WO2023282318A1

WO2023282318A1 - Adhesive composition, adhesive sheet, electromagnetic-wave shielding material, laminate, and printed wiring board

Info

Publication number: WO2023282318A1
Application number: PCT/JP2022/026929
Authority: WO
Inventors: 遼薗田; 隼人入澤; 哲生川楠
Original assignee: 東洋紡株式会社
Priority date: 2021-07-09
Filing date: 2022-07-07
Publication date: 2023-01-12
Also published as: JP7409568B2; JPWO2023282318A1; KR20240031943A; TW202309213A; CN117500895A

Abstract

[Problem] To provide an adhesive composition which has high adhesiveness to not only conventional polyimides and liquid-crystal polymers but also metal substrates, can attain high soldering heat resistance, and is excellent in terms of low-dielectric characteristics and laser processability. [Solution] An adhesive composition comprising a modified polyolefin resin (a), a polyimide resin (b), and a hardener (c), wherein the polyimide resin (b) includes, as a constituent unit, at least one compound selected from the group consisting of polyolefin polyols, dimer diols, dimer diamines, and dimer acids.

Description

Adhesive composition, adhesive sheet, electromagnetic shielding material, laminate and printed wiring board

The present invention relates to adhesive compositions. More particularly, it relates to an adhesive composition used for bonding a resin substrate to a resin substrate or a metal substrate. In particular, it relates to an adhesive composition for flexible printed wiring boards (hereinafter abbreviated as FPC), and adhesive sheets, electromagnetic shielding materials, laminates and printed wiring boards containing the same.

Flexible printed wiring boards (FPC) have excellent flexibility, so they can be used for multifunctional and miniaturized personal computers (PCs) and smartphones. is often used for 2. Description of the Related Art In recent years, electronic devices have become smaller, lighter, denser, and higher in output, and these trends have led to increasingly sophisticated demands for the performance of wiring boards (electronic circuit boards). In particular, along with the speeding up of transmission signals in FPCs, the frequency of signals is increasing. Along with this, FPCs are increasingly required to have low dielectric properties (low dielectric constant, low dielectric loss tangent) in a high frequency region. In order to achieve such low dielectric properties, measures have been taken to reduce the dielectric loss of FPC substrates and adhesives. As adhesives, the combination of polyolefin and epoxy (Patent Document 1) and the combination of elastomer and epoxy (Patent Document 2) are being developed.

WO2016/047289 WO2014/147903

However, in Patent Document 1, it is difficult to say that the adhesive used between reinforcing plates and layers has excellent solder heat resistance. Moreover, in Patent Document 2, the storage stability after blending, which is important during use, was not sufficient.

In addition, due to the recent miniaturization of FPCs, circuit boards have become denser, and drilling such as blind vias and through holes by laser processing is being performed in order to achieve circuit continuity. In order to establish high-precision laser processing technology, UV laser processing is performed, and drilling processing is mainly performed at a wavelength of 355 nm, but the above literature does not consider laser processing properties.

That is, the present invention provides an adhesive composition that has good adhesion to both various resin substrates such as polyimide and metal substrates, and that is also excellent in solder heat resistance, low dielectric properties, and laser processability. intended to provide

As a result of diligent studies, the present inventors have found that the above problems can be solved by the means shown below, and have arrived at the present invention. That is, the present invention consists of the following configurations.

[1] containing a modified polyolefin resin (a), a polyimide resin (b) and a curing agent (c),
The adhesive composition, wherein the polyimide resin (b) has, as a structural unit, at least one selected from the group consisting of polyolefin polyols, polyolefin polyamines, polyolefin polycarboxylic acids, dimer diols, dimer diamines and dimer acids.

[2] The adhesive composition according to [1] above, wherein the modified polyolefin resin (a) has an acid value of 5 to 30 mgKOH/g.

[3] The adhesive composition according to [1] or [2] above, wherein the curing agent (c) contains at least one selected from the group consisting of epoxy resins, polyisocyanates and polycarbodiimides.

[4] Any of the above [1] to [3] containing 50 to 95 parts by mass of the modified polyolefin resin (a) with respect to a total of 100 parts by mass of the modified polyolefin resin (a) and the polyimide resin (b) The adhesive composition described.

[5] The adhesive composition according to any one of [1] to [4], which has a dielectric constant of less than 3.0 at 10 GHz.

[6] The content of the curing agent (c) is 0.5 to 60 parts by mass with respect to a total of 100 parts by mass of the modified polyolefin resin (a) and the polyimide resin (b), above [1] to [5] The adhesive composition according to any one of

[7] An adhesive sheet having a layer made of the adhesive composition according to any one of [1] to [6].

[8] An electromagnetic shielding material having a layer made of the adhesive composition according to any one of [1] to [6].

[9] A laminate having a layer made of the adhesive composition according to any one of [1] to [6].

[10] A printed wiring board comprising the laminate described in [9] above as a component.

The adhesive composition according to the present invention has good adhesion to both various resin substrates such as polyimide and metal substrates, and is excellent in solder heat resistance, low dielectric properties, and laser processability.

<Modified polyolefin resin (a)>
The modified polyolefin resin (a) (hereinafter also simply referred to as component (a)) used in the present invention is not limited, but the polyolefin resin contains at least one α,β-unsaturated carboxylic acid and its acid anhydride. It is preferably obtained by grafting. Polyolefin resin refers to homopolymerization of olefin monomers exemplified by ethylene, propylene, butene, butadiene, isoprene, etc., or copolymerization with other monomers, and hydrocarbons such as hydrides and halides of the resulting polymers. It refers to a polymer mainly composed of a skeleton. That is, the modified polyolefin resin (a) is obtained by grafting at least one of an α,β-unsaturated carboxylic acid and an acid anhydride thereof onto at least one of polyethylene, polypropylene and a propylene-α-olefin copolymer. Those obtained by

The propylene-α-olefin copolymer is mainly composed of propylene and is copolymerized with an α-olefin. As the α-olefin, for example, one or several 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 preferred. The ratio of the propylene component to the α-olefin component in the propylene-α-olefin copolymer is not limited, but the propylene component is preferably 50 mol% or more, more preferably 70 mol% or more.

At least one of α,β-unsaturated carboxylic acids and acid anhydrides thereof includes, for example, maleic acid, itaconic acid, citraconic acid and acid anhydrides thereof. Among these, acid anhydrides are preferred, and maleic anhydride is more preferred. Specifically, the modified polyolefin resin (a) includes maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, and maleic anhydride-modified propylene-ethylene. -butene copolymers, etc., and these maleic anhydride-modified polyolefins can be used singly or in combination of two or more.

The lower limit of the acid value of the modified polyolefin resin (a) is preferably 5 mgKOH/g or more, more preferably 6 mgKOH/g or more, from the viewpoint of solder heat resistance and adhesiveness to resin substrates and metal substrates. and more preferably 7 mgKOH/g or more. When the content is at least the above lower limit, the reactivity with the curing agent (c) is improved, and excellent adhesive strength can be exhibited. In addition, the crosslink density is high and the solder heat resistance is improved. The upper limit is preferably 30 mgKOH/g or less, more preferably 28 mgKOH/g or less, still more preferably 25 mgKOH/g or less. Adhesiveness becomes favorable by making it below the said upper limit. Moreover, the viscosity and stability of the solution are improved, and excellent pot life can be exhibited. Furthermore, manufacturing efficiency is also improved.

The number average molecular weight (Mn) of the modified polyolefin resin (a) is preferably in the range of 10,000 to 50,000. It is more preferably in the range of 15,000 to 45,000, still more preferably in the range of 20,000 to 40,000, and particularly preferably in the range of 22,000 to 38,000. By making it more than the said lower limit, cohesive force becomes favorable and can express the outstanding adhesiveness. Further, when the content is equal to or less than the above upper limit, excellent fluidity and good operability can be obtained.

