JP2006152015A - Adhesive and flexible printed circuit board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive excellent in migration resistance, adhesiveness and heat resistance to soldering and particularly excellent in adhesion to copper foil and a flexible printed circuit board using the adhesive. <P>SOLUTION: The present invention relates to an adhesive composed of a polyesteramide resin (A) having 100-2,000 equivalent/t acid value and an epoxy compound (B). In the adhesive, the ratio (number of moles of amide bond/numbers of moles of ester bond) of the polyesteramide resin (A) component is preferably 0.03-0.7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adhesive for a printed circuit board excellent in migration resistance, adhesion, and soldering heat resistance, and a flexible printed circuit board using the adhesive.

  In recent years, electronic devices have been increasingly reduced in size and density, and the role of a flexible printed circuit board has become important for mounting components in a narrow space. In recent years, the demand for fine patterns and high performance of flexible printed circuit boards has been increasing, and the adhesive for flexible printed circuit boards has been required to further improve migration resistance and adhesion. In addition, since electronic component mounting responds to environmental problems, the use of lead-free solder (lead-free solder) is increasing. Solder used in the past is eutectic of tin and lead (Sn-Pb) and melting point is 183 ° C. Tin-silver-copper (Sn-Ag-Cu) system is mainly used as lead-free solder. Since the melting point is 217 ° C., higher heat resistance is required for the adhesive for flexible printed circuit boards.

  The flexible printed circuit board is coated with an adhesive solution on at least one of an insulating plastic film such as polyimide film or polyester film and copper foil, and then bonded using a hot press or heated roll device. It is manufactured by combining and further heat-curing. As the adhesive, various combinations having an epoxy resin as a main component have been proposed. For example, an epoxy resin-polyvinyl butyral resin type adhesive composition or an epoxy resin-acrylonitrile butadiene rubber type adhesive composition is used. However, the epoxy resin-polyvinyl butyral resin type adhesive composition is inferior in terms of essential adhesiveness, and the epoxy resin-acrylonitrile butadiene rubber type adhesive composition is inferior in terms of heat resistance. In addition, the adhesive has insufficient migration resistance, which causes problems such as short circuit and discoloration of copper.

  As an adhesive that solves the above problem, Patent Document 1 proposes an adhesive made of a polyurethane resin containing a polyester as a copolymerization component and an epoxy compound. The adhesive has excellent migration resistance and solder heat resistance, but has a problem of poor adhesion to copper foil.

JP-A-11-116930 (Example)

  An object of the present invention is to solve such various problems, and in particular, to provide an adhesive excellent in adhesiveness with a copper foil and a flexible printed board using the adhesive.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-described object can be achieved by using an adhesive composed of a specific polyesteramide resin and an epoxy compound. It came to. That is, this invention relates to the following adhesive agents and the flexible printed circuit board using the same.

(1) An adhesive comprising a polyesteramide resin (A) having an acid value of 100 to 2000 equivalent / t and an epoxy compound (B).

(2) Polyesteramide resin (A) component (number of moles of amide bond / number of moles of ester bond) = 0.03 to 0.7.

(3) An adhesive having an acid value of 100 to 2000 equivalent / t and comprising a resin (C) obtained by urethane-modifying a polyesteramide resin and an epoxy compound (B).

(4) The adhesive according to any one of (1) to (3), wherein the acid value is derived from a carboxyl group and / or a phenolic hydroxyl group.

(5) A flexible printed circuit board using the adhesive according to any one of (1) to (4).

  The present invention relates to an adhesive and a flexible circuit board obtained using the adhesive, and the flexible circuit board produced using the adhesive is excellent in migration resistance, adhesiveness, and solder heat resistance.

  The total of carboxyl groups and / or phenolic hydroxyl groups of the polyesteramide resin as component (A) in the adhesive of the present invention is desirably 100 to 1200 equivalent / t, preferably 300 to 1000 equivalent / t. When the total of carboxyl groups and / or phenolic hydroxyl groups is less than 100 equivalent / t, crosslinking with an epoxy compound is insufficient and solder heat resistance is poor. On the other hand, if it exceeds 1200 equivalents / t, the curing reaction proceeds even at room temperature, resulting in problems such as poor storage stability.

