive layer and the resin substrate. The etching solution is not particularly limited, and an iron (III) chloride aqueous solution, a copper (II) chloride aqueous solution, a sulfuric acid hydrogen peroxide water mixed solution, an alkaline etching solution, a nickel etching solution, etc. can be used. Then, the resin substrate of the laminate (X) is peeled off (removed) clean, and the metal layer is formed on both sides of the remaining adhesive layer by thin film methods such as vapor deposition, sputtering, or coating of conductive paste As a capacitor, the electrostatic capacitance is measured, and the relative dielectric constant (ε _c ) is calculated from the thickness and area. In addition, as another method, the aforementioned method can be used to form a metal layer on the resin substrate surface of the laminate (X) as a capacitor, and measure the relative dielectric constant of the combined electrostatic capacitance of the resin substrate and the adhesive layer ( After ε _c ), the metal layer and the adhesive layer are peeled off (removed) from the laminate (X), and the capacitors are similarly formed, the capacitance is measured, and the relative permittivity (ε _c ) of the remaining resin substrate is measured. The dielectric layer of the capacitor obtained from the laminate (X) is regarded as a multilayer dielectric of the resin substrate and the adhesive layer, so the relative dielectric constant (ε _c ) of the adhesive layer can be calculated from the difference between the two .

<Requirement (2)> Requirement (2) is explained. Regarding the laminate (Z) of the present invention, it is necessary that the dielectric tangent (tan δ) of the adhesive layer at a frequency of 1 MHz is 0.02 or less. Specifically, the adhesive composition was applied to the release substrate so that the thickness after drying became 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 harden, and the cured adhesive composition layer (adhesive layer) is peeled from the release film. The dielectric tangent (tanδ) of the adhesive composition after peeling at a frequency of 1 MHz was measured. The dielectric tangent (tanδ) 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 it is 0.0001 practically. In addition, the dielectric tangent (tan δ) in the entire frequency range of 1 MHz to 10 GHz is preferably 0.02 or less, more preferably 0.01 or less, and particularly preferably 0.005 or less.

The dielectric tangent (tanδ) of the adhesive layer in the laminate (Z) can also be measured by the same operation as the above-mentioned dielectric constant.

<Requirement (3)> Requirement (3) is explained. Regarding the laminate (Z) of the present invention, it is necessary that the peel strength between the resin substrate and the metal substrate is 0.5 N/mm or more. Specifically, the adhesive composition was applied to the resin base material so that the thickness after drying became 25 μm, and dried at about 130° C. for about 3 minutes. Then, a metal substrate is bonded to the surface of the adhesive composition layer (adhesive layer). The bonding is performed so that the glossy surface of the metal substrate is in contact with the adhesive composition layer, and the bonding is performed at about 160° C. under a vacuum pressure of about 40 kgf/cm ² for 30 seconds. Then, it was heat-treated at about 140° C. for about 4 hours to harden it to produce a three-layer laminate (Z) of resin substrate/adhesive layer/metal substrate. At normal temperature (about 25°C), the resin substrate of the laminate (Z) was peeled at 90° at a tensile speed of 50 mm/min, and the peel strength was measured. It is necessary for the 90° peel strength to be 0.5 N/mm or more, preferably 0.8 N/mm or more, and more preferably 1.0 N/mm or more. In addition, even the laminate (Z) produced by a method other than the above-mentioned 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 substrate on the surface of the adhesive composition layer (adhesive layer) of the laminate (X). The bonding is performed so that the glossy surface of the metal substrate is in contact with the adhesive composition layer, and the bonding is performed at about 160° C. under a vacuum pressure of about 40 kgf/cm ² for 30 seconds. Then, it was heat-treated at about 140° C. for about 4 hours to harden it to produce a three-layer laminate (Z) of resin substrate/adhesive layer/metal substrate. At normal temperature (about 25°C), the resin substrate of the laminate (Z) was peeled at 90° at a tensile speed of 50 mm/min, and the peel strength was measured. It is necessary for the 90° peel strength 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 substrate on the surface of the adhesive composition layer (adhesive layer) of the laminate (Y). The bonding is performed so that the resin substrate and the adhesive composition layer are brought into contact, and the bonding is performed at about 160° C. under a pressure of about 40 kgf/cm ² under vacuum pressure for 30 seconds. Then, it was heat-treated at about 140° C. for about 4 hours to harden it to produce a three-layer laminate (Z) of resin substrate/adhesive layer/metal substrate. At normal temperature (about 25°C), the resin substrate of the laminate (Z) was peeled at 90° at a tensile speed of 50 mm/min, and the peel strength was measured. It is necessary for the 90° peel strength 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 bonding the resin substrate on one side of the adhesive layer and the glossy surface of the metal substrate on the other side. Laminating is to laminate the release substrate/adhesive layer and the resin substrate at about 100°C under a pressure of about 3kgf/cm ^{2 with a} roll of about 1m/min, and then peel off the release substrate. , So that the glossy surface of the metal substrate is in contact with the adhesive layer, the vacuum pressure is controlled at about 160°C under a pressure of about 40 kgf/cm ² for 30 seconds and then adhered. Then, it was heat-treated at about 140° C. for about 4 hours to harden it to produce a three-layer laminate (Z) of resin substrate/adhesive layer/metal substrate. At normal temperature (about 25°C), the resin substrate of the laminate (Z) was peeled at 90° at a tensile speed of 50 mm/min, and the peel strength was measured. It is necessary for the 90° peel strength 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)> Requirement (4) is explained. Regarding the laminate (Z) of the present invention, the heat resistance of the humidified solder must be 240°C or higher. Specifically, the adhesive composition is applied to the resin substrate so that the thickness after drying becomes 25 μm, and dried at about 130° C. for about 3 minutes. Then, a metal substrate is bonded to the surface of the adhesive composition layer (adhesive layer). The bonding is performed so that the glossy surface of the metal substrate is in contact with the adhesive composition layer, and the bonding is performed at about 160° C. under a vacuum pressure of about 40 kgf/cm ² for 30 seconds. Then, it was heat-treated at about 140° C. for about 4 hours to harden it to produce a three-layer laminate (Z) of resin substrate/adhesive layer/metal substrate. The laminate (Z) was treated under conditions of about 40° C. and about 80 RH% for about 72 hours, and was flowed in a molten solder bath at each temperature for 1 minute, and the temperature at which appearance changes such as swelling did not occur was measured. The heat resistance of the humidified solder is 240°C or higher, preferably 250°C or higher, and more preferably 260°C or higher. In addition, even a laminate (Z) produced by a method other than the above-mentioned method is included in the present invention as long as the heat resistance of the humidified solder is 240°C or higher.

