JP7156267B2 - Carboxylic acid group-containing polyester adhesive composition - Google Patents

Description

The present invention provides an adhesive composition, an adhesive sheet, and a printed wiring board containing the same as a component, which are excellent in adhesion to various plastic films, metals such as copper, aluminum, and stainless steel, and glass epoxy, solder resistance, and sheet life. It is about.

In recent years, adhesives have been used in various fields, but due to the diversification of the purpose of use, the adhesives that have been used in the past have improved their adhesion to various plastic films, metals, glass epoxy, etc., and their resistance to moisture and heat. Further improvement in performance is required. For example, adhesives for circuit boards such as flexible printed wiring boards (hereinafter sometimes abbreviated as FPC) are required to have adhesive properties, workability, electrical properties, and storage stability. Conventionally, epoxy/acrylic butadiene adhesives, epoxy/polyvinyl butyral adhesives, and the like have been used for this purpose.

In recent years, in particular, there has been a demand for adhesives having a higher degree of heat resistance in view of the need for lead-free soldering and the environment in which FPCs are used. In addition, high wiring density, multi-layer FPC wiring boards, and workability have led to strong demands for resistance to soldering under high humidity conditions. In order to solve these problems, a resin composition for an adhesive is disclosed which contains a specific polyester or polyester-polyurethane and an epoxy resin as main components. However, these compositions have poor pot life after blending and sheet life after coating and drying, and may be difficult to distribute at room temperature (for example, Patent Documents 1 and 2).

JP 2010-84005 A JP 2009-096939 A

The object of the present invention is to solve the problems associated with these conventional adhesives, and to maintain good adhesion to various plastic films, metals such as copper, aluminum and stainless steel, and glass epoxy. Another object of the present invention is to provide a carboxylic acid group-containing polyester-based adhesive composition which is excellent in resistance to humidity and heat (solder resistance) and which is excellent in sheet life and can be used for lead-free soldering under high humidity.

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

An adhesive composition containing a carboxylic acid group-containing polyester resin (A) and a compound (B) having two or more glycidyl groups in the molecule, wherein the carboxylic acid group-containing polyester resin (A) has a glass transition temperature ( Tg) of 40 to 90° C., an acid value of 1 to 30 mgKOH/g, and a polymer polyol (A1) as a copolymer component, a polymer polyol (A2) different from the polymer polyol (A1), and a tetracarboxylic acid An adhesive composition comprising an acid dianhydride.

The polymeric polyol (A1) and/or the polymeric polyol (A2) are preferably polyester polyols.

An adhesive sheet containing a cured product of the adhesive composition. A printed wiring board comprising the adhesive sheet as a component.

The carboxylic acid group-containing polyester adhesive composition of the present invention maintains good adhesion to various plastic films, metals such as copper, aluminum, and stainless steel, and glass epoxy, and is lead-free under high humidity. It has excellent heat and humidity resistance (solder resistance) that can be used for soldering, and has excellent sheet life.

<Polymer polyol (A1)>
Although the glass transition temperature of the polymer polyol (A1) is not particularly limited, it is preferably 0°C or higher, more preferably 5°C or higher. If the glass transition temperature is too low, the tackiness of the adhesive composition becomes strong, and air bubbles are likely to be entrapped during lamination, resulting in defects. Also, it is preferably 90°C or lower, more preferably 80°C or lower, and still more preferably 75°C. If the glass transition temperature is too high, the coating film becomes brittle, and there is a concern that brittleness will become a problem or the adhesion to the substrate will be insufficient.

Although the acid value (mgKOH/g) of the polymer polyol (A1) is not particularly limited, it is preferably 0.1 or more, more preferably 0.3 or more, and still more preferably 1 or more. If it is too small, the cross-linking will be insufficient, and the resistance to moist heat may be lowered. Also, it is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. If it is too large, acid addition chain extension by tetracarboxylic dianhydride may not be possible. As a result, the crosslink density increases and the coating film obtained from the adhesive composition becomes hard, which tends to reduce the adhesion.

Although the number average molecular weight (Mn1) of the polymer polyol (A1) is not particularly limited, it is preferably 10,000 or more, more preferably 11,000 or more, still more preferably 12,000 or more. When the Mn1 is less than 10,000, the crosslink density becomes high and the coating film obtained from the adhesive composition becomes hard, so that the adhesive strength tends to decrease. In addition, since it becomes difficult to relax the stress of water vapor generated during humidification-resistant soldering, the humidification-resistant soldering property tends to deteriorate. Also, Mn1 is preferably 50,000 or less, more preferably 40,000 or less, and even more preferably 30,000 or less. If it is too large, the cross-linking may be insufficient and the heat resistance may be lowered. The number average molecular weight (Mn1) of the polymer polyol (A1) is preferably larger than the number average molecular weight (Mn2) of the polymer polyol (A2) and the molecular weight of the tetracarboxylic dianhydride. A maximum is more preferred.

<Polymer polyol (A2)>
Polymeric polyol (A2) is a polyol different from polymeric polyol (A1). “Different from the polymer polyol (A1)” means that at least either composition or physical properties are different. The number average molecular weight (Mn2) of the polymer polyol (A2) is preferably 1,000 or more, more preferably 1,500 or more. If it is less than 1,000, the high molecular weight polyol (A2) tends to form a bond with itself, which tends to result in a low molecular weight and a high acid value, and there is a concern that the coating film becomes fragile and embrittlement becomes a problem. Also, it is preferably less than 10,000, more preferably 8,000 or less, even more preferably 7,000 or less, and particularly preferably 5,000 or less. If it is 10,000 or more, the acid addition chain extension by the tetracarboxylic dianhydride may not be possible.

The difference between the number average molecular weight (Mn1) of the polymer polyol (A1) and the number average molecular weight (Mn2) of the polymer polyol (A2) is not particularly limited, but is preferably 2,000 or more, more preferably It is 3,000 or more, more preferably 4,000 or more. By providing the difference in molecular weight, the compatibility and solder resistance of the carboxylic acid group-containing polyester resin (A) can be improved. That is, by increasing the molecular weight of one of the polymer polyols (A1) and (A2) as long-chain blocks, the stress generated during evaluation of solder resistance can be alleviated. Moreover, since the amount of carboxylic acid groups can be adjusted by making the other a short-chain block, solder resistance can be imparted. Thereby, an improvement in solder resistance can be achieved. Although the upper limit of the difference in molecular weight is not particularly limited, it is preferably 40,000 or less, more preferably 30,000 or less, and still more preferably 20,000 or less.

