KR102665140B1 - Adhesive composition using a resin having an imide bond and a phosphorus compound - Google Patents

Abstract

Provides an excellent adhesive composition that has excellent adhesion, heat resistance, handleability, and insulation reliability, and is suitable for adhesive films, coverlay films, copper-clad laminates, etc. An adhesive composition comprising a resin having an imide bond and a phosphorus compound of a specific structure.

Description

Adhesive composition using a resin having an imide bond and a phosphorus compound

The present invention relates to an adhesive composition using a resin having an imide bond and a phosphorus compound, and to an adhesive film, a coverlay film, a copper-clad laminate, and a flexible printed wiring board using the adhesive composition.

Flexible printed wiring boards are used for electronic device parts that require flexibility and space saving, such as device boards for display devices such as liquid crystal displays and plasma displays, boards for mobile phones, digital cameras, and portable game consoles, relay cables, and operation switch boards. It is widely used, and its uses are expected to expand further.

Adhesives used in flexible printed wiring boards are used among parts that make up flexible wiring boards, such as adhesive films, coverlay films, and copper-clad laminates, and require adhesiveness, heat resistance, flame retardancy, and insulation reliability.

In flexible printed wiring boards, wiring density is increasing in line with recent electronic devices becoming lighter, thinner, and shorter. In order to realize further increase in wiring density, it is necessary to narrow the space width between circuits, and adhesives used in flexible printed wiring boards are required to further improve insulation reliability.

As adhesives used in flexible printed wiring boards, epoxy resins, acrylic resins, and urethane resins have been used in the past, but their heat resistance is insufficient to cope with the recent increase in wiring density and lead-free solder, so adhesives with heat resistance are being used to replace them. As such, polyimide-based resins are being examined.

Additionally, in order to impart flame retardancy to adhesives used in flexible printed wiring boards, a method of blending a phosphorus compound that does not contain halogen elements such as bromine is widely used. Among them, phosphinic acid derivatives having the chemical structure represented by general formula (5) (generally called DOP) are widely used from the viewpoint of heat resistance, flame retardancy, and compatibility.

Specific examples of the phosphinic acid derivative include, for example, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide represented by the formula (6), 9 represented by the formula (7), 10-dihydro-10-benzyl-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa- represented by formula (8) A method using 10-phosphaphenanthrene-10-oxide or the like can be mentioned (for example, see Patent Documents 1 and 2).

Patent Document 1: Japanese Patent No. 5278785 Patent Document 2: Japanese Patent Publication No. 2011-148862

However, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide represented by the formula (6) has a low molecular weight, so its thermal weight reduction temperature is low, and some of it remains uncured. There was a problem that heat resistance deteriorated. In addition, 9,10-dihydro-10-benzyl-9-oxa-10-phosphaphenanthrene-10-oxide represented by the formula (7) does not have a reactive functional group, so it bleeds out in a high temperature and high humidity environment. There was a problem that the insulation reliability deteriorated because it was easy. In addition, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide represented by the formula (8) has low solubility in solvents, making it difficult to handle. There was a task that was being degraded.

The present invention was made to solve the problems of the prior art, and its purpose is to provide an adhesive composition that is excellent in adhesiveness, heat resistance, flame retardancy, and handleability, and has higher insulation reliability.

As a result of intensive studies to achieve the above object, the present inventors completed the present invention by combining a resin having an imide bond and a specific phosphorus compound.

That is, the present invention consists of the following configuration.

An adhesive composition comprising a resin having an imide bond and a phosphorus compound represented by general formula (1).

(R ₁ to _{R 4} in General Formula (1) is any of the following General Formulas (2) to (4), and at least one of R ₁ to R ₄ is General Formula (2). General Formula (2) * in -(4) represents a site directly bonded to the aromatic ring of General Formula (1), and each of plural Xs in General Formula (1) and (3) is independently CH ₂ or C. (CH ₃ ) ₂ , and each Y in the formulas (1) and (3) is independently hydrogen or a hydroxyl group. However, in the formula (1), at least one of the Ys is a hydroxyl group. R ₅ in general formula (4) is hydrogen or an alkyl group having 1 to 10 carbon atoms.

The resin having the imide bond is preferably a polyimide resin, polyamidoimide resin, polyetherimide resin, polyesterimide resin, or polycarbonateimide resin. Additionally, as a copolymerization component of the resin having an imide bond, it is preferable to contain trimellitic anhydride or acrylonitrile butadiene rubber modified with carboxyl groups at both ends.

It is preferable to further contain an epoxy resin, and the properties of the epoxy resin are liquid at 25°C, and it is preferable to have two or more epoxy groups per molecule.

The adhesive composition according to any of the above, characterized in that it is used in printed wiring board applications. An adhesive film characterized by using the above adhesive composition. A coverlay film or copper-clad laminate characterized by using the adhesive film. A flexible printed wiring board using the coverlay film or copper-clad laminate.

According to the present invention, an adhesive composition having excellent adhesion, heat resistance, flame retardancy, handling properties, and even higher insulation reliability by combining a resin having an imide bond and a specific phosphorus compound, and an adhesive film and cover using the same. Ray films, copper-clad laminates, and flexible printed wiring boards can be obtained.

<Resin having an imide bond>

The resin having an imide bond used in the adhesive composition of the present invention has one or more imide bonds in the repeating unit of the resin, such as polyimide resin, polyamidoimide resin, polyetherimide resin, and polyesterimide resin. , polycarbonate imide resin, etc. It is preferable to have two or more imide bonds among the repeating units of the resin. The resin having an imide bond preferably contains an acid component and a diisocyanate component or a diamine component as copolymerization components. Hereinafter, the diisocyanate component or diamine component is collectively referred to as the amine component. The acid component may be any of an acid component having an aromatic ring (aromatic acid component), an aliphatic acid component, or an alicyclic acid component, but is preferably a polycarboxylic acid component having an aromatic ring. Additionally, the amine component (diisocyanate component or diamine component) may be any of an amine component having an aromatic ring, an aliphatic amine component, or an alicyclic amine component, but is preferably an amine component having an aromatic ring. That is, it is preferably composed of a structural unit derived from a polycarboxylic acid component having an aromatic ring, and a structural unit derived from a diisocyanate component having an aromatic ring or a diamine component having an aromatic ring.

The resin having an imide bond used in the adhesive composition of the present invention preferably has a carboxyl group or an acid anhydride group as a reactive functional group. The acid value of the resin having an imide bond is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more, and still more preferably 20 mgKOH/g or more. Also, it is preferably 150 mgKOH/g or less, more preferably 120 mgKOH/g or less, and even more preferably 100 mgKOH/g or less. By keeping it within the above range, the number of crosslinking points with the epoxy resin or curing agent increases, the crosslinking density of the coating film after heat curing increases, and heat resistance can be improved.

As the acid component of the resin having an imide bond of the present invention, it is preferable to use a polycarboxylic acid component having an aromatic ring. As the aromatic polycarboxylic acid component, it is preferable that it is an anhydride of an aromatic polycarboxylic acid, and specifically, it is more preferable to use trimellitic anhydride (TMA). By using trimellitic anhydride, amide bonds can be created in addition to imide bonds, and the solvent solubility of the resin can be improved. When the total acid component is 100 mol%, the trimellitic anhydride is preferably 30 mol% or more, more preferably 40 mol% or more, and even more preferably 50 mol% or more. Additionally, the upper limit is not limited and there is no problem even if it is 100 mol%, but it is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less.

