JP2019203136A - Low-dielectric adhesive composition - Google Patents

Abstract

To provide an adhesive composition that has high adhesiveness to low-polarity resin base materials and metal base materials, such as LCP, as well as conventional polyimide and polyester films, and ensures high solder heat resistance, and also has excellent low-dielectric properties.SOLUTION: An adhesive composition contains the following (A) component, (B) component and (D) component, has a dielectric constant (ε) at frequency 1 MHz of 3.0 or less, and a dielectric loss tangent (tanδ) of 0.02 or less. (A) component: a crystalline acid-modified polyolefin, (B) component: an amorphous polyolefin, and (D) component: an epoxy resin.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive composition exhibiting a low dielectric constant and a low dielectric loss tangent. More specifically, the present invention relates to an adhesive composition used for adhesion between a resin substrate and a resin substrate or a metal substrate. In particular, the present invention relates to an adhesive composition for a flexible printed wiring board (hereinafter abbreviated as FPC), and a coverlay film, a laminated board, a copper foil with resin, and a bonding sheet containing the same.

In recent years, with the increase in the speed of transmission signals in printed wiring boards, the frequency of signals has been increasing. Along with this, the demand for low dielectric properties (low dielectric constant, low dielectric loss tangent) in the high frequency region is increasing for FPC. In response to such requirements, as a base film used for FPC, instead of conventional polyimide (PI) and polyethylene terephthalate film, liquid crystal polymer (LCP) having low dielectric properties, syndiotactic polystyrene (SPS), Base films such as polyphenylene sulfide (PPS) have been proposed.
However, since the base film having low dielectric properties is low in polarity, the adhesive strength is weak when conventional epoxy adhesives or acrylic adhesives are used, so that FPC members such as coverlay films and laminates can be produced. It was difficult. In addition, epoxy adhesives and acrylic 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 FPC adhesive composition using a polyolefin resin has been proposed. For example, Patent Document 1 proposes a modified polyamide adhesive composition in which an olefin skeleton is introduced in order to enhance the electrical characteristics of FPC. In Patent Document 2, an adhesive using an aromatic olefin oligomer modifier and an epoxy resin and a flexible printed wiring board coverlay are proposed.

JP 2007-284515 A JP 2007-63306 A

However, although these adhesive compositions are described as having adhesiveness to polyimide, it is difficult to obtain adhesiveness to a substrate film having low dielectric properties such as LCP. Moreover, since it is used as a modifier and the olefin skeleton occupying the adhesive composition is small, the dielectric properties of the adhesive are inferior.
In the case of using an LCP base material, there is a method in which the LCP is melted without using an adhesive and bonded to a copper foil to produce a two-layer substrate. However, this method has a problem that a machine base for bonding at a high temperature is required, wrinkles are easily generated during processing, and a yield is lowered.

  As a result of intensive studies to solve the above problems, the present invention has an excellent adhesive composition containing a crystalline acid-modified polyolefin and an amorphous polyolefin, and further containing at least one of a carbodiimide resin and an epoxy resin. High adhesiveness and high soldering heat resistance between resin substrates with low dielectric properties and low dielectric properties such as LCP, as well as conventional polyimide and polyethylene terephthalate films, and metal substrates such as copper foil As a result, the present invention has been completed.

That is, the present invention provides an adhesive composition having good adhesion to various resin base materials such as polyimide and LCP and metal base materials, and excellent in heat resistance and low dielectric properties. With the goal.

An adhesive composition containing the following component (A) and component (B), and further containing at least one of component (C) and component (D).
(A) Component: Crystalline acid-modified polyolefin (B) Component: Amorphous polyolefin (C) Component: Carbodiimide resin (D) Component: Epoxy resin

  In the adhesive composition, the component (A) is preferably contained in an amount of 5% by mass or more.

  (A) It contains 10-100 mass parts of (B) component with respect to 100 mass parts of component, (C) It contains 0.5-30 mass parts of component and / or (D) 1-30 mass parts of component. preferable.

  (A) It is preferable to contain 100-1000 mass parts of organic solvents (E) with respect to 100 mass parts of components.

  It is preferable that the dielectric constant (ε) of the adhesive composition according to any one of the above at a frequency of 1 MHz is 3.0 or less and the dielectric loss tangent (tan δ) is 0.02 or less.

  The adhesive composition described in any one of the above is preferably used for adhesion between a resin substrate and a resin substrate or a metal substrate.

  The laminated body of the resin base material adhere | attached with the adhesive composition in any one of the said, and a resin base material or a metal base material.

  An adhesive sheet containing the laminate.

  A printed wiring board comprising the laminate or the adhesive sheet as a constituent element.

  The adhesive composition according to the present invention contains a crystalline acid-modified polyolefin and an amorphous polyolefin, and further contains at least one of a carbodiimide resin and an epoxy resin. Therefore, it exhibits excellent low dielectric properties, and can obtain not only conventional polyimide and polyester films, but also high adhesion between low polarity resin substrates such as LCP and metal substrates, and high solder heat resistance. .

  Hereinafter, embodiments of the present invention will be described in detail.

