JP2009029982A - Flame-retardant adhesive resin composition and adhesive film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant adhesive resin composition that can be subjected to thermocompression bonding at a lower temperature compared to a conventional polyimide adhesive without impairing excellent heat resistance and electric characteristics as original properties of polyimide and that gives excellent flame retardancy although the composition does not contain a halogen element, and to provide an adhesive film obtained from the above composition, which is suitable as an adhesive for a multilayer printed board, an adhesive for a composite circuit board, an adhesive for a cover-lay film or the like. <P>SOLUTION: The flame-retardant adhesive resin composition contains 60 to 98 wt.% silicon modified polyimide resin having a repeating unit containing a silicon unit by 10 to 50 mol% and 2 to 40 wt.% phosphorus-containing epoxy resin containing phosphorus by ≥3.8 wt.% in the structure, and the composition does not substantially contain a halogen element. The adhesive film is obtained from the composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-resistant adhesive resin composition, and more particularly to a high heat-resistant and flame-retardant adhesive resin composition substantially free of halogen elements, and an adhesive film using the same.

As a printed wiring board, conventionally, a base material made of paper-phenolic resin, glass fiber-epoxy resin, or a base material such as a polyimide film or a polyethylene terephthalate film and a metal foil are used.
In this specification, the printed wiring board laminate or the printed wiring board laminate refers to a laminated body before circuit processing, and the metal foil subjected to circuit processing is referred to as a printed wiring board or printed wiring board.

  In recent years, printed wiring boards used in the fields of electrical / electronic equipment and precision equipment have a reduced wiring occupation area, and hence the demand for multilayer wiring boards is increasing. Various adhesives or adhesive films are used in the process of producing a multilayer printed wiring board by laminating printed wiring boards or compounding different kinds of circuit materials.

  As such an adhesive, a prepreg adhesive in which a woven fabric such as glass fiber is impregnated with an epoxy or bismaleimide resin is known. However, these have problems such as insufficient flexibility and poor dimensional stability. Conventionally, adhesives such as acrylonitrile butadiene rubber / phenol resin, phenol resin / butyral resin, acrylonitrile butadiene rubber / epoxy resin have been proposed (for example, JP-A-4-29393 and JP-A-4-36366). JP-A-4-41581). However, these adhesives do not have sufficient chemical resistance and heat resistance, have large thermal degradation, insufficient heat resistance to moisture-absorbing solder, and workability such as generation of smear during drilling to form through holes. The point was not enough.

  In addition, a polyimide adhesive having excellent heat resistance has been proposed (see, for example, US Pat. No. 4,543,295). However, such a polyimide has difficulties in practical use because it requires a thermocompression bonding temperature of 250 ° C. or higher in order to bond substrates such as copper or polyimide film and obtain satisfactory adhesive strength. It was.

  Patent Document 1 discloses an adhesive using polyimide made of diaminopolysiloxane and aromatic tetracarboxylic acid as raw materials for thermocompression bonding at a low temperature. However, such a polyimide alone has a drawback in that the adhesive strength is not sufficient and the reliability is poor.

  As a polyimide adhesive having excellent adhesive strength, for example, Patent Document 2 discloses a film adhesive made of polyamideimide and an epoxy resin as an adhesive for manufacturing a flexible printed wiring board. However, when such a film is used for bonding uneven surfaces on which circuits are formed, such as the production of multilayer printed wiring boards, the filling of the circuit surfaces is not sufficient, and sufficient heat resistance to the solder bath is obtained. I can't.

  For this reason, adhesives for multilayer printed circuit boards and adhesives for coverlay films can be pressed at low temperatures of 250 ° C or lower, and adhesive strength, chemical resistance, heat resistance, hygroscopic solder heat resistance, and dimensional stability during wiring processing Materials with excellent properties and the like have been demanded. Moreover, the material excellent in the flame retardance from the point of ensuring fire safety has been calculated | required.

  In the conventional adhesive film, a resin or additive containing a halogen such as bromine has been used to impart flame retardancy. Halogen has been widely used for the purpose of imparting flame retardancy, cost performance, and resistance to plastic deterioration. However, there is a concern that the halogen contained therein may cause harmful substances such as dioxin during combustion, and it is strongly desired to eliminate the halogen from the material.

  From such a point, a non-halogen flame retardant adhesive film is desired. An example of such an adhesive film is Patent Document 3. However, such an adhesive film has a problem that the migration resistance is lowered by the inclusion of a metal hydroxide or the like.

  In addition, there is a method of adding an organic phosphorus compound as a flame retardant imparting material. However, when a phosphorus-based additive is used, there is a problem that hydrolysis tends to occur and ionization occurs, or phosphorus-containing ions migrate between conductors, thereby lowering electrical insulation.