Polycarboxylic acid components having aromatic rings other than trimellitic anhydride include, for example, pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 3,3',4,4'-Biphenyltetracarboxylic dianhydride (BPDA), ethylene glycol bisanhydrotrimellitate (TMEG), propylene glycol bisanhydrotrimellitate, 1,4-butanediol bisanhydro Alkylene glycol bisanhydrotrimellitate such as trimellitate, hexamethylene glycol bisanhydrotrimellitate, polyethylene glycol bisanhydrotrimellitate, and polypropylene glycol bisanhydrotrimellitate, 1,2,5, 6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetra Carboxylic dianhydride, 3,3',4,4'-diphenylsulfonic acid tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 1,1,1,3,3,3-hexafluoro -2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride, 2,2 -bis[4-(2,3- or 3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-bis[4- (2,3- or 3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride etc. can be mentioned. These may be used individually, or may be used in combination.

As other acid components, aliphatic or alicyclic acid anhydride or aromatic, aliphatic or alicyclic dicarboxylic acid can be used. For example, a hydrogenated version of any of the components mentioned in the preceding paragraph can be used. Specifically, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, meso-butane-1,2,3,4-tetra. Carboxylic dianhydride, pentane-1,2,4,5-tetracarboxylic dianhydride, cyclobutane tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, cyclohexa-1-ene-2,3,5, 6-Tetracarboxylic dianhydride, 3-ethylcyclohexa-1-en-3-(1,2),5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3-(1 ,2),5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexa-1-en-3-(1,2),5,6-tetracarboxylic dianhydride, 1-ethylcyclo Hexane-1-(1,2),3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1-(2,3),3,4-tetracarboxylic dianhydride, 1,3-dipropyl Cyclohexane-1-(2,3),3-(2,3)-tetracarboxylic dianhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, bicyclo[2.2. 1]heptane-2,3,5,6-tetracarboxylic dianhydride, 1-propylcyclohexane-1-(2,3),3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane -1-(2,3),3-(2,3)-tetracarboxylic dianhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, bicyclo[2.2.1] Heptane-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octo-7- N-2,3,5,6-tetracarboxylic dianhydride, cyclohexanedicarboxylic acid, etc. are mentioned. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, oxydibenzoic acid, and stilbenedicarboxylic acid. Aliphatic dicarboxylic acids include, for example, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, dodecanedioic acid, eicosanoic acid, 2-methylsuccinic acid, and 2-methyladipic acid. Acid, 3-methyladipic acid, 3-methylpentanedicarboxylic acid, 2-methyloctanedicarboxylic acid, 3,8-dimethyldecanedicarboxylic acid, 3,7-dimethyldecanedicarboxylic acid, 9 , 12-dimethyleicosandioic acid, fumaric acid, maleic acid, etc. These may be used individually, or may be used in combination. Considering heat resistance, adhesion, solubility, cost, etc., sebacic acid, 1,4-cyclohexanedicarboxylic acid or isophthalic acid is preferable, and among them, sebacic acid is more preferable. When using these components, from the viewpoint of the heat resistance and flame retardancy of the resulting resin having an imide bond, the amount is preferably 5 mol% or more, more preferably 10 mol% or more, based on 100 mol% of the total acid component. , and more preferably 20 mol% or more. Additionally, it is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 45 mol% or less.

As the amine component (diisocyanate component or diamine component) used in the present invention, an amine component (aromatic diisocyanate or aromatic diamine) having an aromatic ring is preferable. Diisocyanates having an aromatic ring include, for example, diphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,2'- or 3,3'- or 4,2 '- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-diethyldiphenylmethane-2, 4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6, 3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenyl ether-4,4'- Diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, m-xylyl Lendiisocyanate, p-xylylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-[2,2 bis(4-phenoxyphenyl)propane]diisocyanate, 3,3'- or 2,2 '-dimethylbiphenyl-4,4'-diisocyanate, 3,3'- or 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4, 4'-diisocyanate, 3,3'-diethoxybiphenyl-4,4'-diisocyanate, etc. are mentioned. Examples of the diamine component having an aromatic ring include diamines corresponding to these diisocyanates. These may be used individually, or may be used in combination. Among them, diphenylmethane-4,4'-diisocyanate is preferable.

The amine component having an aromatic ring is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, when the total amine component is 100 mol%, and 100 mol%. There is no problem with this. By keeping it within the above range, a resin having an imide bond with excellent adhesiveness and heat resistance can be obtained. As the amine component, the diisocyanate component having an aromatic ring may be used independently, the diamine component having an aromatic ring may be used independently, or each may be used in combination. Among these, it is preferable to use the diisocyanate component having an aromatic ring alone.

To the extent that the effect of the present invention is not impaired, as other amine components, an aliphatic amine component (aliphatic diisocyanate or aliphatic diamine) or an alicyclic amine component (alicyclic diisocyanate or alicyclic diamine) can be used. For example, diisocyanate or diamine obtained by hydrogenating any of the components mentioned in the preceding paragraph can be used. Specifically, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, ethylene diisocyanate, propylene diisocyanate, and hexamethylenedi. Isocyanates and diamines corresponding thereto can also be mentioned. These may be used individually, or may be used in combination. From the viewpoint of heat resistance and flame retardancy of the resulting resin having an imide bond, these components are preferably 20 mol% or less, more preferably 10 mol% or less, based on 100 mol% of the total amine components, and even more preferably Typically, it is 5 mol% or less, and there is no problem even if it is 0 mol%.

The resin having an imide bond of the present invention is copolymerized with a compound having three or more functional groups for the purpose of increasing the reaction point with the epoxy resin and improving the heat resistance of the resulting adhesive composition, within a range that does not impair the effect of the present invention. It is possible. For example, polyfunctional carboxylic acids such as trimesic acid, dicarboxylic acids having a hydroxyl group such as 5-hydroxyisophthalic acid, dicarboxylic acids having an amino group such as 5-aminoisophthalic acid, glycerin, polyglycerin, etc. Those having 3 or more hydroxyl groups and those having 3 or more amino groups such as tris(2-aminoethyl)amine can be mentioned. Among these, from the viewpoint of heat resistance, polyfunctional carboxylic acids such as trimesic acid are preferable, and the amount is preferably 10 mol% or less, more preferably 5 mol% or less, based on 100 mol% of the total acid component. . If it exceeds 10 mol%, there is a risk of gelation or formation of insoluble substances during polymerization.