  The polyesteramide resin which is the component (A) in the adhesive of the present invention is a resin containing both an ester bond and an amide bond in the resin. It is desirable that the ratio is (number of moles of amide bond / number of moles of ester bond) = 0.03 to 0.7. If the said calculation result is less than 0.03, the adhesive force with copper foil, SUS, aluminum, and a polyimide film will be inferior, and it will become easy to produce peeling in a base-material interface. On the other hand, if it exceeds 0.7, the moisture absorption rate becomes high and the solder heat resistance after humidification may be inferior.

  The polyesteramide resin as the component (A) in the adhesive of the present invention preferably has an acid value of 100 to 2000 equivalent / t. The method for setting the acid value within this range is not particularly limited. For example, a method in which a polyesteramide resin having a terminal hydroxyl group is polymerized and an acid anhydride is added thereto, or a polyesteramide resin having an unsaturated group introduced therein is polymerized. Examples thereof include a method of polymerizing an acrylic monomer to an unsaturated group, a method using tetracarboxylic dianhydride, a method using dimethylol butanoic acid at the time of urethane modification, and the like.

  As a method for adjusting the acid value in the polyesteramide resin which is the component (A) in the adhesive of the present invention, a phenolic hydroxyl group may be introduced into the resin. The introduction method is not particularly limited, and examples thereof include a method of copolymerizing a basic acid or alcohol containing a phenolic hydroxyl group. Examples of basic acids and alcohols containing phenolic hydroxyl groups include phenolic hydroxyl group-containing dibasic acid components such as 5-hydroxyisophthalic acid, 4,4-bis (4-hydroxyphenyl) valeric acid, p-hydroxyphenylacetic acid, p -Phenolic hydroxyl group-containing monobasic acid components such as hydroxyphenylpropionic acid, 2,6-bis (hydroxymethyl) -4-methylphenol, 2,4-bis (hydroxymethyl) -6-methylphenol phenolic hydroxyl group A glycol component etc. are mentioned. Among these, it is preferable to use 5-hydroxyisophthalic acid because it has an advantage of easy molecular weight adjustment.

  The polyesteramide resin (A) is produced by a polycondensation reaction between a polybasic acid component, a glycol component and a diamine compound, and the basic acid or alcohol containing the phenolic hydroxyl group is used as necessary.

  Examples of the acid component include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 2,2′-diphenyldicarboxylic acid, 4 , 4'-diphenyl ether dicarboxylic acid, adipic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexane Dicarboxylic acid, dimer acid, trimellitic anhydride, pyromellitic anhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, etc. Is mentioned.

  Examples of the glycol component include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4- Butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2 , 4-Trimethyl-1,5-pentanediol, cyclohexanedimethanol, neopentylhydroxypivalate, bisphenol A ethylene oxide adduct and propylene oxide adduct, hydrogenated bisphenol A ethylene oxide Adducts and propylene oxasd adducts, 1,9-nonanedio , 2-methyloctanediol, 1,10-decanediol, 2-butyl-2-ethyl-1,3-propanediol, tricyclodecane dimethanol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. Trivalent or higher polyhydric alcohols such as alcohol and trimethylol propane, trimethylol ethane, pentaerythrito may be used as necessary.

