JP6761588B2 - Low Dielectric Adhesive Composition - Google Patents

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 adhering a resin base material to a resin base material or a metal base material. 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 a resin, and a bonding sheet containing the same.

In recent years, as the speed of transmission signals on printed wiring boards has increased, the frequency of signals has been increasing. Along with this, there is an increasing demand for FPCs to have low dielectric properties (low dielectric constant, low dielectric loss tangent) in the high frequency region. In response to such demands, as a base film used for FPC, a liquid crystal polymer (LCP) having low dielectric properties, a syndiotactic polystyrene (SPS), instead of the conventional polyimide (PI) and polyethylene terephthalate film, Base films such as polyphenylene sulfide (PPS) have been proposed.
However, since the base film having low dielectric properties has low polarity, the adhesive strength is weak when a conventional epoxy adhesive or acrylic adhesive is used, and FPC members such as coverlay films and laminated boards are manufactured. Was difficult. Further, epoxy adhesives and acrylic adhesives are not excellent in low dielectric properties and impair the dielectric properties of FPCs.
On the other hand, polyolefin resins are known to have low dielectric properties. Therefore, an adhesive composition for FPC using a polyolefin resin has been proposed. For example, Patent Document 1 proposes a modified polyamide adhesive composition incorporating an olefin skeleton in order to enhance the electrical properties of FPC. Further, Patent Document 2 proposes an adhesive using an aromatic olefin oligomer type modifier and an epoxy resin, and a flexible printed wiring board coverlay.

JP-A-2007-284515 JP-A-2007-63306

However, although these adhesive compositions have been described as having adhesiveness to polyimide, it is difficult to obtain adhesiveness to a base film having low dielectric properties such as LCP. Further, since it is used as a modifier and the olefin skeleton occupying the adhesive composition is small, the dielectric property of the adhesive is inferior.
Further, when an LCP base material is used, there is a method of melting the LCP without using an adhesive and laminating it with a copper foil to prepare a two-layer substrate. However, this method has problems that a machine base for laminating at a high temperature is required, wrinkles are likely to occur during processing, and the yield is lowered.

As a result of diligent studies to solve the above problems, the present invention is excellent in an 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 solder heat resistance between a resin base material having low dielectric properties such as LCP and a metal base material such as copper foil as well as conventional polyimide and polyethylene terephthalate films while exhibiting low dielectric properties. It was found that the present invention was completed.

That is, the present invention provides an adhesive composition having good adhesiveness to both various resin substrates such as polyimide and LCP and metal substrates, and also having excellent heat resistance and low dielectric properties. With the goal.

An adhesive composition containing the following components (A) and (B), and further containing at least one of the components (C) and (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.

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

It is preferable that the organic solvent (E) is contained in an amount of 100 to 1000 parts by mass with respect to 100 parts by mass of the component (A).

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

The adhesive composition according to any one of the above is preferably used for adhering a resin base material to a resin base material or a metal base material.

A laminate of a resin base material adhered by the adhesive composition according to any one of the above and a resin base material or a metal base material.

An adhesive sheet containing the laminate.

A printed wiring board containing the laminate or the adhesive sheet as a component.

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 is possible to exhibit excellent low dielectric properties, and to obtain not only conventional polyimide and polyester films but also high adhesiveness between a low-polarity resin base material such as LCP and a metal base material and high solder heat resistance. ..

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

<Component (A): 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 crystalline obtained by grafting at least one α, β-unsaturated carboxylic acid and an acid anhydride thereof on the polyolefin resin. Is preferable. The polyolefin resin is a hydrocarbon such as homopolymerization of an olefin monomer exemplified by ethylene, propylene, butene, butadiene, isoprene, or copolymerization with other monomers, and hydrides and halides of the obtained polymer. Refers to a polymer whose main component is the skeleton. That is, the crystalline acid-modified polyolefin is obtained by grafting at least one of α, β-unsaturated carboxylic acid and its acid anhydride on at least one of polyethylene, polypropylene and a propylene-α-olefin copolymer. The crystalline one obtained by the above is preferable.

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

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

The acid value of the crystalline acid-modified polyolefin (A), from the viewpoint of adhesion between the heat resistance and the resin base material or metal substrate, the lower limit is not particularly limited, but is preferably 50 eq / 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. 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 addition, the crosslink density may be low and the heat resistance may be 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, most preferably 600 equivalent / 10 ⁶ g or less. If it exceeds the above value, the adhesiveness may decrease. In addition, the viscosity and stability of the solution may decrease, and the pot life property may decrease. Further, the production efficiency is lowered, which is not preferable.