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

Furthermore, from the adhesive layer, the resin substrate is bonded to one side of the adhesive layer, and the glossy surface of the metal substrate is bonded to the other side to obtain the laminate (Z) of the present invention. Laminating is performed after bonding the adhesive layer and the resin base material so that the glossy surface of the metal base material is in contact with the adhesive layer, and the vacuum pressure is controlled at about 160°C under a pressure of about 40 kgf/cm ² Seconds and then. Then, it was heat-treated at about 140° C. for about 4 hours to harden it to produce a three-layer laminate (Z) of resin substrate/adhesive layer/metal substrate. The laminate (Z) was treated under conditions of about 40° C. and about 80 RH% for about 72 hours, and was flowed in a molten solder bath at each temperature for 1 minute, and the temperature at which appearance changes such as swelling did not occur was measured. The heat resistance of the humidified solder is 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 includes at least a carboxyl group-containing polyolefin resin (A). By including the polyolefin resin (A) containing a carboxyl group, a laminate formed by an adhesive layer composed of the adhesive composition can exhibit the above-mentioned excellent performances (1) to (4).

The adhesive composition of the present invention, in addition to the above-mentioned (A) component, preferably includes a carboxyl group-containing styrene resin (B) (hereinafter also referred to as (B) component), carbodiimide resin (C) (hereinafter also It is abbreviated as (C) component.) and/or epoxy resin (D) (hereinafter also abbreviated as (D) component.) is preferable. The four types of resins including the above-mentioned (A) to (D) components are not only compatible with conventional polyimide and polyester films, but also with low-polarity resin substrates such as LCP films that were not anticipated by the prior art, and metal The substrate also has high adhesion, high solder heat resistance, and excellent low dielectric properties.

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

The modification of the carboxyl group-containing styrene resin (B) can be carried out, for example, by copolymerizing an unsaturated carboxylic acid during polymerization of the styrene resin. Moreover, it can also be performed 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 acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, maleic anhydride, itaconic anhydride, fumaric anhydride, etc. can be mentioned.

The acid value of the carboxyl group-containing styrene resin (B), from the viewpoint of heat resistance and adhesion to the resin substrate or metal substrate, the lower limit is preferably 10 equivalent/10 ⁶ g or more, preferably 100 equivalent/10 ⁶ g or more is more preferable, 150 equivalent/10 ⁶ g is particularly preferable. If the value 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 expressed. In addition, the crosslinking density may be low and heat resistance may be insufficient. The upper limit is preferably 1000 equivalents/10 ⁶ g or less, more preferably 700 equivalents/10 ⁶ g or less, and particularly preferably 500 equivalents/10 ⁶ g or less. If the value exceeds the above value, the adhesion and low dielectric properties may decrease.

In the adhesive composition used in the present invention, the content of the carboxyl-containing styrene resin (B) is preferably 5 to 95 parts by mass of the carboxyl-containing polyolefin resin (A), preferably carboxyl-containing styrene The resin (B) is preferably in the range of 95 to 5 parts by mass, that is, (A) component/(B) component = 5 to 95/95 to 5 (mass ratio). (A) component/(B) component is more preferably 10 to 90/90 to 10 (mass ratio), and (A) component/(B) component = 15 to 85/85 to 15 (mass ratio) is the most preferable range. (A) If the component amount is less than the above-mentioned value, the crosslink density will decrease, and the heat resistance of the humidified solder may decrease. (A) If the amount of the component exceeds the above value, the wettability to the base material 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. Polycarbodiimide having two or more carbodiimide groups in the molecule is preferred. By using carbodiimide resin (C), carboxyl-containing polyolefin resin (A) or carboxyl-containing styrene resin (B), the carboxyl group reacts with the carbodiimide to improve the adhesive composition and substrate Interaction, and can improve adhesion.

