JP4976380B2 - Metal laminate - Google Patents

Description

  The present invention relates to a metal laminate used for a flexible printed circuit board or the like.

Metal laminates made of polymer film substrates and metals are widely used in applications such as semiconductor packages and flexible printed boards in the electrical and electronic industries. In particular, a polyimide metal laminate using a polyimide resin film as a substrate is excellent in heat resistance, and thus is used in applications requiring heat resistance. The polyimide metal laminate is manufactured by using a polymer film made of a polyimide resin as a substrate and bonding a metal foil to one or both sides thereof.
In recent years, lead-free solder has been used for electronic component mounting from the viewpoint of environmental protection. The melting point of lead-free solder is about 220 ° C., which is about 40 ° C. higher than 180 ° C., which is the melting point of current solder. Therefore, higher solder heat resistance is required for polyimide metal laminates used for printed boards and the like.

  However, when the heat resistance of the adhesive used for the polyimide metal laminate is low, the heat resistance of the entire metal laminate is impaired. Therefore, a polyimide metal laminate using an adhesive polyimide resin for the adhesive and excellent in heat resistance and adhesiveness has been proposed. For example, Patent Document 1 discloses an adhesive polyimide using a diamine having a hydroxyl group or a carboxyl group as a raw material. However, when a metal laminate is produced using the adhesive polyimide resin as an adhesive, the bonding temperature needs to be as high as 340 ° C., and other members may be exposed to high temperatures and deteriorate.

  In order to improve this point, Patent Document 2 discloses a polyimide metal laminate using a polyimide resin using a specific tetracarboxylic dianhydride and an adhesive containing a thermosetting resin such as an epoxy resin. It is disclosed. This document discloses that the substrate and the metal foil can be bonded at a relatively low temperature of about 200 ° C.

  Patent Documents 3 and 4 disclose metal laminate adhesives used in semiconductor packages that can be bonded at low temperatures. Specifically, an adhesive containing a polyimide resin having an alkylene group in the main chain is disclosed.

  On the other hand, in recent years, with the miniaturization of electronic devices, flexible printed circuit boards have been finely processed. Conventionally, a process of providing a through hole or a via hole on a printed circuit board has been performed by drilling. However, since drilling is not suitable for microfabrication, a processing method using a laser is being adopted in the step of providing a conduction hole. However, when laser processing is performed on the flexible printed board, adhesive residue (residue) is generated in the processed portion. Therefore, a chemical treatment called desmear treatment for removing this residue is required. Accordingly, there is a need for an adhesive having an easy desmear property that can be decomposed relatively easily into this chemical.

JP 2002-363284 A JP 2003-136431 A JP-A-2005-167101 International Publication No. 2004/101701 Pamphlet

As described above, the adhesive described in Patent Document 1 has a problem that other members deteriorate because the temperature at which the polyimide substrate and the metal foil are bonded is high.
The adhesive described in Patent Document 2 has a low bonding temperature and can prevent other members from deteriorating during the production of the metal laminate, but does not mention desmearability. Actually, when the present inventors evaluated the desmear property of the metal laminate, it was confirmed that the desmear property was not sufficient.

  The adhesives disclosed in Patent Documents 3 and 4 can also prevent other members from deteriorating when the metal laminate is manufactured with a low bonding temperature. However, since the metal laminate is a metal laminate used in a semiconductor package, there is no description regarding desmear property. This is because the members used in the semiconductor package do not undergo desmearing treatment, so that there is no room for considering desmearability in the first place.

  That is, it is possible to bond a polyimide substrate and a metal foil at a low temperature (also referred to as “low-temperature bonding is possible”), and an adhesive for a metal laminate that has excellent heat resistance and excellent desmearability is desired. Despite this, there has been no such adhesive in the past. Accordingly, an object of the present invention is to provide an adhesive for a metal laminate that can be bonded at low temperature, has excellent heat resistance, and has excellent desmear properties, and a metal laminate using the same.

  As a result of intensive studies, the present applicant has found that an adhesive containing a polyimide resin and an epoxy resin using a specific diamine as a raw material solves the above problems, and has completed the present invention. That is, the said subject is solved by the following this invention.

（式中、ｎは１〜５０の整数であり、Ｙは炭素数２〜１０のアルキレン基であり、ｎが２以上である場合、Ｙは同一または異なる基である。）
で表される化合物を、ジアミン成分中５モル％以上２０モル％未満含むジアミン成分と、
（Ａ２）テトラカルボン酸二無水物成分を反応させて得られる、ガラス転移温度２００℃以下のポリイミド、ならびに
（Ｂ）エポキシ樹脂、を含む金属積層体用接着剤。
［２］前記（Ａ１）のジアミン成分が、分子内にフェノール性水酸基を有するジアミン化合物をさらに含む［１］に記載の金属積層体用接着剤。
［３］前記分子内にフェノール性水酸基を有するジアミン化合物の含有量が、前記（Ａ１）の全ジアミン成分中、０．１〜１０モル％である［２］に記載の金属積層体用接着剤。
［４］前記分子内にフェノール性水酸基を有するジアミン化合物が、下記一般式（２）、（３）または（４）で表される化合物を含む、［２］〜［３］いずれかに記載の金属積層体用接着剤。[1] An adhesive for laminating a polymer film substrate and a metal foil to form a metal laminate,
(A1) The following general formula (1)

(In the formula, n is an integer of 1 to 50, Y is an alkylene group having 2 to 10 carbon atoms, and when n is 2 or more, Y is the same or different group.)
A diamine component containing 5 mol% or more and less than 20 mol% in the diamine component,
(A2) A metal laminate adhesive comprising: a polyimide having a glass transition temperature of 200 ° C. or lower obtained by reacting a tetracarboxylic dianhydride component; and (B) an epoxy resin.
[2] The adhesive for a metal laminate according to [1], wherein the diamine component (A1) further includes a diamine compound having a phenolic hydroxyl group in the molecule.
[3] The adhesive for a metal laminate according to [2], wherein the content of the diamine compound having a phenolic hydroxyl group in the molecule is 0.1 to 10 mol% in the total diamine component (A1). .
[4] The diamine compound having a phenolic hydroxyl group in the molecule includes a compound represented by the following general formula (2), (3) or (4), according to any one of [2] to [3]. Adhesive for metal laminates.