The weight average molecular weight (Mw) of the crystalline acid-modified polyolefin (A) is preferably in the range of 40,000 to 180,000. It is more preferably in the range of 50,000 to 160,000, further preferably in the range of 60,000 to 150,000, particularly preferably in the range of 70,000 to 140,000, and most preferably in the range of 80. It ranges from 000 to 130,000. If it is less than the above value, the cohesive force may be weakened and the adhesiveness may be poor. On the other hand, if it exceeds the above value, the fluidity is low and there may be a problem in operability at the time of bonding.

Crystallinity in 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 clear melting occurs during the heating process. Refers to those showing a peak.

Making the acid-modified polyolefin crystalline is advantageous because it has stronger cohesive force and is excellent in adhesiveness and heat resistance as compared with amorphous.

The melting point (Tm) of the crystalline acid-modified polyolefin (A) is preferably in the range of 50 ° C. to 120 ° C. It is more preferably in the range of 60 ° C to 100 ° C, and most preferably in the range of 70 ° C to 90 ° C. If it is less than the above value, the cohesive force derived from the crystal is weakened, and the adhesiveness and heat resistance may be inferior. On the other hand, if it exceeds the above value, the solution stability and fluidity are low, and there may be a problem in operability at the time of adhesion.

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. It is more preferably in the range of 10 J / g to 50 J / g, and most preferably in the range of 20 J / g to 40 J / g. If it is less than the above value, the cohesive force derived from the crystal is weakened, and the adhesiveness and heat resistance may be inferior. On the other hand, if it exceeds the above value, the solution stability and fluidity are low, and there may be a problem in operability at the time of adhesion.

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

The radical generator is not particularly limited, but it is preferable to use an organic peroxide. The organic peroxide is not particularly limited, but is di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-. Peroxides such as 2-ethylhexanoate, tert-butylperoxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide; azobisisobutyronitrile, azobisisopropionitrile, etc. Examples 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, still more preferably 10% by mass or more. Further, it is preferably 90% by mass or less, more preferably 80% by mass or less, and further preferably 70% by mass or less. Adhesiveness and heat resistance may decrease if the amount is too small or too large.

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

Amorphous in amorphous polyolefin (B) means the amount of 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). It is preferably 10 J / g or less.

By blending an amorphous polyolefin, the wettability of the adhesive to the substrate and the flexibility of the adhesive composition can prevent stress concentration of peeling stress at the interface between the adhesive and the substrate. ..

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 further preferably 3 J / g or less. The lower limit is not particularly limited, but is 0 J / g or more. If it exceeds the above value, the crystallinity is increased, 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. It is more preferably in the range of −50 ° C. to 25 ° C., and most preferably in the range of −30 ° C. to 20 ° C. If it is less than the above value, the tack of the adhesive is strong and the processability may be inferior. On the other hand, if it exceeds the above value, there is a problem that the adhesiveness at around 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). It is more preferably in the range of 13 to 90 parts by mass, and most preferably in the range of 15 to 80 parts by mass. If it is less than the above value, the wettability to the base material is lowered, and the peeling stress is concentrated on the interface, so that the adhesive strength may be lowered. If it exceeds the above value, the strength of the adhesive composition itself is lowered, so that there is a problem that the adhesive is lowered.

<Component (C): Carbodiimide resin (C)>
The 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. It is preferably a polycarbodiimide having two or more carbodiimide groups in the molecule. By using the carbodiimide resin (C), the carboxyl group of the acid-modified polyolefin (A) reacts with the carbodiimide, 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). It is more preferably in the range of 1 to 25 parts by mass, and most preferably in the range of 2 to 20 parts by mass. If it is less than the above value, there is a problem that the interaction with the base material is not exhibited and the adhesiveness is lowered. If it exceeds the above value, there is a problem that the pot life of the adhesive is lowered and the low dielectric property is lowered.

<(D) component: epoxy resin (D)>
The component (D) 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 tetraglycidyl diaminodiphenylmethane, triglycidyl paraaminophenol, tetraglycidyl bisaminomethylcyclohexanone, N, N, N', N'-tetraglycidyl-m-xylene diamine can be used. A bisphenol A type epoxy resin, a novolak type epoxy resin or a dicyclopentadiene type epoxy resin is preferable.