In the adhesive composition used in the present invention, the content of the carbodiimide resin (C) is preferably 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 0.1 to 30 parts by mass. The range of 1-25 parts by mass is more preferable, and the range of 2-20 parts by mass is most preferable. If the value is less than the above-mentioned value, the interaction with the base material will not be displayed, and the adhesion will be reduced. If the above value is exceeded, the pot life of the adhesive will be shortened and the low dielectric properties will be reduced.

<Epoxy resin (D)> The epoxy resin (D) is not particularly limited as long as it has a glycidyl group in the molecule, and it is preferably one having two or more glycidyl groups in the molecule. . Although it is not specifically limited, it can be selected from biphenyl type epoxy resin, naphthalene type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and novolac type epoxy resin. , Cycloaliphatic epoxy resin, dicyclopentadiene epoxy resin, tetraglycidyl diamino diphenyl methane, triglycidyl p-aminophenol, tetraglycidyl diamino methyl At least one of the group consisting of cyclohexanone, N,N,N',N'-tetraglycidyl-m-xylenediamine. Preferably, it is bisphenol A epoxy resin, novolac epoxy resin or dicyclopentadiene epoxy resin.

In the adhesive composition used in the present invention, the content of epoxy resin (D) relative to 100 parts by mass of the total of carboxyl group-containing polyolefin resin (A) and carboxyl group-containing styrene resin (B) is preferably 1 The range of -30 parts by mass is preferable, the range of 2-15 parts by mass is more preferable, and the range of 3-10 parts by mass is most preferable. If it is less than the above range, a sufficient curing effect may not be obtained, and adhesiveness and heat resistance may decrease. Moreover, if it is more than the said range, there will be a problem that the pot life of the adhesive is shortened, and the low-dielectric characteristic falls.

The adhesive composition used in the present invention may further contain an organic solvent. As for the organic solvent used in the present invention, as long as it can be made of polyolefin resin (A) containing carboxyl group, styrene resin (B) containing carboxyl group, carbodiimide resin (C), and epoxy resin (D) ) Whatever is dissolved is not particularly limited. Specifically, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, octane, and decane; cyclohexane, cyclohexene, methylcyclohexane, Alicyclic hydrocarbons such as ethyl cyclohexane; halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, chloroform; methanol, ethanol, isopropanol, butanol, pentanol, hexanol, propylene glycol, phenol and other alcohols Solvents; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, acetophenone, etc.; methyl serosol, ethyl serosol and other serosols ; Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, butyl formate, etc.; ethylene glycol mono n-butyl ether, ethylene glycol mono isobutyl ether, ethylene glycol mono tertiary butyl ether , Diethylene glycol mono-n-butyl ether, diethylene glycol mono-isobutyl ether, triethylene glycol mono-n-butyl ether, tetraethylene glycol mono-n-butyl ether and other glycol ether solvents, etc., can be used One or more than two kinds are useful.

Regarding the organic solvent, the range of 100-1000 parts by weight is preferable, 200-900 parts by weight, relative to the total of 100 parts by weight of carboxyl-containing polyolefin resin (A) and carboxyl-containing styrene resin (B) The range is better, and the range of 300 to 800 parts by mass is the best. If it does not reach the above range, the liquidity and pot life characteristics may decrease. Moreover, if it exceeds the said range, there will be a problem that it becomes disadvantageous in terms of manufacturing cost and transportation cost.

In addition, the adhesive composition used in the present invention may further contain other components if necessary. Specific examples of these components include flame retardants, adhesiveness-imparting agents, fillers, and silane coupling agents.

<Flame retardant> In the adhesive composition used in the present invention, a flame retardant may be blended if necessary. Examples of flame retardants include bromine-based, phosphorus-based, nitrogen-based, and metal hydroxide compounds. Among them, phosphorus-based flame retardants are preferred. For example, phosphoric acid esters such as trimethyl phosphate, triphenyl phosphate, and tricresyl phosphate; phosphates such as aluminum hypophosphite; phosphazenes, and other known phosphorus-based flame retardants can be used. These can be used alone or in any combination of two or more kinds. When a flame retardant is contained, the flame retardant is preferably contained in the range of 1 to 200 parts by mass relative to 100 parts by mass of the total of components (A) to (D), more preferably in the range of 5 to 150 parts by mass, and 10 to 100 The range of mass parts is the best. If it does not reach the above range, the flame retardancy may be low. If it exceeds the above range, there will be problems such as deterioration in adhesion, heat resistance, and electrical characteristics.

<Adhesiveness-imparting agent> In the adhesive composition used in the present invention, an adhesiveness-imparting agent may be blended if necessary. Adhesive imparting agents include polyterpene resins, rosin-based resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymerized petroleum resins, styrene resins, and hydrogenated petroleum resins, etc., which are used to improve the bonding strength use. These can be used alone or in any combination of two or more kinds.