<(A) component: crystalline acid-modified polyolefin (A)>
The component (A) is a crystalline acid-modified polyolefin. The crystalline acid-modified polyolefin (A) used in the present invention is not limited, but is a crystalline one obtained by grafting at least one of an α, β-unsaturated carboxylic acid and its acid anhydride onto a polyolefin resin. It is preferable that The polyolefin resin is a hydrocarbon such as a homopolymer of an olefin monomer exemplified by ethylene, propylene, butene, butadiene, isoprene or the like, or a copolymer with other monomers, and a hydride or halide of the obtained polymer. A polymer mainly composed of a skeleton. That is, the crystalline acid-modified polyolefin is grafted with at least one of α, β-unsaturated carboxylic acid and acid anhydride thereof on at least one of polyethylene, polypropylene and propylene-α-olefin copolymer. The crystalline one obtained by

  The propylene-α-olefin copolymer is obtained by copolymerizing α-olefin with propylene as a main component. As the α-olefin, for example, ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate or 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 acid anhydrides thereof include maleic acid, itaconic acid, citraconic acid, and acid anhydrides thereof. Among these, acid anhydrides are preferable, and maleic anhydride is more preferable. Specific examples 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 crystalline acid-modified polyolefin (A) is not particularly limited from the viewpoints of heat resistance and adhesion to a resin substrate or a metal substrate, but is preferably 50 equivalents / 10 ⁶ g or more. , More preferably 100 equivalents / 10 ⁶ g or more, further preferably 150 equivalents / 10 ⁶ g or more, particularly preferably 200 equivalents / 10 ⁶ g or more, and most preferably 250 equivalents / 10 ⁶ g or more. It is. If it is less than the above value, the compatibility with the epoxy resin (D) and / or the carbodiimide resin (C) is low, and the adhesive strength may not be exhibited. In some cases, the crosslinking density is low and the heat resistance is poor. The upper limit is not particularly limited, but is preferably 1000 equivalents / 10 ⁶ g or less, more preferably 900 equivalents / 10 ⁶ g or less, still more preferably 800 equivalents / 10 ⁶ g or less, and particularly preferably 700 Equivalent / 10 ⁶ g or less, and most preferably 600 equivalent / 10 ⁶ g or less. When the above value is exceeded, the adhesiveness may decrease. Moreover, the viscosity and stability of a solution may fall, and pot life property may fall. Furthermore, it is not preferable because the production efficiency is lowered.

  The weight average molecular weight (Mw) of the crystalline acid-modified polyolefin (A) is preferably in the range of 40,000 to 180,000. More preferably, it is the range of 50,000-160,000, More preferably, it is the range of 60,000-150,000, Most preferably, it is the range of 70,000-140,000, Most preferably, it is 80 , 13,000 to 130,000. If it is less than the above value, the cohesive force becomes weak and the adhesiveness may be inferior. On the other hand, when the above value is exceeded, there may be a problem in operability when bonding due to low fluidity.

  The crystallinity in the crystalline acid-modified polyolefin (A) means that the temperature is raised from −100 ° C. to 250 ° C. at 20 ° C./min using a differential scanning calorimeter (DSC), and the melting process is clearly melted. This refers to the peak.

  By making the acid-modified polyolefin crystalline, it is advantageous because it has a stronger cohesive force and better adhesion and heat resistance than amorphous.

  The melting point (Tm) of the crystalline acid-modified polyolefin (A) is preferably in the range of 50 ° C to 120 ° C. More preferably, it is the range of 60 to 100 degreeC, Most preferably, it is the range of 70 to 90 degreeC. If it is less than the above value, the cohesive force derived from the crystal becomes weak, and the adhesiveness and heat resistance may be inferior. On the other hand, when the above value is exceeded, the solution stability and fluidity are low, and there may be a problem in operability when bonding.

  The heat of fusion (ΔH) of the crystalline acid-modified polyolefin (A) is preferably in the range of 5 J / g to 60 J / g. More preferably, it is the range of 10 J / g-50 J / g, Most preferably, it is the range of 20 J / g-40 J / g. If it is less than the above value, the cohesive force derived from the crystal becomes weak, and the adhesiveness and heat resistance may be inferior. On the other hand, when the above value is exceeded, the solution stability and fluidity are low, and there may be a problem in operability when bonding.

  The production method of the crystalline acid-modified polyolefin (A) is not particularly limited. For example, a radical graft reaction (that is, a radical species is generated with respect to a polymer to be a main chain, and the radical species is used as a polymerization initiation point to produce an unsaturated carboxylic acid. Reaction for graft polymerization of acid and acid anhydride), and the like.

  Although it does not specifically limit as a radical generator, It is preferable to use an organic peroxide. The organic peroxide is not particularly limited, but di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy- Peroxides such as 2-ethylhexanoate, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide; azobisisobutyronitrile, azobisisopropionitrile, etc. Examples thereof include azonitriles.

  The content of the component (A) in the adhesive composition of the present invention is preferably 5% by mass or more, more preferably 7% by mass or more, and further preferably 10% by mass or more. Moreover, it is preferable that it is 90 mass% or less, 80 mass% or less is more preferable, and 70 mass% or less is further more preferable. If it is too little or too much, the adhesiveness and heat resistance may be lowered.

<(B) component: amorphous polyolefin (B)>
The component (B) is an amorphous polyolefin. The amorphous polyolefin (B) used in the present invention is not limited, but homopolymerization of olefin monomers exemplified by ethylene, propylene, butene, butadiene, isoprene, etc., or copolymerization with other monomers, and obtained Of the polymers mainly composed of a hydrocarbon skeleton, such as hydrides and halides of polymers, amorphous ones are preferred.