  By the way, Patent Document 4 discloses a heat-resistant adhesive film for printed circuit boards made of a polyimide having a silicon unit and an epoxy resin. However, the epoxy resin used here is a general epoxy resin derived from bisphenol A or a phenol resin, and the type of polyimide and the combination with the epoxy resin are also general, and the flame retardant Consideration was not enough. Further, in JP2003-163426, JP2003-206466, JP2003-238806, JP2003-206466, JP2001-123060, JP2002-188066 Discloses a circuit board material composition having excellent migration resistance due to a phosphorus element-containing epoxy resin and polyimide. However, the expression of flame retardancy is not sufficient.

JP-A-4-23879 JP-A-52-91082 JP 2004-146286 A JP 2001-203467 A JP 2003-163426 A

  An object of the present invention is to provide a non-halogen flame-retardant adhesive resin composition that is capable of low-temperature pressure bonding at 250 ° C. or lower and is excellent in heat resistance, moisture-absorbing solder heat resistance, workability, and the like. Furthermore, it is providing the flame retardant adhesive film using such an adhesive resin composition.

  As a result of intensive studies to achieve the above object, the present inventors have completed the present invention by using a specific polyimide resin and a specific epoxy resin.

（一般式（１）において、Ar₁は４価の芳香族基を示し、R₁及びR₂は２価の炭化水素基を示し、R₃及びR₄は炭素数１〜６の１価の炭化水素基を示し、mは１〜２０の数を示す。一般式（２）において、Ar₁は４価の芳香族基を示し、Ar₂は２価の芳香族基を示す）で表される繰り返し単位を有し、一般式（１）及び（２）で表される繰り返し単位の構成比が、（１）／（２）＝５０／５０〜１０／９０（モル比）の範囲であるシリコンユニット含有ポリイミド樹６０〜９８重量％と、リンをその構造中に３.８重量％以上、好ましくは４〜５重量％含むリン含有エポキシ樹脂２〜４０重量％で構成され、実質的にハロゲン元素を含まない樹脂組成物から形成されたことを特徴とする難燃性接着剤樹脂組成物である。 That is, the present invention includes the following general formula (1) and the following general formula (2).

(In General Formula (1), Ar ₁ represents a tetravalent aromatic group, R ₁ and R ₂ represent a divalent hydrocarbon group, and R ₃ and R ₄ represent a monovalent monovalent group having 1 to 6 carbon atoms. Represents a hydrocarbon group, and m represents a number from 1 to 20. In the general formula (2), Ar ₁ represents a tetravalent aromatic group, and Ar ₂ represents a divalent aromatic group. The constitutional ratio of the repeating units represented by the general formulas (1) and (2) is in the range of (1) / (2) = 50/50 to 10/90 (molar ratio). It is composed of 60 to 98% by weight of a silicone unit-containing polyimide resin and 2 to 40% by weight of a phosphorus-containing epoxy resin containing phosphorus in the structure in an amount of 3.8% by weight or more, preferably 4 to 5% by weight. It is a flame retardant adhesive resin composition characterized by being formed from a resin composition containing no element.

（但し、Ar₃は３価又は４価の芳香族基を示し、Xは水酸基、アミノ基、カルボキシル基又はメルカプト基を示し、kは１又は２を示す） The flame retardant adhesive resin composition contains 1 to 15 parts by weight of an epoxy resin curing agent with respect to a total of 100 parts by weight of an epoxy resin containing a silicon unit-containing polyimide resin and a phosphorus element. The physical properties can be improved. Moreover, 1-20 mol% of Ar < ₂ > in General formula (2) which is a repeating unit of the said silicon unit containing polyimide resin with the epoxy resin hardening | curing agent or instead of an epoxy resin hardening | curing agent is following General formula (3). By setting it as the bivalent aromatic group which has a functional group which reacts with the epoxy group represented, the physical property of cured resin can be made favorable.

(However, Ar ₃ represents a trivalent or tetravalent aromatic group, X represents a hydroxyl group, an amino group, a carboxyl group, or a mercapto group, and k represents 1 or 2)

  Moreover, this invention is a flame retardant adhesive film characterized by forming any one of the above flame retardant adhesive resin compositions into a film.

Furthermore, the present invention is to be used by inserting the above-mentioned flame retardant adhesive film between objects to be bonded and thermocompression bonding under conditions of a pressure of 1 to 100 kg / cm ² and a temperature of 20 to 250 ° C. It is the usage method of the flame-retardant adhesive film characterized.

  Hereinafter, the present invention related to a flame retardant adhesive resin composition will be described, and then the present invention related to a flame retardant adhesive film and a method for using the same will be described, but common parts will be described simultaneously.

  The flame retardant adhesive resin composition of the present invention (hereinafter also referred to as a resin composition) has repeating units represented by the above general formula (1) and general formula (2), and includes the general formula (1) and The constitutional ratio of the repeating unit represented by (2) is 60 to 98% by weight of a silicon unit-containing polyimide resin in the range of (1) / (2) = 50/50 to 10/90 (molar ratio), phosphorus Is formed from a resin composition containing 2 to 40% by weight of a phosphorus-containing epoxy resin containing 3.8% by weight or more in its structure and substantially free of halogen elements.