The modified polyolefin resin (a) is preferably crystalline. The crystallinity referred to in the present invention means that a temperature is raised from −100° C. to 250° C. at a rate of 20° C./min using a differential scanning calorimeter (DSC), and a clear melting peak is exhibited during the heating process. Point.

The melting point (Tm) of the modified polyolefin resin (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. When the content is equal to or higher than the above lower limit, the crystal-derived cohesive force is improved, and excellent adhesiveness and solder heat resistance can be exhibited. Further, when the content is equal to or less than the upper limit, excellent solution stability and fluidity are obtained, and operability at the time of adhesion is improved.

The heat of fusion (ΔH) of the modified polyolefin resin (a) is preferably in the range of 5 J/g to 60 J/g. More preferably in the range of 10 J/g to 50 J/g, most preferably in the range of 20 J/g to 40 J/g. When the content is equal to or higher than the above lower limit, the crystal-derived cohesive force is improved, and excellent adhesiveness and solder heat resistance can be exhibited. Further, when the content is equal to or less than the upper limit, excellent solution stability and fluidity are obtained, and operability at the time of adhesion is improved.

The method for producing the modified polyolefin resin (a) is not particularly limited. reaction of graft-polymerizing an acid anhydride), and the like.

Although the radical generator is not particularly limited, it is preferable to use an organic peroxide. Examples of organic peroxides include, but are not limited to, 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 and the like azonitriles, and the like.

<Polyimide resin (b)>
The polyimide resin (b) used in the present invention (hereinafter also simply referred to as component (b)) is obtained by reacting a polycarboxylic acid derivative having an acid anhydride group with a polyisocyanate compound or a polyamine compound. The polyimide resin (b) used in the present invention is a polyimide resin having at least one type selected from the group consisting of polyolefin polyols, polyolefin polyamines, polyolefin polycarboxylic acids, dimer diols, dimer diamines and dimer acids as structural units. Here, the polyimide resin refers to a polymer having an imide bond, and includes polyimide resin, polyurethaneimide resin, polyesterimide resin, polyamideimide resin, and the like.

The polyimide resin (b) used in the present invention is a polyolefin resin ( b) can be made to have a lower dielectric, and compatibility with the modified polyolefin resin (a) is also improved. The content of the structural unit is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 50% by mass or more in the polyimide resin (b). Also, it is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. When the content is at least the above lower limit, sufficiently low dielectric properties are ensured, and when the content is at most the above upper limit, solder heat resistance and laser workability are improved.

The lower limit of the acid value of the polyimide resin (b) used in the present invention is preferably 1 mgKOH/g or more, more preferably 1 mgKOH/g or more, from the viewpoint of solder heat resistance, adhesion to resin substrates and metal substrates, and low dielectric properties. is 1.5 mgKOH/g or more, more preferably 2 mgKOH/g or more. When the content is at least the above lower limit, the reactivity with the curing agent (c) is improved, and excellent adhesive strength can be exhibited. In addition, the crosslink density is high and the solder heat resistance is improved. The upper limit is preferably 25 mgKOH/g or less, more preferably 23 mgKOH/g or less, still more preferably 20 mgKOH/g or less. By setting the content to be equal to or less than the above upper limit value, low dielectric characteristics are improved. Moreover, the viscosity and stability of the solution are improved, and excellent pot life can be exhibited. Furthermore, manufacturing efficiency is also improved.

The lower limit of the logarithmic viscosity of the polyimide resin (b) used in the present invention is preferably 0.05 dl/g or more, more preferably 0.05 dl/g or more, from the viewpoint of adhesion and compatibility with resin substrates and metal substrates. 06 dl/g or more, more preferably 0.07 dl/g or more. Adhesiveness becomes favorable by making it more than the said lower limit. The upper limit is preferably 0.40 dl/g or less, more preferably 0.38 dl/g or less, still more preferably 0.35 dl/g or less. Compatibility with the modified olefin resin is improved by adjusting the content to the above upper limit or less. Moreover, the viscosity and stability of the solution are improved, and excellent pot life can be exhibited. Furthermore, manufacturing efficiency is also improved.

<Polycarboxylic acid derivative having an acid anhydride group>
The polycarboxylic acid derivative having an acid anhydride group constituting the polyimide resin (b) used in the present invention may be, for example, an aromatic polycarboxylic acid derivative, an aliphatic polycarboxylic acid derivative or an alicyclic polycarboxylic acid derivative. can. These can be used alone or in combination of two or more. Among them, aromatic polycarboxylic acid derivatives are preferred. Also, the valence of the polycarboxylic acid derivative is not particularly limited. It is preferable to have one or two acid anhydride groups in one molecule, and one or more carboxyl groups may be contained in the polycarboxylic acid derivative having an acid anhydride group.

Examples of aromatic polycarboxylic acid derivatives include, but are not limited to, trimellitic anhydride (TMA), 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propanoic dianhydride ( BisDA), p-phenylenebis(trimellitate anhydride) (TAHQ), 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 2,2-bis[4-(2,3-dicarboxy phenoxy)phenyl]propanoic dianhydride, pyromellitic dianhydride, ethylene glycol bis-anhydro trimellitate, propylene glycol bis-anhydro trimellitate, 1,4-butanediol bis-anhydro trimellitate, hexamethylene Alkylene glycol bis-anhydro trimellitate such as glycol bis-anhydro trimellitate, polyethylene glycol bis-anhydro trimellitate, polypropylene glycol bis-anhydro trimellitate, 3,3′-4,4′-benzophenone tetracarboxylic acid dianhydride, 3,3'-4,4'-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 3,3′,4,4′-diphenylsulfone tetra Carboxylic dianhydride, m-terphenyl-3,3',4,4'-tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 1,1,1,3,3,3 -hexafluoro-2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride 1,1,1,3,3,3-hexafluoro-2,2-bis[4-(2,3- or 3,4-dicarboxyphenoxy)phenyl]propane dianhydride, or 1,3 -Bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride and the like.

The aliphatic polycarboxylic acid derivative or alicyclic polycarboxylic acid derivative is not particularly limited, but examples include butane-1,2,3,4-tetracarboxylic dianhydride, pentane-1,2,4,5 -tetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, hexahydropyromellitic dianhydride, cyclohex-1-ene-2,3,5,6-tetracarboxylic dianhydride, 3-ethylcyclohexane Sa-1-ene-3-(1,2),5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3-(1,2),5,6-tetracarboxylic acid dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3-(1,2),5,6-tetracarboxylic dianhydride, 1-ethylcyclohexane-1-(1,2) ,3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1-(2,3),3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane-1- (2,3),3-(2,3)-tetracarboxylic dianhydride, dicyclohexyl-3,4,3′,4′-tetracarboxylic dianhydride, bicyclo[2,2,1] Heptane-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2,2,2]octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, hexahydrotrimellitic anhydride, and the like.

These acid anhydride group-containing polycarboxylic acid derivatives may be used alone or in combination of two or more. Aromatic polycarboxylic acid derivatives are preferable in consideration of low dielectric properties, cost, etc. Among them, trimellitic anhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propanoic acid dianhydride p-phenylenebis(trimellitate anhydride), 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, pyromellitic anhydride, ethylene glycol bisanhydrotrimellitate, 3,3′,4, 4′-benzophenonetetracarboxylic dianhydride or 3,3′,4,4′-biphenyltetracarboxylic dianhydride is more preferred.

The content of the polycarboxylic acid derivative having an acid anhydride group is preferably 1% by mass or more, more preferably 2% by mass or more, and still more preferably 3% by mass or more in the polyimide resin (b). be. Also, it is preferably 30% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. Within the above range, excellent adhesiveness, solder heat resistance, laser workability, and low dielectric properties can be exhibited.