The resin having an imide bond of the present invention includes, as a component for imparting flexibility or adhesion, acrylonitrile butadiene rubber modified with carboxyl groups at both ends, polyester diol, polyether diol, polycarbonate diol, dimer acid, hydrogenated dimer acid, and dimer. It is possible to copolymerize flexible components such as acid diol, polysiloxane modified with carboxyl groups at both ends, polysiloxane modified with acid anhydride groups at both ends, polybutadiene modified with carboxyl groups at both ends, hydrogenated polybutadiene modified with carboxyl groups at both ends, polybutadienediol, and hydrogenated polybutadienediol. . Among these, from the viewpoint of flexibility and adhesiveness, acrylonitrile butadiene rubber modified with carboxyl groups at both ends is preferable. When using these flexible components, the amount is preferably 10% by mass or more, more preferably 20% by mass or more, based on 100% by mass of the total resin solid content. Additionally, it is preferably 60% by mass or less, and more preferably 50% by mass or less. By keeping it within the above range, flexibility can be imparted to the resin without impairing the effects of adhesiveness, heat resistance, and flame retardancy.

The resin having an imide bond of the present invention is produced by a method of producing an acid component and a diisocyanate component (isocyanate method), or by reacting an acid component and a diamine component to form an amic acid and then ring-closing it (direct method). Alternatively, it can be produced by a known method such as a method of reacting a compound having an acid anhydride and an acid chloride with a diamine (acid chloride method). Industrially, the isocyanate method is advantageous.

Hereinafter, the method for producing a resin having an imide bond will be representatively described in terms of the isocyanate method. However, the direct method and the acid chloride method described above can also be used to produce an imide bond in the same way by using the corresponding amine, acid, or acid chloride. Resin can be manufactured.

The polymerization reaction of the resin having an imide bond of the present invention can be carried out by stirring the acid component and the diisocyanate component in a solvent while heating them at 60°C to 200°C as conventionally known. At this time, the molar ratio of acid component/diisocyanate component is preferably in the range of 85/100 to 100/100. In addition, generally, the content of the acid component and the diisocyanate component in the resin having an imide bond is the same as the ratio of each component during polymerization. In addition, to promote the reaction, alkali metals such as sodium fluoride, potassium fluoride, and sodium methoxide, triethylenediamine, triethylamine, 1,8-diazabicyclo[5,4,0]-7-undecene, Amines such as 1,5-diazabicyclo[4,3,0]-5-nonene or catalysts such as dibutyltin dilaurate can be used. If these catalysts are too small, the catalytic effect cannot be obtained, and if they are too small, side reactions may occur. Therefore, 0.01 to 5 mol% is used, with the larger number of moles of each acid component or isocyanate component being 100 mol%. It is preferable, and more preferably 0.1 to 3 mol%.

The resin having an imide bond preferably has a molecular weight corresponding to a logarithmic viscosity of 0.1 to 0.8 (dl/g) at 30°C, and more preferably has a molecular weight equivalent to a logarithmic viscosity of 0.2 to 0.7 (dl/g). It has a molecular weight, and more preferably has a molecular weight corresponding to the logarithmic viscosity of 0.25 to 0.65 (dl/g). By keeping it within the above range, excellent adhesiveness and heat resistance can be achieved.

The glass transition temperature of the resin having an imide bond is preferably 80°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. The upper limit is not particularly limited, but is preferably 300°C or lower, more preferably 290°C or lower, and even more preferably 285°C or lower. By keeping it within the above range, excellent adhesiveness and heat resistance can be achieved.

Solvents that can be used for polymerization of the resin having an imide bond of the present invention include, for example, N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylimidazolidinone, dimethyl sulfoxide, dimethylformamide, Examples include dimethylacetamide, cyclohexanone, and cyclopentanone. Among these, dimethylacetamide is preferable because of its low boiling point and good polymerization efficiency. Additionally, after polymerization, the non-volatile matter concentration or solution viscosity can be adjusted by diluting with the solvent used for polymerization or another low boiling point solvent.

Low boiling point solvents include aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane, heptane, and octane, alcohol solvents such as methanol, ethanol, propanol, butanol, and isopropanol, acetone, methyl ethyl ketone, and methyl isobutyl ketone. , ketone-based solvents such as cyclohexanone and cyclopentanone, ether-based solvents such as diethyl ether and tetrahydrofuran, and ester-based solvents such as ethyl acetate, butyl acetate, and isobutyl acetate.

The content of the resin having an imide bond in the non-volatile components of the adhesive composition of the present invention is preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more. Additionally, it is preferably 90 mass% or less, more preferably 80 mass% or less, and even more preferably 70 mass% or less. By keeping it within the above range, the adhesive composition can exhibit excellent adhesion and heat resistance.

<Phosphorus compound represented by General Formula (1)>

The adhesive composition of the present invention contains a phosphorus compound represented by General Formula (1) (hereinafter also referred to as a phosphorus compound of General Formula (1)). By containing the phosphorus compound of general formula (1), an adhesive composition having excellent adhesiveness, heat resistance, flame retardancy and insulation reliability can be obtained. In general formula (1), R ₁ to _{R 4} are any of general formulas (2) to (4), and at least one of R ₁ to R ₄ is general formula (2). Preferably, two are of the general formula (2), and more preferably, three are of the general formula (2). When there are two general formulas (2), the preferred positions are not particularly limited, and may be R ₁ and R ₂ , or R ₁ and R ₃ . _In General Formulas ( ₁ ) and (3), a _plurality of ) or a site directly bonded to the aromatic ring of general formula (3). Hereinafter, it is simply referred to as CH ₂ or C(CH ₃ ) ₂ . _{Preferably , any} It is ₂ . Additionally, in General Formulas (1) and (3), Y's each independently represent hydrogen or a hydroxyl group. However, in General Formula (1), at least one of Y is a hydroxyl group, and preferably two Y are hydroxyl groups. In General Formula (1), at least one of Y is a hydroxyl group, so that the phosphorus compound of General Formula (1) has a reactive functional group, and can suppress bleed-out and exhibit excellent insulation reliability in a high-temperature, high-humidity environment. The position of the hydroxyl group may be ortho or para to In general formula (3), the number of hydroxyl groups is preferably one or more, more preferably two. The position may be ortho or para to X, but it is preferable that at least one hydroxyl group is para to In general formula (4), R ₅ is hydrogen or an alkyl group having 1 to 10 carbon atoms. Preferably, it is an alkyl group with 2 to 8 carbon atoms, and more preferably, it is an alkyl group with 3 to 5 carbon atoms. The alkyl group may be linear or branched. Specifically, methyl group, ethyl group, propyl group (n-propyl group, isopropyl group), butyl group (n-butyl group, isobutyl group, tert-butyl group), pentyl group, hexyl group, heptyl group, octyl group. , nonyl group, decyl group, etc., preferably propyl group, butyl group, or pentyl group, and more preferably butyl group. The phosphorus compound of General Formula (1) may be a single compound or a mixture of a plurality of compounds having different substituents.

The content of the phosphorus compound of general formula (1) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, based on 100 parts by mass of the resin having an imide bond. and is particularly preferably 20 parts by mass or more. Furthermore, it is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, further preferably 80 parts by mass or less, and especially preferably 70 parts by mass or less. By keeping it within the above range, excellent adhesion, heat resistance, flame retardancy and insulation reliability can be achieved.