Although the acid value (mgKOH/g) of the polymer polyol (A2) is not particularly limited, it is preferably 0.1 or more, more preferably 0.3 or more, and still more preferably 1 or more. If it is too small, the solder resistance may be inferior. Also, it is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. If it is too high, acid addition chain extension by tetracarboxylic dianhydride may not be possible.

Although the glass transition temperature of the polymer polyol (A2) is not particularly limited, it is preferably -20°C or higher, more preferably -10°C or higher, still more preferably 0°C or higher, and even more preferably 10°C. above, particularly preferably 20° C. or higher, most preferably 30° C. or higher. If the glass transition temperature is too low, the tackiness of the adhesive composition tends to increase, and air bubbles tend to be trapped during lamination, resulting in defects. Also, it is preferably 80° C. or lower, more preferably 70° C. or lower. If the glass transition temperature is too high, the coating film becomes brittle, and embrittlement may become a problem.

Polymer polyol (A1) and/or polymer polyol (A2) are not particularly limited, but are preferably polyester polyols.

<Polyester polyol>
The polyester polyol is preferably composed of a polycarboxylic acid component and a polyol component. The polycarboxylic acid component constituting the polyester polyol preferably contains 60 mol % or more of aromatic dicarboxylic acid when the total polycarboxylic acid is 100 mol %. It is more preferably 70 mol % or more, still more preferably 80 mol % or more, and may be 100 mol %. If the amount is too small, the cohesive force of the coating film becomes weak, and the adhesive strength to various substrates may decrease.

The aromatic dicarboxylic acid is not particularly limited, and includes terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and diphenic acid. In addition, aromatic dicarboxylic acids having a sulfonic acid group such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5(4-sulfophenoxy)isophthalic acid, and aromatic dicarboxylic acids having sulfonate groups such as metal salts and ammonium salts thereof. These can be used alone or in combination of two or more. Among them, terephthalic acid, isophthalic acid, and mixtures thereof are particularly preferred because they increase the cohesion of the coating film.

Other polycarboxylic acid components include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and their acid anhydrides, succinic acid and adipic acid. , azelaic acid, sebacic acid, dodecanedioic acid, dimer acid and the like. In addition, 5-hydroxyisophthalic acid, p-hydroxybenzoic acid, p-hydroxyphenyl alcohol, p-hydroxyphenylpropionic acid, p-hydroxyphenylacetic acid, 6-hydroxy-2-naphthoic acid, 4,4-bis(p An oxycarboxylic acid compound having a hydroxyl group and a carboxyl group in the molecular structure such as -hydroxyphenyl)valeric acid can also be used.

As the polyol component constituting the polyester polyol, the glycol component is preferably 90 mol% or more, more preferably 95 mol% or more, more preferably 100 mol% when the total polyol is 100 mol%. I don't mind.

The glycol component is preferably an aliphatic glycol, an alicyclic glycol, an aromatic-containing glycol, or an ether linkage-containing glycol. Examples of aliphatic glycols include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5- Pentanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol (DMH), hydroxypivalic acid neopentyl glycol ester, dimethylolheptane, 2,2,4-trimethyl-1,3-pentanediol and the like. Examples of alicyclic glycols include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, tricyclodecanediol, tricyclodecanedimethylol, spiroglycol, hydrogenated bisphenol A, and hydrogenated bisphenol A. Ethylene oxide adducts, propylene oxide adducts, and the like can be mentioned. Examples of ether bond-containing glycols include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol ethylene oxide adduct, neopentyl glycol propylene oxide adduct. mentioned. Examples of aromatic-containing glycols include para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, ethylene oxide adducts of 1,4-phenylene glycol, bisphenol A, and ethylene oxide addition of bisphenol A. Examples include glycols obtained by adding 1 to several moles of ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, such as bisphenols and propylene oxide adducts. These can be used alone or in combination of two or more. Among them, aliphatic glycols are preferred, and ethylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, or 1,6-hexanediol is more preferred.

For the purpose of introducing a branched skeleton into the polyester polyol, if necessary, the polycarboxylic acid component and/or the polyol component may be copolymerized with a tri- or higher functional component. In the case of copolymerization, the amount is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, and preferably 5 mol% or less, based on 100 mol% of all polycarboxylic acid components and all polyol components, respectively. mol % or less is more preferable. By setting it within the above range, especially when producing a cured coating film by reacting with a curing agent, a branched skeleton can be introduced, the terminal group concentration (reaction point) of the resin increases, the crosslink density is high, and the strength is high. A good coating film can be obtained. On the other hand, if it exceeds 5 mol %, the mechanical properties such as the elongation at break of the coating film may be lowered, and gelation may occur during polymerization.

Examples of tri- or more functional polycarboxylic acid components include trimellitic acid, trimesic acid, ethylene glycol bis (anhydro trimellitate), glycerol tris (anhydro trimellitate), trimellitic anhydride, pyromellitic anhydride. (PMDA), oxydiphthalic dianhydride (ODPA), 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,3′,4,4′-diphenyltetracarboxylic dianhydride (BPDA), 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4′-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), 2,2 and compounds such as '-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA). On the other hand, examples of tri- or more functional polyols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like.

An acid value may be introduced into the polyester polyol. The acid value of the polyester polyol is preferably 10 mgKOH/g or less, more preferably 8 mgKOH/g or less. If it is too high, acid addition chain extension by tetracarboxylic dianhydride may not be possible. Moreover, 0.1 mgKOH/g or more is preferable, and 0.3 mgKOH/g or more is more preferable. If it is too low, the cross-linking will be insufficient, and the resistance to moist heat may be lowered.