（式（２）〜(４)中、Ｚはそれぞれ独立に単結合、あるいは２価の有機基である。）

(In formulas (2) to (4), Z is each independently a single bond or a divalent organic group.)

[5] The adhesive for a metal laminate according to any one of [1] to [4], wherein the (B) epoxy resin has three or more glycidyl groups in the molecule.
[6] The metal laminate according to any one of [1] to [5], comprising 100 parts by weight of polyimide obtained by reacting (A1) and (A2) and 1 to 30 parts by weight of (B) epoxy resin. Adhesive.
[7] The metal laminate adhesive according to any one of [1] to [6], wherein the metal foil is a copper foil or a copper alloy foil.
[8] The adhesive for a metal laminate according to any one of [1] to [7], wherein the polymer film substrate is a polyimide film substrate.
[9] The metal laminate adhesive according to any one of [1] to [8], wherein the metal laminate formed by bonding the polymer film substrate and metal foil is a flexible printed substrate.
[10] A metal laminate including a polymer film substrate, a cured product layer of an adhesive provided on the surface of the substrate, and a metal foil layer provided on the surface of the cured product layer, wherein the adhesive is The metal laminated body containing the metal foil layer which is the adhesive agent in any one of [1]-[9].

  According to the present invention, it is possible to bond a polymer film substrate and a metal foil at a low temperature, and provide an adhesive for a metal laminate having excellent heat resistance and desmear properties, and a metal laminate using the same. it can.

The adhesive of the present invention is an adhesive for bonding a metal foil to one or both sides of a polymer film substrate to form a metal laminate, and is also referred to as an adhesive for a metal laminate.
A metal foil made of a known material can be used. Examples thereof include copper, nickel, aluminum or stainless steel, or alloys thereof. Among these, copper and copper alloys are preferable because of low cost and excellent electrical characteristics. The thickness of the metal foil is preferably 3 μm to 50 μm because it is excellent in fine workability and the like when a metal laminate is formed. In the present invention, “˜” means to include values at both ends thereof.

  A known material can be used for the polymer film substrate. Since the heat resistance of the metal laminate is excellent, the glass transition temperature is preferably 200 ° C. or higher, and more preferably 300 ° C. or higher. Examples of such materials include polyimide, aramid, polyphenylene sulfide, polyether, polyether ketone, polyether ether ketone and the like. Among these, a polyimide film and an aramid film are preferable because they are easily available. Examples include Kapton (registered trademark) manufactured by Toray DuPont Co., Ltd., Upilex (registered trademark) manufactured by Ube Industries, Ltd., Apical (registered trademark) manufactured by Kaneka Corporation, and Aramika (registered trademark) manufactured by Teijin Advanced Film Co., Ltd. Trademark) and the like. The thickness of the polymer film is preferably 3 μm to 50 μm. It is because it is excellent in the fine workability etc. when it is set as a metal laminated body.

The adhesive for metal laminates of the present invention includes a polyimide obtained by a polycondensation reaction between a diamine and tetracarboxylic dianhydride, and an epoxy resin. The polyimide used for the adhesive is sometimes referred to as “adhesive polyimide”.
1. About the adhesive polyimide of the present invention Polyimide is a general term for polymers having an imide ring in the main chain. Polyimide is generally obtained by polycondensing diamine and tetracarboxylic dianhydride to obtain a polyamic acid, and dehydrating and condensing the polyamic acid for cyclization. By selecting the chemical structure of diamine and tetracarboxylic dianhydride, the performance such as heat resistance of the polyimide is determined.

  The adhesive polyimide of the present invention has a glass transition temperature of 200 ° C. or lower. The glass transition temperature is a temperature at which the rigidity and viscosity of the polymer decrease and the fluidity increases when the glass transition temperature is exceeded, and is an important index showing the wettability to the adherend, particularly in bonding. Therefore, when the glass transition temperature of the adhesive polyimide is in the above range, the adhesion temperature when the polyimide is used as an adhesive between the polymer film and the metal foil can be lowered. The glass transition temperature in the present invention is a value determined by solid viscoelastic analysis. Specifically, the tan δ value (= loss elastic modulus / storage elastic modulus) measured by raising the temperature of the polyimide film with a viscoelasticity measuring device (RSA-II, manufactured by Rheometrics) at a frequency of 10 Hz is a peak. Is the temperature at which

  However, if the glass transition temperature of the adhesive polyimide becomes extremely low, the heat resistance of the metal laminate obtained by bonding the polymer film substrate and the metal foil using an adhesive containing the adhesive polyimide may be reduced. There is. In addition, when the adhesive polyimide is used as an adhesive, it may be formed into an adhesive film as will be described later, but stickiness (tackiness) at that time may occur and handling may become a problem. is there. Furthermore, when the glass transition temperature of adhesive polyimide becomes extremely low, the storage stability of the adhesive using the adhesive polyimide also decreases. This is because the adhesive of the present invention contains an epoxy resin, as will be described later, and thus the reaction of the epoxy resin tends to occur when the glass transition temperature of the adhesive is low.

Therefore, it is preferable that the component is selected in consideration of the performance of the metal laminate obtained using the obtained adhesive polyimide as an adhesive and using the adhesive.
That is, the glass transition temperature of the adhesive polyimide is preferably 100 to 200 ° C, and more preferably 150 to 200 ° C.

1-1 (A1) About diamine component A diamine component means the mixture which consists of a diamine compound. A diamine compound is a compound having two amino groups in one molecule. A diamine compound is also simply referred to as a diamine. The amino group in the diamine is preferably a primary amino group. In the present invention, the diamine component contains a compound represented by the following general formula (1) in an amount of 5 mol% or more and less than 20 mol% in the diamine component.