<Polyolefin polyol component>
The polyolefin polyol component constituting the polyimide resin (b) used in the present invention has a role as a softening component of the polyimide resin (b). A polyolefin polyol is a polyolefin backbone polymer having multiple hydroxy groups. Specific examples of such polyolefin polyols include polyethylenebutylene diol (polyethylenebutylene polyol), polybutadiene diol (polybutadiene polyol), and hydrogenated polybutadiene diol (hydrogenated polybutadiene polyol). Polyolefin polyol may be used individually by 1 type, and may be used in combination of 2 or more type. Commercial products of polyethylene butylene diol include trade name "Polytail" (manufactured by Mitsubishi Chemical Corporation). Commercially available products of polybutadiene diol include trade name "KRASOL" (manufactured by Cray Valley). Furthermore, commercial products of hydrogenated polybutadiene diol include the trade name "NISSO-PB" (manufactured by Nippon Soda Co., Ltd.).

<Dimer diol component>
The dimer diol component constituting the polyimide resin (b) used in the present invention has a role as a flexible component of the polyimide resin (b). The dimer diol is preferably a reduction reaction product derived from polymeric fatty acids. Polymeric fatty acids are also called dimer acids, and include unsaturated fatty acids having 18 carbon atoms (C18) such as oleic acid, linoleic acid and linolenic acid, drying oil fatty acids or semi-drying oil fatty acids, and lower monoalcohols of these fatty acids. Dimolecular polymerization of esters in the presence or absence of a catalyst (dimer). The dimer diol may contain residual unsaturated bonds in its molecule and impurities such as trimer triol.

As the dimer diol component, for example, Croda Japan Co., Ltd., trade name "PRIPOL 2033" (mixture having a double bond), "PRIPOL 2030" (mixture having no double bond) and BASF Japan Co., Ltd., trade name " Sovamol 650NS", "Sovamol 908", etc., and these may be used alone or in combination.

<Dimer acid component>
The dimer acid component is a polymeric fatty acid that is the starting material for the dimer diol. A dimer acid can be used individually or in combination of 2 or more types. Examples of commercially available products of dimer acid include "Pripol 1004", "Pripol 1006", "Pripol 1009", "Pripol 1013", "Pripol 1015", "Pripol 1017" and "Pripol 1022" manufactured by Croda Japan. , "Pripol 1025", "Pripol 1040"; BASF Japan's "Enpol 1008", "Enpol 1012", "Enpol 1016", "Enpol 1026", "Enpol 1028", "Enpol 1043", "Enpol 1061" , “Enpol 1062” and the like.

<Dimer diamine component>
The dimer diamine component includes a compound obtained by converting the carboxyl group of the dimer acid to an amino group. Examples of the conversion method include a method in which a carboxylic acid is amidated, aminated by Hoffmann rearrangement, and further distilled and purified. Commercial products of dimer diamine include, for example, Croda Japan's "Priamine 1071", "Priamine 1073", "Priamine 1074" and "Priamine 1075", and BASF Japan's "Versamin 551". A dimer diamine can be used individually or in combination of 2 or more types.

<Polyisocyanate compound>
The polyisocyanate compound constituting the polyimide resin (b) used in the present invention is not particularly limited, and examples thereof include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds and alicyclic polyisocyanate compounds. More preferred are aromatic diisocyanate compounds. Examples of aromatic polyisocyanate compounds include, but are not limited to, diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5, 2'- or 5,3'- or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4 ,3′- or 5,2′- or 5,3′- or 6,2′- or 6,3′-diethyldiphenylmethane-2,4′-diisocyanate, 3,2′- or 3,3′- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4 '-diisocyanate (MDI), diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4' -diisocyanate, tolylene-2,4-diisocyanate (TDI), tolylene-2,6-diisocyanate, m-xylylenediisocyanate, p-xylylenediisocyanate, naphthalene-2,6-diisocyanate, 4,4'-[2, 2bis(4-phenoxyphenyl)propane]diisocyanate, 3,3′- or 2,2′-dimethylbiphenyl-4,4′-diisocyanate, 3,3′- or 2,2′-diethylbiphenyl-4,4 '-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 3,3'-diethoxybiphenyl-4,4'-diisocyanate and the like. Considering solder heat resistance, adhesiveness, solubility, cost, etc., diphenylmethane-4,4'-diisocyanate, tolylene-2,4-diisocyanate, m-xylylene diisocyanate, 3,3'- or 2,2 '-Dimethylbiphenyl-4,4'-diisocyanate is preferred, and diphenylmethane-4,4'-diisocyanate and tolylene-2,4-diisocyanate are more preferred. Moreover, these can be used individually or in combination of 2 or more types.

<Polyamine compound>
The polyamine compound constituting the polyimide resin (b) used in the present invention is not particularly limited, and examples thereof include diamine compounds and polyamine compounds. Diamine compounds include, for example, 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 2, 6-diaminotoluene, 2,4-diaminotoluene, 3,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diamino-1 ,2-diphenylethane, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminobenzophenone, 3,3 Aromatic diamines such as '-diaminodiphenyl sulfone; ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,9-nonanediamine, 1,12 - aliphatic diamines such as dodecamethylenediamine, metaxylenediamine; and alicyclic diamines such as piperazine. A polyamine can be used individually or in combination of 2 or more types.

The content of the isocyanate compound and the polyamine compound in the polyimide resin (b) is preferably 10% by mass or more, more preferably 13% by mass, and still more preferably 15% by mass or more. Also, it is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

The method for producing the polyimide resin (b) used in the present invention is not particularly limited, and conventionally known methods for producing polyimide resins can be applied. The usage ratio of each raw material used for the polymerization reaction of the polyimide resin (b) is the sum of the equivalents of the acid anhydride group, the carboxyl group and the hydroxyl group (A), and the sum of the equivalents of the isocyanate group and the amino group (B). The ratio of (B)/(A) is preferably 0.7 to 1.3, more preferably 0.8 to 1.2. By making it equal to or higher than the lower limit, the molecular weight of the polyimide resin (b) can be increased, and the coating film can be prevented from becoming brittle. Further, by setting the content to the above upper limit or less, the viscosity of the polyimide resin (b) is suppressed, and the leveling property when applying the adhesive solution is improved.

The polymerization reaction of the polyimide resin (b) used in the present invention is preferably carried out by heating and condensing in the presence of one or more organic solvents, for example, in the isocyanate method, while removing the carbon dioxide liberated from the reaction system. .

Any solvent can be used as the polymerization solvent as long as it has low reactivity with isocyanate groups and amine groups. For example, solvents that do not contain basic compounds such as amines are preferred. Examples of such organic solvents include toluene, xylene, ethylbenzene, nitrobenzene, cyclohexane, isophorone, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, and diethylene glycol. Ethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate, acetone, methyl ethyl ketone, cyclohexanone, N,N-dimethylformamide , N,N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, γ-butyrolactone, dimethylsulfoxide, chloroform and methylene chloride. These may be used alone or in combination of two or more.

The polymerization solvent is preferably N,N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, γ-butyrolactone, or cyclohexanone because of their good volatility during drying, polymerizability, and solubility. More preferred are N-methylpyrrolidone and cyclohexanone. They can also be used as diluents for the adhesive composition of the invention.

The amount of solvent used is preferably 0.8 to 5.0 times (mass ratio), more preferably 1.0 to 3.0 times, that of the polyimide resin (b) to be produced. By setting the amount to be at least the above lower limit, the increase in viscosity during synthesis is suppressed and the stirrability is improved. In addition, by making it equal to or less than the above upper limit, it is possible to suppress a decrease in the reaction rate.

The reaction temperature is preferably 60-200°C, more preferably 100-180°C. The reaction time can be shortened by setting the reaction temperature to the above lower limit or higher. Further, when the content is equal to or less than the above upper limit, decomposition of the monomer component can be suppressed, and further gelation due to a three-dimensional reaction can be suppressed. The reaction temperature may be changed in multiple stages. The reaction time can be appropriately selected depending on the scale of the batch, the reaction conditions employed, especially the reaction concentration.

triethylamine, lutidine, picoline, undecene, triethylenediamine (1,4-diazabicyclo[2,2,2]octane), DBU (1,8-diazabicyclo[5,4,0]-7-undecene) to accelerate the reaction ), alkali metals such as lithium methylate, sodium methylate, sodium ethylate, potassium butoxide, potassium fluoride, sodium fluoride, alkaline earth metal compounds, or titanium, cobalt, tin, zinc, aluminum The reaction may be carried out in the presence of a catalyst such as a metal such as a metal, a metalloid compound, or the like. Among them, triethylamine and DBU are preferable in consideration of insulating properties.

