JPWO2011052376A1 - Adhesive resin composition, coverlay film and circuit board - Google Patents

Abstract

［式中、Ａｒは芳香族テトラカルボン酸無水物から誘導される４価の芳香族基、Ｒ_１はジアミノシロキサンから誘導される２価のジアミノシロキサン残基、Ｒ_２は芳香族ジアミンから誘導される２価の芳香族ジアミン残基をそれぞれ表し、ｍ、ｎは各構成単位の存在モル比を示し、ｍは０．７５〜１．０の範囲内、ｎは０〜０．２５の範囲内である］を含むポリイミドシロキサンを１００重量部、（ｂ）平均粒径が２〜２５μｍの範囲内の板状の無機フィラーを５〜２００重量部、を含有する接着剤樹脂組成物。The following components (a) and (b); (a) structural units represented by the following general formulas (1) and (2):
[Chemical 1]

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, and R ₂ is derived from an aromatic diamine. Each represents a divalent aromatic diamine residue, m and n represent the molar ratio of each constituent unit, m is in the range of 0.75 to 1.0, and n is in the range of 0 to 0.25. An adhesive resin composition containing 100 parts by weight of polyimidesiloxane containing, and (b) 5 to 200 parts by weight of a plate-like inorganic filler having an average particle diameter of 2 to 25 μm.

Description

  The present invention relates to an adhesive resin composition useful as an adhesive in a circuit board such as a flexible printed wiring board and the use thereof.

  In recent years, with the progress of downsizing, weight reduction, and space saving of electronic devices, flexible printed wiring boards (FPCs) that are thin, light, flexible, and have excellent durability even after repeated bending are used. The demand for Circuits) is increasing. FPC can be mounted three-dimensionally and densely in a limited space. For example, it can be used not only for wiring of movable parts of electronic devices such as HDDs, DVDs and mobile phones, but also for components such as cables and connectors. Their uses are expanding.

  For the FPC, a coverlay film is used for the purpose of protecting the wiring portion. The coverlay film is formed by laminating a coverlay film material made of a synthetic resin such as a polyimide resin and an adhesive layer. In manufacturing an FPC, a coverlay film material is attached to a circuit board through an adhesive layer by using a method such as hot pressing. The adhesive layer is required to have high adhesion to both the circuit wiring pattern such as copper wiring and the film material for coverlay. As an adhesive for such a coverlay film, it can be processed under relatively low temperature thermocompression bonding conditions, and it has excellent heat resistance and other characteristics, and it can be used as a mixed resin of polyimide resin and epoxy resin having a siloxane unit. In addition, an adhesive resin composition for printed circuit boards, in which one or more plasticizers selected from phosphoric acid ester-based, phthalic acid ester-based, polyester-based and fatty acid ester-based materials are blended has been proposed (for example, Patent Document 1). ).

  In addition, with regard to the film material for coverlay, in order to improve the heat resistance, non-curling property and adhesion as a protective film and to improve the compatibility with the epoxy resin adhesive, soluble polyimidesiloxane, epoxy resin and flat talc Has been proposed (for example, Patent Document 2). Similarly, a resin composition that includes an acid group-containing polyimide siloxane, a terminal epoxy group-containing polyimide siloxane, and talc and further improves the non-curl property as a protective film has also been proposed for the coverlay film material. (For example, patent document 3).

Japanese Unexamined Patent Publication No. 10-212468 Japanese Unexamined Patent Publication No. 7-304950 Japanese Unexamined Patent Publication No. 2009-167260

  By the way, in-vehicle electronic devices for automobiles using FPC are repeatedly placed in a high temperature environment of about 150 ° C., the adhesive strength between the FPC coverlay film and the wiring is lowered over a long period of use, and the wiring protection function is provided. There has been a problem of a significant drop. With the expansion of FPC applications, it is expected that the number of scenes where FPC is used not only in in-vehicle electronic devices but also in severe temperature environments will continue to increase. For this reason, in an FPC used in a high temperature environment, it is strongly required to take measures against a decrease in the adhesive strength of the coverlay film.

  Therefore, the subject of this invention is providing the adhesive agent resin composition which can form the adhesive bond layer which does not reduce the adhesive force of a wiring layer and a coverlay film, even if it puts in a high temperature environment repeatedly.

  As a result of investigating the cause of the above problem, the present inventors have found that copper in copper wiring is oxidized due to long-term use in an environment where high temperatures are repeated, which is a main factor for the decrease in adhesive strength. The inventors have found that by suppressing the oxidation of copper, excellent adhesiveness can be maintained for a long time even in a high temperature environment, and the present invention has been completed. That is, the adhesive resin composition of the present invention comprises 100 parts by weight of polyimidesiloxane containing the structural units represented by the following components (a) and (b); (a) the following general formulas (1) and (2). Part (b), 5 to 200 parts by weight of a plate-like inorganic filler having an average particle diameter of 2 to 25 μm.

［式中、Ａｒは芳香族テトラカルボン酸無水物から誘導される４価の芳香族基、Ｒ_１はジアミノシロキサンから誘導される２価のジアミノシロキサン残基、Ｒ_２は芳香族ジアミンから誘導される２価の芳香族ジアミン残基をそれぞれ表し、ｍ、ｎは各構成単位の存在モル比を示し、ｍは０．７５〜１．０の範囲内、ｎは０〜０．２５の範囲内である］

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, and R ₂ is derived from an aromatic diamine. Each represents a divalent aromatic diamine residue, m and n represent the molar ratio of each constituent unit, m is in the range of 0.75 to 1.0, and n is in the range of 0 to 0.25. Is]

  In the adhesive resin composition of the present invention, the particle size distribution of the inorganic filler is preferably 60% or more and a particle size of 20 μm or more and 10% or less on a number basis.

  In the adhesive resin composition of the present invention, it is preferable that the polyimide siloxane is synthesized using a diaminosiloxane represented by the following general formula (3) as a raw material. In this case, it is preferable that the molar ratio of the diaminosiloxane of the general formula (3) in all the diamine components of the raw material is 80 mol% or more.