  The amorphous property in the amorphous polyolefin (B) is the heat of fusion (ΔH) when the temperature is raised from −100 ° C. to 250 ° C. at 20 ° C./min using a differential scanning calorimeter (DSC). What is 10 J / g or less is preferable.

  By compounding amorphous polyolefin, stress concentration of peeling stress at the interface between the adhesive and the substrate can be prevented by improving the wettability of the adhesive to the substrate and the flexibility of the adhesive composition. .

  The heat of fusion (ΔH) of the amorphous polyolefin (B) is preferably 10 J / g or less, more preferably 5 J / g or less, and even more preferably 3 J / g or less. Although a minimum is not specifically limited, It is 0 J / g or more. When the above value is exceeded, the degree of crystallinity becomes high, so that the wettability to the substrate is lowered, and the peeling stress is concentrated on the interface, so that the adhesive strength may be lowered.

The glass transition temperature (Tg) of the amorphous polyolefin (B) is preferably in the range of −70 to 30 ° C. More preferably, it is the range of -50 degreeC-25 degreeC, Most preferably, it is the range of -30 degreeC-20 degreeC. If it is less than the above value, the tackiness of the adhesive is strong and the processability may be inferior. On the other hand, when the above value is exceeded, there is a problem that the adhesiveness near room temperature is lowered.

  In the adhesive composition of the present invention, the content of the amorphous polyolefin (B) is preferably in the range of 10 to 100 parts by mass with respect to 100 parts by mass of the crystalline acid-modified polyolefin (A). More preferably, it is the range of 13-90 mass parts, Most preferably, it is the range of 15-80 mass parts. If it is less than the above value, the wettability to the substrate is lowered, and the peeling stress is concentrated on the interface, so that the adhesive strength may be lowered. When the above value is exceeded, the strength of the adhesive composition itself is lowered, and there is a problem that the adhesive is lowered.

<(C) component: carbodiimide resin (C)>
Component (C) is a carbodiimide resin. The carbodiimide resin (C) is not particularly limited as long as it has a carbodiimide group in the molecule. Preferably, it is polycarbodiimide having two or more carbodiimide groups in the molecule. By using the carbodiimide resin (C), the carboxyl group of the acid-modified polyolefin (A) reacts with the carbodiimide, so that the interaction between the adhesive composition and the substrate can be enhanced and the adhesiveness can be improved.

In the adhesive composition of the present invention, the content of the carbodiimide resin (C) is preferably in the range of 0.5 to 30 parts by mass with respect to 100 parts by mass of the crystalline acid-modified polyolefin (A). More preferably, it is the range of 1-25 mass parts, Most preferably, it is the range of 2-20 mass parts. If it is less than the above value, there is a problem that the interaction with the substrate does not appear and the adhesiveness is lowered. When the above value is exceeded, there is a problem that the pot life of the adhesive is lowered and the low dielectric properties are lowered.

<(D) component: Epoxy resin (D)>
(D) A component is an epoxy resin. The epoxy resin (D) is not particularly limited as long as it has 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 tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, tetraglycidylbisaminomethylcyclohexanone, N, N, N ′, N′-tetraglycidyl-m-xylenediamine can be used. Bisphenol A type epoxy resin, novolak type epoxy resin or dicyclopentadiene type epoxy resin is preferable.

In the adhesive composition of the present invention, the content of the epoxy resin (D) is preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the crystalline acid-modified polyolefin (A). The range is more preferably in the range of parts by mass, and most preferably in the range of 3 to 10 parts by mass. If it is less than the said range, sufficient hardening effect cannot be acquired but adhesiveness and heat resistance may fall. Further, if the amount is within the above range, there are problems that the pot life of the adhesive is lowered and the low dielectric properties are lowered.

<Adhesive composition>
The adhesive composition of the present invention contains the crystalline acid-modified polyolefin (A) and the amorphous polyolefin (B), and further contains any one of a carbodiimide resin (C) and an epoxy resin (D). It is a thing.

  The adhesive composition of the present invention contains the component (A), the component (B) and the component (C), so that the electrical properties (low dielectric properties) are excellent, and a low-polarity resin substrate such as LCP and a metal High adhesiveness with the substrate can be expressed. Moreover, by containing (A) component, (B) component, and (D) component, it is excellent in electrical characteristics, and expresses high solder heat resistance between a low polarity resin substrate such as LCP and a metal substrate. Can do. Furthermore, by including the components (A) to (D), all of excellent adhesion between a low-polarity resin substrate such as LCP and a metal substrate, solder heat resistance, and electrical properties (low dielectric properties) are exhibited. be able to. That is, the adhesive film (adhesive layer) after applying and curing the adhesive composition on the substrate exhibits excellent low dielectric constant characteristics. Specifically, the dielectric constant (ε) at a frequency of 1 MHz of the cured adhesive coating film is preferably 3.0 or less, more preferably 2.6 or less, and 2.3 or less. More preferably. The dielectric loss tangent (tan δ) is preferably 0.02 or less, more preferably 0.01 or less, and further preferably 0.005 or less. Furthermore, the adhesive composition of the present invention preferably has a dielectric constant (ε) of 3.0 or less in the entire region of the frequency of 1 MHz to 1 GHz of the adhesive coating film after curing, and preferably 2.6 or less. More preferably, it is 2.3 or less. The dielectric loss tangent (tan δ) is preferably 0.02 or less, more preferably 0.01 or less, and further preferably 0.005 or less. Moreover, it is especially preferable that the dielectric constant (ε) and the dielectric loss tangent (tan δ) in the entire region of the frequency of 1 MHz to 10 GHz of the adhesive coating film after curing are in the above ranges.