As the silicon unit-containing polyimide resin, it is desirable to use a solvent-soluble polyimide resin having good film moldability. Furthermore, if a functional group capable of reacting with an epoxy group is contained in the polyimide resin, the epoxy resin curing agent can be dispensed with or in a small amount. In order to have a functional group capable of reacting with an epoxy group in the polyimide resin, 1 to 20 mol%, preferably 2 to 10 mol%, of Ar ₂ in the general formula (2) is the general formula (3). There is a method of using a raw material aromatic diamine so that a polyimide resin having an aromatic group represented by

The silicon unit-containing polyimide resin is usually obtained by reacting diaminosiloxane and aromatic diamine with tetracarboxylic dianhydride. Since Ar ₁ in the above general formulas (1) and (2) can be said to be a residue of tetracarboxylic dianhydride, Ar ₁ is understood from the description of tetracarboxylic dianhydride. Moreover, since the silicon unit in General formula (1) can be said to be a residue of diaminosiloxane, a silicon unit is understood from diaminosiloxane description. Furthermore, since Ar ₂ in the general formula (2) can be said to be a residue of an aromatic diamine, Ar ₂ is understood from the explanation of the aromatic diamine.

  As specific examples of tetracarboxylic dianhydride, preferably 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, And one or more tetracarboxylic dianhydrides selected from 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride and 2,2 ′, 2,3′-benzophenone tetracarboxylic dianhydride. It is done. Also, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 1,4,5 , 8-Naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 3,3,6,7 Other tetracarboxylic acids such as anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 4,4 ′-(hexafluoroisopyridene) phthalic dianhydride Although an anhydride is also mentioned, when using these other tetracarboxylic dianhydrides, it is good to use together with 1 or more types of the tetracarboxylic dianhydride mentioned as said preferable. When other tetracarboxylic dianhydrides are used in combination, the range of 5 to 50 mol% is preferable.

で表されるジアミノシロキサンが用いられる。一般式（４）において、R₁〜R₄は一般式（１）のそれと同じ意味を有する。 As diaminosiloxane, the following general formula (4)

The diaminosiloxane represented by these is used. In the general formula (4), R _{1 to} R ₄ have the same meaning as that in the general formula (1).

R ₁ and R _{2 each} represent a divalent hydrocarbon group, preferably an alkylene group having 1 to 6 carbon atoms or a phenylene group. R ₃ and R ₄ each represent a hydrocarbon group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group. These may be the same or different.

  m is in the range of 1-20, preferably the number average value is in the range of 2-14. If it is less than this range, the filling property of the flame-retardant adhesive film is lowered, and if it is more, the adhesive property is lowered, which is not preferable. The same applies to the silicon unit of the general formula (1).

  By using diaminosiloxane as a silicon unit-containing polyimide resin, the flame-retardant adhesive film of the present invention can be given fluidity at the time of thermocompression bonding and the filling property to the printed circuit board surface can be improved.

Preferable specific examples of diaminosiloxane include diaminosiloxanes represented by the following formula.

More preferable specific examples of the diaminosiloxane include phenyl group-substituted diaminosiloxanes represented by the following formula. Here, j and n in the following formula have a total number of j and n in the range of 1 to 20, but preferably in the range of 2 to 14.

In the general formula (2), specific examples of the aromatic diamine that gives Ar ₂ include m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, and benzidine. 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 4,4′-diamino -P-terphenyl and the like are mentioned, but 2,2-bis (3-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenoxyphenyl) propane, 3 for the purpose of improving the solubility in organic solvents. , 3-bis (3-aminophenoxyphenyl) sulfone, 4,4-bis (3-amino Phenoxyphenyl) sulfone, 3,3-bis (4-aminophenoxyphenyl) sulfone, 4,4-bis (4-aminophenoxyphenyl) sulfone, 2,2-bis (3-aminophenoxyphenyl) hexafluoropropane, 2, , 2-bis (4-aminophenoxyphenyl) hexafluoropropane, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4- (p-phenylenediene) It is preferable to use one or more diamines having three or more aromatic rings such as isopropylidene) bisaniline and 4,4- (m-phenylenediisopropylidene) bisaniline. Aromatic diamines that give Ar ₂ do not have silicon units or siloxane units.

Preferred examples of Ar ₂ are as follows.
-Ph-X-Ph- or -Ph-
(Where Ph is phenylene and X is a single bond or alkylene, alkylidene, S, SO, SO ₂ , O, CO, phenylene, or —O—Ph—O—, —R—Ph—R—, etc. R is alkylene or alkylidene, where the alkylene or alkylidene preferably has 1 to 3 carbon atoms.

It is also advantageous to use a reactive aromatic diamine represented by the following general formula (5) having a functional group reactive with an epoxy resin as a part of the aromatic diamine.