In the adhesive composition of the present invention, the content of the epoxy resin (D) is preferably in the range of 1 to 30 parts by mass, preferably 2 to 15 parts by mass with respect to 100 parts by mass of the crystalline acid-modified polyolefin (A). It 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 above range, a sufficient curing effect may not be obtained and the adhesiveness and heat resistance may be lowered. Further, above the above range, there is a problem that the pot life of the adhesive is lowered and the low dielectric property is lowered.

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

Since the adhesive composition of the present invention contains the component (A), the component (B) and the component (C), it has excellent electrical properties (low dielectric properties), and a low-polarity resin base material such as LCP and a metal. High adhesiveness to the base material can be exhibited. Further, by containing the component (A), the component (B) and the component (D), the electrical characteristics are excellent and the high solder heat resistance between the low-polarity resin base material such as LCP and the metal base material is exhibited. Can be done. Furthermore, by containing the components (A) to (D), all of the excellent adhesiveness, solder heat resistance and electrical properties (low dielectric properties) between the low-polarity resin base material such as LCP and the metal base material are exhibited. be able to. That is, the adhesive coating film (adhesive layer) after the adhesive composition is applied to the base material and cured exhibits excellent low dielectric constant characteristics. Specifically, the dielectric constant (ε) of the cured adhesive coating film at a frequency of 1 MHz is preferably 3.0 or less, more preferably 2.6 or less, and 2.3 or less. Is even more preferable. Further, 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. Further, the adhesive composition of the present invention preferably has a dielectric constant (ε) of 3.0 or less, preferably 2.6 or less, in the entire region of the cured adhesive coating film having a frequency of 1 MHz to 1 GHz. More preferably, it is more preferably 2.3 or less. Further, 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. Further, it is particularly preferable that the dielectric constant (ε) and the dielectric loss tangent (tan δ) in the entire region of the frequency 1 MHz to 10 GHz of the cured adhesive coating film are within 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 done. Specifically, for example, aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as hexane, heptane, octane and decane, and alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane. Halogenized hydrocarbons such as hydrogen, trichloroethylene, dichloroethylene, chlorobenzene, chloroform, alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, phenol, acetone, methylisobutylketone, Ketone solvents such as methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, acetophenone, cell solves such as methyl cellsolve and ethyl cell solve, ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, butyl formate, etc. Ethylene glycol mono n-butyl ether, ethylene glycol mono iso-butyl ether, ethylene glycol mono tert-butyl ether, diethylene glycol mono n-butyl ether, diethylene glycol mono iso-butyl ether, triethylene glycol mono n-butyl ether, tetraethylene glycol mono n-butylate, etc. Glycol ether-based solvents and the like can be used, and one or more of these can be used in combination. A preferred embodiment is a mixed solvent of an alicyclic hydrocarbon and a ketone solvent, in which cyclohexane or methylcyclohexane is preferably used as the alicyclic hydrocarbon and methyl isobutyl ketone or methyl ethyl ketone is used as 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), 55 to 85/45. It is more preferably ~ 15 (mass ratio), and even more preferably 60-80 / 40-20 (mass ratio).

The organic solvent (E) is preferably in the range of 100 to 1000 parts by mass, more preferably in the range of 200 to 900 parts by mass, and 300 parts by mass with respect to 100 parts by mass of the crystalline acid-modified polyolefin (A). Most preferably, it is ~ 800 parts by mass or more. Below this range, the liquid and pot life properties are reduced. Further, if it exceeds the above range, there is a problem that it is disadvantageous in terms of manufacturing cost and transportation cost.

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

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

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

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

(Silane coupling agent)
A silane coupling agent may be added to the adhesive composition of the present invention, if necessary. It is very preferable to add a silane coupling agent because the properties of adhesion to metal and heat resistance are improved. The silane coupling agent is not particularly limited, and examples thereof include those having an unsaturated group, those having a glycidyl group, and those having an amino group. Of these, glycidyls such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltriethoxysilane from the viewpoint of heat resistance. A silane coupling agent having a group is more preferable. The blending amount of the silane coupling agent is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the total of the components (A) to (D). If it is less than 0.5 parts by mass, heat resistance may be poor. On the other hand, if it exceeds 20 parts by mass, heat resistance may be poor and adhesiveness may be lowered.