［式中、Ｒ_３及びＲ_４は、それぞれ、酸素原子を含有していてもよい２価の有機基を示し、Ｒ_５〜Ｒ_８は、それぞれ炭素数１〜６の炭化水素基を示し、平均繰り返し数であるｍ_１は、１〜２０である］

[Wherein, R ₃ and R ₄ each represent a divalent organic group that may contain an oxygen atom, R _{5 to} R ₈ each represent a hydrocarbon group having 1 to 6 carbon atoms, M ₁ that is the average number of repetitions is ₁ to 20]

  The adhesive resin composition of the present invention is preferably used as an adhesive for a coverlay film that protects a wiring portion of a circuit board.

  The cover lay film of the present invention is a cover lay film obtained by laminating an adhesive layer and a cover lay film material layer, and the adhesive layer is formed using any one of the above adhesive resin compositions. Is.

  The circuit board of the present invention includes a base material, a wiring layer formed on the base material, and the coverlay film that covers the wiring layer. This circuit board preferably has a peel strength of 0.2 kN / m or more between the wiring layer and the coverlay film material layer after a long-term heat resistance test at 150 ° C. for 1000 hours in the atmosphere.

  The adhesive resin composition of the present invention can form an adhesive layer that prevents oxidation of the metal wiring layer and does not reduce the adhesive force with the metal wiring layer even when it is repeatedly placed in a high temperature environment. Therefore, the peel strength of the coverlay film in which the adhesive layer is formed by the adhesive resin composition of the present invention can be increased, and the reliability of the circuit board using the coverlay film can be improved.

[Polyimide siloxane]
The adhesive resin composition of this invention contains the polyimidesiloxane containing the structural unit represented by the said General formula (1) and (2) as a component (a). This polyimide siloxane is a thermoplastic resin, the group Ar in the general formulas (1) and (2) is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, and the group R ₁ is a diaminosiloxane. And the group R ₂ is a divalent aromatic diamine residue derived from an aromatic diamine. The abundance of the structural unit represented by the formula (1) in the resin is in the range of 75 mol% to 100 mol%, preferably in the range of 80 mol% to 100 mol%. The diaminosiloxane residue is a group having a siloxane bond (Si-O-Si) obtained by removing an amino group from diaminosiloxane. By increasing the ratio of the siloxane bond, adhesion can be achieved without adding a plasticizer. Sufficient flexibility is imparted to the agent layer, and warpage of the coverlay film can be suppressed. For this reason, in this invention, the value of m in Formula (1) shall be 0.75 or more. If the value of m is less than 0.75, the effect of suppressing warpage cannot be obtained sufficiently. In addition, it is considered that increasing the siloxane bond also has an effect of reducing curing shrinkage due to a decrease in the imide bond site of polyimidesiloxane. Therefore, the value of n in the formula (2) is set to 0 to 0.25, preferably 0 to 0.2. Moreover, the viscosity in the state of the solution of an adhesive resin composition can be reduced by increasing the ratio of a siloxane bond. Accordingly, even when a soft inorganic filler such as talc is used, when the adhesive resin composition is applied in a solution state, the plate-like inorganic filler is layered (the surface portion of the inorganic filler is the coating surface). This is advantageous because it can be easily arranged in a substantially parallel state.

  Examples of the group Ar include those represented by the following formula (4) or formula (5).

［式（５）中、Ｗは単結合、炭素数１〜１５の２価の炭化水素基、−Ｏ−、−Ｓ−、−ＣＯ−、−ＳＯ−、−ＳＯ_２−、−ＮＨ−若しくは−ＣＯＮＨ−から選ばれる２価の基を示す］

Wherein (5), W is a single bond, a divalent hydrocarbon group having 1 to 15 carbon atoms, -O -, - S -, - CO -, - SO -, - SO 2 -, - NH- or A divalent group selected from -CONH-]

In particular, as the group Ar, W in the formula (4) or the formula (5) is a single bond and has 1 to 15 carbon atoms in order to suppress the amount of polar groups contained in the polyimidesiloxane molecule and increase the adhesion. Of the divalent hydrocarbon group, —O—, —S—, —CO—, —SO ₂ —, wherein W in formula (4) or formula (5) is a single bond, carbon A divalent hydrocarbon group of 1 to 15 and a group represented by -CO- are more preferable.

  In addition, the structural unit represented by the general formulas (1) and (2) may be present in the homopolymer or may be present as a structural unit of the copolymer. In the case of a copolymer having a plurality of structural units, it may exist as a block copolymer or a random copolymer.

Since a polyimide resin is generally produced by reacting an acid anhydride and a diamine, a specific example of the polyimide resin can be understood by explaining the acid anhydride and the diamine. In the above general formulas (1) and (2), the group Ar can be referred to as an acid anhydride residue, and the groups R ₁ and R ₂ can be referred to as diamine residues. The product and diamine will be described. However, the polyimide resin is not limited to those obtained from the acid anhydride and diamine described here.

  Examples of the acid anhydride having the group Ar as a residue include pyromellitic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetra Preferred examples include carboxylic dianhydride and 4,4′-oxydiphthalic anhydride. Moreover, 2,2 ', 3,3'-, 2,3,3', 4'- or 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,3 ', 3,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 2,3 ', 3,4'-diphenyl ether tetracarboxylic dianhydride Bis (2,3-dicarboxyphenyl) ether dianhydride, 3,3``, 4,4 ''-, 2,3,3``, 4 ''-or 2,2 '', 3, 3 ''-p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3.4-di Carboxyphenyl) methane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride Products such as 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic acid Dianhydride 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7- Hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3, 6,7- (or 1,4,5,8-) tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 2,3,8 , 9-, 3,4,9,10-, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4- Tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5 -Tetracarboxylic acid Anhydride, 4,4'-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride and the like.

As the group R _2, for example, may include those represented by the following formula (6) to (8).

［式（６）〜式（８）において、Ｒ_９は独立に炭素数１〜６の１価の炭化水素基又はアルコキシ基を示し、Ｚは単結合、炭素数１〜１５の２価の炭化水素基、−Ｏ−、−Ｓ−、−ＣＯ−、−ＳＯ−、−ＳＯ_２−、−ＮＨ−若しくは−ＣＯＮＨ−から選ばれる２価の基を示し、ｎ_１は独立に０〜４の整数を示す］

[In Formula (6)-Formula (8), R < ₉ > shows a C1-C6 monovalent hydrocarbon group or an alkoxy group independently, Z is a single bond and C1-C15 bivalent carbonization. A divalent group selected from a hydrogen group, —O—, —S—, —CO—, —SO—, —SO ₂ —, —NH— or —CONH—, wherein n ₁ is independently 0-4; Indicates an integer]

In particular, as the group R ₂ , Z in the formula (8) is a single bond and is a divalent divalent having 1 to 15 carbon atoms in order to suppress the amount of polar groups contained in the polyimidesiloxane molecule and increase the adhesion. A hydrocarbon group in which n ₁ is 0 is preferable.