  Examples of the diamine compound include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8 -Aliphatic diamines such as diaminooctane and 1,9-diaminononane, o- (or m-, p-) phenylenediamine, o- (or m-, p-) xylenediamine, 3,3 '-(or 3, 4 ′-) diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3 ′-(or 3,4 ′-) diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,3 ′-(or 3,4 ′ -, 4,4 '-) diaminodiphenyldifluoromethane, 3,3'-(or 3,4'-, 4,4 '-) diaminodiphenylsulfone, 3,3'-( 3,4′-, 4,4 ′-) diaminodiphenyl sulfide, 3,3 ′-(or 3,4′-, 4,4 ′-) diaminodiphenyl ketone, 2,2-bis (3-aminophenyl) ) Propane, 2,2 ′-(3,4′-diaminodiphenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2 -(3,4'-diaminodiphenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 1,3- (or 1,4-) bis (3-aminophenoxy) benzene, , 4-bis (4-aminophenoxy) benzene, 3,3 ′-(1-phenylenebis (1-methylethylidene)) bisaniline, 3,4 ′-(1,4-phenylenebis (1-methyl) Ruethylidene)) bisaniline, 4,4 ′-(1,4-phenylenebis (1-methylethylidene)) bisaniline, 2,2-bis (4- (3-aminophenoxy) phenyl) propane, 2,2-bis ( 4- (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane and the like can be mentioned.

  As the acid anhydride for introducing a carboxyl group into polyesteramide, tetracarboxylic dianhydride is preferable from the viewpoint of molecular weight adjustment. Although it does not specifically limit as tetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, 1,2,3,4-pentatetracarboxylic dianhydride Anhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-1,2-dicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetra Carboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, ethylene glycol bistrimellitate dianhydride, 2,2 ', 3,3'-diphenyltetraca Bon dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, ethylene tetracarboxylic dianhydride, and the like.

  In the adhesive of the present invention, a resin (C) obtained by urethane-modifying a polyesteramide resin may be used. The polyurethane-modified resin (C) can be obtained by reacting a polyesteramide and an isocyanate compound, and if necessary, a short chain glycol (chain extender) may be used. In the case of a urethane-modified resin, as a method for introducing a carboxyl group and / or a phenolic hydroxyl group, a method for synthesizing a polyurethane resin using a polyesteramide having a carboxyl group and / or a phenolic hydroxyl group introduced by the method described above, And a method of synthesizing a polyurethane resin using dimethylolpropionic acid, dimethylolbutanoic acid or the like as a chain extender. If necessary, the former method or the latter method can be used alone, or a method combining the former and the latter can be used.

  As the chain extender, short chain glycols such as dimethylolpropionic acid, dimethylolbutanoic acid and neopentyl glycol can be appropriately selected and used.

  As the isocyanate component, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, 3,3′-dimethoxy -4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-diisocyanate, 4,4'-diisocyanate diphenyl ether, 1,5-xylyl Examples include range isocyanate, 1,3 diisocyanate methylcyclohexane, 1,4-diisocyanate methylcyclohexane, and isophorone diisocyanate.

  The acid value of the resin (C) obtained by urethane-modifying the polyesteramide resin is preferably 100 to 2000 equivalent / t. Preferably it is 300-1000 equivalent / t. When the total of carboxyl groups and / or phenolic hydroxyl groups is less than 100 equivalent / t, crosslinking with an epoxy compound is insufficient and solder heat resistance is poor. On the other hand, if it exceeds 1200 equivalents / t, the curing reaction proceeds even at room temperature, resulting in problems such as poor storage stability.

  The epoxy compound as the component (B) of the present invention is not particularly limited as long as it contains at least two epoxy groups in the molecule. For example, bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol S Diglycidyl ether, bisphenol F diglycidyl ether, cresol novolak glycidyl ether, glycidyl ether type such as phenol novolac, glycidyl ester type such as hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane, Glycidylamine such as metaxylenediamine, hydrogenated metaxylenediamine, or 3,4-epoxycyclohexylmethylcarboxylate , Epoxidized polybutadiene, and alicyclic or aliphatic epoxides such as epoxidized soybean oil. In order to impart flame retardancy, it is effective to use a brominated epoxy compound containing bromine in the above epoxy compound.

  In order to impart flame retardancy to the adhesive of the present invention, it is desirable to add antimony trioxide, aluminum hydroxide or magnesium hydroxide in addition to the brominated epoxy compound. These are preferably blended in an amount of 2 to 10% of the total amount of adhesive from the viewpoint of the balance between flame retardancy and adhesiveness.