In the general formula (5), Ar ₃ , X and k have the same meanings as those in the general formula (3). Such reactive aromatic diamines include 2,5-diaminophenol, 3,5-diaminophenol, 4,4 ′-(3,3′-dihydroxy) diaminobiphenyl, 4,4 ′-(2,2 '-Dihydroxy) diaminobiphenyl, 2,2'-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 3,3', 4,4'-biphenyltetraamine, 3,3 ', 4,4' -Tetraaminodiphenyl ether, 4,4 '-(3,3'-dicarboxy) diphenylamine, 3,3'-dicarboxy-4,4'-diaminodiphenyl ether, and the like are particularly preferable. At least one of (3,3′-dihydroxy) diphenylamine and 4,4 ′-(2,2′-dihydroxy) diphenylamine. By using the reactive aromatic diamine, it reacts with the epoxy resin at the time of thermocompression bonding to form a crosslinked structure, so that the adhesive strength and chemical resistance of the adhesive film of the present invention can be further improved. The reactive aromatic diamine is preferably used in the range of 1 to 20 mol%, more preferably in the range of 2 to 10 mol% of the total aromatic diamine.

  The silicon unit-containing polyimide resin is obtained by reacting the above diaminosiloxane and aromatic diamine with tetracarboxylic dianhydride in a solvent to form a precursor resin, and then heating and ring-closing the resin in the general formulas (1) and (2). A polyimide resin having a repeating unit represented can be produced. At this time, the constitutional ratio (molar ratio) of the repeating units represented by the general formulas (1) and (2) is (1) / (2) = 50/50 to 10/90, preferably 50/50 to 20 /. A range of 80. Outside this range, the effect of the present invention cannot be obtained.

  As an epoxy resin, phosphorus is contained in its molecular structure in an amount of 3.8% by weight or more, preferably 4 to 5% by weight, more preferably 4 to 4.9% by weight, and further preferably 4 to 4.7% by weight. Use phosphorus-containing epoxy resin. In the phosphorus-containing epoxy resin, since the phosphorus element is fixed in the epoxy resin by a chemical bond, there is no liberation of phosphorus-containing ions due to hydrolysis unlike conventional phosphorus-based additives, and no migration effect is produced. In addition, when the phosphorus content of the phosphorus-containing epoxy resin is less than 3.8% by weight in the epoxy resin composition, sufficient flame retardancy cannot be obtained. Moreover, when there is too much phosphorus content, the crosslinking density of the epoxy resin after hardening will fall, and physical properties, such as heat resistance and adhesiveness, will fall.

  The phosphorus-containing epoxy resin can be produced by reacting an epoxy resin with, for example, a phosphorus compound represented by the following general formula (8) by a known method. The epoxy resin is preferably a novolac-type epoxy resin. Advantageously, an epoxy resin having a structure represented by the following general formula (6) or (7) and a phosphorus compound represented by the following general formula (8) are known methods. It is possible to manufacture by making it react. In addition, it is possible to use an epoxy resin other than a novolac type epoxy resin as a raw material epoxy resin for obtaining a phosphorus-containing epoxy resin, but in order to improve the flame retardancy, 20% by weight of the total epoxy resin As described above, preferably 40% by weight or more is a novolac type epoxy resin. Examples of the epoxy resin other than the novolac type epoxy resin include, but are not particularly limited to, a bisphenol type epoxy resin, a biphenyl type epoxy resin, a fluorene type epoxy resin, a resorcin type epoxy resin, and a polyglycol type epoxy resin.

但し、Aはベンゼン核又はナフタレン核を示し、Gはグリシジル基を示し、Rは水素原子又は炭素数１〜６のアルキル基を示し、Xはアルキレン基又は-Y-Ar-Y-で表されるアラルキレン基を示し、pは０〜１５の数を示し、qは１又は２を示し、Yはアルキレン基を示し、Arは2価の芳香族基を示す。

However, A shows a benzene nucleus or a naphthalene nucleus, G shows a glycidyl group, R shows a hydrogen atom or a C1-C6 alkyl group, X is represented by an alkylene group or -Y-Ar-Y-. P represents a number from 0 to 15, q represents 1 or 2, Y represents an alkylene group, and Ar represents a divalent aromatic group.

但し、Aはベンゼン核又はナフタレン核を示し、Gはグリシジル基を示し、R₅、R₆ 、R₇及びR₈は水素原子又は炭素数１〜６のアルキル基を示し、pは０〜１５の数であり、qは１又は２である。

However, A is represents a benzene nucleus or a naphthalene nucleus, G is a glycidyl _{group, R 5, R 6, R} 7 and R ₈ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, p is 0 to 15 And q is 1 or 2.

但し、R₉は独立に水素原子又は脂肪族基若しくは芳香族基であり、rは４である。

However, R ₉ is independently a hydrogen atom, an aliphatic group or an aromatic group, and r is 4.