Examples of the diamine having the group R ₂ as a residue include 4,4′-diaminodiphenyl ether, 2′-methoxy-4,4′-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'- Dihydroxy-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] Sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) biphenyl, bis [1- (4-aminophenoxy) )] Biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bi [4- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) ) Phenyl] ether, bis [4- (4-aminophenoxy)] benzophenone, bis [4- (3-aminophenoxy)] benzophenone, bis [4,4 '-(4-aminophenoxy)] benzanilide, bis [4 , 4 '-(3-aminophenoxy)] benzanilide, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2 , 2-bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 4,4'-methylenedi-o- Toluidine, 4,4'-methylenedi-2,6-xy Gin, 4,4'-methylene-2,6-diethylaniline, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenyl Ethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylsulfone, 3,3'- Diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diamino Biphenyl, 3,3'-dimethoxybenzidine, 4,4 ''-diamino-p-terphenyl, 3,3 ''-diamino-p-terphenyl, m-phenylenediamine, p-phenylenediamine, 2,6- Diaminopyridine, 1,4-bis ( 4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4 '-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,3 -Phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene P-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4 -Bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine Amine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, etc. It is done.

As the group R _1, for example, may include those represented by the following formula (3a).

［式中、Ｒ_３及びＲ_４は、それぞれ、酸素原子を含有していてもよい２価の有機基を示し、Ｒ_５〜Ｒ_８は、それぞれ炭素数１〜６の炭化水素基を示し、平均繰り返し数であるｍ_１は、１〜２０である］

[Wherein, R ₃ and R ₄ each represent a divalent organic group that may contain an oxygen atom, R _{5 to} R ₈ each represent a hydrocarbon group having 1 to 6 carbon atoms, M ₁ that is the average number of repetitions is ₁ to 20]

In particular, as the group R ₁ , R ₃ and R ₄ in the formula (3a) are each a divalent hydrocarbon group, and R _{5 to} R ₈ are each 1 to 1 carbon atoms in order to impart solubility of the polyimide. 6 having a mean repeating number of m ₁ of 5 to 15 is preferable.

  In order to improve long-term heat resistance, it is preferable to use aromatic tetracarboxylic acid anhydrides and aromatic diamines as raw materials having few polar groups. Therefore, as the aromatic tetracarboxylic acid anhydride and aromatic diamine, the p value, which is an index representing the amount of polar groups contained in the molecule, calculated based on the following formulas (i) and (ii) It is preferable to use one that is 1.0 or less. In particular, the p value of the aromatic diamine is more preferably 0.7 or less, and further preferably 0.6 or less.

P value of aromatic tetracarboxylic anhydride = (A1 / B1) × 100 (i)
P-value of aromatic diamine = (A2 / B2) × 100 (ii)
[here,
A1 = (number of polar groups in group Ar) × (number of moles of group Ar)
A2 = (number of polar groups in the radical _{R 2)} × (the number of moles of group _{R 2)}
B1 = (molecular weight of group Ar) × (number of moles of group Ar)
B2 = (molecular weight of group R ₂ ) × (number of moles of group R ₂ )]

The polar group serving as a reference for calculating the p value is classified into three stages based on the magnitude of the electric dipole moment. The first category is -X (where X is a halogen atom), -OH, -SH, -O-, -S-, -SO-, -NH-, -CO-, -CN, -P = O and -PO-, each of which is calculated as one polar group. The second category is —SO ₂ — and —CONH—, each of which is calculated as two polar groups. The third segment is —SO ₃ H, which is calculated as 3 polar groups.

  In order to keep the p value low, the aromatic tetracarboxylic acid anhydride suitably used for the preparation of the polyimidesiloxane precursor is, for example, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride ( BPDA), 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA), 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA), pyromellitic acid 2 Anhydrous (PMDA) and the like can be mentioned. Among them, particularly preferred acid anhydrides include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride ( BTDA) and the like. These aromatic tetracarboxylic acid anhydrides can be blended in combination of two or more.

  In order to keep the p value low, examples of the aromatic diamine suitably used for the preparation of the polyimidesiloxane precursor include 2,2-bis (4-aminophenoxyphenyl) propane (BAPP), 2,2 '-Divinyl-4,4'-diaminobiphenyl (VAB), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-diethyl-4,4'-diaminobiphenyl, 2,2 ′, 6,6′-tetramethyl-4,4′-diaminobiphenyl, 2,2′-diphenyl-4,4′-diaminobiphenyl, 9,9-bis (4-aminophenyl) fluorene, etc. Can be mentioned. Among them, particularly preferred diamine components are 2,2-bis (4-aminophenoxyphenyl) propane (BAPP), 2,2′-divinyl-4,4′-diaminobiphenyl (VAB), 2,2′- Examples thereof include dimethyl-4,4′-diaminobiphenyl (m-TB). These aromatic diamines can be blended in combination of two or more.

In the preparation of the polyimidesiloxane precursor, examples of the diaminosiloxane used as one of the raw materials include the diaminosiloxane represented by the general formula (3). By introducing a siloxane skeleton into polyimide siloxane using diaminosiloxane, the adhesive resin composition of the present invention can be given fluidity at the time of thermocompression bonding and the filling property on the printed circuit wiring can be improved. As specific examples of the diaminosiloxane represented by the general formula (3), diaminosiloxanes represented by the following formulas (9) to (13) are preferable, and among these, the formula (9) or (10) is used. Aliphatic diaminosiloxanes are more preferred. These diaminosiloxanes can be blended in combination of two or more. Moreover, when mix | blending in combination of 2 or more types of diaminosiloxane, 90 weight part or more of aliphatic diaminosiloxane represented by Formula (9) or (10) may be mix | blended with respect to 100 weight part of all siloxane diamine. preferable. Incidentally, Equation (3), in equation (9) to Formula (13), _{m 1} is an average repeating number is in the range of 1 to 20, preferably in the range of 5-15. When m ₁ is smaller than _1, the filling property when the adhesive is used is lowered, and when it exceeds 20, the adhesive property is lowered.