<Filler> In the adhesive composition used in the present invention, fillers such as silica may be blended if necessary. By blending silicon dioxide, the heat resistance characteristics are improved, which is very ideal. As far as silica is concerned, hydrophobic silica and hydrophilic silica are generally known. In order to impart moisture resistance, dimethyldichlorosilane, or hexamethyldisilazane, Hydrophobic silica treated with octyl silane, etc. The blending amount of silica is preferably 0.05-30 parts by mass relative to 100 parts by mass of the total of 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, workability may be inconvenient, or adhesiveness may decrease.

<Silane coupling agent> In the adhesive composition used in the present invention, a silane coupling agent may be blended if necessary. By blending the silane coupling agent, the adhesion to metals and the characteristics of heat resistance are improved, which is very ideal. The silane coupling agent is not particularly limited, and examples include those having unsaturated groups, those having glycidyl groups, and those having amine groups. From the viewpoint of heat resistance, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4) -Epoxycyclohexyl) ethyl triethoxy silane and other silane coupling agents having glycidyl groups are more preferable. The blending amount of the silane coupling agent is preferably 0.5-20 parts by mass relative to 100 parts by mass of the total of components (A) to (D). If it is less than 0.5 parts by mass, heat resistance may become poor. On the other hand, if it exceeds 20 parts by mass, heat resistance may be poor or adhesiveness may be reduced.

<Adhesive Sheet> In the present invention, the adhesive sheet is formed by laminating the above-mentioned laminate (Z) and the release base material via an adhesive composition, or on the laminate (X) or the laminate (Y). ) The adhesive layer is laminated with a release substrate, or at least one side of the adhesive layer is laminated with a release substrate. Specific configuration aspects include release substrate/adhesive layer, release substrate/adhesive layer/release substrate, resin substrate/adhesive layer/release substrate, metal substrate/adhesive Layer/release base material, laminate/adhesive layer/release base material, or release base material/adhesive layer/laminated body/adhesive layer/release base material. By laminating the release substrate, it can function as a protective layer of the substrate. In addition, 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.

By applying the adhesive composition used in the present invention to various laminates according to a conventional method and drying, the adhesive sheet of the present invention can be obtained. In addition, if the release base material is attached to the adhesive layer after drying, it can be wound without transferring to the back of the base material, and the workability is excellent, and the adhesive layer is protected at the same time, so it has excellent storage properties and is easy to use. In addition, after coating on a release substrate and drying, if another release substrate is attached as necessary, the adhesive layer itself may be transferred to another substrate.

<Release base material> The mold release base material is not particularly limited. For example, it can be exemplified on both sides of paper such as high-quality paper, kraft paper, roll paper, cellophane, etc., provided with a coating layer of a leveling agent such as clay, polyethylene, and polypropylene. Furthermore, a silicone-based, fluorine-based, and alkyd-based mold release agent is applied on each coating layer. In addition, various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, propylene-α-olefin copolymer, etc. alone, and films such as polyethylene terephthalate are coated with the above-mentioned release agent. Become. Due to the demolding force between the mold release substrate and the adhesive layer, and the adverse effects of silicone on the electrical characteristics, it is advisable to apply polypropylene filling treatment on both sides of high-quality paper and use an alkyd mold release agent on it. It is better to use alkyd mold release agent on polyethylene terephthalate.

<Printed circuit board> The "printed circuit board" in the present invention includes a laminate composed of a metal foil forming a conductor circuit and a resin substrate as a constituent element. The printed circuit board can be manufactured by a conventionally known method such as a subtractive method using a metal-clad laminate, for example. It is used for so-called flexible circuit boards (FPC), flat cables, and tape-to-tape automatic bonding (TAB), which are partially or fully coated with surface film, screen printing ink, etc., if necessary. Generic term for circuit boards, etc.

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

Furthermore, if necessary, it can also be a structure which laminated|stacked two or more said printed circuit boards.

The adhesive composition used in the present invention is suitable for each adhesive layer of a printed circuit board. In particular, when the adhesive composition used in the present invention is used as an adhesive, it is not only compatible with conventional polyimide, polyester film, and copper foil constituting printed circuit boards, but also with low-polarity resin substrates such as LCP. It has high adhesion, can obtain solder reflow resistance, and the adhesive layer itself has excellent low dielectric properties. Therefore, it is suitable as an adhesive composition for surface coating films, laminates, copper foil with resin, and adhesive sheets.

In the printed circuit board of the present invention, as the base film, any resin film that has been conventionally used as a base material of a printed circuit board can be used. As the resin of the base film, polyester resin, polyamide resin, polyimide resin, polyimide resin, liquid crystal polymer, polyphenylene sulfide, parapolystyrene, polyolefin series Resin, fluorine-based resin, etc. In particular, it has excellent adhesion even to low-polarity substrates such as liquid crystal polymer, polyphenylene sulfide, para-polystyrene, and polyolefin resin.

<Surface coating film> As for the surface coating film, any conventionally known insulating film can be used as an insulating film for a printed circuit board. For example, polyimide, polyester, polyphenylene sulfide, polyether ether, polyether ether ketone, aromatic polyamide, polycarbonate, polyarylate, polyimide, polyimide can be used. Films made of various polymers such as imines, liquid crystal polymers, parapolystyrene, and polyolefin resins. Polyimide film or liquid crystal polymer film is more preferable.