A method of introducing an acid value includes a method of introducing a carboxylic acid into a polyester polyol by acid addition after polymerization. If a monocarboxylic acid, dicarboxylic acid, or tri- or more functional polycarboxylic acid compound is used for acid addition, the molecular weight may decrease due to transesterification, so a compound having at least one carboxylic anhydride group should be used. preferable. Carboxylic anhydrides include succinic anhydride, maleic anhydride, orthophthalic acid, 2,5-norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride (PMDA), and oxydiphthalic dianhydride. (ODPA), 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,3′,4,4′-diphenyltetracarboxylic dianhydride (BPDA), 3,3 ',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), 2,2'-bis[(dicarboxyphenoxy ) phenyl]propane dianhydride (BSAA) and the like.

<Tetracarboxylic dianhydride>
Tetracarboxylic dianhydrides include aromatic tetracarboxylic dianhydrides, aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides, with aromatic tetracarboxylic dianhydrides being preferred. Specifically, for example, pyromellitic anhydride (PMDA), oxydiphthalic dianhydride (ODPA), 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,3′, 4,4'-diphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-(hexafluoroisopropylidene)diphthal Acid dianhydride (6FDA) and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA) can be mentioned, and these can be used alone or in combination of two or more. Among them, pyromellitic anhydride is preferred.

<Carboxylic Acid Group-Containing Polyester Resin (A)>
The glass transition temperature of the carboxylic acid group-containing polyester resin (A) of the present invention must be 40°C or higher. It is preferably 45° C. or higher, more preferably 50° C. or higher. If the glass transition temperature is too low, the tackiness of the adhesive composition becomes strong, and air bubbles are likely to be entrapped during lamination, resulting in poor performance and short sheet life. Moreover, it is required that the temperature is 90° C. or less. It is preferably 85° C. or lower, more preferably 80° C. or lower. If the glass transition temperature is too high, the coating film becomes brittle, and embrittlement may become a problem.

The acid value of the carboxylic acid group-containing polyester resin (A) of the present invention must be 1 mgKOH/g or more. It is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more. Moreover, it is necessary to be 30 mgKOH/g or less. It is preferably 28 mgKOH/g or less, more preferably 25 mgKOH/g or less. If the acid value is too small, sufficient solder resistance may not be obtained due to insufficient cross-linking. . Moreover, the storage stability of the varnish obtained by dissolving the carboxylic acid group-containing polyester resin (A) in a solvent is lowered, and the cross-linking reaction tends to proceed at room temperature, and a stable sheet life may not be obtained.

The carboxylic acid group-containing polyester resin (A) is a resin containing the polymer polyol (A1), polymer polyol (A2) and tetracarboxylic dianhydride as copolymer components. Preferably, the number average molecular weight (Mn3) of the carboxylic acid group-containing polyester resin (A) is 1.7 times or less the number average molecular weight (Mn1) of the polymer polyol (A1). That is, Mn3/Mn1≤1.7. More preferably, it is 1.6 times or less. If it exceeds 1.7 times, it is considered that the difference in molecular weight is small or the amount of tetracarboxylic dianhydride is excessive. Therefore, the content of carboxylic acid groups in the carboxylic acid group-containing polyester resin (A) is insufficient, resulting in a decrease in solderability, and the elastic modulus of the cured coating film becomes too high, resulting in a decrease in adhesiveness. The lower limit of Mn3/Mn1 is preferably 0.8 times or more, more preferably 0.9 times or more, and still more preferably 1.0 times or more. If it is too small, the reaction between the polymer polyol (A2) and the chain extender (tetracarboxylic dianhydride) may occur frequently, so the block of the polymer polyol (A1) is sufficiently carboxylic dianhydride. It does not react with objects and may result in insufficient solder resistance. In addition, the carboxylic acid group-containing polyester resin (A) is within the range of the above number average molecular weight (Mn3/Mn1), a resin of only the polymer polyol (A1) and the carboxylic acid dianhydride, or a polymer polyol ( A2) and a resin containing only a carboxylic acid dianhydride may be included.

The copolymerization ratio of the polymer polyol (A1) and the polymer polyol (A2) in the carboxylic acid group-containing polyester resin (A) is that the polymer polyol (A2) is It is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 20 parts by mass or more. Also, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less. The number of ends that can react with substances decreases, and heat resistance may be insufficient.

The copolymerization ratio of the polymer polyol (A1) and the tetracarboxylic dianhydride in the carboxylic acid group-containing polyester resin (A) is 0 parts by mass of the tetracarboxylic dianhydride per 100 parts by mass of the polymer polyol (A1). It is preferably at least 0.5 parts by mass, more preferably at least 1 part by mass, and even more preferably at least 2 parts by mass. Also, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and still more preferably 5 parts by mass or less. becomes hard and sufficient adhesion may not be obtained.

The copolymerization amount of the polymer polyol (A1) in the carboxylic acid group-containing polyester resin (A) is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 50% by mass or more. be. By increasing the copolymerization amount of the polymer polyol (A1), an improvement in wet soldering resistance can be expected. Also, it is preferably 90% by weight or less, more preferably 85% by weight or less, and even more preferably 80% by weight or less. If it is too large, the copolymerization amount of the polymer polyol (A2) or tetracarboxylic dianhydride may decrease, and the solder resistance and adhesiveness may decrease.
The method for producing the carboxylic acid group-containing polyester resin (A) is not particularly limited, but solution polymerization or melt polymerization is preferred, and solution polymerization is more preferred.

<Epoxy resin (B)>
The epoxy resin (B) is not particularly limited as long as it undergoes a curing reaction with the carboxyl groups of the carboxylic acid group-containing polyester resin (A) and crosslinks, but it is a polyfunctional epoxy resin having multiple epoxy groups in one molecule. Preferably. By using a polyfunctional epoxy resin, the cured coating film obtained from the adhesive composition can easily form three-dimensional crosslinks and can be improved in heat resistance. Examples of polyfunctional epoxy resins include cresol novolak type epoxy resins, epoxy resins having a dicyclopentadiene skeleton, and phenol novolac type epoxy resins. A cresol novolak type epoxy resin or a phenol novolak type epoxy resin can reduce the crosslink density of the cured coating film and relax the stress at the time of peeling, thereby improving the solder resistance. Examples of commercially available cresol novolac type epoxy resins include YDCN-700 manufactured by DIC. On the other hand, when the epoxy resin has a dicyclopentadiene skeleton, the dicyclopentadiene skeleton is rigid, so the hygroscopicity of the cured coating film becomes extremely low, and the crosslink density of the cured coating film is lowered, thereby reducing the stress during peeling. can be alleviated. Therefore, solder resistance is improved. Commercially available epoxy resins having a dicyclopentadiene skeleton include HP7200 series manufactured by DIC. These can be used alone or in combination of two or more.