  Each of the acid anhydride and diamine may be used alone or in combination of two or more. In addition, acid anhydrides and diamines other than those described above can be used in combination.

  The polyimidesiloxane having the structural units represented by the general formulas (1) and (2) is heated after reacting the above aromatic tetracarboxylic acid anhydride, diaminosiloxane and aromatic diamine in a solvent to form a precursor resin. It can be produced by ring closure. For example, a polyimide siloxane precursor can be obtained by dissolving an acid anhydride component and a diamine component in an organic solvent in an approximately equimolar amount and stirring and polymerizing at a temperature within a range of 0 to 100 ° C. for 30 minutes to 24 hours. A certain polyamic acid is obtained. In the reaction, the reaction components are dissolved so that the precursor to be produced is in the range of 5 to 30% by weight, preferably in the range of 10 to 20% by weight in the organic solvent. Examples of the organic solvent used for the polymerization reaction include N, N-dimethylformamide, N, N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone, 2-butanone, dimethyl sulfoxide, dimethyl sulfate, cyclohexanone, and dioxane. , Tetrahydrofuran, diglyme, triglyme and the like. Two or more of these solvents can be used in combination, and further, aromatic hydrocarbons such as xylene and toluene can be used in combination.

  The synthesized precursor is usually advantageously used as a reaction solvent solution, but can be concentrated, diluted, or replaced with another organic solvent if necessary. Moreover, since a precursor is generally excellent in solvent solubility, it is advantageously used. The method for imidizing the precursor is not particularly limited, and for example, heat treatment such as heating in the solvent at a temperature within the range of 80 to 400 ° C. for 1 to 24 hours is suitably employed.

  When the adhesive resin composition of the present invention is prepared, the mixing ratio of the acid anhydride component and the diamine component as raw materials is not particularly limited. For example, the mixing ratio of the acid anhydride component and the diamine component is The molar ratio is such that the terminal substituent of the polyimidesiloxane is an amino group (that is, the acid anhydride group is sealed with a diamine), and from the viewpoint of suppressing the polarity of the polyimidesiloxane, the acid anhydride component: the diamine component, It is preferably 1.000: 1.001 to 1.0: 1.2.

Moreover, the polyimidesiloxane which has a structural unit represented by the said Formula (1) and (2) has an imide structure obtained by reaction with aromatic tetracarboxylic anhydride, diaminosiloxane, and aromatic diamine. In order to maintain the adhesive strength with the wiring layer, a completely imidized structure is most preferable. The imidation ratio was measured at about 1015 cm ⁻¹ by measuring the infrared absorption spectrum of the polyimide thin film by a single reflection ATR method using a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO Corporation). Based on the absorbance of C═O stretching derived from an imide group of 1780 cm ⁻¹ , based on the benzene ring absorber. In addition, a part of polyimide siloxane may be amic acid. In this case, unreacted amic acid sites (—CONH— and —COOH) are regarded as polar groups, and in the calculation of P value described later. One amic acid is calculated as a substituent having 4 polar groups (2 for -CONH- and 2 for -COOH).

[Inorganic filler]
The adhesive resin composition of this invention contains the plate-shaped inorganic filler in the range whose average particle diameter is 2-25 micrometers as a component (b). As these inorganic fillers, plate-shaped ones are used in order to impart sufficient gas barrier properties to the adhesive layer. Here, the “plate shape” is used to mean, for example, a flat shape, a flat plate shape, a flake shape, a scale shape, etc., and the thickness of the inorganic filler is sufficiently smaller than the major axis or minor axis of the plane portion (preferably 1/2 or less). In particular, it is preferable to use a scale-like inorganic filler. From another viewpoint, “plate-like” means that the ratio of the major axis to the thickness (major axis / thickness) of the filler particles is preferably 5 or more, more preferably 10 or more, and still more preferably 15 or more. In the plate-like inorganic filler, the relationship between the long diameter and the average particle diameter is preferably long diameter ≧ average particle diameter> 0.4 × long diameter, more preferably long diameter ≧ average particle diameter ≧ 0.5 ×. It is good that it is a long diameter. In the present invention, the major axis (or minor axis) and thickness of the filler particles, and the ratio of the major axis to the thickness are the average values when ten arbitrary fillers are measured with a stereomicroscope. When the shape of the inorganic filler is not a plate shape, for example, a spherical shape, the gas barrier property of the adhesive layer is lowered, the wiring layer is oxidized, and the adhesive strength may be lowered.

  As the inorganic filler, it is preferable to use insulating inorganic fillers such as talc, mica, sericite, clay and kaolin.

  The inorganic filler has an average particle size calculated by a laser diffraction method in the range of 2 to 25 μm, and preferably in the range of 5 to 20 μm. Here, the particle size of the inorganic filler is based on the average value of the longitudinal diameters of the particles. When the average particle size exceeds the upper limit, the surface of the adhesive layer tends to be rough, and when the average particle size is lower than the lower limit, it is difficult to obtain the effect of suppressing oxygen transmission.

  In addition, the particle size distribution of the inorganic filler is preferably 60% or more, more preferably 65% or more, and preferably the particle size of 20 μm or more is 10% or less on a number basis. When the inorganic filler having a particle diameter of 10 μm or less is less than 60%, when the adhesive resin composition is formed into a film, the fillers are arranged in layers, and protrusions appear on the film surface, which causes the film surface to become rough. In addition, if the inorganic filler having a particle size of 20 μm or more exceeds 10%, protrusions appear on the film surface, causing the surface of the film to become rough. For example, when a thin film of 15 μm or less is produced, the surface tends to be rough. Cheap.

  Moreover, 0.1-100 micrometers is preferable and, as for the frequency distribution of the particle size of an inorganic filler, 0.5-70 micrometers is more preferable. If the frequency distribution exceeds the upper limit, the surface of the adhesive layer tends to be rough, and if the frequency distribution is lower than the lower limit, it is difficult to obtain the effect of suppressing oxygen transmission.