  The adhesive of the present invention can be appropriately mixed with a catalyst for the purpose of accelerating the curing reaction during heating. In particular, in the reaction between a polyester resin containing a phenolic hydroxyl group and an epoxy compound, it is desirable to add a curing catalyst. Curing catalysts include imidazole compounds such as 2-methylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, triethylamine, triethylenediamine, N '-Methyl-N- (2-dimethylaminoethyl) piperazine, 1,8-diazabicyclo [5.4.0] undecene (hereinafter abbreviated as DBU), 1,5-diazabicyclo [4.3.0] -nonene, Tertiary amines such as 6-dibutylamino-1,8diazabicyclo [5.4.0] undecene, and compounds obtained by converting these tertiary amines into amine salts with phenol, octylic acid or quaternized tetraphenylborate salts, Allylsulfonium hexafluoroantimonate or diallyl iodonium hexafluoro Cationic catalyst such antimonate, triphenyl phosphine. Of these, tertiary amines such as DBU and compounds obtained by converting tertiary amines to amine salts with phenol, octylic acid, or the like or quaternized tetraphenylborate salts are preferred from the viewpoints of thermosetting acceleration and storage stability.

  In the adhesive of the present invention, silica, a silane coupling agent, alumina, talc, montmorillonite or the like may be used alone or in combination of two or more for the purpose of improving heat resistance and metal adhesion.

  A flexible printed circuit board is manufactured by applying and drying an adhesive solution to at least one of an insulating film or a metal foil, and then bonding the two together using a heating press or a heating roll device, followed by heat curing. it can.

  In order to describe the present invention in more detail, examples are given below, but the present invention is not limited to the examples. In addition, the measured value described in the Example is measured by the following method. In the examples, “parts” means “parts by mass”.

Composition: ¹ H-NMR analysis was carried out using a Varian nuclear magnetic resonance analyzer (NMR) Gemini-200 in deuterated chloroform solvent.

  Number average molecular weight: Calculated from the results of GPC measurement at a column temperature of 35 ° C. and a flow rate of 1 ml / min using Waters Gel Permeation Chromatography (GPC) 150c with tetrahydrofuran as an eluent. Measurements were obtained. However, Showa Denko Co., Ltd. shodex KF-802, 804, 806 was used for the column.

  Glass transition temperature: 5 mg of sample was placed in an aluminum sample pan and sealed, and the differential scanning calorimetry (DSC) DSC-220 manufactured by Seiko Instruments Inc. was used to increase the temperature up to 200 ° C. at a heating rate of 20 ° C./min. And measured at the temperature of the intersection of the base line extension below the glass transition temperature and the tangent indicating the maximum slope at the transition.

  Acid value: 0.2 g of resin was dissolved in 20 ml of chloroform and neutralized with 0.1 N KOH ethanol solution using phenolphthalein as an indicator to determine the acid value (equivalent / t) per ton of resin.

  Ratio of amide bond / ester bond: Determined by dividing the molar ratio of the diamine compound by the molar ratio of the glycol compound from the composition of the polyesteramide determined by NMR.

<Synthesis example 1 of polyester polyol>
In a reaction vessel equipped with a stirrer, a thermometer, and an outflow cooler, 115 parts of dimethyl terephthalate, 155 parts of dimethyl isophthalate, 139 parts of ethylene glycol, 142 parts of neopentyl glycol and 0.07 part of tetrabutyl titanate are added, The transesterification was carried out at 160 ° C to 230 ° C for 3 hours. Next, 121 parts of sebacic acid and 27 parts of m-xylenediamine were added and reacted at 230 ° C. for 2 hours. Next, the pressure was reduced to 5 mmHg over 20 minutes at 250 ° C., and further a polycondensation reaction was performed over 30 minutes under a high vacuum of 0.3 mmHg or less. Subsequently, the pressure was returned to normal pressure using nitrogen gas, the reaction system temperature was lowered to 210 ° C., 3.8 parts of trimellitic anhydride was added, and the reaction was continued for 30 minutes to obtain a polyester resin (A-1). . A polyesteramide resin (A-1) was obtained. The number average molecular weight was 15000 and the glass transition temperature was 21 ° C. The composition of the polyesteramide resin determined by NMR is such that the total of glycol is 90 mol% with respect to 10 mol% of m-xylenediamine, and the amide bond / ester bond is 0.11.