The phosphorus compound of general formula (1) is any of the phosphorus compounds having structures represented by formulas (9) to (11) (hereinafter also referred to as phosphorus compounds of formulas (9) to (11)). It is preferable, and especially, it is preferable that it is a phosphorus compound of the general formula (9). The proportion of the total amount of the phosphorus compounds of formulas (9) to (11) in the phosphorus compounds of formula (1) is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass. % or more, especially preferably 90% by mass or more, and even if it is 100% by mass, there is no problem. By containing it in the above ratio, excellent insulation reliability can be achieved. In addition, the proportion of the phosphorus compound of the formula (9) in the total of the phosphorus compounds of the formula (9) to (11) is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass. % or more, especially preferably 90% by mass or more, and even if it is 100% by mass, there is no problem. If there is a large amount of the phosphorus compound of the general formula (10), the adhesiveness may decrease, and if there is a large amount of the phosphorus compound of the general formula (11), there is a risk that the flame retardancy may decrease.

Since the phosphorus compound of general formula (1) has high solubility in solvents, it has good handleability even after producing an adhesive composition. Solvents include N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylimidazolidinone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, cyclohexanone, cyclopentanone, etc. . In addition, as low boiling point solvents, aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane, heptane, and octane, alcohol solvents such as methanol, ethanol, propanol, butanol, and isopropanol, acetone, methyl ethyl ketone, and methyl isobutyl. Examples include ketone-based solvents such as ketone, cyclohexanone, and cyclopentanone, ether-based solvents such as diethyl ether and tetrahydrofuran, and ester-based solvents such as ethyl acetate, butyl acetate, and isobutyl acetate. The phosphorus compound of General Formula (1) is preferably dissolved in the solvent at room temperature (25°C) in an amount of 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more.

Phosphorus compounds other than the phosphorus compound of general formula (1) can be added to the extent that the effect of the present invention is not impaired. For example, phosphinic acid derivatives such as BCA, HCA (registered trademark), BzHCA, M-Acid, M-Ester, HCA-HQ, and HCA-NQ manufactured by Sanko Co., Ltd., brand name CR manufactured by Daihachi Chemical Co., Ltd. -733S, CR-741, PX-200, PX-202, brand name manufactured by ADEKA Co., Ltd. Adekastabe (registered trademark) Condensed phosphoric acid ester compounds such as FP-600 and PFR, brand name manufactured by Otsuka Chemical Co., Ltd. SPB-100, SPE-100, SPB-100L, SPH-100, brand names FP-100, FP-110, FP-300, FP-400, FP-430, FP-500, manufactured by Fushimi Pharmaceutical Co., Ltd. Cyclic phosphazene compounds such as FP-800E, FP-800H, FP-900H, FP-1000, etc., brand name Exolit (registered trademark) OP series manufactured by Clariant Japan Co., Ltd. Phosphorus aluminum salt compounds manufactured by Nissan Chemical Co., Ltd. melamine-based compounds such as the brand name Hosmel (registered trademark) 200, and intumescent flame retardants such as the brand name Adekastave FP-2100JC, FP-2200S, and FP-2500S manufactured by ADEKA Co., Ltd. There is, and these may be used individually or in combination of plurality.

The preferred phosphorus content in the non-volatile component of the adhesive composition of the present invention is 1.0 to 5.0 mass%, more preferably 1.0 to 3.0 mass%. If the phosphorus content is low, good flame retardancy cannot be obtained, and if the phosphorus content is high, adhesion, heat resistance, and insulation reliability tend to decrease.

A flame retardant that does not contain phosphorus can be added to the extent that the effect of the present invention is not impaired. For example, aluminum hydroxide such as H-42, H-42M, H-43, H-43M under the brand name Hi-G-Lite (registered trademark) manufactured by Showa Denko Co., Ltd., and brand name Kisma (registered trademark) manufactured by Kyowa Chemical Co., Ltd. Registered trademark) Magnesium hydroxide such as 5, 8, 5Q-S, 200-06H, and melamine cyanurate compounds such as MC-4000, MC-4500, and MC-6000 manufactured by Nissan Chemical Co., Ltd., etc. , these may be used individually, or may be used in combination.

<Epoxy Resin>

In the adhesive composition of the present invention, an epoxy resin can be blended. The content of the epoxy resin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and still more preferably 25 parts by mass or more, based on 100 parts by mass of the resin having an imide bond. Furthermore, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less. By setting it below the above upper limit, the content ratio of the resin having an imide bond can be maintained at a certain amount or more. Therefore, the epoxy resin does not remain uncured, and the heat resistance of the adhesive composition after curing becomes good. Moreover, by setting it above the lower limit, a sufficient crosslinking reaction can be formed with the resin having an imide bond, and the heat resistance and insulation reliability after curing of the adhesive composition become good.

The epoxy resin used in the adhesive composition of the present invention may be in a liquid, semi-solid or solid state at 25°C, but an epoxy resin that is liquid at 25°C and has two or more epoxy groups per molecule is preferred. . The epoxy resin may be modified and may contain a sulfur atom, a nitrogen atom, a phosphorus atom, etc. in the molecular skeleton. For example, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, or those obtained by adding hydrogen to them, phenol novolac-type epoxy resin, naphthalene-type epoxy resin, dicyclopentadiene-type epoxy resin, NBR (carboxyl group-modified acrylic resin at both ends) Nitrile butadiene rubber) modified epoxy resin, dimer acid modified epoxy resin, polybutadiene modified epoxy resin, aliphatic epoxy resin, and cycloaliphatic epoxy resin. These commercial products include, for example, jER (registered trademark) 825, jER827, jER828, YL980, manufactured by Mitsubishi Chemical Corporation, Epiclon (registered trademark) 840, 840-S, 850, manufactured by DIC Corporation. 850-S, EXA-850CRP, 850-LC, brand names YD-127, YD-128, YD-128G, YD-128S, YD-128CA, YD-8125, YD-825GS manufactured by Shin-Nitetsu Sumikin Chemical Co., Ltd. , bisphenol A type liquid epoxy resin such as YD-825GHS, brand names jER806, jER806H, jER807, YL983U manufactured by Mitsubishi Chemical Corporation, brand names Epiclon 830, 830-S, 835, EXA-830CRP manufactured by DIC Corporation, Bisphenol F type liquid epoxy resin such as EXA-830LVP, EXA-835LV, brand name YDF-170, YDF-170N, YDF-8170C, YDF-870GS manufactured by Shin-Nitetsu Sumikin Chemical Co., Ltd., manufactured by Mitsubishi Chemical Co., Ltd. Product names YX8000, YX8034, brand name ST-3000, etc. manufactured by Shin-Nitetsu Sumikin Chemical Co., Ltd., hydrogenated bisphenol A type liquid epoxy resin, brand name jER152 manufactured by Mitsubishi Chemical Corporation, brand name Epiclon N- manufactured by DIC Corporation. Phenol novolak-type liquid epoxy resin such as 730A, brand name manufactured by DIC Co., Ltd. Naphthalene-type liquid epoxy resin such as Epiclon HP-4032D, manufactured by ADEKA Co., Ltd., brand name Adeka Resin (registered trademark) EP-4088S, EP -Dicyclopentadiene type liquid epoxy resin such as 4088L, brand name Epiclon manufactured by DIC Corporation NBR modified epoxy resin such as TSR-960 and TSR-601 manufactured by Mitsubishi Chemical Corporation brand name jER871, jER872, Shinnitetsu Dimeric acid-modified epoxy resins such as Epototo (registered trademark) YD-172, manufactured by Sumikin Chemical Co., Ltd., butadiene-modified epoxy resins, such as brand names JP-100, JP-200, and JP-400, manufactured by Nippon Soda Co., Ltd. Epoxy resins, alicyclic epoxy resins such as brand name Celoxide (registered trademark) 2021P and 2081 manufactured by Daicel Chemical Industries, Ltd., triglycidyl isocyanur such as TEPIC (registered trademark) manufactured by Nissan Chemical Industries, Ltd. Rate, brand names manufactured by Nagase Chemtex Co., Ltd. include Denacol (registered trademark) EX-1000 series, Denacol L series, Denacol DLC series, Denarex (registered trademark) series, EX991, etc., which are used alone. You may use it, or you may use it in plural combinations.