<Curing agent (c)>
The resin composition of the present invention contains a curing agent (c). By including the curing agent (c) in the resin composition, it is possible to further improve adhesiveness and soldering heat resistance. A well-known thing can be used as a hardening|curing agent (c). Examples of curing agents (c) include epoxy resins, polyisocyanates, polycarbodiimides, oxazoline cross-linking agents, and aziridine cross-linking agents. Epoxy resins, polyisocyanates and polycarbodiimides are preferred. One type of these cross-linking agents can be used alone or two or more types can be used in combination.

<Epoxy resin>
The epoxy resin used in the present invention is not particularly limited as long as it has an epoxy group in the molecule, but preferably has two or more epoxy 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, tetraglycidyldiaminodiphenylmethane, triglycidyl para-aminophenol, tetraglycidylbisaminomethylcyclohexanone, N,N,N',N'-tetraglycidyl-m-xylenediamine, epoxy-modified polybutadiene, and the like, which may be used singly or Two or more kinds can be used in combination. Biphenyl-type epoxy resins, novolac-type epoxy resins, and dicyclopentadiene-type epoxy resins are preferred. More preferred are novolac type epoxy resins and dicyclopentadiene type epoxy resins.

The epoxy equivalent of the epoxy resin is preferably 50 g/eq or more, more preferably 70 g/eq or more, and even more preferably 80 g/eq or more. Also, it is preferably 400 g/eq or less, more preferably 350 g/eq or less, and still more preferably 300 g/eq or less. By setting it within the above range, excellent solder heat resistance can be exhibited.

<Polycarbodiimide>
The polycarbodiimide used in the present invention is not particularly limited as long as it has a carbodiimide group in the molecule. Polycarbodiimide having two or more carbodiimide groups in the molecule is preferred.
Polycarbodiimide may be an aromatic carbodiimide compound, an alicyclic carbodiimide compound or an aliphatic carbodiimide compound, and these can be used alone or in combination of two or more. Examples of aromatic carbodiimide compounds include poly-m-phenylenecarbodiimide, poly-p-phenylenecarbodiimide, polytolylenecarbodiimide, poly(diisopropylphenylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(4,4′-diphenylmethanecarbodiimide). ) and the like. The alicyclic carbodiimide compounds include poly-m-cyclohexylcarbodiimide, poly-p-cyclohexylcarbodiimide, poly(4,4'-dicyclohexylmethanecarbodiimide, poly(3,3'-dicyclohexylmethanecarbodiimide, etc.). The carbodiimide compound may be either a linear or branched aliphatic carbodiimide compound, preferably a linear aliphatic carbodiimide compound, specifically polymethylene carbodiimide, polyethylene carbodiimide, Polypropylene carbodiimide, polybutylene carbodiimide, polypentamethylene carbodiimide, polyhexamethylene carbodiimide, etc. These can be used alone or in combination of two or more, among them aromatic carbodiimide compounds or alicyclic carbodiimides. A compound is preferred.
Further, when polycarbodiimide and an epoxy resin are used together as a curing agent, the effect of improving solder heat resistance can be expected.

<Polyisocyanate>
The polyisocyanate used in the present invention is preferably a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule. Compounds derived from polyfunctional isocyanate compounds can also be used.

The polyisocyanate may be an aromatic isocyanate compound, an alicyclic isocyanate compound or an aliphatic isocyanate compound, and these can be used alone or in combination of two or more. Among them, aliphatic isocyanate compounds are preferable, and aliphatic diisocyanate compounds are more preferable. Examples of aromatic isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, and 1,8-naphthalene. Diisocyanate, 3,3'-biphenyl diisocyanate, 4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-4,4'-diisocyanate , 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, and the like, and these can be used alone or in combination of two or more. Among them, 3,3'-dimethyl-4,4'-biphenyl diisocyanate is preferred. Alicyclic isocyanate compounds include isophorone diisocyanate, norbornene diisocyanate, 1,2-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and the like. can be used alone or in combination of two or more. The aliphatic isocyanate compound may be either linear or branched aliphatic isocyanate. Linear aliphatic diisocyanate compounds are preferable, and specifically, 1,3-propane diisocyanate, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1 ,7-heptamethylene diisocyanate, 1,8-octamethylene diisocyanate, 1,9-nonamethylene diisocyanate, and the like, and these can be used alone or in combination of two or more. Among them, 1,6-hexamethylene diisocyanate is preferred.

The polyisocyanate may be an isocyanurate, adduct, biuret, uretdione, or allophanate of the isocyanate compound. Also, as the polyisocyanate, a blocked isocyanate in which an isocyanate group is blocked may be used. These compounds may be used alone, or two or more of them may be used in combination. Among them, isocyanurate and biuret are preferred.

In the adhesive composition of the present invention, the content of the curing agent (c) is preferably 0.5 parts by mass or more with respect to a total of 100 parts by mass of the modified polyolefin (a) and the polyimide resin (b). , more preferably 1 part by mass or more, still more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more. When the content is at least the above lower limit, a sufficient curing effect can be obtained, and excellent adhesiveness and soldering heat resistance can be exhibited. Also, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less. When the content is equal to or less than the above upper limit, the low dielectric properties of the adhesive composition are improved. That is, within the above range, an adhesive composition having excellent low dielectric properties in addition to adhesiveness, solder heat resistance and pot life can be obtained.

<Adhesive composition>
The adhesive composition of the present invention, by containing the three components (a) to (c), exhibits excellent adhesion to low-polarity resin substrates such as liquid crystal polymers (LCP) and metal substrates. , low dielectric properties, solder heat resistance and laser processability. That is, the adhesive coating film (adhesive layer) after the adhesive composition is applied to the substrate and cured can exhibit excellent low dielectric properties, solder heat resistance and laser processability.

In the adhesive composition of the present invention, the content of the modified polyolefin resin (a) is preferably 50 parts by mass or more with respect to a total of 100 parts by mass of the modified polyolefin resin (a) and the polyimide resin (b). More preferably 60 parts by mass or more, still more preferably 65 parts by mass or more. Also, it is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less. When the content of the modified polyolefin resin (a) is within the above range, adhesion, low dielectric properties, laser processability and compatibility are improved.

The adhesive composition of the present invention can further contain an organic solvent. The organic solvent that can be used in the present invention is not particularly limited as long as it dissolves or disperses the modified polyolefin (a), the polyimide resin (b) and the curing agent (c). 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. Halogenated hydrocarbons such as hydrogen, trichlorethylene, dichloroethylene, chlorobenzene, and chloroform, alcoholic solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol, acetone, methyl isobutyl ketone, ketone solvents such as methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone and acetophenone; cellosolves such as methyl cellosolve and ethyl cellosolve; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate and 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 mono-n-butyl ether, tetraethylene glycol mono-n-butyl ether, etc. A glycol ether solvent or the like can be used, and one or more of these can be used in combination. In particular, methylcyclohexane and toluene are preferred from the standpoint of working environment and drying properties.

The organic solvent is preferably in the range of 100 to 1000 parts by mass, and 200 to 900 parts by mass with respect to 100 parts by mass of the total solids of the modified olefin (a), the polyimide resin (b) and the curing agent (c). A range of 300 to 800 parts by mass is most preferred. By making it more than the said lower limit, liquid state and pot-life property become favorable. Moreover, setting the content to the above upper limit or less is advantageous in terms of manufacturing costs and transportation costs.