  The novolac type epoxy resin is obtained by epoxidizing a hydroxyl group of a phenol novolak resin obtained by condensing phenols and aldehydes with epichlorohydrin or the like, and a commercially available product can also be used. Specific examples thereof include Epototo YDPN-638 (manufactured by Toto Kasei Co., Ltd., phenol novolac type epoxy resin), Epototo YDCN-701, YDCN-703, YDCN-704 (manufactured by Toto Kasei Co., Ltd., cresol novolac type epoxy resin), Epototo ZX-1071T, ZX-1270, ZX-1342 (manufactured by Toto Kasei Co., Ltd., aralkyl novolac type epoxy resin), Epototo ZX-1247 (manufactured by Toto Kasei Co., Ltd., styrenated phenol novolac type epoxy resin), Epototo ZX-1142L (Tohto Kasei Co., Ltd., naphthol novolak type epoxy resin), bisphenol novolak type epoxy resin, aralkylphenol novolak type epoxy resin, phenylphenol novolak type epoxy resin and the like. These epoxy resins may be used alone or in combination of two or more.

  Specific examples of the phosphorus compound represented by the general formula (8) include HCA (manufactured by Sanko Chemical Co., Ltd., 9,8-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide). Further, as reported in JP-A-11-279258, a quinone compound may be mixed and reacted.

  As a method of reacting the phosphorus compound represented by the general formula (8) and the epoxy resin, the reaction temperature is, for example, 100 to 200 ° C. with stirring. The active hydrogen directly bonded to phosphorus of the phosphorus compound represented by the general formula (8) and the epoxy group of the epoxy resin react to obtain the target phosphorus-containing epoxy resin, but in order to have a function as an epoxy resin The reaction may be carried out so that at least one, preferably two, epoxy groups remain per molecule of epoxy resin. Considering this, the upper limit of the phosphorus content is 5% by weight. In order to perform the reaction sufficiently, for example, tertiary amines such as benzyldimethylamine, quaternary ammonium salts such as tetramethylammonium chloride, triphenylphosphine, tris (2,6-dimethoxyphenyl) Various catalysts such as phosphines such as phosphine, phosphonium salts such as ethyltriphenylphosphonium bromide, and imidazoles such as 2-methylimidazole may be used. However, it is necessary to select the raw material epoxy resin and the raw material phosphorus compound, calculate the use ratio, and control the reaction rate so that the phosphorus content in the epoxy resin composition falls within the above range.

  Phosphorus-containing epoxy resins with a controlled phosphorus content have already been reported in JP-A-11-166035, JP-A-11-279258, JP-A-2000-309623, and the like. Thus, for the purpose of imparting flame retardancy, it is known to contain phosphorus in the epoxy resin composition, but in the blending with the above-mentioned silicon unit-containing polyimide resin, the phosphorus content is 3. Unless 8% by weight or more of the phosphorus-containing epoxy resin is blended, the flame retardancy effect cannot be obtained.

  A commercially available thing can also be utilized as this phosphorus containing epoxy resin, for example, ZX-1548-4 (the Toto Kasei Co., Ltd. make, phosphorus content 4.0 weight%) is mentioned.

  The blending ratio of the silicon unit-containing polyimide resin and the phosphorus-containing epoxy resin is 60 to 98% by weight of the polyimide resin, 2 to 30% by weight of the phosphorus-containing epoxy resin, preferably 70 to 90% by weight of the polyimide resin, and 10 to 10% of the phosphorus-containing epoxy resin. It is in the range of 30% by weight. By mix | blending in this range, heat resistance and adhesiveness can further be improved, without reducing the original characteristic of a polyimide resin. In addition, the phosphorus-containing epoxy resin can be used alone or in combination of two or more if the phosphorus content is 4 to 5% by weight in the epoxy resin composition.

  Although the resin composition of this invention contains the said component as an essential component, it can also mix | blend the epoxy resin hardening | curing agent which does not contain a halogen element if necessary. In this case, the blending ratio is 1 to 15% by weight, preferably 5 to 10% by weight, based on 100 parts by weight of the total of the polyimide resin and the epoxy resin. From another viewpoint, the range of 20 to 70% by weight of the epoxy resin is preferable. The use of the epoxy resin curing agent is effective when a silicon unit-containing polyimide resin that does not have the functional group represented by the general formula (3) in the molecule is used.

  Specific examples of the epoxy resin curing agent include phenols such as phenol novolak, o-cresol novolak, phenol resole, amines such as naphthols and diethylenetriamine, and acid anhydrides such as pyromellitic anhydride and phthalic anhydride. Can be mentioned.

  In addition to the above-described components, the resin composition of the present invention may optionally contain a conventionally known curing accelerator not containing a halogen element, a coupling agent, a filler, a pigment, and the like. Moreover, other polyimide resins or other epoxy resins other than the silicon unit-containing polyimide resin or phosphorus-containing epoxy resin can be blended in a small amount as long as the effects of the present invention are not impaired.

  The resin composition of the present invention can be used in the form of a film. In this case, it is possible to form a film using a conventionally known method, but as an example of a suitable molding method, the above resin composition is dissolved in a solvent, and the resulting resin solution is subjected to a surface peeling treatment. A method for forming a flame retardant adhesive film for a printed circuit board according to the present invention by coating on a base material such as a metal foil, a polyester film or a polyimide film by a conventionally known method, then drying and peeling from the base material There is.