As the epoxy resin, a semi-solid or solid epoxy resin can be used at 25°C. The semi-solid or solid epoxy resin at 25°C may be modified and may contain sulfur atoms, nitrogen atoms, phosphorus atoms, etc. in the molecular skeleton. For example, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, or hydrogenated products thereof, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, biphenyl-type epoxy resin, naphthalene-type epoxy resin, dicyclopenta. Diene type epoxy resin, aliphatic epoxy resin, and alicyclic epoxy resin can be mentioned. These commercial products include, for example, brand names jER1001, jER1004, jER1007, and jER1010 manufactured by Mitsubishi Chemical Corporation, brand names Epototo YD-134, YD-011, and YD-014 manufactured by Shin-Nitetsu Sumikin Chemical Co., Ltd. YD-017, bisphenol A type epoxy resin such as Epiclon 860, 1050, 1055, 2050, 3050, 4050, 7050, etc., manufactured by DIC Corporation, brand names jER4004P, jER4005P, jER4007P, jER4010P, manufactured by Mitsubishi Chemical Corporation. Bisphenol F-type epoxy resins, such as brand name EPOTOT YDF-2001 and YDF-2004, manufactured by Shinnitetsu Sumikin Chemical Co., Ltd., and hydrogenated bisphenol A-type epoxy resins, such as brand name ST-4000D, manufactured by Shinnitetsu Sumikin Chemical Co., Ltd. Resin, brand name jER154 manufactured by Mitsubishi Chemical Corporation, brand name Epiclon N-740, N-770, N-775 manufactured by DIC Corporation, brand name EPPN (registered trademark)-201 manufactured by Nippon Kayaku Co., Ltd., Phenol novolac type epoxy resins such as EPPN-501H, EPPN-501HY, EPPN-502H, NC-2000L, brand name DEN-438 manufactured by Dow Chemical Co., Ltd., brand names Epiclon N-660, N-665 manufactured by DIC Corporation. , N-670, N-673, N-680, N-690, N-695, brand name Epototo YDCN-700-7, YDCN-700-10, manufactured by Shin-Nitetsu Sumikin Chemical Co., Ltd., Nippon Kayaku Cresol novolak-type epoxy resins such as EOCN (registered trademark)-1020, EOCN-102S, EOCN-103S, and EOCN-104S manufactured by Mitsubishi Chemical Corporation, brand names YX4000, YX4000H, and Nippon Kayaku Co., Ltd. ( Biphenyl type epoxy resins such as NC-3000, NC-3000L, NC-3000H, NC-3100, etc., manufactured by DIC Co., Ltd., brand names Epiclon HP-4700, HP-4710, HP-4770, HP Naphthalene type epoxy resins such as -5000, HP-6000, brand names NC-7000L, NC-7300L manufactured by Nippon Kayaku Co., Ltd., brand names Epiclon HP-7200L, HP-7200, HP-7200H manufactured by DIC Co., Ltd. , dicyclopentadiene type epoxy resins such as HP-7200HH, HP-7200HHH, brand name family epoxy resins, and phosphorus-containing epoxy resins such as EXA-9726 manufactured by DIC Co., Ltd., and these may be used individually or in combination.

Some of the epoxy resins and phosphorus compounds generally contain chlorine as an impurity during their production. However, from the viewpoint of reducing environmental load, it is required to reduce the amount of halogen, and it is known that if there is a large amount of chlorine, especially hydrolyzable chlorine, the insulation property decreases. Therefore, the total amount of chlorine in the non-volatile components of the adhesive composition is preferably 500 ppm or less, and more preferably 300 ppm or less.

In addition to the above-mentioned solvent, an organic solvent with a surface tension of 33 dyn/cm or less may be added to the adhesive composition of the present invention in order to increase coating stability without impairing the effect of the present invention. For example, aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane, heptane, and octane, alcoholic solvents such as methanol, ethanol, propanol, butanol, and isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexamethylene. Ketone-based solvents such as rice paddy and cyclopentanone, ether-based solvents such as diethyl ether and tetrahydrofuran, ester-based solvents such as ethyl acetate, butyl acetate, and isobutyl acetate, diethylene glycol monoethyl ether acetate, diethylene glycol Acetate-based solvents, such as monobutyl ether acetate, etc. are mentioned, and these may be used individually, or may be used in combination of plurality. The amount of the solvent to be blended is not particularly limited as long as the resin having an imide bond is dissolved, and is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, with respect to 100 parts by mass of the resin having an imide bond. Typically, it is 200 parts by mass or more. Moreover, it is preferably 2000 parts by mass or less, more preferably 1500 parts by mass or less, and even more preferably 1000 parts by mass or less.

A surface regulator may be added to the adhesive composition of the present invention in order to increase coatability stability within a range that does not impair the effect of the present invention. From the viewpoint of adhesiveness, the surface conditioner preferably has a boiling point of 150°C or lower, and more preferably has a boiling point of 120°C or lower. Specifically, although not particularly limited, Safinol (registered trademark) 104E, 104H, 104A, 104PA, 104S, 420, 440, 465, 485, SE, SE-F, Olfin (registered trademark) manufactured by Nisshin Chemical Co., Ltd. ) EXP. Examples include 4001, 4123, 4200, and 4300, and these may be used singly or in combination. The compounding amount of these surface conditioners is preferably 0.01 to 0.5% by mass, more preferably 0.05 to 0.3% by mass, based on the total mass of the resin having an imide bond and the epoxy resin in the adhesive composition. If the mixing amount of the surface conditioner is small, coating stability may become difficult to obtain, and if the mixing amount is large, there is a risk that adhesiveness may become difficult to develop.

A highly heat-resistant resin can be added to the adhesive composition of the present invention in order to increase insulation reliability in a high-temperature, high-humidity environment at a higher level without impairing the effects of the present invention. The highly heat-resistant resin is preferably a resin having a glass transition temperature of 200°C or higher, and more preferably a resin having a glass transition temperature of 250°C or higher. Although it is not specifically limited, polyimide resin, polyamidoimide resin, polyetherimide resin, polyetheretherketone resin, etc. are mentioned. Additionally, it is preferable that the highly heat-resistant resin is soluble in a solvent. As for satisfying these conditions, a resin in which the anhydride of a polycarboxylic acid having an aromatic ring is 90 mol% or more when the structural units derived from all acid components are 100 mol% is preferable, and among them, polyamideimide resin. is most desirable. Specific raw materials are the same as described above.