The adhesive composition according to the present invention preferably has a dielectric constant (ε _c ) of 3.0 or less at a frequency of 10 GHz. It is more preferably 2.6 or less, still more preferably 2.3 or less. Although the lower limit is not particularly limited, it is practically 2.0 or more. Also, the dielectric constant (ε) in the entire frequency range of 1 GHz to 60 GHz is preferably 3.0 or less, more preferably 2.6 or less, and even more preferably 2.3 or less.

The adhesive composition according to the present invention preferably has a dielectric loss tangent (tan δ) of 0.02 or less at a frequency of 10 GHz. It is more preferably 0.01 or less, and still more preferably 0.008 or less. Although the lower limit is not particularly limited, it is practically 0.0001. Also, the dielectric loss tangent (tan δ) in the entire frequency range of 1 GHz to 60 GHz is preferably 0.02 or less, more preferably 0.01 or less, and even more preferably 0.008 or less.

In the present invention, the dielectric constant (ε _c ) and dielectric loss tangent (tan δ) can be measured as follows. That is, the adhesive composition is applied to the release substrate so that the thickness after drying is 25 μm, and dried at about 130° C. for about 3 minutes. Then, it is cured by heat treatment at about 140° C. for about 4 hours, and the cured adhesive composition layer (adhesive layer) is peeled off from the release film. The dielectric constant (ε _c ) of the adhesive composition layer after peeling is measured at a frequency of 10 GHz. Specifically, the dielectric constant (ε _c ) and the dielectric loss tangent (tan δ) can be calculated from measurements by the cavity resonator perturbation method.

In addition, the adhesive composition of the present invention may further contain other components as necessary within a range that does not impair the effects of the present invention. Specific examples of such components include flame retardants, tackifiers, fillers, and silane coupling agents.

<Flame retardant>
The adhesive composition of the present invention may optionally contain a flame retardant within a range that does not impair the effects of the present invention. Flame retardancy can be imparted to the adhesive composition by containing a flame retardant. The flame retardant is not particularly limited as long as it exhibits flame retardancy, but it is preferably insoluble in an organic solvent. The flame retardant is preferably a flame-retardant filler, including inorganic flame-retardant fillers and organic flame-retardant fillers. Examples of inorganic flame-retardant fillers include metal hydroxide compounds such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, and barium hydroxide; basic magnesium carbonate, zinc carbonate, magnesium-calcium carbonate ( mixture of magnesium carbonate and calcium carbonate), calcium carbonate, barium carbonate, and other metal carbonate compounds; magnesium oxide, molybdenum oxide, zirconium oxide, tin oxide, tin oxide hydrate, antimony oxide, and other metal oxides; zinc borate borate metal compounds such as , zinc metaborate, and barium metaborate; inorganic metal compounds such as dolomite, hydrotalcite, and borax; and inorganic phosphorus compounds such as red phosphorus. Examples of organic flame-retardant fillers include melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, amide ammonium phosphate, amide ammonium polyphosphate, carbamate phosphate, polyphosphorus acid carbamate, aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, tetrakisdiethylphosphine Phosphorus-based flame retardants such as titanium oxide, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, and titanium tetrakisdiphenylphosphinate; triazine compounds such as melamine, melam, and melamine cyanurate; Nitrogen-based flame retardants such as acid compounds, isocyanuric acid compounds, triazole compounds, tetrazole compounds, diazo compounds, and urea; silicon-based flame retardants such as silicone compounds and silane compounds; As flame retardants, metal hydroxide compounds and phosphorus compounds are preferable, and phosphorus compounds are more preferable. For example, phosphorus-based flame-retardant fillers such as aluminum phosphinate can be used. There are two types of phosphorus-based flame retardants: a type that does not dissolve in organic solvents (phosphorus-based flame-retardant filler) and a type that dissolves in organic solvents (phosphorus-based flame-retardant non-filler). A non-flammable type (phosphorus-based flame-retardant filler) is preferred. The flame-retardant filler may be used alone, or two or more of them may be used in combination. When a flame retardant is contained, it is preferably contained in the range of 1 to 200 parts by mass, more preferably 5 to 150 parts by mass, with respect to the total 100 parts by mass of components (a) to (c). A range of 100 parts by weight is most preferred. The effect of the tackifier can be exhibited by setting the content to be equal to or higher than the lower limit. Further, by setting the content to the above upper limit or less, adhesion, solder heat resistance, low dielectric properties, etc. are not deteriorated.

<Tackifier>
The adhesive composition of the present invention may optionally contain a tackifier within a range that does not impair the effects of the present invention. Examples of tackifiers include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymer petroleum resins, styrene resins and hydrogenated petroleum resins. used in These may be used alone, or may be used in any combination of two or more. When a tackifier is contained, it is preferably contained in the range of 1 to 200 parts by mass, more preferably 5 to 150 parts by mass, with respect to the total 100 parts by mass of components (a) to (c). A range of to 100 parts by weight is most preferred. The effect of the tackifier can be exhibited by setting the content to be equal to or higher than the lower limit. Further, by setting the content to the above upper limit or less, adhesion, solder heat resistance, low dielectric properties, etc. are not deteriorated.

<Filler>
The adhesive composition of the present invention may optionally contain a filler as long as the effects of the present invention are not impaired. Here, the filler is different from the flame retardant filler described in the flame retardant, and examples thereof include silica. Addition of silica is very preferable because it improves solder heat resistance. Hydrophobic silica and hydrophilic silica are generally known as silica, but here, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, etc. is used to impart moisture absorption resistance. is good. When silica is blended, the blending amount is preferably 0.05 to 30 parts by mass per 100 parts by mass of components (a) to (c). The effect of improving the soldering heat resistance can be exhibited by making it equal to or higher than the lower limit. In addition, when the content is equal to or less than the above upper limit, poor dispersion of silica does not occur, and the solution viscosity is good and the workability is good. Moreover, the adhesiveness does not decrease.

<Silane coupling agent>
The adhesive composition of the present invention may optionally contain a silane coupling agent as long as the effects of the present invention are not impaired. Addition of a silane coupling agent is very preferable because it improves adhesion to metals and solder heat resistance. The silane coupling agent is not particularly limited, but examples include those having an unsaturated group, those having a glycidyl group, those having an amino group, and the like. Among these, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane and the like are used from the viewpoint of solder heat resistance. A silane coupling agent having a glycidyl group is more preferable. When a silane coupling agent is blended, the blending amount is preferably 0.5 to 20 parts by mass per 100 parts by mass of components (a) to (c). When the content is 0.5 parts by mass or more, excellent solder heat resistance is obtained. On the other hand, when the content is 20 parts by mass or less, solder heat resistance and adhesiveness are improved.

<Laminate>
The laminate of the present invention is obtained by laminating an adhesive composition on a base material (two-layer laminate of base material/adhesive layer), or further laminating a base material (base material/adhesive layer/ A three-layer laminate of substrates). Here, the adhesive layer refers to a layer of the adhesive composition after the adhesive composition of the present invention has been applied to a substrate and dried. The laminate of the present invention can be obtained by applying the adhesive composition of the present invention to various substrates, drying it, and further laminating another substrate in accordance with conventional methods.

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

Examples of resin substrates include polyester resins, polyamide resins, polyimide resins, polyamideimide resins, liquid crystal polymers, polyphenylene sulfides, syndiotactic polystyrene, polyolefin resins, fluorine resins, and the like. A film-like resin (hereinafter also referred to as a base film layer) is preferred.

Any conventionally known conductive material that can be used for circuit boards can be used as the metal base material. Examples of materials include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, and their alloys, plated products, and metals treated with other metals such as zinc and chromium compounds. Metal foil is preferred, and copper foil is more preferred. Although the thickness of the metal foil is not particularly limited, it is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 10 μm or more. Also, it is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit. Metal foils are 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 using a ribbon-shaped metal foil, the length is not particularly limited. Also, the width is not particularly limited, but it is preferably about 250 to 500 cm.