The printed circuit board of the present invention can be manufactured using any conventionally known process in addition to the materials of the above-mentioned layers.

A preferred embodiment is a semi-finished product (hereinafter referred to as "semi-finished product on the surface-coated film side") formed by laminating an adhesive layer on a surface coating film. On the other hand, it is a semi-finished product in which a metal foil layer is laminated on a base film and a desired circuit pattern is formed (hereinafter referred to as a "base film side two-layer semi-finished product"), or an adhesive layer is laminated on the base film and A semi-finished product (hereinafter referred to as "3-layer semi-finished product on the base film side") on which a metal foil layer is laminated and a desired circuit pattern is formed (hereinafter, a 2-layer semi-finished product on the substrate film side and a 3-layer semi-finished product on the substrate film side are combined Called "substrate film side semi-finished products"). By bonding the semi-finished product on the surface film side and the semi-finished product on the base film side obtained in this way, a 4-layer or 5-layer printed circuit board can be obtained.

The semi-finished product on the substrate film side, for example, can be obtained by a manufacturing method including the following steps: (A) a step of coating the metal foil with a resin solution that becomes the substrate film, and performing preliminary drying of the coating film; (B) A step of heat-treating and drying the laminate of the metal foil and the preliminary dried coating film obtained in (A) (hereinafter referred to as "heat-treatment and solvent removal step").

For the formation of the circuit in the metal foil layer, a conventionally known method can be used. Additive and subtractive methods can be used. The subtraction method is better.

The obtained semi-finished product on the film side of the substrate can be directly used for bonding with the semi-finished product on the side of the surface covering film, and it can also be used for bonding with the semi-finished product on the side of surface covering film after being laminated with a release film.

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

The obtained semi-finished product on the surface film side can be directly used for bonding with the semi-finished product on the substrate film side, or it can be used for bonding with the semi-finished product on the substrate film side after being pasted with a release film for storage.

The semi-finished product on the base film side and the semi-finished product on the surface film side are stored in the form of a reel, for example, and then bonded together to produce a printed circuit board. As for the bonding method, any method can be used, for example, pressing or rollers can be used for bonding. In addition, it is also possible to bond the two while heating by heating and pressing or using a heating roller device.

The semi-finished product on the side of the reinforcing material, for example, in the case of a reinforcing material that is flexible and windable like a polyimide film, it is ideal to manufacture the reinforcing material by coating an adhesive. In addition, for example, in the case of hard and unwindable reinforcing plates such as metal plates such as SUS, aluminum, etc., and glass fibers that are hardened with epoxy resin, it is performed by applying an adhesive that is pre-coated on the release substrate. It is ideal for manufacturing by transfer coating. In addition, the crosslinking reaction in the applied adhesive can be performed when necessary. In a preferred embodiment, the adhesive layer is semi-hardened.

The obtained semi-finished product on the side of the reinforcing material can be directly used for bonding with the back of the printed circuit board, and it can also be used for bonding with the semi-finished product on the side of the base film after being laminated with a release film for storage.

The semi-finished product on the base film side, the semi-finished product on the surface film side, and the semi-finished product on the reinforcing material side are all laminates for printed circuit boards in the present invention.

<Examples> Hereinafter, the present invention will be explained in more detail with examples. However, the present invention is not limited to the Examples. The abbreviated parts in the examples and comparative examples indicate parts by mass.

(Physical property evaluation method)

(Acid value (A) component: carboxyl group-containing polyolefin resin) The acid value (equivalent/10 ⁶ g) in the present invention uses FT-IR (manufactured by Shimadzu Corporation, FT-IR8200PC) and uses maleic anhydride The absorbance (I) of the stretch peak (1780cm ^-1 ) of the carbonyl (C=O) bond, the absorbance (II) of the peak (840cm ^-1 ) unique to the same row of polymers, and the absorbance of maleic anhydride (Tokyo The coefficient (f) obtained from the calibration curve of the chloroform solution produced by Kasei Co., Ltd. is calculated according to the following formula, and the calculated value is expressed as the equivalent (equivalent/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 of component (B): the carboxyl group-containing styrene resin) of the present invention, the acid value (eq / 10 ⁶ g), a styrene-based resin containing a carboxyl group dissolved in toluene, and to the solution of sodium methoxide in methanol Phenolphthalein is used as an indicator for titration. It is expressed as the equivalent weight in 1 ton of resin (equivalent weight/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 referred to as GPC, standard material: polystyrene resin, mobile phase: tetrahydrofuran).