In order to promote curing within the range that does not impair the effect of the present invention, a glycidylamine-type epoxy resin may be further added to the adhesive composition of the present invention in addition to the above-mentioned epoxy resin. The amount of glycidylamine type epoxy resin added is preferably 0.01% by mass to 5% by mass, and more preferably 0.05% by mass to 2% by mass, relative to the total mass of the resin having an imide bond in the adhesive composition and the epoxy resin. desirable. If the compounding amount of the glycidylamine type epoxy resin is small, there is a risk that the effect of promoting curing may not be obtained. If the mixing amount is large, the effect of promoting curing of the epoxy groups is large, and the reaction between the reactive functional group of the resin having an imide bond and the epoxy group does not proceed sufficiently, and there is a risk that heat resistance and adhesiveness may decrease. Glycidylamine type epoxy resins include brand names TETRAD (registered trademark)- ) Manufactured brand names YH-434, YH-434L, ADEKA Co., Ltd. brand names Adeka Resin EP-3950S, EP-3950L, EP-3980S, manufactured by Nippon Kayaku Co., Ltd. brand names GAN (registered trademark), GOT (registered trademark) and the like, and these may be used singly or in combination.

An epoxy resin curing agent or curing accelerator can be added to the adhesive composition of the present invention within a range that does not impair the effect of the present invention. The curing agent is not particularly limited as long as it is a compound that reacts with the epoxy resin, and examples include amine-based curing agents, compounds having a phenolic hydroxyl group, compounds having a carboxylic acid, and compounds having an acid anhydride. The curing catalyst is not particularly limited as long as it promotes the reaction between the resin having an imide bond with the epoxy resin and the curing agent, and examples include: 2MZ, 2E4MZ, C11Z, C17Z, 2PZ manufactured by Shikoku Chemical Industry Co., Ltd.; 1B2MZ, 2MZ-CN, 2E4MZ-CN, C11Z-CN, 2PZ-CN, 2PHZ-CN, 2MZ-CNS, 2E4MZ-CNS, 2PZ-CNS, 2MZ-AZINE, 2E4MZ-AZINE, C11ZAZINE, 2MA-OK, 2P4MHZ, Imidazole derivatives such as 2PHZ and 2P4BHZ, guanamines such as acetoguanamine and benzoguanamine, diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenyl sulfone, dicyandiamide, and urea. , polyamines such as urea derivatives, melamine, and polybasic hydrazide, their organic acid salts and/or epoxy adducts, amine complexes of boron trifluoride, ethyldiamino-S-triazine, and 2,4-diamino-S. -Triazine derivatives such as triazine, 2,4-diamino-6-xylyl-S-triazine, trimethylamine, triethanolamine, N,N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N -Methylmorpholine, hexa(N-methyl)melamine, 2,4,6-tris(dimethylaminophenol), tetramethylguanidine, DBU(1,8-diazabicyclo[5,4,0]-7-unde Tertiary amines such as sen) and DBN (1,5-diazabicyclo[4,3,0]-5-nonene), their organic acid salts and/or tetraphenylboroate, polyvinylphenol, and polyvinylphenol bromine. Cargo, organic phosphines such as tributylphosphine, triphenylphosphine, and tris-2-cyanoethylphosphine, tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide, and hexadecyltributyl. Quaternary phosphonium salts such as phosphonium chloride and tetraphenylphosphonium tetraphenylboroate, quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride, the polycarboxylic acid anhydride, and diphenyliodonium tetrafluoride. Roboroate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, Irgacure-261 (manufactured by Chiba Specialty Chemicals Co., Ltd.), Opto Photocationic polymerization catalysts such as Mer SP-170 (manufactured by ADEKA Co., Ltd.), styrene-maleic anhydride resin, equimolar reactants of phenyl isocyanate and dimethylamine, or organic polyisocyanates such as tolylene diisocyanate and isophorone diisocyanate and dimethyl. Equimolar reactants of amines, etc. can be mentioned. These may be used individually, or may be used in combination.

A silane coupling agent may be added to the adhesive composition of the present invention for the purpose of improving adhesiveness within a range that does not impair the effects of the present invention. The silane coupling agent is not particularly limited as long as it is a conventionally known one. Specific examples include aminosilane, mercaptosilane, vinylsilane, epoxysilane, methacrylsilane, isocyanatesilane, ketiminesilane, mixtures or reactants thereof, or compounds obtained by reaction of these with polyisocyanate. You can. Such silane coupling agents include, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylethyldiethoxysilane, and bistrimethoxysilyl. Propylamine, bistriethoxysilylpropylamine, bismethoxydimethoxysilylpropylamine, bisethoxydiethoxysilylpropylamine, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2 -(Aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylethyldiethoxysilane Aminosilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyl, etc. Mercaptosilanes such as ethyldiethoxysilane, vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, tris-(2-methoxyethoxy)vinylsilane, γ-glycidoxypropyltrimethoxysilane, γ -Glycidoxypropyldimethylethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β -Epoxy silanes such as (3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropylmethyldie. Methacrylsilanes such as oxysilane and 3-methacryloxypropyltriethoxysilane, isocyanate silanes such as isocyanate propyltriethoxysilane and isocyanate propyltrimethoxysilane, ketiminated propyltrimethoxysilane, and ketiminated propyltriene. Ketimine silanes, such as toxysilane, can be mentioned, and these may be used individually or in combination of plurality. Among these silane coupling agents, epoxysilane has a reactive epoxy group and can react with a resin having an imide bond, so it is preferable in terms of improving heat resistance and heat-and-moisture resistance. Additionally, the amount of the silane coupling agent added is preferably 0 to 3% by mass, more preferably 0.1 to 2% by mass, based on the non-volatile content of the resin composition. If the mixing amount is large, there is a risk that heat resistance may decrease.

Organic/inorganic fillers may be added to the adhesive composition of the present invention for the purpose of improving solder heat resistance within a range that does not impair the effects of the present invention. Examples of the organic filler include powders such as polyimide and polyamideimide, which are heat-resistant resins. Additionally, inorganic fillers include, for example, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), titania (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), zirconia (ZrO ₂ ), and silicon nitride (Si ₃ N _{4 ).} ), barium titanate (BaO·TiO ₂ ), barium carbonate (BaCO ₃ ), lead titanate (PbO·TiO ₂ ), lead zirconate titanate (PZT), lead lanthanum titanate (PLZT), gallium oxide (Ga ₂ O ₃ ) , spinel (MgO·Al ₂ O ₃ ), mullite (3Al ₂ O ₃ ·2SiO ₂ ), cordierite (2MgO·2Al ₂ O ₃ ·5SiO ₂ ), talc (3MgO·4SiO ₂ ·H ₂ O), Aluminum titanate (TiO ₂ -Al ₂ O ₃ ), yttria-containing zirconia (Y ₂ O ₃ -ZrO ₂ ), barium silicate (BaO·8SiO ₂ ), boron nitride (BN), calcium carbonate (CaCO ₃ ), calcium sulfate. (CaSO ₄ ), zinc oxide (ZnO), magnesium titanate (MgO·TiO ₂ ), barium sulfate (BaSO ₄ ), organic bentonite, clay, mica, aluminum hydroxide, magnesium hydroxide, etc. Among these, dispersion Silica is preferred for ease of use and improved heat resistance. These may be used individually, or may be used in combination. Moreover, the addition amount of these organic/inorganic fillers is preferably 1 to 30% by mass, more preferably 3 to 15% by mass, relative to the non-volatile component of the adhesive composition. If the mixing amount is large, the adhesive coating film becomes embrittled, and if the mixing amount is small, there is a risk that sufficient heat resistance improvement may not be achieved.