<Laminated body>
The laminate of the present invention is one in which an adhesive composition is laminated on a base material (two-layer laminate of a base material / adhesive layer), or one in which a base material is further bonded (base material / adhesive layer / It is a three-layer laminate of a base material). Here, the adhesive layer refers to a layer of the adhesive composition after the adhesive composition of the present invention is applied to a base material and dried. The laminated body of the present invention can be obtained by applying and drying the adhesive composition of the present invention to various base materials according to a conventional method, and further laminating other base materials.

<Base material>
In the present invention, the base material is not particularly limited as long as the adhesive composition of the present invention can be applied and dried to form an adhesive layer, but the base material is a resin base material such as a film-like resin or a metal. Examples include metal substrates such as plates and metal foils, papers, and the like.

Examples of the resin base material 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.

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

Examples of papers include high-quality paper, kraft paper, roll paper, and glassine paper. Further, as the composite material, glass epoxy or the like can be exemplified.

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

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

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

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

In the present invention, the method of coating the adhesive composition on the base material is not particularly limited, and examples thereof include a comma coater and a reverse roll coater. Alternatively, if necessary, the adhesive layer may be provided directly or by a transfer method on the rolled copper foil or the polyimide film which is the constituent material of the printed wiring board. The thickness of the adhesive layer after drying is appropriately changed as necessary, but is preferably in the range of 5 to 200 μm. If the adhesive film thickness is less than 5 μm, the adhesive strength is insufficient. If the thickness is 200 μm or more, drying is insufficient, the amount of residual solvent increases, and there is a problem that blister is generated during pressing for manufacturing a printed wiring board. The drying conditions are not particularly limited, but the residual solvent ratio after drying is preferably 1% by mass or less. If it exceeds 1% by mass, there is a problem that the residual solvent foams when the printed wiring board is pressed, causing blisters.

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

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

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

The adhesive composition 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 adhesiveness not only to the conventional polyimide, polyester film, and copper foil constituting the printed wiring board, but also to a low-polarity resin base material such as LCP. , Solder reflow resistance can be obtained, and the adhesive layer confidence is excellent in low dielectric properties. Therefore, it is suitable as an adhesive composition used for coverlay films, laminated plates, copper foils with resins, and bonding sheets.

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

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

The printed wiring board of the present invention can be manufactured by any conventionally known process other than using the above-mentioned materials for each layer.

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

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

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

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

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

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

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

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

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

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

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

(Physical property evaluation method)

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

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)
The melting point, calorific value of melting, and glass transition temperature (Tg) in the present invention are annealed from room temperature to 200 ° C. at a heating rate of 20 ° C./min using a differential scanning calorimeter (DSC), and rapidly cooled with liquid nitrogen. , From -100 ° C to 200 ° C at a heating rate of 20 ° C / min, the intersection of the tangents at the baseline and the turning point (glass transition temperature), the top temperature of the melting peak (melting point), 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 The pot life property is a blend of crystalline acid-modified polyolefin, amorphous polyolefin, carbodiimide resin, and epoxy resin, immediately after blending, or after 24 hours have passed 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 does not increase so much that it can be stored for a long period of time. If the pot life is poor, the viscosity of the solution increases (thickening), and in severe cases It means that a gelation phenomenon occurs, it becomes difficult to apply it to a base material, and it cannot be stored for a long period of time.
<Evaluation criteria>
◯: Applicable △: Increased viscosity and inferior workability, but applicable ×: Cannot be applied due to increased viscosity or gelation

(2) Peeling strength (adhesiveness)
The adhesive composition described later is applied to a polyimide film (manufactured by Kaneka Corporation, Apical) having a thickness of 25 μm or an LCP film (manufactured by Kuraray Co., Ltd., Vexter) having a thickness of 50 μm 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 an 18 μm rolled copper foil. For bonding, the glossy surface of the rolled copper foil was brought into contact with the adhesive, and the foil was pressed at 160 ° C. under a pressure of 40 kgf / cm ² for 30 seconds to bond the foil. Then, it was heat-treated at 140 ° C. for 4 hours to be cured to obtain a sample for evaluation of peel strength. The peel strength was measured by performing a 90 ° peel test at a film pulling rate of 50 mm / min at 25 ° C. This test shows the adhesive strength at room temperature.
<Evaluation criteria>
☆: 1.5N / mm or more ◎: 1.3N / mm or more and less than 1.5N / mm ○: 1.0N / mm or more and less than 1.3N / mm Δ: 0.8N / mm or more and less than 1.0N / mm ×: Less than 0.8 N / mm