<(E) component: organic solvent (E)>
The adhesive composition of the present invention can further contain an organic solvent (E). The organic solvent (E) used in the present invention is particularly limited as long as it dissolves the crystalline acid-modified polyolefin (A), the amorphous polyolefin (B), the carbodiimide resin (C), and the epoxy resin (D). Not. Specifically, for example, aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as hexane, heptane, octane and decane, and alicyclic carbons such as cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane Halogenated hydrocarbons such as hydrogen, trichloroethylene, dichloroethylene, chlorobenzene, chloroform, alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, phenol, acetone, methyl isobutyl ketone, Ketone solvents such as methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, acetophenone, cellsolves such as methyl cellosolve, ethyl cellosolve, methyl acetate, ethyl acetate, vinegar Ester solvents such as butyl, methyl propionate, butyl formate, ethylene glycol mono n-butyl ether, ethylene glycol mono iso-butyl ether, ethylene glycol mono tert-butyl ether, diethylene glycol mono n-butyl ether, diethylene glycol mono iso-butyl ether, triethylene glycol Glycol ether solvents such as mono n-butyl ether and tetraethylene glycol mono n-butyl ether can be used, and one or more of these can be used in combination. A preferred embodiment is a mixed solvent of an alicyclic hydrocarbon and a ketone solvent, and among them, cyclohexane or methylcyclohexane is preferably used for the alicyclic hydrocarbon, and methyl isobutyl ketone or methyl ethyl ketone is preferably used for the ketone solvent. . The mixing ratio of the alicyclic hydrocarbon and the ketone solvent is preferably alicyclic hydrocarbon / ketone solvent = 50 to 90/50 to 10 (mass ratio), and is preferably 55 to 85/45. It is more preferable that it is -15 (mass ratio), and it is further more preferable that it is 60-80 / 40-20 (mass ratio).

  The organic solvent (E) is preferably in the range of 100 to 1000 parts by weight, more preferably in the range of 200 to 900 parts by weight, with respect to 100 parts by weight of the crystalline acid-modified polyolefin (A). Most preferably, it is ˜800 parts by mass or more. If it is less than the said range, liquid state and pot life property will fall. Moreover, when the said range is exceeded, there exists a problem which becomes disadvantageous from the surface of manufacturing cost and transport cost.

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

(Flame retardants)
You may mix | blend a flame retardant with the adhesive composition of this invention as needed. Examples of the flame retardant include bromine, phosphorus, nitrogen, and metal hydroxide compounds. Among these, phosphorus-based flame retardants are preferable, and phosphoric acid esters such as trimethyl phosphate, triphenyl phosphate, tricresyl phosphate, phosphates such as aluminum phosphinate, phosphazenes, and other known phosphorus flame retardants can be used. . When the flame retardant is contained, the flame retardant is preferably contained 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 100 parts by mass in total of the components (A) to (D). The range of 10 to 100 parts by mass is most preferable. If it is less than the said range, a flame retardance is low. When the above range is exceeded, there is a problem that the adhesiveness, heat resistance, electrical characteristics and the like deteriorate.

(Tackifier)
You may mix | blend a tackifier with the adhesive composition of this invention as needed. Examples of tackifiers include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymer petroleum resins, styrene resins, and hydrogenated petroleum resins, which improve adhesive strength. Used for purposes. These may be used alone or in any combination of two or more.

(Filler)
You may mix | blend fillers, such as a silica, with the adhesive composition of this invention as needed. It is very preferable to add silica because heat resistance 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 good. It is preferable that the compounding quantity of a silica is a compounding quantity of 0.05-30 mass parts with respect to a total of 100 mass parts of component (A)-(D). If it is less than 0.05 parts by mass, the effect of improving the heat resistance may not be exhibited. On the other hand, when the amount exceeds 30 parts by mass, there may be a case where poor dispersion of silica occurs, the solution viscosity becomes too high, and the workability is deteriorated or the adhesiveness is lowered.

(Silane coupling agent)
You may mix | blend a silane coupling agent with the adhesive composition of this invention as needed. It is very preferable to add a silane coupling agent because adhesion to metal and heat resistance are improved. Although it does not specifically limit as a silane coupling agent, What has an unsaturated group, What has a glycidyl group, What has an amino group, etc. are mentioned. Among these, from the viewpoint of heat resistance, glycidyl such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and the like. A silane coupling agent having a group is more preferable. It is preferable that the compounding quantity of a silane coupling agent is a compounding quantity of 0.5-20 mass parts with respect to a total of 100 mass parts of component (A)-(D). If it is less than 0.5 parts by mass, heat resistance may be deteriorated. On the other hand, if it exceeds 20 parts by mass, heat resistance failure and adhesiveness may decrease.