(1) Peel strength (adhesiveness) The adhesive composition described later is applied to a polyimide film (manufactured by Kaneka Co., Ltd., Apical) with a thickness of 12.5 μm or a thickness of 25 μm so that the thickness after drying becomes 25 μm LCP film (manufactured by KURARAY Co., Ltd., Vecstar), and dried at 130°C for 3 minutes. The adhesive film (B-stage product) thus obtained was bonded to 18 μm rolled copper foil. The bonding was performed so that the glossy surface of the rolled copper foil was brought into contact with the adhesive, and pressed at 160° C. under a pressure of 40 kgf/cm ² for 30 seconds, and then adhered. Then, it was heat-treated at 140°C for 4 hours to be hardened, and a sample for peel strength evaluation was obtained. The peel strength is to stretch the film at 25°C, and perform a 90° peel test at a tensile speed of 50 mm/min to measure the peel strength. This test indicates the bonding strength at room temperature. <Evaluation criteria> ◎: 1.0N/mm or more ○: 0.8N/mm or more and less than 1.0N/mm △: 0.5N/mm or more and less than 0.8N/mm ×: less than 0.5N/mm

(2) Heat resistance of dry solder. Samples were prepared by the same method as above. A sample piece of 2.0cm×2.0cm was dried at 120°C for 30 minutes, and then flowed in a molten solder bath at each temperature for 1 minute. The temperature that causes changes in appearance such as swelling. <Evaluation criteria> ◎: 310°C or higher ○: 300°C or higher and less than 310°C △: 290°C or more and less than 300°C ×: Less than 290°C

(3) Heat resistance of humidified solder. Samples are made by the same method as above, and the 2.0cm×2.0cm sample piece is processed at 40℃×80RH%×72 hours, and flows in the molten solder bath for 1 minute at each temperature , Measure the temperature that does not cause changes in appearance such as swelling. <Evaluation criteria> ◎: 260°C or higher ○: 250°C or higher and less than 260°C △: 240°C or more and less than 250°C ×: less than 240°C

(4) Relative permittivity (ε _c ) and dielectric tangent (tanδ) The adhesive composition described below is applied to the glossy surface of 35 μm electrolytic copper foil so that the thickness after drying and curing becomes 25 μm, and Dry at 130°C for 3 minutes. Then, it was heat-treated at 140°C for 4 hours to harden it to obtain a copper clad laminate for testing. On the hardened adhesive composition surface of the obtained copper-clad laminate for testing, screen printing was used to apply an evaporation-dry conductive silver paste into a circle with a diameter of 50 mm, and then dried at 120°C for 30 minutes It was cured, and a lead with a length of 30 mm was bonded with a conductive adhesive at the center of the circle formed by the conductive silver paste to obtain a parallel plate capacitor. Using PRECISION LCR meter HP-4284A, the capacitance Cap and the loss coefficient D (dielectric tangent) of the parallel plate capacitor obtained were measured at 22°C at a frequency of 1MHz, and the relative permittivity (ε _c ) was calculated according to the following formula ). ε _c =(Cap×d)/(S×ε ₀ ) Here, Cap: electrostatic capacitance [F] d: thickness of dielectric layer = 25×10 ^-6 [m] S: area of measured dielectric = π ×(25×10 ^-3 ) ² ε ₀ : The dielectric constant of the vacuum 8.854×10 ^-12 The obtained relative dielectric constant and dielectric tangent were evaluated as follows. <Evaluation criteria of relative permittivity> ◎: 2.3 or less ○: more than 2.3 to 2.6 or less △: more than 2.6 to 3.0 or less ×: more than 3.0 <dielectric tangent evaluation criteria> ◎: 0.005 or less ○: more than 0.005 to 0.01 or less △: more than 0.01 to 0.02 or less ×: more than 0.02

(Carboxyl group-containing polyolefin resin) [Manufacturing Example 1] In a 1L autoclave, 100 parts by mass of propylene-butene copolymer ("TAFMER (registered trademark) XM7080" manufactured by Mitsui Chemicals Co., Ltd.) and 150 mass parts of toluene were added Parts, 19 parts by mass of maleic anhydride, and 6 parts by mass of di-tert-butyl peroxide were heated to 140° C., and then stirred for further 3 hours. Then, after cooling the obtained reaction liquid, it was poured into a container containing a large amount of methyl ethyl ketone and the resin was precipitated. Then, by centrifugal separation of the resin-containing solution, the acid-modified propylene-butene copolymer obtained by graft polymerization of maleic anhydride is separated and purified from (poly)maleic anhydride and low molecular weight products. Thereafter, it was dried for 5 hours at 70°C under reduced pressure to obtain a maleic anhydride modified propylene-butene copolymer (CO-1, acid value 410 equivalent/10 ⁶ g, weight average molecular weight 60,000, Tm 80°C , △H35J/g).

[Production Example 2] Except that the amount of maleic anhydride added was changed to 11 parts by mass, the same method as that of Production Example 1 was used to obtain a maleic anhydride modified propylene-butene copolymer (CO-2, acid value 220 equivalent/10 ⁶ g, weight average molecular weight 65,000, Tm78°C, △H25J/g).

[Example 1] In a 500 mL four-neck 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 was added, containing 20 parts by mass of carboxyl-based styrene resin (Tuftec (registered trademark) M1943) and 500 parts by mass of toluene were heated to 80° C. while stirring, and the stirring was continued for 1 hour to dissolve. 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 are blended to obtain an adhesive composition. The blending amount, adhesive strength, solder heat resistance, and electrical properties are shown in Table 1.

[Examples 2-10] The polyolefin resin (A) containing carboxyl group, styrene resin (B) containing carboxyl group, carbodiimide resin (C), and epoxy resin (D) were changed as shown in Table 1 , Examples 2-14 were implemented by the same method as Example 1, and they were changed to each blending amount shown in Table 1. The subsequent strength, solder heat resistance, and electrical characteristics are shown in Table 1.