  The diamine represented by the general formula (1) in the present invention has o-, m-, or p-aminobenzoic acid ester groups at both ends. Among these, those having a p-aminobenzoic acid ester group at both ends are preferred because of their availability.

  In general formula (1), n is an integer of 1-50, Preferably it is an integer of 3-25. Y is an alkylene group having 2 to 10 carbon atoms, preferably an alkylene group having 2 to 5 carbon atoms. When n is 2 or more, a plurality of Y are present in one molecule. Each Y may be the same or different. Examples of the alkylene group having 2 to 10 carbon atoms include ethylene, trimethylene, tetramethylene, pentamethylene and the like. Of these, tetramethylene is preferred because of its availability. Thus, the diamine represented by the general formula (1) is characterized by having an aromatic ring and a fatty chain. The diamine represented by the general formula (1) may be referred to as “alkylene chain-containing diamine”.

  Specific examples of the diamine represented by the general formula (1) include polytetramethylene oxide-di-o-aminobenzoate, polytetramethylene oxide-di-m-aminobenzoate, polytetramethylene oxide-di-p-amino. Examples include benzoate, polytrimethylene oxide-di-o-aminobenzoate, polytrimethylene oxide-di-m-aminobenzoate, polytrimethylene oxide-di-p-aminobenzoate and the like. Of these, polytetramethylene oxide-di-p-aminobenzoate is preferred.

As shown in Formula (1), the alkylene chain-containing diamine has an alkylene group in the molecule. The alkylene group has a bent structure. Therefore, a polyimide obtained using an alkylene chain-containing diamine as a raw material has a skeleton bent to the main chain.
In general, since the glass transition temperature largely depends on the primary structure (chemical structure) of the polyimide molecule, a polyimide using an alkylene chain-containing diamine as a raw material has a low glass transition temperature. Therefore, the glass transition temperature of polyimide can be adjusted by adjusting the structure and content of the alkylene chain-containing diamine. For example, when an alkylene chain-containing diamine having a long alkylene group is used as a raw material, the glass transition temperature of the resulting polyimide is lowered. Moreover, even if it increases content of an alkylene chain containing diamine, the glass transition temperature of the polyimide obtained becomes low.

  Also, alkyl chains have low chemical resistance. Therefore, when the content of the alkyl chain in the polyimide is increased, the desmear property of the polyimide is improved.

Therefore, the content and structure of the alkylene chain-containing diamine are preferably determined in consideration of the low-temperature adhesiveness and desmear property of the polyimide obtained thereby. However, if the glass transition temperature becomes too low, the problem as described above occurs. Further, if the desmear property is too high, problems such as extremely low chemical resistance occur, so it is necessary to adjust to an appropriate value.
In the structure of the alkylene chain-containing diamine, the value of n in the formula (1) is preferably 5 to 30, and more preferably 10 to 20.

The alkylene chain-containing diamine is 5 mol% or more and less than 20 mol% in the diamine component, but preferably 7 to 15 mol%.
The alkylene chain-containing diamine can be obtained by a known method. Examples of the synthesis of the alkylene chain-containing diamine include a method of esterifying aminobenzoic acid and an aliphatic diol.

  The diamine component of the present invention preferably further contains a “diamine having a phenolic hydroxyl group”. A polyimide using a diamine having a phenolic hydroxyl group as a raw material has a phenolic hydroxyl group in the side chain. Since the adhesive of this invention contains an epoxy resin so that it may mention later, the heat resistance of an adhesive etc. can be improved more because the said hydroxyl group reacts with an epoxy group.

  A diamine having a phenolic hydroxyl group refers to a compound having two amino groups and a phenolic hydroxyl group in one molecule. Although a well-known thing can be used for a hydroxyl-containing diamine, it is preferable to use the compound represented by General formula (2), (3) or (4). A diamine having a phenolic hydroxyl group may be referred to as a “hydroxyl group-containing diamine”.

  In the above formulas (2) to (4), Z is each independently a single bond or a divalent organic group. Examples of the divalent organic group include an aliphatic group having 2 to 27 carbon atoms, an alicyclic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, an aromatic group directly, or an alkylene group. Non-condensed cyclic aromatic groups connected to each other through the like. These divalent organic groups may have a substituent such as an alkyl group or a hydroxyl group.

  Examples of diamines represented by the general formulas (2) to (4) include 2,3-diaminophenol, 2,4-diaminophenol, 2,5-diaminophenol, 2,6-diaminophenol, 3,4 -Diaminophenol, 3,5-diaminophenol, 3,6-diaminophenol, 4,5-diaminophenol, 4,6-diaminophenol, 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4 '-Diamino-3,3'-dihydroxybiphenyl, 4,4'-diamino-2,2'-dihydroxybiphenyl, 4,4'-diamino-2,2', 5,5'-tetrahydroxybiphenyl, 3, 3'-diamino-4,4'-dihydroxydiphenylmethane, 4,4'-diamino-3,3'-dihydroxydiphenylmethane, 4,4'-diamy -2,2'-dihydroxydiphenylmethane, 4,4'-diamino-2,2 ', 5,5'-tetrahydroxydiphenylmethane, 2,2-bis [3-amino-4-hydroxyphenyl] propane, 2,2 -Bis [4-amino-3-hydroxyphenyl] propane and the like are included.

The content and structure of the hydroxyl group-containing diamine is preferably selected so that the glass transition temperature of the adhesive polyimide is 200 ° C. or lower, preferably 100 to 200 ° C., more preferably 150 to 200 ° C. In the hydroxyl group-containing diamine, in formulas (2) to (4), it is preferable that one Z is a single bond and the other Z is a phenylene group. Furthermore, it is preferable that one Z is a single bond and the other Z is a hydroxyphenylene group. In particular, in the formula (1), 4,4′-dimiano-3,3′-dihydroxybiphenyl in which one Z is a single bond and the other Z is a hydroxyphenylene group is preferable.
The content of the hydroxyl group-containing diamine is preferably selected in consideration of the content of the epoxy resin used. The content of the hydroxyl group-containing diamine is preferably 0.1 to 10 mol% and more preferably 1 to 5 mol% in the diamine component.