<Laminated body>
The laminate of the present invention is a laminate in which an adhesive composition is laminated on a substrate (two-layer laminate of substrate / adhesive layer), or a laminate in which a substrate is further bonded (substrate / adhesive layer / 3 layer laminate of base materials). Here, an adhesive layer means the layer of the adhesive composition after apply | coating the adhesive composition of this invention to a base material, and making it dry. By applying and drying the adhesive composition of the present invention on various substrates according to a conventional method, and further laminating other substrates, the laminate of the present invention can be obtained.

<Base material>
In the present invention, the substrate is not particularly limited as long as it can apply and dry the adhesive composition of the present invention to form an adhesive layer, but it is not limited to a resin substrate such as a film-like resin, metal Examples thereof include metal substrates such as plates and metal foils, and papers.

  Examples of the resin substrate include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluorine resin. A film-like resin (hereinafter also referred to as a base film layer) is preferable.

  Any conventionally known conductive material that can be used for the circuit board can be used as the metal substrate. Examples of the material include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, and alloys, plated products, metals treated with other metals such as zinc and chromium compounds, and the like. Metal foil is preferable, and copper foil is more preferable. Although there is no limitation in particular about the thickness of metal foil, Preferably it is 1 micrometer or more, More preferably, it is 3 micrometers or more, More preferably, it is 10 micrometers or more. Moreover, 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. On the other hand, if the thickness is too thick, the processing efficiency at the time of circuit fabrication may be reduced. The metal foil is usually provided in the form of a roll. The form of the metal foil used when manufacturing the printed wiring board of this invention is not specifically limited. In the case of using a ribbon-like metal foil, the length is not particularly limited. Moreover, the width is not particularly limited, but is preferably about 250 to 500 cm.

  Examples of the paper include high-quality paper, kraft paper, roll paper, and glassine paper. Moreover, glass epoxy etc. can be illustrated as a composite material.

  From the adhesive strength and durability with the adhesive composition, as a base material, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, fluorine resin, A SUS steel plate, copper foil, aluminum foil, or glass epoxy is preferred.

<Adhesive sheet>
In the present invention, the adhesive sheet is obtained by laminating the laminate and the release substrate via an adhesive composition. Specific examples of the configuration include laminate / adhesive layer / release substrate, or release substrate / adhesive layer / laminate / adhesive layer / release substrate. By laminating the release substrate, it functions as a protective layer for the substrate. Further, by using a release substrate, the release substrate can be released from the adhesive sheet, and the adhesive layer can be transferred to another substrate.

  The adhesive sheet of this invention can be obtained by apply | coating and drying the adhesive composition of this invention to various laminated bodies according to a conventional method. In addition, when a release substrate is pasted to the adhesive layer after drying, it can be rolled up without causing any back-off to the substrate, and it is excellent in operability and the adhesive layer is protected so that it can be stored. Excellent and easy to use. Further, after application and drying on the release substrate, if another release substrate is attached as necessary, the adhesive layer itself can be transferred to another substrate.

<Release substrate>
The release substrate is not particularly limited. For example, a coating layer of a sealant such as clay, polyethylene, or polypropylene is formed on both surfaces of paper such as fine paper, kraft paper, roll paper, and glassine paper. Further, there may be mentioned those in which a silicone-type, fluorine-type, or alkyd-type release agent is further applied on each coating layer. In addition, various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, propylene-α-olefin copolymer alone, and those obtained by applying the release agent on a film such as polyethylene terephthalate are also included. For the reasons such as the release force between the release substrate and the adhesive layer, and the adverse effect of silicone on the electrical characteristics, polypropylene seal treatment is applied to both sides of the fine paper and an alkyd release agent is used on it. Or what uses an alkyd type mold release agent on polyethylene terephthalate is preferred.

  In addition, although it does not specifically limit as a method of coating an adhesive composition on a base material in this invention, A comma coater, a reverse roll coater, etc. are mentioned. Alternatively, if necessary, an adhesive layer can be provided directly or by a transfer method on a rolled copper foil, which is a printed wiring board constituent material, or a polyimide film. Although the thickness of the adhesive bond layer after drying is changed suitably as needed, Preferably it is the range of 5-200 micrometers. When the adhesive film thickness is less than 5 μm, the adhesive strength is insufficient. When the thickness is 200 μm or more, there is a problem that drying is insufficient, a residual solvent increases, and bulge is generated at the time of printed circuit board production. 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 in that the residual solvent is foamed during the printed circuit board press, resulting in blistering.

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

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

  Furthermore, if necessary, a configuration in which two or three or more of the above-described printed wiring boards are stacked may be employed.

  The adhesive composition of the present invention can be suitably used for each adhesive layer of a printed wiring board. In particular, when the adhesive composition of the present invention is used as an adhesive, it has high adhesion to low-polarity resin base materials such as LCP as well as conventional polyimide, polyester film and copper foil constituting printed wiring boards. 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 a coverlay film, a laminate, a resin-coated copper foil, and a bonding sheet.

  In the printed wiring board of the present invention, as the substrate film, any resin film conventionally used as a substrate for printed wiring boards can be used. Examples of the resin for 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 adhesion to low-polar substrates such as liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resins.

<Cover film>
As the cover film, any conventionally known insulating film can be used as an insulating film for a printed wiring board. 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, polyolefin resin, etc. Film can be used. More preferably, it is a polyimide film or a liquid crystal polymer film.

The printed wiring board of the present invention can be produced using any conventionally known process except that the material of each layer described above is used.