[Table 1]

[Comparative Examples 1-7] The polyolefin resin (A) containing carboxyl group, styrene resin (B) containing carboxyl group, carbodiimide resin (C), and epoxy resin (D) were changed as shown in Table 2 In the same manner as in Example 1, Comparative Examples 1 to 7 were implemented, and the blending amounts shown in Table 2 were changed. The blending amount, adhesive strength, solder heat resistance, and electrical properties are shown in Table 2.

[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. Styrene resin containing carboxyl group: Tuftec (registered trademark) M1911 (manufactured by Asahi Kasei Chemical Co., Ltd.) Styrene resin containing carboxyl group: Tuftec (registered trademark) M1913 (manufactured by Asahi Kasei Chemical Co., Ltd.) Styrene resin containing carboxyl group: Tuftec (registered trademark) M1943 (manufactured by Asahi Kasei Chemical Co., Ltd.) Polyolefin resin: TAFMER (registered trademark) XM7080 (manufactured by Mitsui Chemicals Co., Ltd.) Styrene resin: Tuftec (registered trademark) H1052 (manufactured by Asahi Kasei Chemical Co., Ltd.) Acrylonitrile-butadiene rubber NBR containing carboxyl groups (Manufactured by JSR Co., Ltd.) Carbodiimide resin: V-05 (manufactured by Nisshinbo Chemical Co., Ltd.) Carbodiimide resin: V-03 (manufactured by Nisshinbo Chemical Co., Ltd.) Ortho-cresol novolac epoxy resin: YDCN-700- 10 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) Dicyclopentadiene epoxy resin: HP-7200 (manufactured by DIC Corporation)

It can be seen from Table 1 that in Examples 1-14, polyimide (PI) and copper foil have excellent adhesion and solder heat resistance, and liquid crystal polymer (LCP) and copper foil also have excellent adhesion , Solder heat resistance. In addition, regarding the electrical properties of the adhesive composition, both the dielectric constant and the dielectric tangent are low, which is good. On the other hand, it can be seen from Table 2: Comparative Example 1 did not incorporate a carboxyl group-containing styrene resin, so the heat resistance and adhesive strength of the humidified solder were poor. In Comparative Example 2, a polyolefin resin containing a carboxyl group was not blended, so the crosslink density was low, and the heat resistance of the humidified solder was poor. In Comparative Example 3, the polyolefin resin does not contain a carboxyl group, so the crosslink density is low, and the humidified solder has poor heat resistance. In Comparative Example 4, the styrene resin does not contain a carboxyl group, so the crosslink density is low, and the heat resistance of the humidified solder is poor. In Comparative Example 5, the carbodiimide resin was not blended, so the interaction with the LCP interface was small, and the bonding strength was low. In Comparative Example 6, no epoxy resin was blended, so the crosslinking density was low and the solder heat resistance was poor. In Comparative Example 7, no polyolefin resin or styrene resin was blended, so the adhesive composition had poor low dielectric properties. [Industrial availability]

According to the present invention, it is possible to provide a laminated body that is not only compatible with conventional polyimide and polyethylene terephthalate films, but also with LCP and other low-dielectric resin substrates, copper foils and other metal substrates. It also has high adhesiveness, high solder heat resistance, and excellent low dielectric properties. Based on the above characteristics, it is useful for flexible printed circuit board applications, especially FPC applications that require low dielectric properties (low dielectric constant, low dielectric tangent) in the high-frequency region.

Claims (11)