  Typical examples of the solvent used in the film forming step include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-diethylacetamide. Amide solvents such as N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, γ-butyrolactone, xylenol, phenol, methyl cellosolve, ethyl cellosolve, Mention may be made of ethers, esters and alcohol solvents such as methyl cellosolve acetate, ethyl cellosolve acetate, toluene, xylene and methyl ethyl ketone. In addition, the solvent used at the time of forming the polyimide resin may be used as it is as the solvent for forming the film.

  As a suitable usage method of the adhesive film of the present invention, for example, a flexible printed wiring board laminate, a glass fiber-epoxy wiring board laminate, a paper-phenol wiring board laminate, or a circuit obtained from these can be obtained. Suitable for adhesion of various printed wiring boards, metals, resin base materials and the like. A laminate for a printed wiring board can be obtained by adhering a metal foil and a resin base material, and a multilayer for a printed wiring board or a printed wiring can be obtained by adhering the laminated body for a printed wiring board or printed wiring boards to each other. A board can be obtained and a printed wiring board with a cover lay can be obtained by bonding a printed wiring board and a coverlay film. In addition, it can be used as an adhesive film for connection of a laminate for a printed wiring board or a printed wiring board. In any case, it is used in the process of manufacturing or processing printed circuit boards such as a printed wiring board laminate and a printed wiring board.

  As a method of bonding using the adhesive film of the present invention, an adhesive film is inserted between two adherends, and the temperature is 20 to 250 ° C., preferably 100 to 220 ° C., and the pressure is 0.1 to 0.1. The adhesive layer is bonded between the objects to be bonded by thermocompression bonding under conditions of 10 MPa, preferably 0.5 to 5 MPa, and further heat-treated at a temperature of 50 to 250 ° C. for a predetermined time to completely cure the epoxy resin. The method of forming is mentioned.

  The flame-retardant adhesive resin composition of the present invention and an adhesive film using the same are capable of thermocompression bonding at a lower temperature than conventional polyimide adhesives without impairing the inherent excellent heat resistance and electrical characteristics of the polyimide. It becomes possible. Excellent flame retardancy even without halogen elements. Therefore, at the time of incineration disposal, the risk of generating harmful substances such as dioxins can be reduced. The flame-retardant adhesive film of the present invention can also be suitably used for an adhesive for multilayer printed circuit boards, an adhesive for composite circuit boards, an adhesive for coverlay films, and the like.

  Unless otherwise specified in the examples of the present invention, various measurements and evaluations on the adhesive film are as follows.

[Measurement of tensile strength]
The tensile strength of the adhesive film was measured using a tensile tester (Toyo Seiki Co., Ltd., Strograph-R1), cutting the test piece into a strip shape with a width of 12.5 mm and a length of 120 mm, and a crosshead speed of 25 mm / min. Measurement is performed at a distance between chucks of 101.6 mm, and the value obtained by dividing the measured load by the cross-sectional area of the test piece (0.31 mm ² ) is the tensile strength.

[Measurement of glass transition temperature]
Glass transition temperature was tested using a thermomechanical analyzer (Bruker, 4000SA) with a test piece of 2 mm width and 30 mm length at a distance of 15 mm between chucks, a load of 2 g and a heating rate of 5 ° C / min. The amount of thermal expansion in the length direction of the piece is measured, and the inflection point is defined as the glass transition temperature.

[Measurement of adhesive strength]
Adhesive strength was measured by using a tensile tester (Toyo Seiki Co., Ltd., Strograph-M1) to cut out a test piece with a width of 10 mm and a length of 100 mm, and this test piece was made of two copper foils (35 μm thick). Sandwiched between two surfaces and sandwiched between two polyimide films (manufactured by Kaneka Corporation, Apical NPI), thermocompression bonded at 180 ° C for 60 minutes at 40 kg / cm ² , and then at a speed of 50 mm / min in the 180 ° direction The force at the time of peeling is taken as the adhesive strength. The adhesive strength 1 is the adhesive strength to the copper foil, and the adhesive strength 2 is the adhesive strength to the polyimide film.

[Measurement of relative permittivity]
The relative dielectric constant was measured using a test piece prepared by thermosetting under a condition of 40 kg / cm ² at 180 ° C for 60 minutes using a dielectric loss automatic measuring device (TR-1100, manufactured by Ando Electric Co., Ltd.). The electrode pattern of JIS C-6481 was printed with silver paste on both sides of the test piece. The test piece after printing the electrode pattern is allowed to stand at 25 ° C. and 50% relative humidity for 24 hours, and the value obtained by measuring the relative dielectric constant at 1 Hz is taken as the relative dielectric constant.

[Measurement of volume resistivity]
The volume resistivity is a value measured based on JIS C-2330.

[Measurement of thermal decomposition temperature]
The thermal decomposition temperature is a value obtained by measuring a 5% weight loss temperature in a nitrogen atmosphere using TG / DTA6200 manufactured by SII.