  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 produced. On the other hand, an adhesive layer is laminated on a semi-finished product (hereinafter referred to as “base film side two-layer semi-product”) or a base film layer in which a desired circuit pattern is formed by laminating a metal foil layer on the base film layer. And a semi-finished product (hereinafter referred to as “base film side three-layer semi-product”) having a desired circuit pattern formed by laminating a metal foil layer thereon (hereinafter referred to as base film side two-layer semi-product) The base film side three-layer semi-finished product is collectively referred to as “base film side semi-finished product”). A four-layer or five-layer printed wiring board can be obtained by laminating the cover film side semi-finished product and the base film side semi-finished product thus obtained.

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

  A conventionally known method can be used to form a circuit in the metal foil layer. An active method may be used and a 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 pasting with the cover film side semi-finished product. May be used.

  The cover film side semi-finished product is manufactured, for example, by applying an adhesive to the cover film. If necessary, a crosslinking reaction in the applied adhesive can be performed. 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 pasting with the base-side semi-finished product, or after being laminated and stored with the release film for pasting with the base-film-side semi-finished product. May be used.

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

  In the case of a reinforcing material that can be rolled up softly, such as a polyimide film, the reinforcing material-side semi-finished product is preferably manufactured by applying an adhesive to the reinforcing material. Also, for example, in the case of a reinforcing plate that cannot be rolled up hard, such as a metal plate such as SUS or aluminum, or a plate in which glass fibers are cured with an epoxy resin, by transferring and applying an adhesive previously applied to a release substrate. It is preferred to be manufactured. Moreover, the crosslinking reaction in the apply | coated adhesive agent can be performed as needed. In a preferred embodiment, the adhesive layer is semi-cured.

  The obtained reinforcing material-side semi-finished product may be used as it is for pasting with the back side of the printed wiring board, and after being used for pasting with the base film-side semi-finished product after storing the release film. May be.

  The base film side semi-finished product, the cover film side semi-finished product, and the reinforcing agent side semi-finished product are all laminated bodies for printed wiring boards 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, “parts” simply means “parts by mass”.

(Physical property evaluation method)

Acid value The acid value (equivalent / 10 ⁶ g) in the present invention was determined by using FT-IR (manufactured by Shimadzu Corporation, FT-IR8200PC), a stretching peak (1780 cm) of a carbonyl (C = O) bond of maleic anhydride. ^-1 ) absorbance (I), isotactic specific peak (840 cm ^-1 ) absorbance (II), and factor (f) obtained from a calibration curve prepared with a chloroform solution of maleic anhydride (manufactured by Tokyo Kasei). It is the value calculated by the following formula using.
Acid value = [absorbance (I) / absorbance (II) × (f) / molecular weight of maleic anhydride × 2 × 10 ⁴ ]
Maleic anhydride molecular weight: 98.06

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).

Melting point (Tm), heat of fusion (ΔH), glass transition temperature (Tg)
In the present invention, the melting point, heat of fusion, and glass transition temperature (Tg) were annealed from room temperature to 200 ° C. at a rate of temperature increase of 20 ° C./minute using a differential scanning calorimeter (hereinafter referred to as DSC), and then rapidly cooled with liquid nitrogen The temperature is increased from −100 ° C. to 200 ° C. at a rate of 20 ° C./min, the intersection of the tangent at the base line and the inflection point (glass transition temperature), the top temperature (melting point) of the melting peak, and the baseline It is a value measured from the area surrounded by the extension line and the melting peak.

(1) Evaluation of pot life property Pot life property means that a crystalline acid-modified polyolefin, an amorphous polyolefin, a carbodiimide resin, and an epoxy resin are blended and immediately after blending or after 24 hours have elapsed in a room temperature atmosphere after blending. Refers to the stability of the solution. If the pot life is good, it means that the viscosity of the solution is small and can be stored for a long time. If the pot life is poor, the viscosity of the solution increases (thickens). It means that gelation occurs, application to a substrate becomes difficult, and long-term storage is impossible.
<Evaluation criteria>
○: Applicable △: Increased in viscosity and inferior in workability, but can be applied ×: Not applicable due to increased viscosity or gelation

(2) Peel strength (adhesiveness)
An adhesive composition described later is applied to a 25 μm thick polyimide film (manufactured by Kaneka Corporation, Apical) or a 50 μm thick LCP film (manufactured by Kuraray Co., Ltd., Bexter) so that the thickness after drying is 25 μm. It was applied and dried at 130 ° C. for 3 minutes. The adhesive film (B stage product) thus obtained was bonded to 18 μm rolled copper foil. Bonding was performed by pressing for 30 seconds under a pressure of 40 kgf / cm ² at 160 ° C. so that the glossy surface of the rolled copper foil was in contact with the adhesive. Subsequently, it was cured by heat treatment at 140 ° C. for 4 hours to obtain a sample for peel strength evaluation. The peel strength was measured by pulling a film at 25 ° C., performing a 90 ° peel test at a tensile speed of 50 mm / min, and measuring the peel strength. This test shows the adhesive strength at room temperature.
<Evaluation criteria>
☆: 1.5 N / mm or more ◎: 1.3 N / mm or more and less than 1.5 N / mm ○: 1.0 N / mm or more and less than 1.3 N / mm △: 0.8 N / mm or more and less than 1.0 N / mm ×: Less than 0.8 N / mm