<Synthetic Examples 2 to 4 of Polyester Polyol>
Polyester polyols (A-2) to (A-4) were synthesized in the same manner as in “Polyester polyol synthesis example 1”. However, the polyester polyol (A-3) was synthesized without post-addition reaction of trimellitic anhydride. These resin compositions and characteristic values are shown in Table 1.

<Synthesis Example 1 of Polyurethane Resin Modified with Polyesteramide Resin>
In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a distillation tube, 100 parts of polyester polyol (A-1) was dissolved in 67 parts of toluene, azeotroped and 34 parts of toluene was distilled off. Subsequently, 34 parts of methyl ethyl ketone were added. Subsequently, after adding 9 parts of dimethylolbutanoic acid at 60 ° C. and stirring for 20 minutes, 7.5 parts of 1,6-hexamethylene diisocyanate and 0.02 part of dibutyltin laurate are added, and stirred at 80 ° C., followed by urethane polymerization. Went. After confirming that the remaining isocyanate groups were consumed, 54 parts of methyl ethyl ketone and 54 parts of toluene were added to adjust the solid content concentration to 40%. The polyurethane resin (B-1) had a number average molecular weight of 30,000, a carboxyl group concentration of 630 equivalent / t, and a glass transition temperature of 24 ° C.

<Synthesis Examples 2 and 3 of Polyurethane Resin Modified with Polyesteramide Resin>
Polyurethane resins (B-2) to (B-3) were obtained in the same manner as in “Synthesis Example 1 of Polyurethane Resin Modified with Polyesteramide Resin”. These resin compositions and characteristic values are shown in Table 2.

<Comparative Examples 1-2 of Comparative Polyurethane Resin>
Comparative polyurethane resins (C-1) to (C-2) were obtained in the same manner as in “Synthesis Example 1 of Polyurethane Resin Modified with Polyesteramide Resin”. These resin compositions and characteristic values are shown in Table 3. Since (C-1) has an acid value of less than 100 equivalents / t and (C-2) does not contain an amide bond, these urethane resins are outside the scope of the present invention.

<Synthesis example 1 of polyesteramide resin containing phenolic hydroxyl group>
In a reaction vessel equipped with a stirrer, a thermometer, and an outflow cooler, 76 parts of terephthalic acid, 76 parts of isophthalic acid, 26 parts of sebacic acid, 46 parts of 5-hydroxyisophthalic acid, 1.3 parts of trimellitic anhydride, Add 89 parts of ethylene glycol, 187 parts of 1,9-nonanediol, 18 parts of m-xylenediamine and 0.02 part of tetrabutyl titanate, gradually raise the temperature to 230 ° C. over 4 hours, and use the distilled water as the system. The esterification was carried out while removing it outside. Next, the pressure was reduced to 5 mmHg over 20 minutes at 250 ° C., and further a polycondensation reaction was performed under a high vacuum of 0.3 mmHg or less over 30 minutes to obtain a polyesteramide resin (D-1). The number average molecular weight was 17,000 and the glass transition temperature was 8 ° C.

<Synthesis example 2-4 of polyesteramide resin containing phenolic hydroxyl group>
Polyesteramide resins (D-2) to (D-4) were synthesized in the same manner as in “Synthesis example 1 of polyesteramide resin containing phenolic hydroxyl group”. These compositions and characteristic values are shown in Table 4.