Furthermore, in addition to the polyfunctional epoxy resins described above, epoxy resins containing nitrogen atoms can also be used. When an epoxy resin containing a nitrogen atom is used in combination, the coating film of the adhesive composition can be brought to a semi-cured state (hereinafter sometimes referred to as B-stage) by heating at a relatively low temperature, and the B-stage can be obtained. It tends to be possible to suppress the fluidity of the film and improve the workability in the bonding operation. Moreover, it is preferable because the effect of suppressing the foaming of the B-stage film can be expected. Examples of epoxy resins containing nitrogen atoms include glycidylamines such as tetraglycidyldiaminodiphenylmethane, triglycidyl para-aminophenol, tetraglycidylbisaminomethylcyclohexanone, and N,N,N',N'-tetraglycidyl-m-xylenediamine. system and the like. The amount of these nitrogen atom-containing epoxy resins to be blended is preferably 20 mass % or less of the total epoxy resin (B). If the amount is more than 20% by mass, the rigidity tends to be excessively high, the adhesiveness tends to decrease, and the cross-linking reaction tends to progress during storage of the adhesive sheet, which tends to shorten the sheet life. A more preferable upper limit of the blending amount is 10% by mass, more preferably 5% by mass.

Other epoxy resins can also be used in combination as the epoxy resin (B) used in the present invention. For example, glycidyl ether types such as bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, glycidyl ester types such as hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, triglycidyl isocyanurate, 3 , 4-epoxycyclohexylmethyl carboxylate, epoxidized polybutadiene, epoxidized soybean oil, and other alicyclic or aliphatic epoxides, which may be used alone or in combination of two or more.

The epoxy resin (B) is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, per 100 parts by mass of the carboxylic acid group-containing polyester resin (A). Also, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. If the amount is too small, the curing may be insufficient and the adhesiveness and resistance to moist heat may be lowered. In addition, the hydroxyl group generated when the carboxylic acid and the epoxy group react increases the water absorption, which may deteriorate the resistance to moist heat.

In the present invention, a curing catalyst can be used for the curing reaction of the epoxy resin (B). imidazole compounds such as 2-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, or 1-cyanoethyl-2-ethyl-4-methylimidazole; triethylamine, triethylenediamine, N'-methyl-N-(2-dimethylaminoethyl)piperazine, 1,8-diazabicyclo(5,4,0)-undecene-7, 1,5-diazabicyclo(4,3,0) -Nonene-5 or tertiary amines such as 6-dibutylamino-1,8-diazabicyclo(5,4,0)-undecene-7, and phenol, octylic acid, or quaternization of these tertiary amines Compounds converted into amine salts with tetraphenylborate salts or the like; cationic catalysts such as triallylsulfonium hexafluoroantimonate or diallyiodonium hexafluoroantimonate; and triphenylphosphine. Of these, 1,8-diazabicyclo(5,4,0)-undecene-7, 1,5-diazabicyclo(4,3,0)-nonene-5, or 6-dibutylamino-1,8-diazabicyclo(5 ,4,0)-undecene-7 and other tertiary amines and compounds obtained by converting these tertiary amines into amine salts with phenol, octylic acid, or quaternary tetraphenylborate salts are thermosetting and heat resistant. , adhesion to metal, and storage stability after compounding. The amount of the curing catalyst to be blended is preferably 0.01 to 1.0 parts by mass with respect to 100 parts by mass of the carboxylic acid group-containing polyester resin (A). Within this range, the catalytic effect on the reaction between the carboxylic acid group-containing polyester resin (A) and the epoxy resin (B) is further increased, and strong adhesion performance can be obtained.

<Organic solvent>
The adhesive composition of the present invention can be dissolved in an organic solvent to form a resin solution. The organic solvent is not particularly limited as long as it dissolves the carboxylic acid group-containing polyester resin (A), and more preferably one that dissolves the epoxy resin (B) as well. Examples of organic solvents include aromatic hydrocarbons such as benzene, toluene and xylene; alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane; methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol; Alcohol solvents such as propanediol and phenol, ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, and acetophenone, cellosolves such as methyl cellosolve and ethyl cellosolve, methyl acetate, ethyl acetate , ester solvents such as butyl acetate, methyl propionate, and butyl formate, and halogenated hydrocarbons such as trichlorethylene, dichlorethylene, chlorobenzene, and chloroform. can do. Among them, a mixed solvent of an aromatic hydrocarbon and a ketone solvent is preferable, and a mixed solvent of toluene and methyl ethyl ketone is more preferable.

The amount of the organic solvent is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and still more preferably 100 parts by mass or more with respect to 100 parts by mass of the carboxylic acid group-containing polyester resin (A). . Also, it is preferably 700 parts by mass or less, more preferably 600 parts by mass or less, and even more preferably 500 parts by mass or less. If the amount is too small, the storage stability of the adhesive composition may deteriorate, and if it is too large, it may be industrially disadvantageous.

<Other additives>
The adhesive composition of the present invention may further contain various curable resins and additives as long as the effects of the present invention are not impaired. Examples of curable resins include phenolic resins, amino resins, isocyanate compounds, silane coupling agents, and the like.

Examples of phenolic resins include alkylated phenols and formaldehyde condensates of cresols. Specifically alkylated (eg, methyl, ethyl, propyl, isopropyl, butyl)phenol, p-tert-amylphenol, 4,4′-sec-butylidenephenol, p-tert-butylphenol, o-cresol, m -cresol, p-cresol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl-o-cresol, p-phenylphenol, xylenol, etc. formaldehyde condensates of These can be used alone or in combination of two or more.

Examples of amino resins include formaldehyde adducts such as urea, melamine and benzoguanamine, and alkyl ether compounds of these alcohols having 1 to 6 carbon atoms. Specific examples include methoxymethylolurea, methoxymethylol N,N-ethyleneurea, methoxymethyloldicyandiamide, methoxymethylolmelamine, methoxymethylolbenzoguanamine, butoxymethylolmelamine, butoxymethylolbenzoguanamine, and the like. Methoxylated methylolmelamine, butoxylated methylolmelamine, and methylolated benzoguanamine are preferred, and each can be used alone or in combination.