A laminated body (Z) comprising a resin base material and a metal base material laminated through an adhesive; the adhesive layer contains a carboxyl group-containing polyolefin resin (A) and a carbodiimide resin (C); The characteristics are: (1) the relative dielectric constant (ε _c ) of the adhesive layer at a frequency of 1MHz is 3.0 or less, (2) the dielectric tangent (tanδ) of the adhesive layer at a frequency of 1MHz is 0.02 or less, (3) The peel strength between the resin base material and the metal base material is 0.5 N/mm or more, and (4) the heat resistance of the humidified solder of the laminate (Z) is 240° C. or more. A laminate (X), a laminate of the adhesive layer and the resin substrate used in a laminate (Z) in which a resin substrate and a metal substrate are laminated via an adhesive; the adhesive The agent layer contains carboxyl group-containing polyolefin resin (A) and carbodiimide resin (C); it is characterized by: (1) The relative dielectric constant (ε _c ) of the adhesive layer at a frequency of 1 MHz is 3.0 or less, ( 2) The dielectric tangent (tanδ) of the adhesive layer at a frequency of 1MHz is 0.02 or less, (3) When the metal substrate is laminated on the adhesive layer of the laminate (X), the resin substrate in the laminate The peel strength between the metal substrate and the metal substrate is 0.5N/mm or more. (4) When the metal substrate is laminated on the adhesive layer of the laminate (X), the heat resistance of the humidified solder of the laminate is 240°C or more . A laminate (Y), a laminate of the adhesive layer and the metal substrate used in a laminate (Z) formed by laminating a resin substrate and a metal substrate via an adhesive; the adhesive The agent layer contains carboxyl group-containing polyolefin resin (A) and carbodiimide resin (C); it is characterized by: (1) The relative dielectric constant (ε _c ) of the adhesive layer at a frequency of 1 MHz is 3.0 or less, ( 2) The dielectric tangent (tanδ) of the adhesive layer at a frequency of 1MHz is 0.02 or less, (3) When the resin substrate is laminated on the adhesive layer of the laminate (Y), the resin substrate in the laminate The peel strength with the metal substrate is 0.5N/mm or more. (4) When the resin substrate is laminated on the adhesive layer of the laminate (Y), the heat resistance of the humidified solder of the laminate is 240°C or higher . An adhesive layer, which is used in a laminate (Z) formed by laminating a resin substrate and a metal substrate via an adhesive; the adhesive layer contains a carboxyl group-containing polyolefin resin (A) And carbodiimide resin (C); characterized in that: (1) the relative dielectric constant (ε _c ) of the adhesive layer at a frequency of 1MHz is 3.0 or less, (2) the dielectric constant of the adhesive layer at a frequency of 1MHz The tangent (tanδ) is 0.02 or less, (3) when the resin substrate is laminated on one side of the adhesive layer and the metal substrate is laminated on the other side, the peeling between the resin substrate and the metal substrate in the laminate The strength is 0.5N/mm or more. (4) When the resin substrate is laminated on one side of the adhesive layer and the metal substrate is laminated on the other side, the heat resistance of the wetted solder of the laminate is 240°C or more. A laminate (Z), a resin base material and a metal base material laminated through an adhesive; the adhesive layer contains a carboxyl-containing polyolefin resin (A), and further contains a carboxyl-containing styrene resin (B ), carbodiimide resin (C) and epoxy resin (D); the content of the carbodiimide resin (C) is relative to the carboxyl-containing polyolefin resin (A) and carboxyl-containing styrene resin (B) A total of 100 parts by mass is in the range of 0.1-30 parts by mass; the content of the epoxy resin (D) is relative to the total 100 parts by mass of the carboxyl-containing polyolefin resin (A) and the carboxyl-containing styrene resin (B) , Is the range of 1-30 parts by mass. A laminate (X), a laminate of the adhesive layer and the resin substrate used in a laminate (Z) in which a resin substrate and a metal substrate are laminated via an adhesive; the adhesive The agent layer contains carboxyl-containing polyolefin resin (A), and carboxyl-containing styrene resin (B), carbodiimide resin (C) and epoxy resin (D); the carbodiimide resin (C) The content of carboxyl-containing polyolefin resin (A) and carboxyl-containing styrene resin (B) total 100 parts by mass, in the range of 0.1-30 parts by mass; the content of epoxy resin (D) is relative to the The total of 100 parts by mass of the carboxyl group-containing polyolefin resin (A) and carboxyl group-containing styrene resin (B) is in the range of 1-30 parts by mass. A laminate (Y), a laminate of the adhesive layer and the metal substrate used in a laminate (Z) formed by laminating a resin substrate and a metal substrate via an adhesive; the adhesive The agent layer contains carboxyl-containing polyolefin resin (A), and carboxyl-containing styrene resin (B), carbodiimide resin (C) and epoxy resin (D); The content of the carbodiimide resin (C) is in the range of 0.1-30 parts by mass relative to the total 100 parts by mass of the carboxyl-containing polyolefin resin (A) and the carboxyl-containing styrene resin (B); the epoxy The content of the resin (D) is in the range of 1-30 parts by mass relative to 100 parts by mass of the total of the carboxyl-containing polyolefin resin (A) and the carboxyl-containing styrene resin (B). An adhesive layer, which is used in a laminate (Z) formed by laminating a resin substrate and a metal substrate via an adhesive; the adhesive layer contains a carboxyl group-containing polyolefin resin (A) , It also contains carboxyl-containing styrene resin (B), carbodiimide resin (C) and epoxy resin (D); the content of the carbodiimide resin (C) is relative to the carboxyl-containing polyolefin resin (A) ) And carboxyl-containing styrene resin (B) total 100 parts by mass, in the range of 0.1-30 parts by mass; the content of the epoxy resin (D) is relative to the carboxyl-containing polyolefin resin (A) and carboxyl-containing The total 100 parts by mass of the styrene resin (B) is in the range of 1-30 parts by mass. An adhesive composition containing carboxyl-containing polyolefin resin (A), carboxyl-containing styrene resin (B), carbodiimide resin (C) and epoxy resin (D); the carbodiimide resin ( The content of C) is in the range of 0.1-30 parts by mass relative to the total 100 parts by mass of the carboxyl-containing polyolefin resin (A) and carboxyl-containing styrene resin (B); the content of the epoxy resin (D) is relative The total 100 parts by mass of the carboxyl-containing polyolefin resin (A) and the carboxyl-containing styrene resin (B) is in the range of 1-30 parts by mass. An adhesive sheet containing, for example, the laminated body (Z) of the first patent application, the laminated body (X) of the second patent application, the laminated body (Y) of the third patent application, or Such as the adhesive layer of item 4 in the scope of patent application. A printed circuit board that contains the adhesive sheet as described in item 10 of the scope of patent application as a constituent element.