  The amount of the inorganic filler is 5 to 200 parts by weight, preferably 10 to 150 parts by weight, more preferably 30 to 100 parts by weight, and preferably 40 to 80 parts by weight with respect to 100 parts by weight of polyimidesiloxane. Parts by weight. When the blending amount of the inorganic filler is less than 5 parts by weight with respect to 100 parts by weight of the polyimidesiloxane, the blending effect cannot be obtained, and the effect of suppressing oxygen transmission cannot be obtained. Moreover, when the compounding quantity of an inorganic filler exceeds 200 weight part with respect to 100 weight part of polyimide siloxane, since an adhesive bond layer becomes weak and as a result the intensity | strength fall by the cohesive failure in an adhesive bond layer arises, it is apparent. Adhesion is significantly reduced. In the present invention, a plate-like inorganic filler is used, but it is also possible to use a non-plate-like inorganic filler in combination. When an inorganic filler that is not plate-shaped is used in combination, it is preferable that the total amount of the inorganic filler (total of plate-shaped and other shapes) does not exceed 200 parts by weight with respect to 100 parts by weight of polyimidesiloxane.

When the adhesive resin composition of the present invention is used for forming an adhesive layer of a coverlay film, in order to exert a particularly excellent effect, for example, as the raw acid anhydride component and diamine component, the following A to C;
A) Aromatic tetracarboxylic anhydride:
One or more selected from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA);
B) Diaminosiloxane:
Diaminosiloxane represented by the above formula (9) or formula (10) (weight average molecular weight is preferably in the range of 230 to 1,000); and C) aromatic diamine:
2,2-bis (4-aminophenoxyphenyl) propane (BAPP);
It is most preferable to use in combination.

  In addition, the blending ratio is from 75 to 100 mol%: 25 to 100 mol% of the A component with respect to the A component of 100 mol% from the viewpoint of the solubility of the polyimide siloxane, the low warpage of the coverlay, and the flexibility. It is preferably 0 mol%, more preferably 80 to 90 mol%: 20 to 10 mol%, and preferably 80 to 85 mol%: 20 to 15 mol%.

  By mix | blending AC component with the said ratio and mix | blending an inorganic filler, the adhesiveness of the coverlay film which uses the obtained polyimide siloxane as an adhesive bond layer can be made very excellent. More specifically, the peel strength from the copper wiring layer after a long-term heat resistance test at 150 ° C. for 1000 hours in the atmosphere can be 0.20 kN / m or more. Such an extremely high peel strength could not be obtained with a conventional coverlay film, and was realized for the first time by the present invention. Moreover, by setting the blending ratio of the B component to the total diamine component to 75 mol% or more, it is possible to impart excellent solvent solubility to the polyimidesiloxane, and even without adding a plasticizer, the coverlay can be provided. Film warpage can be prevented.

  Further, the adhesive resin composition of the present invention includes, in addition to the polyimide siloxane of the component (a) and the inorganic filler of the component (b), other optional resin components such as an epoxy resin as necessary. , Plasticizers, curing accelerators, coupling agents, pigments, viscosity modifiers, and the like can be appropriately blended. However, in order to maintain excellent adhesiveness under high temperature use conditions, it is preferable that all the resin components in the adhesive resin composition are composed of the above-described component (a) polyimidesiloxane. In addition, some plasticizers contain a large number of polar groups, which may promote the diffusion of copper from the copper wiring and reduce the adhesive force. Therefore, it is preferable that the plasticizer is not used as much as possible. Further, as described above, in the adhesive resin composition of the present invention, a plasticizer is added by setting the molar ratio of the diaminosiloxane of the general formula (3) in the total diamine component of the raw material to 75 mol% or more. Even if not, sufficient flexibility can be obtained and warping of the coverlay film can be prevented. For this reason, when using a plasticizer, it is preferable to mix | blend in the range which does not impair the effect of this invention.

  When blending optional components in the adhesive resin composition of the present invention, for example, the total amount of optional components is preferably 1 to 10 parts by weight, based on 100 parts by weight of polyimidesiloxane, and 2 to 7 weights. It is more preferable to set it as a blending amount of parts.

In addition, when the adhesive resin composition of the present invention having the above essential components and optional components is used as an adhesive such as a coverlay film, the adhesive force can be maintained even when repeatedly placed in a high temperature environment. The P value calculated based on the following mathematical formula (iii) is preferably 0.7 or less, and more preferably 0.6 or less.
P value = {(A1 + A2 + An) / (B1 + B2 + Bn)} × 100 (iii)
[here,
An = (number of polar groups in one optional component) × (number of moles of optional component)
Bn = (molecular weight of one arbitrary component) × (number of moles of arbitrary component)
A1, A2, B1, and B2 have the same meaning as described above, and An and Bn are added for each arbitrary component. The number of polar groups is calculated in the same manner as in the case of the p value. ]

This P value is an index representing the amount of polar groups contained in the composition containing polyimidesiloxane, and the larger the P value, the larger the amount of polar groups in the composition containing polyimidesiloxane. . When used as an adhesive for a coverlay film or the like, the polar group contained in the adhesive layer becomes a factor inducing copper diffusion from the copper wiring. That is, if a large amount of polar groups are contained in the adhesive layer, copper from the copper wiring diffuses widely into the adhesive layer while heating is repeated. As a result, the adhesive force of the adhesive layer is weakened and the coverlay film is easily peeled off. In the adhesive resin composition of the present invention, by reducing the P value to 0.7 or less (preferably 0.6) or less, the amount of polar groups contained in the composition is reduced and the decrease in adhesive strength is suppressed. it can. In calculating the P value, the reason why the polar group contained in the group Ar (aromatic tetracarboxylic anhydride residue) and the group R ₂ (aromatic diamine residue) of the polyimidesiloxane is based on these groups an amount of polar group contained in and in the radical R ₂ in Ar, because the overall polarity of the polyimide siloxane is a major component of the adhesive generally is determined. Therefore, the polar group contained in the diaminosiloxane residue and the polar group involved in the imide bond are not considered in calculating the P value.

  The adhesive resin composition of the present invention is prepared by mixing and stirring the component (a) polyimide siloxane and the component (b) inorganic filler.

  The adhesive resin composition of the present invention obtained as described above has excellent flexibility and thermoplasticity when it is used to form an adhesive layer, such as FPC, rigid flex circuit board, etc. It has preferable characteristics as an adhesive for a coverlay film that protects the wiring part. When used as an adhesive layer of a cover lay film, after applying the adhesive resin composition of the present invention in a solution state on one side of the cover lay film material, for example, by heat treatment at a temperature of 60 to 200 ° C., The coverlay film of the present invention having a coverlay film material layer and an adhesive layer can be formed. In addition, the adhesive resin composition of the present invention is applied in the form of a solution on an arbitrary substrate, and dried at a temperature of, for example, 80 to 180 ° C., and then peeled to form an adhesive film. The coverlay film of the present invention having a coverlay film material layer and an adhesive layer can also be formed by thermocompression bonding the adhesive film with the coverlay film material.