Isocyanate compounds include aromatic or aliphatic diisocyanates and polyisocyanates having a valence of 3 or more, and may be either low-molecular-weight compounds or high-molecular-weight compounds. Examples include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds. Furthermore, excess amounts of these isocyanate compounds and low-molecular-weight active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, or triethanolamine, or various polyester polyols, Examples include terminal isocyanate group-containing compounds obtained by reacting polyether polyols, polyamides with high-molecular active hydrogen compounds, and the like.

The isocyanate compound may be a blocked isocyanate. Examples of isocyanate blocking agents include phenols such as phenol, thiophenol, methylthiophenol, cresol, xylenol, resorcinol, nitrophenol and chlorophenol; oximes such as acetoxime, methylethylketoxime and cyclohexanone oxime; methanol, ethanol, propanol, alcohols such as butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; tertiary alcohols such as t-butanol and t-pentanol; ε-caprolactam and δ-valero Examples include lactams such as lactam, γ-butyrolactam, β-propyllactam. In addition, aromatic amines, imides, active methylene compounds such as acetylacetone, acetoacetate and ethyl malonate, mercaptans, imines, ureas, diaryl compounds, sodium bisulfite and the like can also be used. The blocked isocyanate can be obtained by addition reaction of the isocyanate compound, the isocyanate compound and the isocyanate blocking agent by a conventionally known appropriate method.

A silane coupling agent may be added to the adhesive composition of the present invention, if necessary. Addition of a silane coupling agent is very preferable because it improves adhesion to metals and heat resistance. The silane coupling agent is not particularly limited, but examples include those having an unsaturated group, those having a glycidyl group, those having an amino group, and the like. Silane coupling agents having unsaturated groups include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane and the like. Silane coupling agents having a glycidyl group include γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane. etc. can be mentioned. Silane coupling agents having an amino group include N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-phenyl-γ -aminopropyltrimethoxysilane and the like. Among these, from the viewpoint of heat resistance, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, etc. A silane coupling agent having a glycidyl group is preferred. The amount of the silane coupling agent compounded is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the carboxylic acid group-containing polyester resin (A). If the amount of the silane coupling agent is less than 0.5 parts by mass, the resulting adhesive composition may have poor heat resistance, and if it exceeds 20 parts by mass, poor heat resistance or poor adhesion may occur. There is

Additives such as flame retardants such as bromine-based, phosphorus-based, nitrogen-based and metal hydroxide compounds, leveling agents, pigments and dyes can be appropriately added to the adhesive composition of the present invention, if necessary.

<Adhesive sheet>
In the present invention, the adhesive sheet includes a coating film of an adhesive composition obtained by curing the adhesive composition of the present invention (hereinafter also referred to as an adhesive layer). The adhesive sheet has the function of adhering the substrate to the adherend by means of the adhesive layer. The substrate of the adhesive sheet functions as a protective layer for the adherend after adhesion. Also, when a release substrate is used, the release substrate can be released and the adhesive layer can be transferred to another adherend. An adhesive sheet is obtained by applying an adhesive composition to a substrate or release substrate, drying and curing. Specific configurations include base material/adhesive layer, release base material/adhesive layer, release base material/adhesive layer/base material, release base material/adhesive layer/release base material, etc. is mentioned. In some cases, the adhesive layer alone may be obtained by peeling off the release base material. Moreover, the adhesive sheet may contain a trace amount or a small amount of organic solvent.

The adhesive sheet can be obtained by applying the adhesive composition of the present invention to various substrates, removing at least part of the solvent, and drying. In addition, if at least part of the solvent is removed and the adhesive layer is dried, then a release base material is attached to the adhesive layer. Since the agent layer is protected, it has excellent storage stability and is easy to use. Further, if the adhesive layer itself is applied to a release base material and dried, and if necessary, another release base material is applied, the adhesive layer itself can be transferred to another base material.

The base material is not particularly limited, and film-like resins, metal plates, metal foils, papers and the like can be mentioned. Examples of film-like resins include polyester resins, polyamide resins, polyimide resins, polyamideimide resins, olefin resins, and the like. Examples of materials for metal plates and metal foils include various metals such as SUS, copper, aluminum, iron, and zinc, and their alloys and plated products. Papers include fine paper, kraft paper, and roll paper. , glassine paper, and the like. Moreover, glass epoxy etc. can be illustrated as a composite material. Polyester resins, polyamide resins, polyimide resins, polyamideimide resins, SUS steel plates, copper foils, aluminum foils, and glass epoxies are preferred from the viewpoints of adhesive strength and durability between the substrate and the adhesive composition.

The release substrate is not particularly limited. For example, a coating layer of a filler such as clay, polyethylene, polypropylene is provided on both sides of paper such as woodfree paper, kraft paper, roll paper, and glassine paper. , and further coated with a silicone-based, fluorine-based or alkyd-based release agent on each coating layer. Other examples include various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer and propylene-α-olefin copolymer alone, and films such as polyethylene terephthalate coated with the release agent. For reasons such as the release force between the release base material and the adhesive layer, and the fact that silicone has an adverse effect on electrical properties, both sides of high-quality paper are filled with polypropylene and an alkyd-based release agent is used on top of it. Alternatively, it is preferable to use an alkyd release agent on polyethylene terephthalate.

The method of coating the adhesive composition on the base material or the release base material is not particularly limited, and examples thereof include a comma coater, a reverse roll coater, and the like. Alternatively, if necessary, an adhesive layer can be provided directly or by a transfer method on the rolled copper foil or polyimide film, which are the constituent materials of the printed wiring board. The thickness of the adhesive layer after drying may be changed as required, but is preferably in the range of 5 to 200 μm. If the thickness of the adhesive layer is less than 5 μm, the adhesive strength may be insufficient. If the thickness is more than 200 μm, the drying is insufficient, the residual solvent increases, and there is a problem that blistering occurs during pressing for manufacturing a printed wiring board. The drying conditions are not particularly limited, but the residual solvent rate after drying is preferably 4% by mass or less, more preferably 1% by mass or less. If it exceeds 4% by mass, the residual solvent foams during pressing of the printed wiring board, which may cause a problem of causing blisters.