(3) Solder heat resistance A sample was prepared by the same method as above, and a 2.5 cm × 2.5 cm sample piece was dried at 120 ° C. for 30 minutes and flowed into a solder bath melted at each temperature for 1 minute. The temperature at which the appearance did not change such as swelling was measured.
<Evaluation criteria>
☆: 310 ° C or higher ◎: 300 ° C or higher and lower than 310 ° C ○: 290 ° C or higher and lower than 300 ° C Δ: 270 ° C or higher and lower than 290 ° C ×: less than 270 ° C

(4) Permittivity (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 as to have a thickness of 30 μm after drying, and dried at 130 ° C. for 3 minutes. Then, it was heat-treated at 140 ° C. for 4 hours to be cured, peeled off from the release film, and measured. Measurements were carried out using a PRECISION LCR meter HP-4284A at 22 ° C. and 58% RH under the condition of a frequency of 1 MHz, and evaluated as follows. Similarly, using VECTOR NETWORK ANALYZER HP8510C, SYNTHESIZED SWEEPER HP83651A, and TEST SET HP8517B, measurements were performed under the condition of 22 ° C. 58RH% and frequency 1 GHz, and evaluated as follows.
<Evaluation criteria for permittivity>
⊚: 2.3 or less ○: More than 2.3 and 2.6 or less Δ: More than 2.6 and 3.0 or less ×: More than 3.0 <Evaluation criteria for dielectric loss tangent>
⊚: 0.005 or less ○: 0.005 or more and 0.01 or less Δ: 0.01 or more and 0.02 or less ×: 0.02 or more

(Crystalline acid-modified polyolefin)
Manufacturing example 1
100 parts by mass of propylene-butene copolymer (“Toughmer® XM7080” manufactured by Mitsui Chemicals, Inc.), 150 parts by mass of toluene, 22 parts by mass of maleic anhydride, 6 parts by mass of di-tert-butyl peroxide in 1 L autoclave. Was added, the temperature was raised to 140 ° C., and the mixture was further stirred for 3 hours. Then, the obtained reaction solution was cooled and then poured into a container containing a large amount of methyl ethyl ketone to precipitate a resin. Then, the liquid containing the resin was centrifuged to separate and purify the acid-modified propylene-butene copolymer graft-polymerized with maleic anhydride, (poly) maleic anhydride and a low molecular weight substance. Thereafter, by drying under vacuum for 5 hours 70 ° C., maleic acid-modified propylene anhydride - butene copolymer (CO-1, acid value 570 equivalent / ¹⁰ 6 g, weight average molecular weight 55,000, Tm75 ℃, △ H25J / G) was obtained.

Manufacturing example 2
By except that the charged amount of maleic anhydride was changed to 19 parts by weight is in the same manner as in Production Example 1, maleic anhydride-modified propylene anhydride - butene copolymer (CO-2, acid value 410 equivalent / 10 6 ^g, the weight An average molecular weight of 60,000, Tm75 ° C., ΔH30J / g) was obtained.

Manufacturing example 3
A maleic anhydride-modified propylene-butene copolymer (maleic anhydride-modified propylene-butene copolymer) was prepared in the same manner as in Production Example 1 except that the amount of maleic anhydride charged was changed to 4 parts by mass and the di-tert-butyl peroxide was changed to 0.5 parts by mass. CO-3, acid value 150 equivalent / ¹⁰ 6 g, weight average molecular weight 160,000, Tm80 ℃, △ H25J / g) was obtained.

Manufacturing example 4
By except that the charged amounts of maleic anhydride in 30 parts by weight is in the same manner as in Production Example 1, maleic anhydride-modified propylene anhydride - butene copolymer (CO-4, acid value 980 equivalent / 10 6 ^g, the weight An average molecular weight of 40,000, Tm 70 ° C., ΔH25J / g) was obtained.

Production example 5
A maleic anhydride-modified propylene-butene copolymer (maleic anhydride-modified propylene-butene copolymer) was prepared in the same manner 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, Tm80 ℃, △ H25J / g) was obtained.