  The coverlay film material in the coverlay film of the present invention is not limited, but, for example, polyimide resin films such as polyimide resin, polyetherimide resin, and polyamideimide resin, polyamide resin film, and polyester resin A film or the like can be used. Among these, it is preferable to use a polyimide resin film having excellent heat resistance. The thickness of the coverlay film material layer is not particularly limited, but is preferably 5 μm or more and 100 μm or less, for example. The thickness of the adhesive layer is not particularly limited, but is preferably 25 μm or more and 50 μm or less, for example.

  Moreover, what formed the adhesive resin composition of this invention in the film form can be utilized also as a bonding sheet of multilayer FPC, for example. When used as a bonding sheet, an adhesive film obtained by applying the adhesive resin composition of the present invention in the form of a solution on an arbitrary base film, drying at a temperature of, for example, 80 to 180 ° C., and then peeling. May be used as a bonding sheet as it is, or may be used in a state where this adhesive film is laminated with an arbitrary substrate film.

  Moreover, a coverlay film and a bonding sheet are good also as a form which has a release material layer by bonding a release material on the adhesive surface. The material of the release material is not particularly limited as long as it can be peeled without impairing the form of the coverlay film or the bonding sheet. For example, resin films such as polyethylene terephthalate, polyethylene, and polypropylene, and these resin films And the like laminated on paper can be used.

  The method for forming the adhesive resin composition of the present invention as an adhesive layer is not particularly limited as long as the adhesive resin composition is formed by application in a solution state, and examples thereof include a comma, a die, a knife, and a lip. It is possible to apply with a coater. By forming the adhesive layer by coating, a plate-like inorganic filler is formed in a layer shape (in a state where the surface portion of the inorganic filler is substantially parallel to the coated surface) without any special device.

  As long as the circuit board of this invention is provided with the coverlay film and bonding sheet which are obtained as mentioned above, there is no restriction | limiting in particular in the structure. For example, the preferred form of the circuit board of the present invention includes at least a base material, a wiring layer made of a metal such as copper formed on the base material in a predetermined pattern, and the cover lay film of the present invention covering the wiring layer. And. The base material of the circuit board is not particularly limited, but in the case of FPC, the same material as the coverlay film material is preferably used, and the base material made of polyimide resin is preferably used.

By using the cover lay film of the present invention, the circuit board of the present invention is filled with an adhesive layer having excellent flexibility and thermoplasticity between the wirings, and high adhesion between the cover lay film and the wiring layer is obtained. It is done. Moreover, the gas barrier property which was excellent in the adhesive bond layer can be provided by forming an adhesive bond layer using the adhesive resin composition of this invention which mix | blended the inorganic filler. That is, by allowing the inorganic filler to be present in the adhesive layer close to the wiring layer, even if oxygen permeates through the cover lay body, it is possible to block immediately before the wiring layer. In addition, since the adhesive layer formed by the adhesive resin composition of the present invention containing polyimide siloxane rich in flexibility is closely packed between the wirings and closely adhered to the wiring layer, the gas barrier property of this adhesive layer By increasing the resistance, the oxidation of the wiring layer can be most reliably suppressed. Moreover, the diffusion of copper from the wiring layer into the adhesive layer can also be suppressed by the filler present in the adhesive layer. Therefore, even if the use in a high temperature environment is repeated, excellent adhesion can be maintained over a long period of time. More specifically, the peel strength between the copper wiring layer and the coverlay film material layer can be maintained at 0.2 kN / m or more after a long-term heat resistance test at 150 ° C. for 1000 hours in the atmosphere. is there. In particular, by selecting the group Ar, the group R ₁ and the group R ₂ in the general formulas (1) and (2), it is possible to obtain an extremely high peel strength of 0.35 kN / m or more. In addition, by setting the blending ratio of diaminosiloxane to the total diamine component of the raw material to 75 mol% or more, it is possible to obtain excellent solubility and prevent warping of the coverlay film without blending a plasticizer. it can.

  The circuit board of the present invention may be configured as a multilayer circuit board. In this case, the adhesive film obtained from the adhesive resin composition of the present invention can be used not only for the coverlay film but also for the bonding sheet.

  The production of the circuit board of the present invention is not particularly limited. For example, after the metal foil of a metal-clad laminate such as a copper-clad laminate is processed into a predetermined pattern by a method such as chemical etching, the circuit is produced. For example, a method of laminating a cover lay film on the necessary portion above and performing thermocompression bonding using, for example, a hot press apparatus can be used. In this case, although the pressure bonding conditions are not particularly limited, for example, the pressure bonding temperature is preferably 130 ° C. or higher and 200 ° C. or lower, and the pressure is preferably 0.1 MPa or higher and 4 MPa or lower.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Measurement of average particle size]
The average particle diameter was measured using a laser diffraction type particle size distribution measuring apparatus (manufactured by Shimadzu Corporation, SALD-2000J).

[Measurement of adhesive strength]
The adhesive strength of the test piece cut out to a width of 10 mm and a length of 100 mm was placed on a glossy surface (thickness of rust-proof metal) of a copper foil (35 μm thickness), 180 ° C., 4 MPa, 60 minutes. After thermocompression bonding under the above conditions, it was measured by peeling it off at a speed of 50 mm / min in the 180 ° direction using a tensile tester (manufactured by Toyo Seiki Co., Ltd., Strograph-M1). The force at the time of peeling was defined as the adhesive strength. In this experiment, the case where the adhesive strength was 0.2 kN / m or more was determined as “good”, and the case where it was 0.35 kN / m or more was determined as “good”.

[Measurement of weight average molecular weight]
The weight average molecular weight was measured by a gel permeation chromatograph (manufactured by Tosoh Corporation, using HLC-8220GPC). Polystyrene was used as a standard substance, and N, N-dimethylacetamide was used as a developing solvent.