  The diamine of the present invention may contain a diamine compound other than an alkylene chain-containing diamine and a hydroxyl group-containing diamine. Examples of such diamines include m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, bis (3-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfoxide. Bis (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2- Bis [4- (3-aminophenoxy) phenyl] butane, 1,3-bis (3-aminophenoxy) benzene, bis (3- (3-aminophenoxy) phenyl) ether, 1,3-bis (3- ( 3-aminophenoxy) phenoxy) benzene, bis (3- (3- (3-aminophenoxy) phenoxy) Eniru) ether, 1,3-bis (3- (3- (3-aminophenoxy) phenoxy) phenoxy) benzene, 4,4'-bis (3-aminophenoxy) biphenyl and the like. These diamine compounds are sometimes referred to as “aromatic diamines”.

  The structure and content of the aromatic diamine are preferably selected so that the glass transition temperature of the resulting polyimide is 200 ° C. or lower, preferably 100 to 200 ° C., more preferably 150 to 200 ° C. The aromatic diamine is preferably 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis (3-aminophenoxy) benzene or the like. The content of the aromatic diamine is preferably greater than 70 mol% and 94.9 mol% or less in the diamine component.

1-2 (A2) Tetracarboxylic dianhydride component The tetracarboxylic dianhydride component refers to a mixture of tetracarboxylic dianhydride compounds. The tetracarboxylic dianhydride compound is a compound having two “acid anhydride groups” in the molecule formed by dehydration condensation of two carboxyl groups. The tetracarboxylic dianhydride compound is sometimes simply referred to as tetracarboxylic dianhydride. The tetracarboxylic dianhydride of the present invention is preferably selected so that the resulting polyimide has a glass transition temperature of 200 ° C. or lower, preferably 100 to 200 ° C., more preferably 150 to 200 ° C.

  Examples of tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid Dianhydride, oxy-4,4′-diphthalic dianhydride, ethylene glycol bistrimellitic dianhydride, 2,2-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride, α , Ω-polydimethylsiloxane tetracarboxylic dianhydride, α, ω-bis (3,4-dicarboxyphenyl) polydimethylsiloxane dianhydride, and the like.

1-3 About the manufacturing method of a polyimide The adhesive polyimide of this invention can be manufactured by a well-known method. Especially, it is preferable to manufacture by the reaction performed in an organic solvent. Examples of the solvent used in the reaction include N, N-dimethylacetamide, N-methyl-2-pyrrolidone, toluene, xylene, mesitylene, phenol, cresol and the like.

  The concentration of the raw material in the reaction performed in the organic solvent is preferably 2 to 50% by weight, and more preferably 5 to 40% by weight. The tetracarboxylic dianhydride component and the diamine component are preferably reacted in such a range that “tetracarboxylic dianhydride component”: “diamine component” is “0.8 to 1.2”: “1”. A polyimide having a tetracarboxylic dianhydride component and a diamine component in the above ranges is excellent in heat resistance.

  Polyimide is usually synthesized in two steps as follows. First, a polycarboxylic acid as a precursor is synthesized by dehydrating and condensing a tetracarboxylic dianhydride component and a diamine component (first stage). Next, the polyamic acid is dehydrated and condensed to form an imide ring to obtain a polyimide (second stage). The reaction temperature in the first stage polyamic acid synthesis is preferably 60 ° C. or less, and more preferably 10 ° C. to 50 ° C. The reaction pressure is not particularly limited and may be normal pressure. Moreover, although reaction time changes with the kind of reaction raw material, the kind of solvent, and reaction temperature, it is preferable to set it as 0.5 to 24 hours.

  The imidization reaction in the second stage is performed either by heating the polyamic acid to 100 to 400 ° C. (thermal imidation) or by adding an imidizing agent such as acetic anhydride to the polyamic acid (chemical imidization). May be performed.

  In addition, a diamine component and a tetracarboxylic dianhydride component may be suspended or dissolved in an organic solvent and reacted at 130 to 250 ° C. to synthesize a polyimide. In this reaction, since the formation of polyamic acid and the thermal imidization reaction proceed simultaneously, polyimide can be obtained in one step.

The molecular weight of the adhesive polyimide of the present invention is not particularly limited, and is preferably adjusted as appropriate depending on the application and processing method. The molecular weight can be adjusted by adjusting the quantitative ratio of the diamine component and tetracarboxylic dianhydride component as raw materials. As is generally known in the polycondensation reaction, the molecular weight increases as the composition ratio of the two approaches the stoichiometric amount.
For the measurement of the molecular weight, a known method such as GPC may be used, but in the present invention, it is preferable to evaluate the molecular weight by relative viscosity. The molecular weight of the adhesive polyimide of the present invention is preferably such that the relative viscosity measured by the following method is 0.1 to 3.0 dl / g. The relative viscosity is measured by an Ubbelohde viscometer at 35 ° C. by dissolving polyimide in N-methyl-2-pyrrolidone to give a 0.5 g / dl solution.

The polyimide solution obtained by the above reaction can be used as it is. Alternatively, the polyimide solution may be poured into a poor solvent to reprecipitate the polyimide and purified before use.
In the present invention, the polyimide means a polyimide in which the polyamic acid is completely imidized, but may contain a polyamic acid that is not partly imidized.

2. (B) Epoxy resin The adhesive of this invention has an epoxy resin other than the said polyimide. Epoxy resin refers to a compound containing an epoxy group in the molecule. The epoxy resin reacts with an amino group, a carboxyl group or a self epoxy group in the polyimide. In particular, when the polyimide has the above-described phenolic hydroxyl group, the epoxy resin can be bonded to the phenolic hydroxyl group. Therefore, the heat resistance of the adhesive is improved. Furthermore, the adhesiveness is improved by the alcoholic hydroxyl group produced by the reaction of the epoxy group.