An example of a method for producing the adhesive composition of the present invention will be described. A solvent solution of a resin having an imide bond (hereinafter also referred to as a resin varnish having an imide bond), a solvent solution of an epoxy resin (hereinafter also referred to as an epoxy resin varnish), and a phosphorus compound of general formula (1) are mixed. , Stir so that the system becomes uniform. When using a filler, what is made into a slurry with the above solvent is added as a filler and further stirred. As a result, the adhesive composition of the present invention is obtained. Additionally, when obtaining the adhesive composition, a diluting solvent or a curing accelerator for viscosity adjustment may be added as needed.

The adhesive composition of the present invention can be used as an adhesive composition suitable for flexible printed wiring boards. The layer of the adhesive composition after applying the adhesive composition to a substrate such as a film and drying it is called an adhesive layer. In flexible printed wiring boards, the areas where adhesives made of the adhesive composition are used include adhesive films for reinforcement plates and adhesives for interlayer applications. Examples include films, coverlay films, and copper-clad laminates.

The adhesive film is a film consisting of “protective film/adhesive layer” or “protective film/adhesive layer/protective film”. In some cases, an insulating film layer is formed in the adhesive layer, and the structure is "protective film/adhesive layer/insulating film/adhesive layer/protective film layer." In flexible printed wiring boards, it is often used as an adhesive film for reinforcement plates or as an adhesive film for interlayer applications.

The insulating film is a film with a thickness of 1 to 200 ㎛ made of plastic such as polyimide, polyamidoimide, polyester, polyphenylene sulfide, polyether sulfone, polyether ether ketone, aramid, polycarbonate, and polyarylate, A plurality of films selected from these may be laminated.

The protective film is not particularly limited as long as it can be peeled without damaging the properties of the adhesive, but for example, polyethylene, polypropylene, polyolefin, polyester, polymethylpentene, polyvinyl chloride, polyvinylidene fluoride, polyphenylene sulfide, etc. Examples include plastic films, films coated with silicone, fluoride, or other mold release agents, paper laminated with these films, and paper impregnated or coated with a peelable resin.

A coverlay film is a film composed of “insulating film/adhesive layer” or “insulating film/adhesive layer/protective film”.

A copper clad laminate is a laminate made of “copper foil/adhesive layer/insulating film” or “copper foil/adhesive layer/insulating film/adhesive layer/copper foil”. The copper foil is not particularly limited, but rolled copper foil and electrolytic copper foil conventionally used for flexible printed wiring boards can be used.

In any of the above applications, it is obtained by applying the adhesive composition onto a base film or copper foil, drying it with a solvent, and then performing heat compression and heat curing treatment with the adherend. In adhesive films and coverlay films, for the purpose of adjusting the fluidity of the adhesive composition during heat compression, heat treatment is performed after solvent drying to form a resin having an imide bond and a phosphorus having a reactive group containing a phosphorus compound of the general formula (1). In some cases, the compound and epoxy resin are partially reacted. In addition, the state before thermocompression bonding is called B stage.

In any of the above applications, adhesion, heat resistance, and insulation reliability are required after heat curing, and it is also desirable to have flame retardancy. Additionally, with adhesive films and coverlay films, it is common to perform processing such as winding, preservation, cutting, and punching in the B-stage state, and flexibility in the B-stage state is also required. On the other hand, in copper clad laminates, it is common to perform heat compression and heat curing immediately after forming the B stage state, and flexibility in the B stage state is not required as much as the coverlay film and adhesive film.

The adhesive film and coverlay film of the present invention preferably have a residual solvent amount of less than 1.5% by mass in the adhesive layer in the B stage state. More preferably, it is 1.0 mass% or less. The residual solvent is a solvent used in the adhesive composition that was not completely removed in the B staging process, and when multiple solvents are used in combination, a solvent with a higher boiling point remains. Since insulation reliability may deteriorate if the amount of residual solvent is large, as described above, the amount of residual solvent in the adhesive layer in the B stage is preferably less than 1.5% by mass, and more preferably 1.0% by mass. % or less.

The adhesive composition containing the resin having an imide bond of the present invention and the phosphorus compound of general formula (1) is excellent in adhesiveness, heat resistance, flame retardancy and insulation reliability. In addition, the phosphorus compound of general formula (1) has excellent solvent solubility and thus has excellent handleability. In addition, the phosphorus compound of general formula (1) has excellent compatibility with resins having an imide bond and has a reactive functional group, so it is incorporated into crosslinking by heat curing and is difficult to bleed out under a high temperature and high humidity environment. there is. Therefore, the adhesive composition containing the resin having an imide bond of the present invention and the phosphorus compound of general formula (1) exhibits high insulation reliability.

Example

Hereinafter, the effects of the present invention will be demonstrated by examples, but the present invention is not limited to these. Evaluation of the properties in the examples was performed by the following method. In the Examples and Comparative Examples, simply parts indicate parts by mass.

logarithmic viscosity;

The resin having an imide bond was dissolved in N-methyl-2-pyrrolidone so that the polymer concentration was 0.5 g/dl. The solution viscosity and solvent viscosity of the obtained solution were measured using an Ubberod-type viscosity tube at 30°C, and the logarithmic viscosity was calculated according to the following equation.

Logarithmic viscosity (dl/g)=[ln(V2/V1)]/V3

In the above formula, V1 represents the resin solution viscosity measured with an Ubbelode-type viscosity tube, and V2 represents the solvent viscosity measured with an Ubbelrod-type viscosity tube. V1 and V2 were determined from the time for the resin solution and solvent (N-methyl-2-pyrrolidone) to pass through the capillary of the viscosity tube. Additionally, V3 is the resin concentration (g/dl).

acid value;

0.1 g of a resin having an imide bond is dissolved in 20 ml of N-methyl-2-pyrrolidone, titrated with a 0.1 N KOH ethanol solution using thymolphthalein as an indicator, and the carboxyl group per 10 ⁶ g of resin is obtained. The equivalent weight (eq/ton) was measured, and the acid value was calculated according to the formula below.