<Comparative polyester resin synthesis examples 1 and 2>
Polyester resins (E-1) to (E-2) were synthesized in the same manner as in “Synthesis example 1 of polyesteramide resin containing phenolic hydroxyl group”. These compositions and characteristic values are shown in Table 5. These resins are outside the scope of the present invention because (E-1) does not contain a phenolic hydroxyl group and (E-2) does not contain an amide bond.

<Synthesis example of polyester resin modified with acid anhydride>
In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a distillation tube, 100 parts of polyester polyol (A-4) was dissolved in 67 parts of toluene, azeotroped and 14 parts of solvent was distilled off. Subsequently, after adding 5.4 parts of hydroxypivalate neopentyl glycol at 80 ° C. and stirring for 20 minutes, 11 parts of benzophenone tetracarboxylic dianhydride and 0.53 parts of triethylamine were added, and the mixture was stirred at 110 ° C. The polyester resin (F-1) was obtained by modification with a product. The polyester resin (F-1) had a number average molecular weight of 30000, a carboxyl group concentration of 680 equivalent / t, and a glass transition temperature of 34 ° C.

<Example 1>
To 100 parts of the polyurethane resin obtained in Synthesis Example 1 of polyurethane resin, 8 parts of BREN-S (brominated phenol novolac type epoxy compound) manufactured by Nippon Kayaku Co., Ltd., YDB- manufactured by Toto Kasei Co., Ltd. are used as epoxy compounds. 400 parts (brominated bisphenol A type epoxy compound) 400 parts, Japan Epoxy Resin Co., Ltd. EP5051 (brominated bisphenol A type epoxy compound) 15 parts are dissolved in methyl ethyl ketone so that the solid content concentration is 30%. Then, 6 parts of antimony trioxide was added and sufficiently stirred to obtain an adhesive solution. The obtained adhesive was evaluated by the method shown below. The results are shown in Table 6.

The FPC for migration resistance test was prepared and tested as follows.
The adhesive solution was applied to a 25 μm polyimide film so that the thickness after drying was 30 μm, and dried at 120 ° C. for 3 minutes. When the adhesive film thus obtained is bonded to a 30 μm rolled copper foil, the acid-treated surface of the rolled copper foil is in contact with the adhesive so that the pressure is maintained at 140 ° C. under a pressure of 5 kg / cm ² for 1 minute. Pressed and glued. The obtained adhesion sample was heat-treated at 150 ° C. for 4 hours to be cured. In this way, a copper-clad laminate was obtained. Using this copper-clad laminate, apply a photoresist to the copper foil surface, pattern exposure, development, copper foil pattern etching, and photoresist stripping process to create a pattern substrate so that the distance between the copper wires is 0.1 mm. did.

Moreover, the said adhesive agent solution was apply | coated to the polyimide film of 25 micrometers so that the thickness after drying might be set to 30 micrometers, and it dried at 120 degreeC for 3 minutes. This film was heat-treated at 140 ° C. for 2 hours to obtain a cover film for a flexible printed wiring board. The cover film and the patterned substrate were pressed and bonded at 140 ° C. under a pressure of 5 kg / cm ² for 1 minute. This sample was heat-treated at 170 ° C. for 3 hours to obtain a target sample. The conductivity test of the migration resistance test FPC thus obtained was conducted.

(Conditions) Temperature 85 ° C., Humidity 85%, DC 100V, 1000 hours (Test result judgment) ○: No short circuit, no discoloration
×: Causes short circuit or discoloration

A sample for test of solder resistance and peel strength and a test method were performed as follows.
The adhesive solution was applied to a 25 μm polyimide film so that the thickness after drying was 30 μm, and dried at 120 ° C. for 5 minutes. When the adhesive film obtained in this manner is bonded to a 30 μm rolled copper foil, the acid-treated surface of the rolled copper foil is in contact with the adhesive, and the pressure is maintained at 140 ° C. under a pressure of 5 kg / cm ² for 30 seconds. Pressed and glued. The obtained adhesive sample was cured by heat treatment at 140 ° C. for 4 hours.