<Printed wiring board>
The printed wiring board in the present invention includes an adhesive sheet as a component, and more specifically, a laminate (metal foil/adhesive layer/resin base) formed of a metal foil forming a conductive circuit and a resin base. material) as a component. A printed wiring board is manufactured, for example, by a conventionally known method such as a subtractive method using a metal-clad laminate. If necessary, so-called flexible circuit boards (FPC), flat cables, tape automated bonding ( It is a general term for circuit boards for TAB).

The printed wiring board of the present invention can be of any laminate construction that can be employed as a printed wiring board. For example, it can be a printed wiring board composed of four layers: a base film layer, a metal foil layer, an adhesive layer, and a cover film layer. Further, for example, a printed wiring board can be made up of five layers: a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer. If necessary, the printed wiring board may be reinforced with a reinforcing material, in which case the reinforcing material and adhesive layer are provided under the base film layer.

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

The adhesive composition of the present invention can be suitably used for each adhesive layer of a printed wiring board. In particular, when the adhesive composition of the present invention is used as an adhesive, it has high adhesiveness to the substrate constituting the printed wiring board and can impart high heat resistance that can be used with lead-free solder. It is possible. In particular, in the high temperature range where solder resistance is evaluated, by giving a well-balanced physical cross-linking between the resin and the inorganic filler along with the chemical cross-linking between the resins, the impact caused by the evaporation of moisture in the solder resistance test under humid conditions It is possible to relax the stress without swelling or deformation. Therefore, it is suitable as an adhesive between a metal foil layer and a cover film layer and as an adhesive between a base film layer and a reinforcing material layer. In particular, when using a metal reinforcing material such as a SUS plate or an aluminum plate, the adhesive layer between the base film layer and the reinforcing material layer cannot evaporate from the reinforcing material during soldering in a humid state. The impact is particularly strong, and it is suitable as an adhesive composition used for adhesion in such cases.

The inorganic filler used in the present invention is not particularly limited, but examples include alumina, silica, titania, tantalum oxide, zirconia, silicon nitride, barium titanate, barium carbonate, lead titanate, lead zirconate titanate, and titanium. Lead lanthanum zirconate, gallium oxide, spinel, mullite, cordierite, talc, aluminum hydroxide, magnesium hydroxide, aluminum titanate, yttria-containing zirconia, barium silicate, boron nitride, calcium carbonate, calcium sulfate, zinc oxide , zinc borate, magnesium titanate, magnesium borate, barium sulfate, organic bentonite, carbon and the like can be used, and these can be used alone or in combination of two or more. From the viewpoint of transparency, mechanical properties and heat resistance of the adhesive composition, silica is preferred, and fumed silica having a three-dimensional network structure is particularly preferred. Hydrophobic silica treated with monomethyltrichlorosilane, dimethyldichlorosilane, hexamethyldisilazane, octylsilane, silicone oil, or the like is preferred for imparting hydrophobicity. When fumed silica is used as the inorganic filler, the average primary particle size is preferably 30 nm or less, more preferably 25 nm or less. When the average diameter of the primary particles exceeds 30 nm, the interaction between the particles and the resin tends to decrease and the heat resistance tends to decrease. The average diameter of the primary particles referred to here is the average value of circle-equivalent diameters of 100 particles randomly selected from primary particle images obtained using a scanning electron microscope.

The amount of the inorganic filler compounded is preferably 10 parts by mass or more, more preferably 13 parts by mass or more, and still more preferably 15 parts by mass or more based on 100 parts by mass of the carboxylic acid group-containing polyester resin (A). If it is less than 10 parts by mass, the effect of improving the heat resistance may not be exhibited. Also, it is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less. If the amount exceeds 50 parts by mass, the inorganic filler may be poorly dispersed, or the viscosity of the solution may become too high, resulting in poor workability or reduced adhesion.

In the printed wiring board of the present invention, any resin film conventionally used as a base material for printed wiring boards can be used as the base film. As the resin for the base film, a halogen-containing resin may be used, or a halogen-free resin may be used. From the viewpoint of environmental problems, it is preferable to use a halogen-free resin, but from the viewpoint of flame retardancy, a halogen-containing resin can also be used. The base film is preferably a polyimide film or a polyamideimide film.

Any conventionally known conductive material that can be used for circuit boards can be used as the metal foil used in the present invention. As the material, for example, copper foil, aluminum foil, steel foil, nickel foil, etc. can be used, and composite metal foils composed of these and metal foils treated with other metals such as zinc and chromium compounds are also used. be able to. Copper foil is preferred.

Although the thickness of the metal foil is not particularly limited, it is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 10 μm or more. Also, it is preferably 50 μm or less, more preferably 30 μm or less, and still more preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit.

Metal foils are usually provided in roll form. The form of the metal foil used in manufacturing the printed wiring board of the present invention is not particularly limited. When using a roll-shaped metal foil, the length is not particularly limited. Also, the width is not particularly limited, but it is preferably about 250 to 1000 mm.

As the cover film, any insulating film conventionally known as an insulating film for printed wiring boards can be used. For example, films made from various polymers such as polyimides, polyesters, polyphenylene sulfides, polyethersulfones, polyetheretherketones, aramids, polycarbonates, polyarylates, polyimides, and polyamideimides can be used. A polyimide film or a polyamide-imide film is more preferred, and a polyimide film is even more preferred.

As the material resin of the cover film, a halogen-containing resin may be used, or a halogen-free resin may be used. From the viewpoint of environmental problems, it is preferable to use a halogen-free resin, but from the viewpoint of flame retardancy, a halogen-containing resin can also be used.

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

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

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

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

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

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

The semi-finished product on the cover film side thus obtained may be used as it is for lamination with the semi-finished product on the base film side, or may be used for lamination with the semi-finished product on the base film side after the release film has been laminated and stored. may be used.

The base film-side semi-finished product and the cover film-side semi-finished product are each stored in the form of rolls, for example, and then laminated together to manufacture a printed wiring board. Any method can be used as the bonding method, and for example, the bonding can be performed using a press or a roll. Also, both can be bonded together while being heated by a method such as using a hot press or a hot roll device.