[Method for evaluating solder heat resistance]
A test piece having a width of 10 m and a length of 100 mm was sandwiched between two glossy surfaces of copper foil (35 μm thickness), and thermocompression bonded under conditions of 180 ° C., 60 minutes, 40 kg / cm ² . This test piece with copper foil was left for 24 hours at 25 ° C and 50% relative humidity, then immersed in a solder bath at 260 ° C for 60 seconds, and observed for adhesion, foaming, blistering, peeling, etc. It was confirmed. > 300 ° C. means that these defects are not observed below 300 ° C.

[Flame retardancy evaluation method]
The flame retardancy was evaluated at a level indicating the degree of flame retardancy by a combustion test based on UL-94. VTM-0 means that there is flame retardancy, and the case where flame retardancy was not expressed was judged as NG.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, of course, this invention is not limited to this. In addition, the symbol used in the present Example shows the following compounds.
ODPA: 3,3 ', 4,4'-diphenyl ether tetracarboxylic dianhydride
DSDA: 3,3 ', 4,4'-diphenylsulfonetetracarboxylic dianhydride
BAPP: 2,2'-bis (4-aminophenoxyphenyl) propane
BAPS: Bis (4-aminophenoxyphenyl) sulfone
mBAPS: Bis (3-aminophenoxyphenyl) sulfone
HAB: 4,4 '-(3,3'-dihydroxy) diaminobiphenyl
PSX-A, PSX-B, PSX-C and PSX-D: diaminosiloxane represented by the following formula (9) (however, the average m number is in the range of 1 to 20, and the average molecular weight of PSX-A is 740) PSX-B has an average molecular weight of 1000, PSX-C has an average molecular weight of 1240, and PSX-D has an average molecular weight of 2000.)
PSX-Ph: diaminosiloxane represented by the following formula (10) (however, the total number of j and n is in the range of 2 to 20, j and n are both 1 or more, and the average molecular weight is 1320).

Synthesis example 1
A reaction vessel was charged with 67 parts by weight of 2,6-dimethylol-4-methylphenol, 173 parts by weight of 2-naphthol, 25 parts by weight of water and 140 parts by weight of 1-butanol, and concentrated hydrochloric acid was added to adjust the reaction mixture to pH 1. did. The reaction mixture was heated to 50 ° C. to dissolve 1-naphthol and then reacted at 95 ° C. for 2 hours. After completion of the reaction, the reaction mixture was neutralized with an aqueous sodium hydroxide solution, washed with water and dried, and the solid obtained was pulverized, washed with toluene, and dried to obtain 119 parts by weight of a novolak resin. The obtained novolak resin had a softening point of 200 to 210 ° C. and a hydroxyl group equivalent of 148.
To 100 parts by weight of the novolak resin thus obtained, 700 parts by weight of epichlorohydrin was added, and 56 parts by weight of a 48% by weight aqueous sodium hydroxide solution was added dropwise over 250 minutes while heating at 115 ° C., and the reaction was continued for another 15 minutes. I let you. During this reaction, the produced water was removed out of the system by azeotropy with epichlorohydrin. After completion of the reaction, excess epichlorohydrin was distilled off under reduced pressure, and 400 parts by weight of methyl isobutyl ketone was added to the residue to dissolve and recover the epoxy resin. After washing twice with water, the methyl isobutyl ketone was kept under reduced pressure. To obtain 130 parts by weight of an epoxy resin. The resulting epoxy resin had a softening point of 91 ° C. and an epoxy equivalent of 236.

Synthesis example 2
130 parts by weight of the epoxy resin obtained in Synthesis Example 1 was charged into a reaction vessel, stirred while introducing nitrogen gas, and heated to 150 ° C. to dissolve. Thereafter, 0.15 part by weight of triphenylphosphine was added as a catalyst, and 112 parts by weight of HCA (manufactured by Sanko Chemical Co., Ltd., 9,8-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) was gradually added. In addition, the reaction was performed at 150 ° C. for 4 hours. The phosphorus content of the obtained phosphorus-containing epoxy resin was 4.6% by weight.

Example 1
A 1000 ml separable flask was charged with 50.16 g of DSDA (0.14 mol), 200 g of N-methyl-2-pyrrolidone and 200 g of xylene and mixed well at room temperature, then using a dropping funnel 31 .54 g of PSX-A (0.0434 mol) was added dropwise and the reaction solution was ice-cooled with stirring to give 37.36 g of BAPP (0.091 mol) and 1.30 g of HAB (0.006 mol). 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 a having a logarithmic viscosity of 0.9 dl / g.

Next, 30 parts by weight of a phosphorus-containing epoxy resin (manufactured by Toto Kasei Co., Ltd., ZX-1548-4EK75, phosphorus content 4.0% by weight) is mixed with 70 parts by weight of the solid content of the obtained polyimide solution a. The mixture was stirred for 2 hours at room temperature to prepare an adhesive resin (resin composition) solution. This resin solution was applied on a glass plate, dried to form a film, and an adhesive film was obtained. The glass transition temperature of this film was 182 ° C. The tensile strength of this film was 70 MPa, the relative dielectric constant was 3.1, the volume resistivity was 2.5 × 10 ¹⁵ Ωcm, the adhesive strength was 0.8 kN / m, and the thermal decomposition temperature was 440 ° C. Also, the solder heat resistance was good, with no defects such as blistering and peeling being observed. The results are shown in Tables 2 and 3.