  Since the epoxy resin is a low molecular weight compound before curing, the glass transition temperature of the entire adhesive can be lowered. Therefore, when the polymer film substrate and the metal foil are bonded, it is possible to bond them at a low temperature.

However, if the glass transition temperature is extremely lowered, problems as described above may occur. Moreover, since polyimide is inherently flame retardant, the polyimide adhesive has flame retardancy. However, since epoxy resins are generally not flame retardant, the flame retardancy of the adhesive decreases when the amount of the epoxy resin in the adhesive increases.
Therefore, the blending amount of the epoxy resin is preferably determined in consideration of low-temperature adhesiveness, heat resistance of the adhesive after curing, flame retardancy of the adhesive, and the like. For the reasons described above, the compounding amount of the epoxy resin is 1 to 30 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polyimide.

  Examples of the epoxy resin include glycidyl ether of bisphenol A, bisphenol S, bisphenol F, phenol novolac type epoxy resin, biphenyl type epoxy compound and the like. Among these, an epoxy resin having 3 or more glycidyl groups in the molecule is preferable. Examples of such epoxy resins include VG3101 manufactured by Mitsui Chemicals, Inc. Epicoat 1031S manufactured by Japan Epoxy Resin Co., Ltd., Epicoat 604, NC3000H manufactured by Nippon Kayaku Co., Ltd., and the like.

  You may mix | blend a hardening | curing agent with an epoxy resin as needed. Examples of the curing agent include an imidazole curing agent, a phenol curing agent, an amine curing agent, and an acid anhydride curing agent. The type and blending amount of the curing agent are preferably selected in consideration of the storage stability of the adhesive.

  Examples of the curing agent having excellent storage stability include a latent curing agent or a curing agent having a long pot life. A latent curing agent is a curing agent that does not exhibit curing activity up to a certain temperature but develops curing activity above a certain temperature. A curing agent having a long pot life means a curing agent that does not undergo a rapid curing reaction even when mixed with an epoxy resin and is heated, and that can be processed for a certain period of time under heating. Examples of such a curing agent include 2MaOK-PW manufactured by Shikoku Kasei Co., Ltd. It is preferable that the compounding quantity of a hardening | curing agent is 0-20 weight part with respect to 100 weight part of epoxy resins.

3. Other Additives The adhesive of the present invention may have a filler. The filler is an inorganic or organic filler added to the resin composition. Examples of the organic filler include those obtained by curing epoxy resin, melamine resin, urea resin, phenol resin and the like into fine particles.
Examples of the inorganic filler include particles such as alumina, aluminum nitride, and silica. The amount of the filler is preferably 0 to 5000 parts by weight and more preferably 0 to 3000 parts by weight with respect to 100 parts by weight of the polyimide. This is because when the adhesive is dissolved in a solvent to form a solution, the filler does not easily settle and storage stability is excellent. In general, if there is too much filler, the adhesiveness of the adhesive may be lowered, but if the filler content is in the above range, the adhesiveness of the adhesive will not be impaired.

  The adhesive of the present invention may contain a coupling agent. The coupling agent is not particularly limited as long as it does not impair the object of the present invention, but is preferably one that dissolves in a solvent used when the adhesive is used as a solution. Examples of such coupling agents include silane coupling agents and titanium coupling agents. The blending amount of the coupling agent is preferably 0 to 50 parts by weight, and more preferably 0 to 30 parts by weight with respect to 100 parts by weight of polyimide. This is because the heat resistance of the adhesive is excellent.

4). Adhesive of the Present Invention The adhesive of the present invention is obtained by mixing the above-mentioned components containing (A) an adhesive polyimide and (B) an epoxy resin as main components. As mentioned above, the mixing ratio of each component takes into consideration the handling properties when used as an adhesive, solder heat resistance when used as a metal laminate, desmear properties, and low-temperature adhesiveness when manufacturing a metal laminate. It is preferable to select them.

  In particular, when the metal laminate is a flexible printed board, higher solder heat resistance is required. The flexible printed board is directly heated when an element or the like is mounted on the board. For this reason, higher solder heat resistance is required as compared with, for example, a metal laminate used in a semiconductor package. In addition, as described above, the flexible printed circuit board is required to have desmearability because microfabrication is possible. High solder heat resistance, desmear property, and low-temperature adhesiveness are greatly affected by the glass transition temperature before curing of the adhesive and the glass transition temperature after curing. Therefore, it is preferable to determine the above-mentioned blending of the adhesive of the present invention in consideration of the glass transition temperatures before and after curing. The glass transition temperature before curing of the adhesive of the present invention is preferably 100 to 200 ° C.

5. Metal laminate using the adhesive of the present invention The metal laminate of the present invention was provided on a polymer film substrate, a cured product layer of an adhesive provided on the substrate surface, and the cured product layer surface. Includes a metal foil layer. The metal laminate is preferably obtained by attaching a metal foil to one or both sides of a polymer film substrate via the adhesive of the present invention.

  The metal laminate of the present invention may be a flexible printed board. A flexible printed circuit board is a metal laminate having flexibility, and refers to an electronic member in which a wiring pattern is provided on a metal foil. The flexible printed board of the present invention preferably has excellent desmear properties while having excellent solder heat resistance.

The solder heat resistance is tested by leaving the metal laminate in a high temperature and high humidity state and then floating (floating) it on the heated solder layer. Specifically, a metal laminate having metal foils on both sides is left for 48 hours at a high temperature and high humidity of 85 ° C./85%, and then floated in a heated solder bath for testing. Excellent solder heat resistance means that defects such as swelling and peeling do not occur in the metal laminate subjected to the above test. For example, when a test is performed in a 340 ° C. solder bath and no defect occurs, the metal laminate is said to have “340 ° C. solder heat resistance”.
The metal laminate of the present invention preferably has solder heat resistance of 340 ° C. or higher when tested under the above conditions.