The base film-side semi-finished product, the cover film-side semi-finished product, and the reinforcing agent-side semi-finished product are all the printed wiring board laminate of the present invention.

The adhesive composition of the present invention is suitably used for each adhesive layer of a printed wiring board. By containing the conductive powder, it can be used for applications such as electromagnetic wave shielding, circuit formation of touch panels and electronic parts, and conductive adhesives for terminals and lead wires.

Examples and comparative examples are given below to describe the present invention in more detail, but the present invention is not limited by the examples. Each measured value described in Examples and Comparative Examples was measured by the following method. In addition, unless otherwise specified, "part" means "mass part" and "%" means "mass%".

Polymerization Example of Polymer Polyol (A1-1) In a reactor equipped with a stirrer, thermometer, and outflow cooler, 90 parts of terephthalic acid, 358 parts of isophthalic acid, 5 parts of trimellitic anhydride, 2-methyl- 319 parts of 1,3-propanediol, 172 parts of 1,4-cyclohexanediol, and 0.2 parts of tetrabutyl titanate were charged, the temperature was gradually raised to 250°C, and an esterification reaction was carried out while distilling water was removed from the system. did After completion of the esterification reaction, initial polymerization was carried out while gradually reducing the pressure to 10 mmHg, the temperature was raised to 250° C., and post-polymerization was carried out until a predetermined torque was obtained at 1 mmHg or less. Thereafter, the pressure was returned to normal pressure with nitrogen, 5 parts of trimellitic anhydride was added, and the mixture was reacted at 220° C. for 30 minutes to obtain a polymer polyol (A1). Table 1 shows the composition and characteristic values of the polymer polyol (A1) thus obtained. Each measurement evaluation item followed the method described above.

Polymerization Example of Polymer Polyol (A2-1) In a reactor equipped with a stirrer, thermometer, and outflow cooler, 390 parts of terephthalic acid, 390 parts of isophthalic acid, 367 parts of ethylene glycol, 2,2-dimethyl- 362 parts of 1,3-propanediol and 0.2 parts of tetrabutyl titanate were charged, the temperature was gradually raised to 250° C., and an esterification reaction was carried out while distilling water was removed from the system. After completion of the esterification reaction, initial polymerization under reduced pressure is performed while gradually reducing the pressure to 10 mmHg, the temperature is raised to 250° C., and post-polymerization is performed at 1 mmHg or less until a predetermined torque is achieved, thereby obtaining a polymer polyol (A2-1 ). Table 1 shows the composition and characteristic values of the polymer polyol (A2-1) thus obtained. Each measurement evaluation item followed the method described above.

Polymer polyols (A1-2 to A1-5) were obtained in the same manner as for polymer polyol (A1-1). Further, a polymer polyol (A2-2) was obtained in the same manner as the polymer polyol (A2-1). These characteristic values are shown in Table 1.

(1) Composition of Carboxylic Acid Group-Containing Polyester Resin (A) The carboxylic acid group-containing polyester resin (A) was dissolved in heavy chloroform, and the molar ratio of each component was determined by ¹ H-NMR analysis.

(2) number average molecular weight (Mn)
A sample (carboxylic acid group-containing polyester resin (A), polymer polyol (A1) or polymer polyol (A2)) was dissolved or diluted in tetrahydrofuran so that the sample concentration was about 0.5% by mass, and the pore size was 0. A sample for measurement was obtained by filtering through a polytetrafluoroethylene membrane filter of 0.5 μm. The number average molecular weight was measured by gel permeation chromatography using tetrahydrofuran as a mobile phase and a differential refractometer as a detector. The flow rate was 1 mL/min and the column temperature was 30°C. Showa Denko KF-802, 804L, and 806L columns were used. Monodisperse polystyrene was used as a molecular weight standard. However, when the sample did not dissolve in tetrahydrofuran, N,N-dimethylformamide was used instead of tetrahydrofuran. Low-molecular-weight compounds (oligomers, etc.) having a number average molecular weight of less than 1,000 were omitted without being counted.

(3) Glass transition temperature With a differential scanning calorimeter "DSC220 type" manufactured by Seiko Electronics Industries Co., Ltd., 5 mg of the measurement sample is placed in an aluminum pan, the lid is pressed and sealed, and once held at 250 ° C. for 5 minutes. , quenched with liquid nitrogen, and then measured from -150°C to 250°C at a heating rate of 20°C/min. The inflection point of the obtained curve was taken as the glass transition temperature. When there were two or more inflection points, it was assumed that block copolymerization had occurred, and each mutation point was read and treated as having a plurality of glass transition temperatures.

(4) Acid value 0.2 g of a sample (carboxylic acid group-containing polyester resin (A), polymer polyol (A1) or polymer polyol (A2)) was dissolved in 20 ml of chloroform, and phenolphthalein was used as an indicator. It was titrated with 0.1N potassium hydroxide ethanol solution. From this titration amount, the number of mg of KOH consumed for neutralization was converted into the amount per 1 g of resin to calculate the acid value (mgKOH/g).

<Synthesis Example of Carboxylic Acid Group-Containing Polyester Resin (A-1)>
160 parts of polymer polyol (A1), 40 parts of polymer polyol (A2), 5.2 parts of pyromellitic anhydride, and 200 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and reflux tube. It was dissolved in toluene while gradually raising the temperature to °C. After the dissolution was completed, 0.1 part of triethylamine was added as a reaction catalyst, and then the temperature was gradually raised to 105° C. and the mixture was reacted for 24 hours. After confirming the completion of the reaction by IR, the mixture was diluted with 108 parts of toluene to obtain a solution of carboxylic acid group-containing polyester resin (A-1) having a solid concentration of 40%. Table 2 shows the composition and characteristic values of the carboxylic acid group-containing polyester resin (A-1) thus obtained. Each measurement evaluation item followed the method described above.

<Synthesis Examples of Carboxylic Acid Group-Containing Polyester Resins (A-2) to (A-10)>
Carboxylic acid group-containing polyester resins (A-2) to (A-10) were obtained in the same manner as Synthesis Example (A-1) of carboxylic acid group-containing polyester resin.