(3) Solder heat resistance A sample is prepared by the same method as described above, and a 2.5 cm × 2.5 cm sample piece is dried at 120 ° C. for 30 minutes, and flows into a solder bath melted at each temperature for 1 minute. The temperature at which no change in appearance such as blistering occurred was measured.
<Evaluation criteria>
☆: 310 ° C or more ◎: 300 ° C or more and less than 310 ° C ○: 290 ° C or more and less than 300 ° C △: 270 ° C or more and less than 290 ° C ×: less than 270 ° C

(4) Dielectric constant (ε) and dielectric loss tangent (tan δ)
The adhesive composition described later was applied to a release film having a thickness of 50 μm so that the thickness after drying was 30 μm, and dried at 130 ° C. for 3 minutes. Subsequently, it was cured by heat treatment at 140 ° C. for 4 hours, peeled off from the release film, and measured. Using a PRECISION LCR meter HP-4284A, measurement was carried out under the conditions of 22 MHz 58% RH and a frequency of 1 MHz, and evaluated as follows. Similarly, using VECTOR NETWORK ANALYZER HP8510C, SYNTHESIZED SWEEPER HP83651A, and TEST SET HP8517B, measurement was performed under the conditions of 22 ° C. and 58 RH% at a frequency of 1 GHz and evaluated as follows.
<Evaluation criteria for dielectric constant>
◎: 2.3 or less ○: 2.3 to 2.6 or less Δ: 2.6 to 3.0 or less ×: 3.0 or more <Evaluation criteria of dielectric loss tangent>
◎: 0.005 or less ○: Over 0.005 and 0.01 or less △: Over 0.01 and 0.02 or less ×: Over 0.02

(Crystalline acid-modified polyolefin)
Production Example 1
In a 1 L autoclave, propylene-butene copolymer (“Tuffmer (registered trademark) XM7080” manufactured by Mitsui Chemicals) 100 parts by mass, toluene 150 parts by mass and maleic anhydride 22 parts by mass, di-tert-butyl peroxide 6 parts by mass Was added and the temperature was raised to 140 ° C., followed by further stirring for 3 hours. Then, after cooling the obtained reaction liquid, it poured into the container containing a lot of methyl ethyl ketone, and resin was deposited. Thereafter, the liquid containing the resin was centrifuged to separate and purify an acid-modified propylene-butene copolymer grafted with maleic anhydride, (poly) maleic anhydride and a low molecular weight product. Thereafter, by drying for 5 hours at 70 ° C. under reduced pressure, a maleic anhydride-modified propylene-butene copolymer (CO-1, acid value 570 equivalents / 10 ⁶ g, weight average molecular weight 55,000, Tm 75 ° C., ΔH25J / G).

Production Example 2
A maleic anhydride-modified propylene-butene copolymer (CO-2, acid value 410 equivalents / 10 ⁶ g, weight) except that the amount of maleic anhydride charged was changed to 19 parts by mass. Average molecular weight 60,000, Tm 75 ° C., ΔH 30 J / g).

Production Example 3
A maleic anhydride-modified propylene-butene copolymer (with the same procedure as in Production Example 1 except that the amount of maleic anhydride charged was changed to 4 parts by mass and the amount of di-tert-butyl peroxide was changed to 0.5 parts by mass ( CO-3, acid value 150 equivalents / 10 ⁶ g, weight average molecular weight 160,000, Tm 80 ° C., ΔH 25 J / g).

Production Example 4
A maleic anhydride-modified propylene-butene copolymer (CO-4, acid value of 980 equivalents / 10 ⁶ g, weight, except that the amount of maleic anhydride charged was changed to 30 parts by mass. Average molecular weight 40,000, Tm 70 ° C., ΔH25 J / g).

Production Example 5
A maleic anhydride-modified propylene-butene copolymer (with the same procedure as in Production Example 1 except that the amount of maleic anhydride charged was changed to 2 parts by mass and the di-tert-butyl peroxide was changed to 0.5 parts by mass ( CO-5, acid value 53 equivalent / 10 ⁶ g, weight average molecular weight 200,000, Tm 80 ° C., ΔH 25 J / g).

(Amorphous polyolefin)
Production Example 6
To 1 L autoclave, 100 parts by mass of amorphous polyolefin (“Tufselen (registered trademark) X1102) manufactured by Sumitomo Chemical Co., Ltd.”, 150 parts by mass of methylcyclohexane and 1 part by mass of maleic anhydride and 1 part by mass of di-tert-butyl peroxide were added. After heating up to 140 ° C., the mixture was further stirred for 3 hours, after which 130 parts by mass of methylcyclohexane and 120 parts by mass of methyl ethyl ketone were added to form an amorphous acid-modified polyolefin (AO-1, acid value 50 equivalents / 10 ⁶ g, A solution having a weight average molecular weight of 140,000, ΔH0J / g, Tg−10 ° C. was obtained.

Production Example 7
In a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer, 100 parts by mass of amorphous polyolefin (“Tufselen (registered trademark) X1102) manufactured by Sumitomo Chemical Co., Ltd.”, 280 parts by mass of methylcyclohexane, and 120 parts by mass of methyl ethyl ketone were added. In addition, a solution of amorphous polyolefin (Tuff Selenium X1102, acid value 0 equivalent / 10 ⁶ g, weight average molecular weight 658,000, ΔH 0 J / g, Tg-9 ° C.) was obtained.