  The desmear property means that when the resin is brought into contact with a desmear liquid mainly composed of potassium permanganate or sodium permanganate, the part is swollen or dissolved by the desmear liquid and removed. . An excellent desmear property or an easy desmear property means that the resin portion in contact with the desmear liquid is easily removed. Originally, the desmear property is evaluated by immersing the metal laminate in a desmear solution after laser processing. However, in the present invention, an adhesive film is prepared, the film is immersed in a desmear liquid, and evaluated by “weight reduction rate when a resin is immersed in the desmear liquid”.

The desmear property varies depending on the desmear solution used. In the present invention, a desmear solution (Macu9250: MacuDizer9276: ion-exchanged water = 50 g: 50 ml: 1 L) manufactured by Nippon Macder Mid Co., Ltd. is used. The adhesive film prepared to a thickness of 15 μm is immersed in the liquid. Then, the initial weight of the resin and the weight after being immersed for an arbitrary time are measured, and the weight reduction rate is calculated. The adhesive of the present invention preferably has a weight reduction rate of 1.0 to 5.0 μg / cm ² / min.

6). Manufacturing method of metal laminated body The metal laminated body of this invention is manufactured by a well-known method. For example, a resin solution (also simply referred to as “resin solution”) in which the adhesive of the present invention is dissolved in an organic solvent is obtained. The resin solution is cast on one or both sides of a polymer film substrate to form a film precursor on the substrate. Next, the film precursor is heated to evaporate (dry) the solvent to form a film. Then, the said polymer film base material and metal foil are heat-pressed, and are made to adhere.

  Or you may manufacture the metal laminated body of this invention as follows. The resin solution is cast on a substrate such as glass to form a film precursor. The film precursor is heated and then peeled from the glass substrate to obtain an adhesive film. Subsequently, the polymer film substrate, the adhesive film, and the metal foil are superposed in this order and hot pressed to obtain a metal laminate.

  A well-known thing can be used for the solvent used in the process of obtaining the said resin solution. Examples include N, N-dimethylacetamide, N-methyl-2-pyrrolidone, toluene, xylene, mesitylene, phenol, cresol and the like. Among them, the same solvent as used for synthesizing the adhesive polyimide is preferable.

  A known method can be used for casting the resin solution on one or both sides of the polymer film substrate. Examples of this include a flow coating method, a dipping method, a spray method, and the like. In that case, known apparatuses such as a bar coater, a knife coater, a blade coater, a die coater, a comma coater, a roll coater, a gravure coater, a curtain coater, a spray coater, and a spin coater can be used. A similar method can be used when casting the resin solution onto a substrate such as glass.

  A well-known method can also be used for the method of drying the film precursor formed on the polymer film substrate obtained in the above step or the film precursor of the resin solution formed on the glass substrate. Examples include a method using a dryer. Drying can be performed in an atmosphere of air, inert gas (nitrogen, argon), or the like.

  The polymer film substrate on which the adhesive is applied or the polymer film substrate on which the adhesive film is superposed, obtained in the above process, is further overlaid with a metal foil. And these laminated bodies are heat-pressed and a metal laminated body is obtained. The metal laminated body of this invention can perform the said adhesion process at low temperature.

The low-temperature adhesiveness of the adhesive of the present invention is evaluated as follows. The adhesive of the present invention is cast on both surfaces of the polymer film substrate, and copper foil is superimposed on both surfaces. Subsequently, hot pressing is performed. At this time, the pressure and time are fixed at 25 kg / cm ² and 5 minutes, and the laminate is prepared by pressing at various temperatures. The peel strength between the foil / polymer film of the obtained laminate is measured according to PC-TM650 method 2.4.9. The press temperature at which this value is 0.8 kN / m or more is defined as an adherable temperature. Therefore, the low temperature adhesiveness is evaluated based on the bonding possible temperature. In the present invention, the term “low temperature adhesiveness” means that the bonding possible temperature is 200 ° C. or less.

The metal laminate of the present invention preferably has a bondable temperature of 200 ° C. or lower, and more preferably 100 to 200 ° C. However, when the metal laminate is actually manufactured, the heating temperature may be adjusted as appropriate, with the press pressure and the press time being appropriately adjusted.
The metal laminate of the present invention may be post-cured as necessary. Post-curing is preferably performed at 200 ° C. for about 3 hours.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples. Each physical property value of the polyimide in the examples was measured by the following method.
(Logarithmic viscosity measurement)
N-methyl-2-pyrrolidone was added to the polyimide solution obtained by the method shown in the synthesis examples described later to prepare a solution having a concentration of 0.5 g (polyimide solid content) / dl. The logarithmic viscosity of the solution at 35 ° C. was measured using an Ubbelohde viscometer.

(Glass-transition temperature)
A solution containing polyimide as a solute was prepared, and cast on a surface-treated PET film (manufactured by Teijin DuPont Films, Inc., A31, thickness 50 μm) to prepare a film precursor. The said film precursor was heated at 150 degreeC for 20 minute (s), and the polyimide film was obtained on PET film. Next, the PET film was peeled off to obtain a polyimide single layer film having a thickness of 750 μm.
The film was set in solid viscoelasticity measurement (RSA-II, manufactured by Rheometrics), heated while giving a frequency of 10 Hz, storage elastic modulus E ′, loss elastic modulus E ″, tan δ (= E ″ / E ′) The temperature dependence of was measured. The temperature at which tan δ peaked was taken as the glass transition temperature.

(Desmear property)
A single-layer polyimide film having a thickness of 15 μm was produced as described above. Next, the film was immersed in a desmear liquid (Macu9250: MacuDizer9276: ion-exchanged water = 50 g: 50 ml: 1 L) manufactured by Nippon Macder Mid Co., Ltd., and the change with time in weight was measured. The weight reduction rate (μg / cm ² / min) was calculated from the initial weight of the film and the change in weight.