(Condition and test result judgment)
Solder resistance Normal state: The sample was dried at 120 ° C. for 30 minutes, then immersed in a heated solder bath for 1 minute, and the upper limit temperature at which no swelling occurred was measured. Higher measured values indicate better heat resistance.
Humidification: The sample was allowed to stand at 40 ° C. and 80% humidification for 1 day, then immersed in a heated solder bath for 1 minute, and the upper limit temperature at which swelling did not occur was measured. A higher measured value indicates better heat resistance.
Those indicated as NG in the table indicate that swelling has already occurred at the melting temperature of the solder, and the heat resistance is very poor.
Peel strength In a 25 ° C. and 80 ° C. atmosphere, a 90 ° peel test was performed at a pulling speed of 50 mm / min.

  In Examples 2 to 10 and Comparative Examples 1 to 5, in the same manner as in Example 1, an adhesive was prepared using a polyurethane resin or a polyester resin, and samples were manufactured and evaluated. The evaluation results of the examples are shown in Table 6, and the evaluation results of the comparative examples are shown in Table 7.

Comparative Example 6: Nipol 1072J (nitrile butylene rubber) manufactured by Nippon Zeon Co., Ltd. 25 parts, 20 parts of BREN-S, 20 parts of YDB400, 30 parts of YD014 (bisphenol A type epoxy compound) manufactured by Toto Kasei Co., Ltd., benzophenone tetra Carboxylic dianhydride 5 parts, Shin Nippon Rika Co., Ltd. Rikacid TMTA-C (acid anhydride compound) 4 parts, Shikoku Fine Chemicals Co., Ltd. C ₁₁ Z-AZINE (imidazole catalyst) 0.5 parts , 0.5 parts of 2PHZ-CN (imidazole catalyst) manufactured by Shikoku Fine Chemicals Co., Ltd. and 30 parts of aluminum hydroxide value using methyl ethyl ketone were dissolved to a solid content concentration of 30% to obtain an adhesive solution. It was. Evaluation similar to Example 1 was performed using the adhesive solution thus obtained. The results are shown in Table 7.

YDCN703: Toto Kasei Co., Ltd., o-cresol novolac type epoxy compound UCAT-5002: San Apro Co., Ltd. 1,8 diazabicyclo (5,4,0) -undecene tetraphenylborate salt coronate L: Nippon Polyurethane Trimethylolpropane modified product of tolylene diisocyanate, manufactured by

  According to the Example of Table 6, it turns out that the adhesive agent of this invention is excellent in migration resistance, adhesiveness, and heat resistance. On the other hand, in Comparative Example 1, since the isocyanate compound is used as the curing agent instead of the epoxy compound, the heat resistance is lowered and the solder resistance is inferior. In Comparative Examples 2 and 4, since the urethane resin or the polyester resin does not have a carboxyl group or a phenolic hydroxyl group, curing with an epoxy resin is insufficient, and solder resistance is lowered. In Comparative Examples 3 and 5, since the amide bond is not included in the polyester resin, the adhesion with the copper foil is lowered and the adhesiveness is inferior. Moreover, in the comparative example 6, it is an epoxy resin-nitrile butylene rubber system conventionally used, and it is inferior to migration resistance compared with this invention adhesive agent.

  Since the adhesive of the present invention is excellent in migration resistance, adhesiveness, and solder heat resistance, it can be effectively used as an adhesive for flexible printed circuit boards.

Claims (5)

  An adhesive comprising a polyesteramide resin (A) having an acid value of 100 to 2000 equivalent / t and an epoxy compound (B).   2. The adhesive according to claim 1, wherein (mole number of amide bond / mole number of ester bond) of the component of polyester amide resin (A) is 0.03 to 0.7.   An adhesive having an acid value of 100 to 2000 equivalent / t and comprising a resin (C) obtained by urethane-modifying a polyesteramide resin and an epoxy compound (B).   The adhesive according to any one of claims 1 to 3, wherein the acid value is derived from a carboxyl group and / or a phenolic hydroxyl group.   The flexible printed circuit board using the adhesive agent in any one of Claims 1-4.