[Evaluation method of warpage]
The warpage was evaluated by the following method. A polyimide adhesive was applied onto a 25 μm thick Kapton film so that the thickness after drying was 35 μm. In this state, the Kapton film was placed on the lower surface, and the average of the heights at which the four corners of the film were warped was measured.

The abbreviations used in the examples represent the following compounds.
BTDA: 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA polar group; 1, p value = 0.56)
BAPP: 2,2-bis (4-aminophenoxyphenyl) propane (polar group of BAPP; 2, p value = 0.53)
PSX-A: diaminosiloxane represented by the above formula (9) (however, the number average value of m ₁ is in the range of 1 to 20 and the weight average molecular weight is 740)

[Example 1]
To a 1000 ml separable flask was added 9.89 g BAPP (0.0240 mol), 71.30 g PSX-A (0.0964 mol), 168 g N-methyl-2-pyrrolidone and 112 g xylene. Further, 38.66 g of BTDA (0.120 mol) was added to the separable flask and stirred at room temperature for 2 hours to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours to obtain a polyimide solution having completed imidization. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80% (m value = 0.8). In addition, "m value" means the presence molar ratio of the structural unit represented by the said General formula (1) contained in the obtained polyimide resin (hereinafter the same). Moreover, P value which is a parameter | index showing the quantity of the polar group contained in the obtained polyimide resin is 0.55.

  In this solution, talc (trade name: MICRO ACE K-1, manufactured by Nippon Talc Co., Ltd .; shape; scale-like, average major axis: 7.0 μm, average minor axis: 5.8 μm, ratio of major axis to thickness; 15 or more, Average particle size: 6.6 μm, median diameter (D50): 6.9 μm, maximum particle size: 64.9 μm, minimum particle size: 0.5 μm, mode diameter: 8.7 μm, integrated particle amount of particle size of 10 μm or less 60% of a cumulative particle amount of 77% and a particle size of 20 μm or more; 5%) was blended and further stirred for 1 hour to obtain a polyimide solution a.

  The obtained polyimide solution a was applied to one side of a polyimide film (manufactured by DuPont, trade name: Kapton ENS, length × width × thickness = 200 mm × 300 mm × 25 μm), dried at 80 ° C. for 15 minutes, and adhesive A coverlay film 1 having a layer thickness of 35 μm was obtained. This cover lay film 1 was placed on a copper foil from which the rust-proof metal layer on the surface was removed, and pressed under conditions of a temperature of 180 ° C., a pressure of 4 MPa, and a time of 60 minutes. The adhesive strength between the coverlay film and the copper foil after curing of the adhesive layer was 0.56 kN / m. Moreover, the warp of the coverlay film was no problem.

  Next, the evaluation sample 1 was heat-treated in an oven in the atmosphere at 150 ° C. for 1000 hours. It was 0.52 kN / m when the copper foil after a process and the adhesive strength of the coverlay film were measured. The peeling surface at this time was in the adhesive layer, and cohesive failure of the adhesive layer occurred. The measured adhesive strength was due to cohesive failure in this adhesive layer.

  Further, a printed board having a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} formed of copper on both sides of the polyimide film is prepared. The coverlay film 1 obtained in Example 1 is printed board. Was placed on the circuit surface and pressed under conditions of a temperature of 180 ° C., a pressure of 4 MPa, and a time of 60 minutes to obtain a wiring substrate 1 provided with a coverlay film.

[Example 2]
Instead of blending 60 g of talc in Example 1, except that 84 g of talc was blended, after obtaining a polyimide solution b in the same manner as in Example 1, a coverlay film 2 was obtained, and an evaluation sample 2 was obtained. Obtained. The adhesive strength between the coverlay film and the copper foil after curing of the adhesive layer was 0.41 kN / m. Moreover, the warp of the coverlay film was no problem.

  Next, the evaluation sample 2 was heat-treated in an oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.35 kN / m when the copper foil after a process and the adhesive strength of the coverlay film were measured. The peeling surface at this time was in the adhesive layer, and cohesive failure of the adhesive layer occurred. The measured adhesive strength was due to cohesive failure in this adhesive layer.

  Further, in the same manner as in Example 1, a printed circuit board on which a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} is prepared, and the coverlay film 2 obtained in Example 2 is printed. The wiring board 2 provided with the coverlay film was obtained by placing and pressing on the circuit surface of the board.

Comparative Example 1
60 g of heavy calcium carbonate (manufactured by Takehara Chemical Co., Ltd., trade name: SL-300, shape: granular, average particle size: 5.7 μm) instead of 60 g of talc in Example 1 Except for the above, a polyimide solution was obtained in the same manner as in Example 1, and then a coverlay film was obtained to obtain an evaluation sample. The adhesive strength between the coverlay film and the copper foil after curing of the adhesive layer was 0.66 kN / m. Moreover, the warp of the coverlay film was no problem.

  Next, the evaluation sample was heat-treated in an oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.16 kN / m when the copper foil after a process and the adhesive strength of the coverlay film were measured. The peeling surface at this time was at the interface between the adhesive layer and the copper foil, and interface peeling occurred. The measured adhesive strength was due to this interfacial debonding.

Comparative Example 2
Instead of blending 60 g of talc in Example 1, 84 g of heavy calcium carbonate (manufactured by Takehara Chemical Industry Co., Ltd., trade name: SL-300, shape: granular, average particle size: 5.7 μm) was blended. Except for the above, a polyimide solution was obtained in the same manner as in Example 1, and then a coverlay film was obtained to obtain an evaluation sample. The adhesive strength between the coverlay film and the copper foil after curing of the adhesive layer was 0.62 kN / m. Moreover, the warp of the coverlay film was no problem.

  Next, the evaluation sample was heat-treated in an oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.13 kN / m when the copper foil after a process and the adhesive strength of the coverlay film were measured. The peeling surface at this time was at the interface between the adhesive layer and the copper foil, and interface peeling occurred. The measured adhesive strength was due to this interfacial debonding.

Comparative Example 3
Example 1 except that 60 g of silica (manufactured by Micron Co., Ltd., trade name: SP30, shape: spherical, average particle size: 2.7 μm) was blended instead of blending 60 g of talc in Example 1. Similarly, after obtaining a polyimide solution, a coverlay film was obtained and an evaluation sample was obtained. The adhesive strength between the coverlay film and the copper foil after curing of the adhesive layer was 0.59 kN / m. Moreover, the warp of the coverlay film was no problem.