(Polyimide synthesis example 1)
A 500 ml five-neck separable flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a Dean-Stark tube filled with mesitylene was prepared. To this flask, polytetramethylene oxide-di-p-aminobenzoate (Ihara Chemical Industry Co., Ltd., trade name: Elastomer 1000, average molecular weight 1261) 7.93 g (10 mol% in the diamine component); 2,2- 22.00 g of bis [4- (4-aminophenoxy) phenyl] propane (85.2 mol% in the diamine component); 19.50 g of oxy-4,4′-diphthalic dianhydride; N-methyl-2- Pyrrolidone 82 g; mesitylene 35 g was charged. A nitrogen atmosphere was set in the flask, and the mixture was stirred to obtain a uniform solution.

  A nitrogen introduction tube was inserted into the solution (bubbled), and the reaction was carried out at a temperature in the system of 170 ° C. to 180 ° C. while stirring the solution. The reaction was carried out for 10 hours while azeotropically removing water produced during the reaction. The reaction mixture was then cooled and 220 g of dimethylformamide was added. To the reaction mixture, 0.64 g (4.8 mol% in the diamine component) of 4,4′-dimiano-3,3′-dihydroxybiphenyl (manufactured by Wakayama Seika Kogyo Co., Ltd., trade name: HAB) was added. A polyimide solution was obtained by reaction. About the polyimide obtained in this way, logarithmic viscosity and glass transition temperature were measured by the said method. The logarithmic viscosity was 1.3 dl / g, and the glass transition temperature was 172 ° C.

(Polyimide synthesis example 2)
A 500 ml five-necked separable flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a Dean-Stark tube filled with mesitylene was prepared. To this flask, polytetramethylene oxide-di-p-aminobenzoate (Ihara Chemical Industry Co., Ltd., trade name: Elastomer 1000, average molecular weight 1261) 8.97 g (10 mol% in diamine component); 1,3-bis (3-aminophenoxy) benzene 18.00 g (87.2 mol% in diamine component); oxy-4,4′-diphthalic dianhydride 21.93 g; N-methyl-2-pyrrolidone 81 g; mesitylene 35 g It is. The flask was placed in a nitrogen atmosphere and the mixture was stirred to obtain a uniform solution.

  A nitrogen introduction tube was inserted into the solution (bubbled), and the reaction was carried out at a temperature in the system of 170 ° C. to 180 ° C. while stirring the solution. The reaction was carried out for 10 hours while azeotropically removing water produced during the reaction. The reaction mixture was then cooled and 220 g of dimethylformamide was added. To the reaction mixture was added 0.45 g (2.8 mol% in the diamine component) of 4,4′-dimiano-3,3′-dihydroxybiphenyl (manufactured by Wakayama Seika Kogyo Co., Ltd., trade name: HAB). Reaction was performed to obtain a polyimide solution. About the polyimide obtained in this way, logarithmic viscosity and glass transition temperature were measured by the said method. The logarithmic viscosity was 1.3 dl / g, and the glass transition temperature was 157 ° C.

(Polyimide synthesis example 3)
A 500 ml five-neck separable flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a Dean-Stark tube filled with mesitylene was prepared. Polytetramethylene oxide-di-p-aminobenzoate (trade name: Elastomer 1000, average molecular weight 1261) 7.93 g (10 mol% in the diamine component); 2,2-bis [ 4- (4-aminophenoxy) phenyl] propane 22.00 g (85.2 mol% in the diamine component); oxy-4,4′-diphthalic dianhydride 19.50 g; N-methyl-2-pyrrolidone 82 g; 35 g of mesitylene was charged. The inside of the flask was placed in a nitrogen atmosphere, and these mixtures were stirred to obtain a uniform solution.

  A nitrogen introduction tube was inserted into the solution (bubbled), and the reaction was carried out at a temperature in the system of 170 ° C. to 180 ° C. while stirring the solution. The reaction was carried out for 10 hours while azeotropically removing water produced during the reaction. The reaction mixture was then cooled and 220 g of dimethylformamide was added. Subsequently, 0.88 g of 1,3-bis (3-aminophenoxy) benzene (4.8 mol% in the diamine component) was added to the reaction mixture to obtain a polyimide solution reacted with the reaction mixture. About the polyimide obtained in this way, logarithmic viscosity and glass transition temperature were measured by the said method. The logarithmic viscosity was 1.4 dl / g, and the glass transition temperature was 170 ° C.

(Polyimide synthesis example 4)
A 500 ml five-neck separable flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a Dean-Stark tube filled with mesitylene was prepared. Into this flask, 24.00 g of 1,3-bis (3-aminophenoxy) benzene (97 mol% in the diamine component); 26.23 g of oxy-4,4′-diphthalic dianhydride; N-methyl-2- Pyrrolidone 83 g; mesitylene 36 g was charged. The inside of the flask was placed in a nitrogen atmosphere, and these mixtures were stirred to obtain a uniform solution.

  A nitrogen introduction tube was inserted into the solution (bubbled), and the reaction was carried out at a temperature in the system of 170 ° C. to 180 ° C. while stirring the solution. The reaction was carried out for 10 hours while azeotropically removing water produced during the reaction. After the reaction, the reaction mixture was cooled and 220 g of dimethylformamide was added. To the reaction mixture, 4,4′-dimiano-3,3′-dihydroxybiphenyl (manufactured by Wakayama Seika Kogyo Co., Ltd., trade name: HAB) 0.54 g (3 mol% in the diamine component) was added and reacted with the reaction mixture. To obtain a polyimide solution. About the polyimide obtained in this way, logarithmic viscosity and glass transition temperature were measured by the said method. The logarithmic viscosity was 1.2 dl / g, and the glass transition temperature was 180 ° C.

Example 1
The polyimide resin solution obtained in Synthesis Example 1 and the epoxy resin (manufactured by Mitsui Chemicals, VG3101) were sufficiently mixed with a stirrer to obtain an adhesive resin solution. The compounding ratio was 15 parts by weight of epoxy resin with respect to 100 parts by weight of resin (solid content) in the polyimide resin solution. The adhesive resin solution was cast on a surface-treated PET film (manufactured by Teijin DuPont Films, Inc., A31, thickness 50 μm) to prepare a film precursor.