Example 1
In a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer, 100 parts by mass of the maleic anhydride-modified propylene-butene copolymer (CO-1) obtained in Production Example 1 and amorphous acid modification 100 parts by mass of polyolefin solution (20 parts by mass as a solid resin), 224 parts by mass of methylcyclohexane, and 96 parts by mass of methyl ethyl ketone were charged, heated to 80 ° C. with stirring, and dissolved by continuing stirring for 1 hour. To the solution obtained by cooling, 5 parts by mass of carbodiimide resin V-05 and 10 parts by mass of epoxy resin YDCN-700-10 were blended to obtain an adhesive composition. Table 1 shows the blending amount, pot life, adhesive strength, solder heat resistance, and electrical characteristics (frequency 1 MHz).

Examples 2-13
The crystalline acid-modified polyolefin, the amorphous polyolefin, the carbodiimide resin, and the epoxy resin are changed to those shown in Table 1, and are changed to the respective compounding amounts shown in Table 1 in the same manner as in Example 1. Examples 2-13 were performed. Table 1 shows the pot life, adhesive strength, solder heat resistance, and electrical characteristics (frequency 1 MHz). In Example 2, the electrical characteristics were measured under the condition of a frequency of 1 GHz. As a result, the dielectric constant (ε) was evaluated as “◎” and the dielectric loss tangent (tan δ) was evaluated as “◎”.

Comparative Example 1
The crystalline acid-modified polyolefin, the amorphous polyolefin, the carbodiimide resin, and the epoxy resin are changed to those shown in Table 2, and are changed in the same manner as in Example 1 so that the blending amounts shown in Table 2 are obtained. Example 1 was performed. Table 2 shows the blending amount, pot life, adhesive strength, solder heat resistance, and electrical characteristics (frequency 1 MHz).

Comparative Example 2
Carboxyl group-containing acrylonitrile butadiene rubber NBR (manufactured by JSR Co., Ltd.), carbodiimide resin, and epoxy resin were changed to those shown in Table 2, and changed to the compounding amounts shown in Table 2 in the same manner as in Example 1. Comparative Example 2 was performed. Table 2 shows the blending amount, pot life, adhesive strength, solder heat resistance, and electrical characteristics (frequency 1 MHz). When the electrical characteristics were measured under the condition of a frequency of 1 GHz, the dielectric constant (ε) was evaluated as “x” and the dielectric loss tangent (tan δ) was evaluated as “x”.

The carbodiimide resin (C) and epoxy resin (D) used in Tables 1 and 2 are as follows.
Carbodiimide resin: V-05 (Nisshinbo Chemical Co., Ltd.)
Carbodiimide resin: V-03 (Nisshinbo Chemical Co., Ltd.)
o-Cresol novolac type epoxy resin: YDCN-700-10 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Bisphenol A type epoxy resin: JER-828 (Mitsubishi Chemical Corporation)
Dicyclopentadiene type epoxy resin: HP-7200 (manufactured by DIC)

  As is apparent from Table 1, in Examples 1 to 13, both the liquid crystal polymer (LCP) and the copper foil were excellent in pot life, and had excellent adhesion and solder heat resistance with polyimide (PI) and copper foil. Excellent adhesion and solder heat resistance. Also, the electrical properties of the adhesive composition are low and good in both dielectric constant and dielectric loss tangent. On the other hand, as is clear from Table 2, Comparative Example 1 does not contain amorphous polyolefin, and therefore cannot relieve stress and has low adhesive strength. Since Comparative Example 2 does not contain crystalline acid-modified polyolefin, the adhesive strength with LCP is low, and 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 a resin base material having a low dielectric property such as LCP and a metal base material such as copper foil has high adhesiveness and high solder heat resistance. An adhesive composition that can be obtained and has excellent low dielectric properties. An adhesive sheet and a laminated body bonded using the adhesive sheet can be obtained. Due to the above characteristics, it is useful in flexible printed wiring board applications, particularly in FPC applications that require low dielectric properties (low dielectric constant, low dielectric loss tangent) in a high frequency region.

Claims (8)

An adhesive containing the following components (A), (B) and (D), having a dielectric constant (ε) of 3.0 or less and a dielectric loss tangent (tan δ) of 0.02 or less at a frequency of 1 MHz. Composition.
(A) Component: Crystalline acid-modified polyolefin (B) Component: Amorphous polyolefin (D) Component: Epoxy resin   The adhesive composition according to claim 1, wherein the component (A) is contained in an amount of 5% by mass or more.   The adhesive composition according to claim 1 or 2, comprising 10 to 100 parts by mass of (B) component and 1 to 30 parts by mass of component (D) with respect to 100 parts by mass of (A) component.   (A) The adhesive composition in any one of Claims 1-3 which contains 100-1000 mass parts of organic solvents (E) with respect to 100 mass parts of components.   The adhesive composition according to any one of claims 1 to 4, which is used for adhesion between a resin substrate and a resin substrate or a metal substrate.   The laminated body of the resin base material adhere | attached with the adhesive composition in any one of Claims 1-5, and a resin base material or a metal base material.   An adhesive sheet containing the laminate according to claim 6.   A printed wiring board comprising the laminate according to claim 6 or the adhesive sheet according to claim 7 as a component.