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

Based on adhesive strength and durability with the adhesive composition, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, fluororesin, 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 configuration modes include laminate/adhesive layer/release substrate, or release substrate/adhesive layer/laminate/adhesive layer/release substrate. By laminating the release base material, it functions as a protective layer for the base material. Moreover, by using a 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, when a release base material is applied to the adhesive layer after drying, it is possible to wind up the product without set-off to the base material, resulting in excellent workability and preservability due to the protection of the adhesive layer. excellent and easy to use. Further, if the adhesive layer itself is applied to a release base material and dried, and if necessary, another release base material is applied, the adhesive layer itself can be transferred to another base material.

<Release substrate>
The release substrate is not particularly limited, but for example, a coated layer of filler such as clay, polyethylene, polypropylene, etc. is applied to both sides of paper such as woodfree paper, kraft paper, roll paper, and glassine paper. and a silicone type, fluorine type or alkyd type release agent is applied on each coating layer. Other examples include various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer and propylene-α-olefin copolymer alone, and films such as polyethylene terephthalate coated with the release agent. For reasons such as the release force between the release base material and the adhesive layer, and the fact that silicone adversely affects low dielectric properties, both sides of high-quality paper are filled with polypropylene and an alkyd-based release agent is used on top of that. , or polyethylene terephthalate with an alkyd release agent is preferred.

The method of coating the substrate with the adhesive composition in the present invention is not particularly limited, but includes a comma coater, a reverse roll coater, and the like. Alternatively, if necessary, an adhesive layer can be provided directly or by a transfer method on the rolled copper foil or polyimide film, which are the constituent materials of the printed wiring board. The thickness of the adhesive layer after drying may be changed as required, 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, the drying is insufficient, the residual solvent increases, and there is a problem that blistering occurs during pressing in the manufacture of printed wiring boards. The drying conditions are not particularly limited, but the residual solvent rate 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, resulting in blisters.

<Printed wiring board>
The "printed wiring board" in the present invention includes, as constituent elements, a laminate formed from a metal foil forming a conductor circuit and a resin base material. A printed wiring board is manufactured, for example, by a conventionally known method such as a subtractive method using a metal-clad laminate. If necessary, so-called flexible circuit boards (FPC), flat cables, tape automated bonding ( 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 employed as a 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, a printed wiring board can be made up of five layers: a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

Furthermore, if necessary, a configuration in which two or three or more of the above printed wiring boards are laminated can be used.

The adhesive composition of the present invention can be suitably used for each adhesive layer of printed wiring boards. In particular, when the adhesive composition of the present invention is used as an adhesive, it has high adhesiveness not only to conventional polyimides, polyester films, and copper foils constituting printed wiring boards, but also to low-polarity resin substrates such as LCP. , soldering heat resistance can be obtained, and the adhesive layer itself is excellent in low dielectric properties. Therefore, it is suitable as an adhesive composition used for coverlay films, laminates, resin-coated copper foils and bonding sheets.

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

<Cover film>
As the cover film, any insulating film conventionally known as an insulating film for printed wiring boards can be used. For example, films made from various polymers such as polyimide, polyester, polyphenylene sulfide, polyethersulfone, polyetheretherketone, aramid, polycarbonate, polyarylate, polyamideimide, liquid crystal polymer, syndiotactic polystyrene, and polyolefin resin are used. It is possible. Polyimide films or liquid crystal polymer films are more preferred.

The printed wiring board of the present invention can be manufactured using any conventionally known process except for using the materials for each layer described above.

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 in which a desired circuit pattern is formed by laminating a metal foil layer on a base film layer (hereinafter referred to as a "two-layer semi-finished product on the base film side"), or a semi-finished product in which an adhesive layer is laminated on a base film layer. , a semi-finished product having a desired circuit pattern formed by laminating a metal foil layer thereon (hereinafter referred to as "base film side 3-layer semi-finished product") (hereinafter referred to as "base film side 2-layer semi-finished product"). Together with the base film side three-layer semi-finished product, it is referred to as the “base film side semi-finished product”). By laminating the semi-finished product on the cover film side and the semi-finished product on the base film side thus obtained, a printed wiring board having four or five layers can be obtained.

The semi-finished product on the substrate film side includes, for example, (A) a step of applying a solution of a resin that will be the substrate film to the metal foil and initially drying the coating film, and (B) the metal foil obtained in (A) and It is obtained by a production method including a process of heat-treating and drying the laminate with the initially dried coating film (hereinafter referred to as "heat-treatment/solvent removal process").

A conventionally known method can be used to form a circuit in the metal foil layer. An additive method may be used, or a subtractive method may be used. A subtractive method is preferred.

The semi-finished product on the base film side thus obtained may be used as it is for lamination with the semi-finished product on the cover film side. may be used.

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

The semi-finished product on the cover film side thus obtained may be used as it is for bonding to the semi-finished product on the base film side. may be used for

The semi-finished product on the base film side and the semi-finished product on the cover film side are each stored, for example, in the form of a roll, and then laminated together 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. Also, both can be bonded together while being heated by a method such as using a hot press or a hot roll device.

For the semi-finished product on the reinforcing material side, for example, in the case of a soft and windable reinforcing material such as a polyimide film, it is preferable to manufacture it by applying an adhesive to the reinforcing material. In addition, in the case of reinforcing plates such as metal plates such as SUS and aluminum, and glass fiber hardened plates with epoxy resin that cannot be rolled up, the adhesive applied in advance to the release base material can be transferred and applied. It is preferably manufactured. Also, if necessary, a cross-linking reaction in the applied adhesive can be carried out. In a preferred embodiment, the adhesive layer is semi-cured.

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

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

<Electromagnetic wave shielding material>
The electromagnetic wave shielding material of the present invention is an article provided with an adhesive layer formed using the adhesive composition of the present invention. A preferred embodiment of the present invention is an electromagnetic shielding material in which the adhesive layer contains a conductive filler. As a result, it is possible to prevent electronic equipment from malfunctioning due to electromagnetic wave noise and confidential information from being leaked due to interception of communication radio waves.
As a method for producing the electromagnetic wave shielding material of the present invention, for example, a method of bonding a conductive bonding sheet provided with an adhesive layer containing a conductive filler and a shielding material can be applied.

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the examples. Parts in the examples and comparative examples indicate parts by mass.

(Physical property evaluation method)
(Acid value (modified polyolefin resin))
The acid value (mgKOH/g) in the present invention was determined by dissolving a resin sample in toluene and titrating with a methanol solution of sodium methoxide using phenolphthalein as an indicator.

(Acid value (polyimide resin))
The acid value (mgKOH/g) in the present invention was determined by dissolving a resin sample in N-methylpyrrolidone (NMP) and titrating with a methanol solution of sodium methoxide using phenolphthalein as an indicator.

(Number average molecular weight (Mn))
The number average molecular weight in the present invention is determined by Shimadzu Corporation Gel Permeation Chromatography (hereinafter referred to as GPC, standard substance: polystyrene resin, mobile phase: tetrahydrofuran, column: Shodex KF-802 + KF-804L + KF-806L, column temperature: 30°C, flow rate: 1.0 ml/min, detector: RI detector).