The film precursor was heated at 150 ° C. for 20 minutes and further cured at 200 ° C. for 3 hours. The cured film was peeled from the PET film to obtain a single-layer polyimide film having a thickness of 15 μm.
When the desmear property of the obtained film was evaluated, the weight reduction rate was 2.0 μg / cm ² / min, and it was confirmed that the film had excellent desmear property.

  The adhesive resin solution was cast on both surfaces of a 20 μm-thick polyimide film (manufactured by Toray DuPont, Kapton (registered trademark), glass transition temperature of 300 ° C. or higher). The film was dried at 150 ° C. to obtain a double-sided adhesive film having a 3 μm-thick adhesive layer on both sides.

This double-sided adhesive film is sandwiched between two 12 μm-thick copper foils (F1-WS, manufactured by Furukawa Circuit Foil Co., Ltd.), and press-bonded at 200 ° C. and 25 kg / cm ² for 5 minutes to form a metal laminate. Got. The peel strength between the copper foil / polymer film of the metal laminate was measured according to PC-TM650 method 2.4.9 and found to be 1.1 kN / m. It was confirmed that the adhesive obtained in this example has excellent low-temperature adhesiveness.

  The metal laminate obtained as described above was post-cured by heating at 200 ° C. for 3 hours. The post-cured metal laminate was allowed to stand at 85 ° C./85% high temperature and high humidity for 48 hours, and then floated in a solder bath heated to 340 ° C. to evaluate solder heat resistance at 340 ° C. As a result, it was confirmed that there was no occurrence of blistering or peeling, and excellent solder heat resistance.

(Examples 2 and 3)
A polyimide film and a metal laminate were prepared and evaluated in the same manner as in Example 1 except that the amount of the epoxy resin used in Example 1 was changed as shown in Table 1. The results are shown in Table 1.

Example 4
A polyimide film and a metal laminate were prepared and evaluated in the same manner as in Example 1 except that the polyimide in Example 1 was changed to the polyimide obtained in Synthesis Example 2. The results are shown in Table 1.

(Example 5)
A polyimide film and a metal laminate were prepared and evaluated in the same manner as in Example 1 except that the epoxy resin in Example 1 was changed to NC3000H manufactured by Nippon Kayaku Co., Ltd. The results are shown in Table 1.

(Example 6)
A polyimide film and a metal laminate were prepared and evaluated in the same manner as in Example 1 except that the polyimide in Example 1 was changed to the polyimide obtained in Synthesis Example 3. The results are shown in Table 1.

(Comparative Example 1)
A polyimide film and a metal laminate were prepared and evaluated in the same manner as in Example 1 except that the polyimide in Example 1 was changed to the polyimide obtained in Synthesis Example 4. The results are shown in Table 1.

(Comparative Example 2)
A polyimide film and a metal laminate were prepared and evaluated in the same manner as in Comparative Example 1 except that the epoxy resin in Comparative Example 1 was changed to NC3000H manufactured by Nippon Kayaku Co., Ltd. The results are shown in Table 1.

(Comparative Example 3)
A polyimide film and a metal laminate were evaluated in the same manner as in Example 1 except that no epoxy resin was blended. The results are shown in Table 1.

  From Table 1, it is clear that the adhesive of the present invention can satisfactorily bond the polymer film substrate and the metal foil at 200 ° C. It is also clear that the adhesive of the present invention is excellent in desmearability. Furthermore, it is clear that the metal laminate obtained using the adhesive of the present invention is excellent in solder heat resistance.

  The adhesive for metal laminates of the present invention can bond a substrate and a metal foil at a low temperature, is excellent in heat resistance, and is excellent in desmearability. Therefore, it is useful as an adhesive for metal laminates.

  This application claims priority based on application number JP2006-101532 filed Apr. 3, 2006. All the contents described in the application specification are incorporated herein by reference.

Claims (10)

An adhesive for laminating a polymer film substrate and a metal foil to form a metal laminate,
(A1) The following general formula (1)

(In the formula, n is an integer of 1 to 50, Y is an alkylene group having 2 to 10 carbon atoms, and when n is 2 or more, Y is the same or different group.)
A diamine component containing 5 mol% or more and less than 20 mol% in the diamine component,
(A2) A metal laminate adhesive comprising: a polyimide having a glass transition temperature of 200 ° C. or lower obtained by reacting a tetracarboxylic dianhydride component; and (B) an epoxy resin.   The adhesive for metal laminates according to claim 1, wherein the diamine component (A1) further contains a diamine compound having a phenolic hydroxyl group in the molecule.   The adhesive for metal laminates according to claim 2, wherein the content of the diamine compound having a phenolic hydroxyl group in the molecule is 0.1 to 10 mol% in the total diamine component (A1). The adhesive for metal laminates according to claim 2, wherein the diamine compound having a phenolic hydroxyl group in the molecule includes a compound represented by the following general formula (2), (3) or (4).

(In formulas (2) to (4), Z is each independently a single bond or a divalent organic group.)   The adhesive for metal laminates according to claim 1, wherein the (B) epoxy resin has three or more glycidyl groups in the molecule.   The adhesive for metal laminated bodies of Claim 1 containing 100 weight part of polyimides obtained by making said (A1) and (A2) react, and 1-30 weight part of said (B) epoxy resins.   The adhesive for a metal laminate according to claim 1, wherein the metal foil is a copper foil or a copper alloy foil.   The adhesive for metal laminates according to claim 1, wherein the polymer film substrate is a polyimide film substrate.   The metal laminate adhesive according to claim 1, wherein the metal laminate formed by bonding the polymer film substrate and the metal foil is a flexible printed substrate.   A metal laminate comprising a polymer film substrate, a cured product layer of an adhesive provided on the surface of the substrate, and a metal foil layer provided on the surface of the cured product layer, wherein the adhesive is claimed in claim 1. The metal laminated body which is the adhesive agent of description.