Examples 2-7
A polyimide solution was prepared in the same manner as in Example 1 with the composition shown in Table 1, a resin composition was prepared by mixing a phosphorus-containing epoxy resin with the composition shown in Table 2, and a film was formed. Tables 2 and 3 show the results of measuring the various characteristics. When an epoxy resin curing agent was used, an imidazole derivative (Shikoku Kasei Kogyo Co., Ltd., 2MZ) was used as the epoxy resin curing agent. As the epoxy resin, phosphorus-containing epoxy resin ZX-1548-4EK75 manufactured by Toto Kasei Co., Ltd. was used.

Example 8
A polyimide solution was prepared in the same manner as in Example 1 with the composition shown in Table 1. A resin composition was prepared by mixing the phosphorus-containing epoxy resin obtained in Synthesis Example 2 with the composition shown in Table 2, and a film was formed. Tables 2 and 3 show the results of measuring the various characteristics.

Furthermore, the practical test was done about the film (adhesive film) obtained in Examples 1-8. Two sets of flexible printed circuit boards in which circuits (line / space 0.15 mm / 0.15 mm) are formed on both sides of the film by copper are prepared, and the adhesive film obtained in Example 1 is inserted between them. After thermocompression bonding under conditions of 180 ° C. and pressure of 25 kgf / cm ² for 60 minutes, the cross section of each film was observed. As a result, no film remained between the circuits, and good circuit filling properties were exhibited. In addition, two flexible printed circuit boards each having a circuit formed of copper on both sides of a polyimide film were prepared, and the adhesive film obtained in Examples 1 to 8 was inserted between them, and the temperature was 180 ° C. and the pressure was 25 kgf / cm. ^2. After thermocompression bonding under conditions for 60 minutes, through holes were formed to produce a multilayer printed wiring board. For any of the films, there was no smear or the like during the formation of the through hole, and a good through hole was obtained.

Comparative Examples 1-5
A polyimide solution was prepared with the composition shown in Table 1 in the same manner as in the Examples, a resin composition was prepared with the composition shown in Table 2, and a film was formed. The results of measuring various properties of the film are shown in Tables 2 and 3. In Table 2, DGEBA is an epoxy resin obtained by converting bisphenol A to glycidyl ether (Japan Epoxy Resin Co., Ltd., EPIKOTE 828), oCNB is an epoxy resin obtained by converting o-kuzol novolac resin to glycidyl ether (Japan) 2. EOCN-1020) manufactured by Kayaku Co., Ltd., FX-305 is a phosphorus-containing epoxy resin having a phosphorus content of 2.0% by weight manufactured by Toto Kasei Co., Ltd. 0% by weight phosphorus-containing epoxy resin.

Claims (6)

The following general formula (1) and the following general formula (2)

(In General Formula (1), Ar ₁ represents a tetravalent aromatic group, R ₁ and R ₂ represent a divalent hydrocarbon group, and R ₃ and R ₄ represent a monovalent monovalent group having 1 to 6 carbon atoms. Represents a hydrocarbon group, and m represents a number from 1 to 20. In the general formula (2), Ar ₁ represents a tetravalent aromatic group, and Ar ₂ represents a divalent aromatic group. The constitutional ratio of the repeating units represented by the general formulas (1) and (2) is in the range of (1) / (2) = 50/50 to 10/90 (molar ratio). Containing substantially halogen element characterized by being formed from 60 to 98% by weight of silicon unit-containing polyimide resin and 2 to 40% by weight of phosphorus-containing epoxy resin containing 3.8% by weight or more of phosphorus in its structure Not flame retardant adhesive resin composition.   2. The flame retardant adhesive resin composition according to claim 1, comprising 1 to 15 parts by weight of an epoxy resin curing agent with respect to a total of 100 parts by weight of the silicon unit-containing polyimide resin and the phosphorus-containing epoxy resin. 1 to 20 mol% of Ar ₂ in the general formula (2) is represented by the following general formula (3)

Wherein Ar ₃ represents a trivalent or tetravalent aromatic group, X represents a hydroxyl group, an amino group, a carboxyl group or a mercapto group, and k represents 1 or 2, and is reactive. The flame retardant adhesive resin composition according to claim 1, which is a divalent aromatic group having a functional group having   The flame-retardant adhesive resin composition according to any one of claims 1 to 3, wherein the phosphorus-containing epoxy resin contains 4 to 5% by weight of phosphorus in its structure.   A flame retardant adhesive film, wherein the flame retardant adhesive resin composition according to claim 1 is formed into a film.   The flame-retardant adhesive film according to claim 5 is inserted between objects to be bonded and used by thermocompression bonding under conditions of pressure 0.1 to 10 MPa and temperature 20 to 250 ° C. How to use flammable adhesive film.