(Amorphous polyolefin)
Production example 6
To 1 L autoclave, add 100 parts by mass of amorphous polyolefin (Sumitomo Chemical Co., Ltd. "Tough Serene (registered trademark) X1102), 150 parts by mass of methylcyclohexane, 1 part by mass of maleic anhydride, and 1 part by mass of di-tert-butyl peroxide. , after raising the temperature to 140 ° C., and stirred for further 3 hours. after that, 130 parts by weight of methylcyclohexane, methylethylketone 120 parts by weight was added, amorphous acid-modified polyolefin (AO-1, acid value 50 equivalent / ¹⁰ 6 g, A solution having a weight average molecular weight of 140,000, ΔH0J / g, and 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 (“Tough Serene (registered trademark) X1102) manufactured by Sumitomo Chemical Co., Ltd.), 280 parts by mass of methylcyclohexane, and 120 parts by mass of methylethylketone were placed. It was added to give amorphous polyolefin (Tafthren X1102, acid value 0 eq / ¹⁰ 6 g, weight average molecular weight 658,000, △ H0J / g, Tg -9 ℃) a solution of.

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 was modified with amorphous acid. 100 parts by mass of the polyolefin solution (20 parts by mass as a solid resin), 224 parts by mass of methylcyclohexane, and 96 parts by mass of methylethylketone were charged, the temperature was raised to 80 ° C. with stirring, and the mixture was dissolved by continuing stirring for 1 hour. 5 parts by mass of carbodiimide resin V-05 and 10 parts by mass of epoxy resin YDCN-700-10 were added to the solution obtained by cooling 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, amorphous polyolefin, carbodiimide resin, and epoxy resin were changed to those shown in Table 1, and changed to the respective blending amounts shown in Table 1 in the same manner as in Example 1 and carried out. Examples 2 to 13 were performed. Table 1 shows the 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 in Example 2, the evaluation of the dielectric constant (ε) was “⊚” and the evaluation of the dielectric loss tangent (tan δ) was “⊚”.

Comparative Example 1
The crystalline acid-modified polyolefin, amorphous polyolefin, carbodiimide resin, and epoxy resin were changed to those shown in Table 2, and changed to the respective compounding amounts shown in Table 2 in the same manner as in Example 1 for comparison. 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
The carboxyl group-containing acrylonitrile butadiene rubber NBR (manufactured by JSR Corporation), carbodiimide resin, and epoxy resin were changed to those shown in Table 2, and the blending amounts shown in Table 2 were changed 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 (manufactured by Nisshinbo Chemical Co., Ltd.)
Carbodiimide resin: V-03 (manufactured by Nisshinbo Chemical Co., Ltd.)
o-cresol novolac type epoxy resin: YDCN-700-10 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Bisphenol A type epoxy resin: JER-828 (manufactured by Mitsubishi Chemical Corporation)
Dicyclopentadiene type epoxy resin: HP-7200 (manufactured by DIC Corporation)

As is clear from Table 1, in Examples 1 to 13, both the liquid crystal polymer (LCP) and the copper foil have excellent pot life, excellent adhesiveness to the polyimide (PI) and the copper foil, and solder heat resistance. Has excellent adhesiveness and solder heat resistance. Further, the electrical characteristics of the adhesive composition are both low and good in both dielectric constant and dielectric loss tangent. On the other hand, as is clear from Table 2, in Comparative Example 1, since the amorphous polyolefin was not blended, stress relaxation could not be performed and the adhesive strength was low. In Comparative Example 2, since the crystalline acid-modified polyolefin was not blended, the adhesive strength with the LCP was low, and the low dielectric property of the adhesive composition was inferior.

According to the present invention, not only conventional polyimide and polyethylene terephthalate films but also resin base materials having low dielectric properties such as LCP and metal base materials such as copper foil have 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 for flexible printed wiring board applications, especially for FPC applications where low dielectric properties (low dielectric constant, low dielectric loss tangent) in a high frequency region are required.

Claims (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, which contains 10 to 100 parts by mass of the component (B) and 1 to 30 parts by mass of the component (D) with respect to 100 parts by mass of the component (A). (A) The adhesive composition according to any one of claims 1 to 3, which contains 100 to 1000 parts by mass of the organic solvent (E) with respect to 100 parts by mass of the component. The adhesive composition according to any one of claims 1 to 4, which is used for adhering a resin base material to a resin base material or a metal base material. A laminate of a resin base material adhered by the adhesive composition according to any one of claims 1 to 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 including the laminate according to claim 6 or the adhesive sheet according to claim 7 as a component.