＜実施例１＞
カルボン酸基含有ポリエステル樹脂（Ａ－１）の固形分１００部に、エポキシ樹脂として、新日鉄住金化学（株）製ＹＤＣＮ－７００－１０（ノボラック型エポキシ樹脂）９部と三菱ガス化学（株）製ＴＥＴＲＡＤ（登録商標）－Ｘ（Ｎ，Ｎ，Ｎ’，Ｎ’－テトラグリシジル－ｍ－キシレンジアミン）を０．１部加え、メチルエチルケトンを用いて固形分濃度が３５％になるように調整し、接着剤組成物を得た。得られた接着剤組成物を下記に示した方法で評価を行った。

<Example 1>
In 100 parts of the solid content of the carboxylic acid group-containing polyester resin (A-1), as an epoxy resin, YDCN-700-10 (novolac type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. 9 parts and Mitsubishi Gas Chemical Co., Ltd. 0.1 part of TETRAD (registered trademark)-X (N,N,N',N'-tetraglycidyl-m-xylenediamine) was added, and methyl ethyl ketone was used to adjust the solid content concentration to 35%, An adhesive composition was obtained. The obtained adhesive compositions were evaluated by the methods shown below.

<Examples 2 to 13, Comparative Examples 1 to 2>
The carboxylic acid group-containing polyester resin and the epoxy resin were changed to those shown in Table 3, and the amounts shown in Table 3 were changed in the same manner as in Example 1. Examples 2 to 13 and Comparative Example 1 and 2 were performed. Table 3 shows the results.

(5) Peel strength, solder resistance, sheet life (5)-1 Peel strength (adhesion)
The adhesive composition obtained in Examples or Comparative Examples was applied to a polyimide film having a thickness of 12.5 μm (manufactured by Kaneka Corporation, Apical (registered trademark)) so that the thickness after drying was 25 μm. C. for 5 minutes to obtain an adhesive film (B stage product). A 20 μm rolled copper foil was laminated so that the glossy surface of the adhesive film was in contact with the adhesive layer surface of the adhesive film, and pressed at 160° C. under a pressure of 30 kgf/cm ² for 30 seconds to bond. Then, it was cured by heat treatment at 140° C. for 4 hours to prepare a sample for evaluation.

Peel strength: A sample for evaluation was subjected to a 180° peel test at a tensile speed of 50 mm/min by pulling a film at 25°C to measure the peel strength. This test indicates the peel strength at normal temperature. Considering practical performance, it is preferably 3.5 N/cm or more, more preferably 5 N/cm or more.
Evaluation criteria ◎: 10 N / cm or more ○: 5 N / cm or more, less than 10 N / cm △: 3.5 N / cm or more, less than 5 N / cm ×: less than 3.5 N / cm

(5)-2 Solder resistance Solder resistance (drying): After the evaluation sample was left in an environment of 120 ° C. for 30 minutes, it was floated in a heated solder bath for 1 minute. Measured at °C pitch. In this test, a higher measured value indicates better heat resistance. Considering practical performance, the temperature is preferably 350° C. or higher, more preferably 360° C. or higher.
Evaluation Criteria A: No swelling even at 360°C or higher.
○: No swelling at 350°C or higher and lower than 360°C.
Δ: No swelling at 340° C. or more and less than 350° C.
x: Blisters below 340°C.

Solder resistance (humidification): After the evaluation sample was left at 40°C and 80% humidity for 3 days, it was floated in a heated solder bath for 1 minute, and the upper limit temperature at which blisters did not occur was measured at intervals of 10°C. In this test, the higher the measured value, the better the heat resistance. Severe heat resistance is required. Considering practical performance, the temperature is preferably 260° C. or higher, more preferably 270° C. or higher.
Evaluation Criteria ⊚: No swelling even at 270°C or higher.
○: No swelling at 260°C or higher and lower than 270°C.
Δ: No swelling at 250° C. or more and less than 260° C.
x: Blisters below 250°C.

(5)-3 Evaluation of sheet life Preparation of sample for measuring sheet life: The adhesive composition obtained in Examples or Comparative Examples was applied to a polyimide film having a thickness of 12.5 μm (manufactured by Kaneka Corporation, Apical (registered trademark) ) to a thickness of 25 μm after drying, and dried at 130° C. for 5 minutes to obtain an adhesive film (B stage product). This B-stage product was left in an environment of 40° C.×80% for two weeks. The B-stage product was adhered to the adhesive layer surface of the adhesive film so that the glossy surface of the 20 μm rolled copper foil was in contact, and pressed at 160° C. under a pressure of 30 kgf/cm ² for 30 seconds to bond. Then, it was cured by heat treatment at 140° C. for 4 hours to prepare a sample for evaluation. Samples for evaluation of peel strength and solder resistance were prepared in the same manner as described above.

The examples in Table 3 show that the adhesive compositions of the present invention are excellent in initial peel strength, solder resistance, and sheet life.

The adhesive compositions of Comparative Examples 1 to 3 are insufficient in peel strength, solder resistance, sheet life and the like.

The adhesive composition of the present invention is excellent in adhesion to various plastic films, metals such as copper, aluminum and stainless steel, and glass epoxy, solder resistance and sheet life. Therefore, it is particularly useful as an adhesive for circuit boards such as FPC.

Claims (3)

An adhesive composition containing a carboxylic acid group-containing polyester resin (A) and an epoxy resin (B), wherein the carboxylic acid group-containing polyester resin (A) has a glass transition temperature (Tg) of 40 to 90° C. and an acid value of is 1 to 30 mgKOH / g, and contains a high molecular polyol (A1) as a copolymer component, a high molecular polyol (A2) different from the high molecular polyol (A1), and a tetracarboxylic dianhydride, and the high The molecular polyol (A1) and the polymer polyol (A2) are polyester polyols, the number average molecular weight (Mn1) of the polymer polyol (A1) is 10,000 or more and 50,000 or less, and the polymer polyol ( A2) has a number average molecular weight (Mn2) of 1,000 or more and less than 10,000, and the difference between Mn1 and Mn2 is 2,000 or more . An adhesive sheet containing a cured product of the adhesive composition according to claim 1 . A printed wiring board comprising the adhesive sheet according to claim 2 as a component.