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

(logarithmic viscosity)
The polyimide resin (b) was dissolved in NMP so that the polymer concentration was 0.6 g/dl. The solution viscosity and solvent viscosity of the solution were measured at 30° C. with an Ubbelohde viscometer and calculated by the following formula.
Logarithmic viscosity (dl/g) = [ln (V1/V2)]/V3
V1: Calculated from the time for the solvent (NMP) to pass through the capillary of the Ubbelohde viscosity tube V2: Calculated from the time that the polymer solution passes through the capillary of the Ubbelohde viscosity tube V3: Polymer concentration (g/dl)

(1) Adhesive strength The adhesive composition described later is applied to a polyimide (PI) film with a thickness of 12.5 μm (manufactured by Kaneka Co., Ltd., Apical (registered trademark)), or a LCP film with a thickness of 25 μm (manufactured by Kuraray Co., Ltd., Vecstar (registered trademark)) so that the thickness after drying becomes 25 μm, and dried at 130° C. for 3 minutes. The adhesive film (B stage product) thus obtained was laminated to a rolled copper foil (BHY series, manufactured by JX Metals Co., Ltd.) having a thickness of 18 μm. The bonding was performed by pressing the rolled copper foil so that the glossy surface of the rolled copper foil was in contact with the adhesive layer, and pressing for 30 seconds under a pressure of 40 kgf/cm ² at 160°C. Then, it was cured by heat treatment at 160° C. for 1 hour to obtain a sample for peel strength evaluation. The peel strength was measured by pulling the film at 25°C and performing a 90° peel test at a tensile speed of 50 mm/min. This test shows the bond strength at room temperature.
<Evaluation Criteria>
◎: 1.0 N / mm or more ○: 0.8 N / mm or more and less than 1.0 N / mm △: 0.5 N / mm or more and less than 0.8 N / mm ×: less than 0.5 N / mm

(2) Solder heat resistance A sample was prepared in the same manner as in (1) above, and a sample piece of 2.0 cm x 2.0 cm was subjected to aging treatment at 23 ° C. for 2 days, and immersed in a solder bath melted at 280 ° C. for 10 seconds. It floated, and it was confirmed whether there was any change in appearance such as swelling.
<Evaluation Criteria>
◎: No swelling ○: Partial swelling △: Many swelling ×: Swelling and discoloration

(3) Low dielectric properties (relative dielectric constant (ε _c ) and dielectric loss tangent (tan δ))
An adhesive composition described below was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so that the thickness after drying and curing was 25 μm, and dried at 130° C. for 3 minutes. Then, it was cured by heat treatment at 160° C. for 1 hour to obtain an adhesive resin sheet for testing. The obtained test adhesive resin sheet was cut into strips of 8 cm×3 mm to obtain test samples. The dielectric constant (εc) and the dielectric loss tangent (tan δ) were measured by a cavity resonator perturbation method using a network analyzer (manufactured by Anritsu Corporation) under conditions of a temperature of 23°C and a frequency of 10 GHz. The obtained relative permittivity and dielectric loss tangent were evaluated as follows.
<Evaluation Criteria for Relative Permittivity>
◎: 2.3 or less ○: More than 2.3 and 2.6 or less △: More than 2.6 and 3.0 or less ×: More than 3.0 <Evaluation criteria for dielectric loss tangent>
◎: 0.008 or less ○: more than 0.008 and 0.01 or less △: more than 0.01 and 0.02 or less ×: more than 0.02

(4) Absorbance at 355 nm The adhesive composition described below was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so that the thickness after drying and curing was 25 μm, and dried at 130° C. for 3 minutes. Then, it was cured by heat treatment at 140° C. for 4 hours to obtain an adhesive resin sheet for testing. Using the obtained adhesive resin sheet, the absorbance at 355 nm was measured with an ultraviolet-visible spectrophotometer V-650 (manufactured by JASCO Corporation).
<Evaluation Criteria>
Good: Abs 0.3 or more.
(triangle|delta): It is Abs 0.2-0.3.
x: Less than Abs 0.2.

(5) Compatibility An adhesive composition to be described later was applied to a polypropylene film having a thickness of 50 μm so that the thickness after drying and curing was 25 μm, and dried at 130° C. for 3 minutes. The appearance of the obtained adhesive resin sheet was visually confirmed.
<Evaluation Criteria>
◯: No foreign matter or unevenness.
Δ: Slight unevenness is observed.
x: There are foreign matter and unevenness, or coating is not possible.

(Production example of modified polyolefin resin (a))
(Production example 1)
In a 1 L autoclave, 100 parts by mass of propylene-butene copolymer ("Tafmer (registered trademark) XM7080" manufactured by Mitsui Chemicals, Inc.), 150 parts by mass of toluene, 19 parts by mass of maleic anhydride, and 6 parts by mass of di-tert-butyl peroxide was added, the temperature was raised to 140° C. with stirring, and the mixture was further stirred for 3 hours. Thereafter, the obtained reaction solution was cooled and then poured into a container containing a large amount of methyl ethyl ketone to precipitate a resin. Thereafter, the liquid containing the resin was centrifuged to separate and purify the acid-modified propylene-butene copolymer graft-polymerized with maleic anhydride, the (poly)maleic anhydride and the low molecular weight substances. Then, by drying at 70° C. for 5 hours under reduced pressure, a maleic anhydride-modified propylene-butene copolymer (a-1, acid value 19 mgKOH/g, number average molecular weight 25,000, Tm 80° C., ΔH35 J/g) was obtained.

(Production example 2)
A maleic anhydride-modified propylene-butene copolymer (a-2, acid value 14 mg KOH/g , number average molecular weight 30,000, Tm 78° C., ΔH 25 J/g).

(Production example 3)
A maleic anhydride-modified propylene-butene copolymer (a-3, acid value 11 mg KOH/g , number average molecular weight 33,000, Tm 80°C, ΔH 25 J/g).

(Production example 4)
A maleic anhydride-modified propylene-butene copolymer (a-4, an acid value of 7 mg KOH/g , number average molecular weight of 35,000, Tm of 82° C., ΔH of 25 J/g).

(Production example of polyimide resin (b))
(Production example 5)
17.3 parts by mass of trimellitic anhydride (manufactured by Polynt), 315.0 parts by mass of polybutadiene diol (trade name GI-1000 manufactured by Nippon Soda, molecular weight 1500), 4,4'-diphenylmethane diisocyanate (MDI) (MDI) as an isocyanate component ( 75.9 parts by mass of Millionate MT manufactured by Tosoh was placed in a flask and dissolved in 611.1 parts by mass of cyclohexanone. Also, 0.69 parts by mass of DBU was added as a catalyst. Thereafter, the mixture was reacted at 130° C. for 5 hours while stirring under a nitrogen stream, and then cooled to room temperature to give a nonvolatile content (solid content) of 40% by mass, an acid value of 4.6 mg KOH/g, and a logarithmic viscosity of 0.190 dl. /g of polyimide resin (b-1) solution was obtained.

(Production example 6)
Trimellitic anhydride (manufactured by Polynt) 17.3 parts by mass, dimer diol (trade name Pripol 2033 manufactured by Croda Japan, molecular weight 560) 117.6 parts by mass, 4,4'-diphenylmethane diisocyanate (MDI) (Tosoh) as an isocyanate component 75.1 parts by mass of Millionate MT (manufactured by Kao Corporation) was placed in a flask and dissolved in 157.5 parts by mass of cyclohexanone and 157.5 parts by mass of N-methylpyrrolidone. Also, 0.69 parts by mass of DBU was added as a catalyst. Thereafter, the mixture was reacted at 130° C. for 6 hours while stirring under a nitrogen stream, and then cooled to room temperature to give a nonvolatile content (solid content) of 40% by mass, an acid value of 6.7 mg KOH/g, and a logarithmic viscosity of 0.168 dl. /g of polyimide resin (b-2) solution was obtained.

(Production Example 7)
210.00 parts by mass of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (manufactured by Evonik Japan), 1000.80 parts by mass of cyclohexanone, and 201.60 parts by mass of methylcyclohexane were charged and heated to 60°C. bottom. Then, after dropping 341.67 parts by mass of dimer diamine (trade name Priamine 1075, molecular weight 549, manufactured by Croda Japan), imidization reaction was carried out at 140° C. for 10 hours, and the mixture was cooled to room temperature to obtain a nonvolatile content (solid content) of 30. A polyimide resin (b-3) solution having a mass %, an acid value of 5.6 mgKOH/g and a logarithmic viscosity of 0.240 dl/g was obtained.