  Next, the evaluation sample was heat-treated in an oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.18 kN / m when the copper foil after a process and the adhesive strength of a coverlay film were measured. The peeling surface at this time was at the interface between the adhesive layer and the copper foil, and interface peeling occurred. The measured adhesive strength was due to this interfacial debonding.

Comparative Example 4
Example 1 is the same as Example 1 except that 84 g of silica (manufactured by Micron Co., Ltd., trade name: SP30, shape; spherical shape, average particle diameter: 2.7 μm) is blended instead of 60 g of talc in Example 1. Similarly, after obtaining a polyimide solution, a coverlay film was obtained and an evaluation sample was obtained. The adhesive strength between the coverlay film and the copper foil after curing of the adhesive layer was 0.35 kN / m. Moreover, the warp of the coverlay film was no problem.

  Next, the evaluation sample was heat-treated in an oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.19 kN / m when the copper foil after a process and the adhesive strength of the coverlay film were measured. The peeling surface at this time was at the interface between the adhesive layer and the copper foil, and interface peeling occurred. The measured adhesive strength was due to this interfacial debonding.

Comparative Example 5
To a 1000 ml separable flask was added 15.35 g BAPP (0.0374 mol), 64.53 g PSX-A (0.0872 mol), 168 g N-methyl-2-pyrrolidone and 112 g xylene. Furthermore, 40.14 g of BTDA (0.1246 mol) was added to the separable flask and stirred at room temperature for 2 hours to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours to obtain a polyimide solution having completed imidization. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 70% (m value = 0.7).

  To this solution, 60 g of talc used in Example 1 was blended and further stirred for 1 hour to obtain a polyimide solution.

  The obtained polyimide solution was applied to one side of a polyimide film (manufactured by DuPont, trade name: Kapton ENS, length × width × thickness = 200 mm × 300 mm × 25 μm), dried at 80 ° C. for 15 minutes, and adhesive layer A coverlay film having a thickness of 35 μm was obtained. This cover lay film was placed on a copper foil from which the surface antirust metal layer had been removed, and pressed under conditions of a temperature of 180 ° C., a pressure of 4 MPa, and a time of 60 minutes to obtain an evaluation sample. The adhesive strength between the coverlay film and the copper foil after curing of the adhesive layer was 0.56 kN / m. Moreover, the warp of the coverlay film was large and was not satisfactory.

  Next, the evaluation sample was heat-treated in an oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.20 kN / m when the copper foil after a process and the adhesive strength of the coverlay film were measured. The peeling surface at this time was at the interface between the adhesive layer and the copper foil, and interface peeling occurred. The measured adhesive strength was due to this interfacial debonding.

  The above results are shown in Table 1. In Table 1, the adhesive strength 1 indicates the adhesive strength between the cured copper foil and the coverlay film, and the adhesive strength 2 indicates the adhesion between the copper foil and the coverlay film after heat treatment at 150 ° C. for 1000 hours in the air. Indicates strength. Example 1 and 2 which mix | blended polyimidesiloxane which has a structural unit represented by General formula (1) and (2), and the plate-shaped inorganic filler in the range whose average particle diameter is 2-25 micrometers in predetermined ratio. By using this adhesive composition, it was confirmed that even after heat treatment at 150 ° C. for 1000 hours, there was almost no decrease in the adhesive strength of the coverlay film, and excellent adhesiveness was obtained. On the other hand, in Comparative Examples 1 to 4 using granular heavy calcium carbonate or spherical silica as the inorganic filler, the adhesive force of the cover lay film after the heat treatment was greatly reduced. This is thought to be because the copper foil of the evaluation sample was oxidized and the adhesive force was lowered because the gas barrier performance was insufficient with the granular or spherical inorganic filler. Further, in Comparative Example 5 where the blending ratio of diaminosiloxane in the diamine component of the raw material was as low as 0.70, warpage occurred in the coverlay film.

  As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict | limited to the said embodiment. Those skilled in the art can make many modifications without departing from the spirit and scope of the present invention, and these are also included within the scope of the present invention. For example, in the above-described embodiment, the application of the adhesive resin composition of the present invention is exemplified by coverlay films and bonding sheets of circuit boards such as FPC, but the adhesive resin composition is used for applications other than those described above. For example, it can be used to form an adhesive resin in tape automated bonding (TAB), chip size package (CSP), or the like.

Claims (8)

The following components (a) and (b);
(A) Structural units represented by the following general formulas (1) and (2):

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, and R ₂ is derived from an aromatic diamine. Each represents a divalent aromatic diamine residue, m and n represent the molar ratio of each constituent unit, m is in the range of 0.75 to 1.0, and n is in the range of 0 to 0.25. Is]
100 parts by weight of polyimidesiloxane containing
(B) 5 to 200 parts by weight of a plate-like inorganic filler having an average particle diameter of 2 to 25 μm,
An adhesive resin composition comprising:   2. The adhesive resin composition according to claim 1, wherein a particle size distribution of the inorganic filler is, on a number basis, a particle size of 10 μm or less is 60% or more and a particle size of 20 μm or more is 10% or less. The polyimidesiloxane has the following general formula (3):

[Wherein, R ₃ and R ₄ each represent a divalent organic group that may contain an oxygen atom, R _{5 to} R ₈ each represent a hydrocarbon group having 1 to 6 carbon atoms, M ₁ that is the average number of repetitions is ₁ to 20]
The adhesive resin composition according to claim 1 or 2, which is synthesized using a diaminosiloxane represented by the formula:   The adhesive resin composition according to claim 3, wherein a molar ratio of the diaminosiloxane of the general formula (3) in all diamine components of the raw material is 80 mol% or more.   The adhesive resin composition according to any one of claims 1 to 4, wherein the adhesive resin composition is used as an adhesive for a coverlay film that protects a wiring portion of a circuit board. A cover lay film in which an adhesive layer and a cover lay film material layer are laminated,
The coverlay film, wherein the adhesive layer is formed using the adhesive resin composition according to any one of claims 1 to 5.   The circuit board provided with the base material, the wiring layer formed on this base material, and the coverlay film of Claim 6 which coat | covers this wiring layer.   The circuit board according to claim 7, wherein the peel strength between the wiring layer and the coverlay film after a long-term heat resistance test at 150 ° C. for 1000 hours in the air is 0.2 kN / m or more.