(Production Example 8)
Trimellitic anhydride (manufactured by Polynt) 34.6 parts by mass, dimer acid (trade name Pripol 1009 manufactured by Croda Japan, molecular weight 566) 235.2 parts by mass, 4,4'-diphenylmethane diisocyanate (MDI) (Tosoh) as an isocyanate component 145.7 parts by mass of Millionate MT (trade name) was put in a flask and dissolved in 623.1 parts by mass of N-methylpyrrolidone. Also, 1.37 parts by mass of DBU was added as a catalyst. After that, the mixture was reacted at 130° C. for 5 hours while stirring under a nitrogen stream, and then cooled to room temperature to give a nonvolatile content (solid content) of 40% by mass, an acid value of 10.4 mg KOH/g, and a logarithmic viscosity of 0.318 dl. /g of polyimide resin (b-4) solution was obtained.

(Production Example 9)
Trimellitic anhydride (manufactured by Polynt) 28.8 parts by mass, polybutadiene diol (product name GI-1000 manufactured by Nippon Soda) 225.0 parts by mass, 4,4'-diphenylmethane diisocyanate (MDI) (manufactured by Tosoh) as an isocyanate component 75.1 parts by mass of Millionate MT) was placed in a flask and dissolved in 236.8 parts by mass of cyclohexanone and 236.8 parts by mass of N-methylpyrrolidone. After that, the mixture was reacted at 130° C. for 5 hours while stirring under a nitrogen stream, and then cooled to room temperature to give a nonvolatile content (solid content) of 40% by mass, an acid value of 11.8 mg KOH/g, and a logarithmic viscosity of 0.139 dl. /g of polyimide resin (b-5) solution was obtained.

(Production Example 10)
Trimellitic anhydride (manufactured by Polynt) 17.3 parts by mass, polyester diol (manufactured by DIC, trade name ODX-2044, molecular weight 2000) 420.0 parts by mass, 4,4'-diphenylmethane diisocyanate (MDI) (Tosoh) as an isocyanate component 72.8 parts by mass of Millionate MT (trade name) was placed in a flask and dissolved in 765.2 parts by mass of cyclohexanone. After that, the mixture was reacted at 130° C. for 8 hours while stirring under a nitrogen stream, and then cooled to room temperature to give a nonvolatile content (solid content) of 40% by mass, an acid value of 8.4 mg KOH/g, and a logarithmic viscosity of 0.250 dl. /g of polyimide resin (b-6) solution was obtained.

(Production Example 11)
Polybutadiene diol (manufactured by Nippon Soda, trade name GI-1000) 360.0 parts by mass, 2,2-bis(hydroxymethyl)butyric acid 8.89 parts by mass, 4,4'-diphenylmethane diisocyanate (MDI) (manufactured by Tosoh) as an isocyanate component 74.2 parts by mass of Millionate MT (trade name) was placed in a flask and dissolved in 664.8 parts by mass of cyclohexanone. Also, 0.69 parts by mass of DBU was added as a catalyst. Thereafter, the mixture was reacted at 130° C. for 5 hours while stirring under a nitrogen stream, and then cooled to room temperature to give a nonvolatile content (solid content) of 40% by mass, an acid value of 5.6 mg KOH/g, and a logarithmic viscosity of 0.176 dl. /g of a polyurethane resin (b-7) solution was obtained.

Curing agents (c) used in Table 1 are as follows.
(Epoxy resin)
c-1: Dicyclopentadiene type epoxy resin: HP-7200H (manufactured by DIC, epoxy equivalent 278 g / eq)
c-2: cresol novolak type epoxy resin: jER-152 (manufactured by Mitsubishi Chemical, epoxy equivalent 177 g / eq
c-3: Glycidylamine type epoxy resin: jER-630 (manufactured by Mitsubishi Chemical, epoxy equivalent 98 g / eq
(polyisocyanate)
c-4: Isocyanurate form of hexamethylene diisocyanate: Sumidur (registered trademark) N-3300 (manufactured by Bayer AG)
(Polycarbodiimide)
c-5: Carbodiimide resin: V-09GB (manufactured by Nisshinbo Chemical Co., carbodiimide equivalent 216 g / eq)
c-6: Carbodiimide resin: V-03 (manufactured by Nisshinbo Chemical Co., carbodiimide equivalent 209 g / eq)

<Example 1>
The modified polyolefin resin (a-1) was dissolved in an organic solvent (methylcyclohexane/toluene=80/20 (volume ratio)) to prepare a solution with a solid concentration of 20% by mass. A curing agent (c-1) (epoxy resin, HP-7200H) was dissolved in an organic solvent (methyl ketone) to prepare a solution with a solid concentration of 70% by mass. 80 solid parts by mass of modified polyolefin resin (a-1), 20 parts by solid mass of polyimide resin (b-1) and 10 parts by solid mass of curing agent (c-1) were blended to form an adhesive composition. got stuff Table 1 shows the evaluation results of adhesive strength, solder heat resistance, low dielectric properties, absorbance at 355 nm and compatibility of the resulting adhesive composition.

<Examples 2 to 23, Comparative Examples 1 to 5>
Examples 2 to 2 were prepared in the same manner as in Example 1, except that the amounts (parts by solid mass) of the modified polyolefin resin (a), the polyimide resin (b), and the curing agent (c) were changed as shown in Table 1. 21 and Comparative Examples 1-5 were performed. Table 1 shows the evaluation results of adhesion strength, solder heat resistance, low dielectric properties, absorbance at 355 nm and compatibility.

As is clear from Table 1, in Examples 1 to 23, the adhesive has excellent adhesion and solder heat resistance with polyimide (PI) and LCP, and also has excellent adhesion and solder heat resistance with copper foil. and showed good absorption in the absorbance at 355 nm, which is an index of laser processability. On the other hand, in Comparative Example 1, since the polyimide resin (b) was not blended, the absorbance at 355 nm was low and the laser processability was poor. In Comparative Example 2, since the curing agent (c) was not blended, the solder heat resistance was inferior. In Comparative Example 3, the adhesion was inferior because the modified polyolefin resin (a) was not blended. In Comparative Example 4, since the polyimide resin (b) did not contain polyolefin polyol, dimer acid derivative, etc., low dielectric properties and compatibility were inferior. In Comparative Example 5, since the component (b) was a polyurethane resin containing no imide group, the absorbance at 355 nm was low and the laser processability was poor.

The adhesive composition of the present invention has high adhesion not only to conventional polyimides and liquid crystal polymers, but also to metal substrates such as copper foil, can obtain high solder heat resistance, and has low dielectric properties. and excellent in laser processability. The adhesive composition of the present invention can be used to obtain an adhesive sheet and an adhered laminate. Due to the above properties, 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 range are required, and electromagnetic wave shielding materials.

Claims

containing a modified polyolefin resin (a), a polyimide resin (b) and a curing agent (c),
The adhesive composition, wherein the polyimide resin (b) has, as a structural unit, at least one selected from the group consisting of polyolefin polyols, polyolefin polyamines, polyolefin polycarboxylic acids, dimer diols, dimer diamines and dimer acids.
The adhesive composition according to claim 1, wherein the modified polyolefin resin (a) has an acid value of 5 to 30 mgKOH/g.
The adhesive composition according to claim 1 or 2, wherein the curing agent (c) contains at least one selected from the group consisting of epoxy resins, polyisocyanates and polycarbodiimides.
The adhesive composition according to claim 1 or 2, containing 50 to 95 parts by mass of the modified polyolefin resin (a) with respect to a total of 100 parts by mass of the modified polyolefin resin (a) and the polyimide resin (b).
The adhesive composition according to claim 1 or 2, which has a dielectric constant of less than 3.0 at 10 GHz.
The adhesive composition according to claim 1 or 2, wherein the content of the curing agent (c) is 0.5 to 60 parts by mass with respect to a total of 100 parts by mass of the modified polyolefin resin (a) and the polyimide resin (b). thing.
An adhesive sheet having a layer made of the adhesive composition according to claim 1 or 2.
An electromagnetic shielding material having a layer made of the adhesive composition according to claim 1 or 2.
A laminate having a layer made of the adhesive composition according to claim 1 or 2.
A printed wiring board comprising the laminate according to claim 9 as a component.