Acid value (mgKOH/g)=[Carboxyl group equivalent (eq/ton)×56.12]/1000

Glass transition temperature:

A solution of a resin having an imide bond was applied to the glossy surface of copper foil and dried in a hot air dryer at 140°C for 3 minutes. After that, copper foil with resin was obtained by drying in a nitrogen atmosphere at 250°C for 30 minutes. After that, a resin film with a thickness of 20 μm was produced by etching the copper foil. The glass transition point of the resin film produced in this way was measured by the TMA (thermo-mechanical analysis device) tensile method under the conditions of a load of 50 mN and a temperature increase rate of 10°C/min.

adhesiveness;

The solution of the adhesive composition was applied to a polyimide (PI) film (Kaneka Apical (registered trademark) 12.5NPI) so that the adhesive layer had a thickness of 20 ㎛ after drying, and dried in a hot air circulation dryer at 140°C for 3 minutes. Thus, a sample in the B stage state (PI film/adhesive layer) was obtained. The adhesive-coated surface of this B-stage sample (PI film/adhesive layer) and rolled copper foil (BHY-13 F-T manufactured by JX Metals: thickness 18 ㎛) were subjected to reduced pressure at 160°C, 20 kgf, and 60 seconds using a vacuum press laminating machine. It was heat compressed. Afterwards, it was heat-cured at 170°C for 3 hours. The cured sample (PI film/adhesive layer/rolled copper foil) was tested using a tensile tester (Autograph AG-X plus manufactured by Shimadzu) in an atmosphere of 25°C, and the polyimide film was tested in a 90° direction at a speed of 50 mm/min. The adhesive strength was measured by peeling.

◎: Adhesive strength is 0.7 N/mm or more or polyimide film is broken.

○: Adhesive strength is 0.5 N/mm or more and less than 0.7 N/mm

×: Adhesive strength is less than 0.5 N/mm

Solder heat resistance;

A heat-cured sample (PI film/adhesive layer/rolled copper foil) was produced in the same manner as the evaluation of adhesiveness, cut into 20 mm x 20 mm, and floated in a 300°C solder bath with the polyimide side up for 1 minute. Appearance was evaluated.

○: No swelling or peeling

×: Expansion or peeling

flame retardant;

The solution of the adhesive composition was applied to a polyimide film (Apical 12.5NPI, manufactured by Kaneka) so that the thickness of the adhesive layer after drying was 20 ㎛, dried in a hot air circulation dryer at 140°C for 3 minutes, and a sample in the B stage was obtained. (PI film/adhesive layer) was obtained. The adhesive-coated surface of this B-stage sample (PI film/adhesive layer) and the polyimide film (Apical 12.5NPI manufactured by Kaneka) were heat-compressed under reduced pressure at 160°C, 20 kgf, and 60 seconds using a vacuum press laminating machine. I ordered it. Afterwards, it was heat-cured at 170°C for 3 hours. The flame retardancy of the cured sample (PI film/adhesive layer/PI film) was evaluated based on the UL-94VTM standard.

○: VTM-0 equivalent

×: Does not satisfy VTM-0

insulation reliability;

The solution of the adhesive composition was applied to a polyimide film (Apical 12.5NPI, manufactured by Kaneka) so that the thickness of the adhesive layer after drying was 20 ㎛, dried in a hot air circulation dryer at 140°C for 3 minutes, and a sample in the B stage was obtained. (PI film/adhesive layer) was obtained. The adhesive-coated surface of this B-stage sample (PI film/adhesive layer) and a single-sided copper-clad laminate etched in a comb-shaped pattern with L/S = 50/50 ㎛ (trade name: Espanex, manufactured by Shinnitetsu Sumikin Chemical Co., Ltd.) (registered trademark: MC12-25-00CEM) was heat-compressed using a vacuum press laminating machine at 160°C, 20 kgf, and reduced pressure for 60 seconds. Afterwards, it was heat-cured at 170°C for 3 hours. A voltage of 200 V was applied to the cured sample (PI film/adhesive layer/single-sided copper-clad laminate) in an environment with a temperature of 85°C and a humidity of 85% for 250 hours.

◎: Resistance value after 250 hours is 1×10 ¹⁰ Ω or more, and there are no dendrites.

○: Resistance value after 250 hours is 1×10 ⁹ Ω or more but less than 1×10 ¹⁰ Ω, and no dendrite occurs.

×: Resistance value after 250 hours is less than 1×10 ⁹ Ω or dendrites occur.

××: Short circuit within 250 hours

Synthesis Example 1;

In a four-necked flask equipped with a stirrer, a solvent recovery device with a cooling tube, a nitrogen introduction tube, and a thermometer, HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene, brand name, manufactured by Sanko Co., Ltd.) Add 558.3 g of -10-oxide and 391.6 g of brand name Phenodur (registered trademark) PR411 (75% solid content in butanol) manufactured by Allnex Co., Ltd., stir and flow nitrogen, and raise the temperature in the flask to 199°C for 180 minutes. The temperature was raised throughout. In the process, butanol contained in the raw materials and butanol produced by the reaction were discharged through a solvent recovery device. After that, the reaction was maintained at 200°C for 20 minutes, and the volatile matter remaining in the reaction product was distilled out. The obtained solid was taken out from the flask to obtain phosphorus compound A. Phosphorus Compound A has the structure of formula (9).

Polymerization of resins 1 to 2 having an imide bond;

Polymerization of a resin having an imide bond was performed using the resin composition (mol%) of the raw materials shown in Table 1. Specifically, polymerization was performed as follows.

Polymerization of Resin 1 with Imide Bonds

In a four-necked separable flask equipped with a stirrer, cooling pipe, nitrogen inlet pipe, and thermometer, 110.47 g (0.575 mole) of TMA (trimellitic acid anhydride), 80.90 g (0.40 mole) of sebacic acid, and NBR (acrylic modified with carboxyl groups at both ends) Ronitrile butadiene rubber) 87.5 g (0.025 mol), MDI (diphenylmethane-4,4'-diisocyanate) 250.25 g (1.00 mol), and dimethylacetamide 714.50 so that the concentration of the resin content after decarboxylation is 40% by mass. g was added, the temperature was raised to 100°C under nitrogen and reaction was carried out for 2 hours, and the temperature was raised to 150°C and reaction was continued for another 5 hours. After that, 396.94 g of dimethylacetamide was added and diluted so that the concentration of the resin content was 30% by mass, and a solution of Resin 1 having an imide bond was obtained.

Polymerization of Resin 2 with Imide Bonds

In a four-necked separable flask equipped with a stirrer, cooling pipe, nitrogen introduction pipe, and thermometer, 192.13 g (1.00 mol) of trimellitic anhydride, 225.23 g (0.90 mol) of diphenylmethane-4,4'-diisocyanate, and decarburization were added. 494.05 g of N-methyl-2-pyrrolidone was added so that the concentration of the postpartum resin content was 40% by mass, the temperature was raised to 100°C under nitrogen and reaction was carried out for 2 hours, and the temperature was raised to 150°C and reaction was continued for 5 hours. After that, 117.63 g of dimethylacetamide was added and diluted so that the concentration of the resin content was 35% by mass, and a solution of Resin 2 having an imide bond was obtained.

Preparation of solutions of adhesive compositions;

A dimethylacetamide solution or N-methyl-2-pyrrolidone solution of the adhesive composition of Examples 1 to 7 and Comparative Examples 1 to 4 was prepared according to the adhesive formulation (solid content (% by mass)) shown in Table 2, and characteristics were evaluated.

As can be seen in Table 2, the adhesive compositions of Examples 1 to 7 that satisfy the conditions of the present invention show excellent results in adhesiveness, solder heat resistance, flame retardancy, and insulation reliability, while those that do not contain a phosphorus compound Comparative Example 1, Comparative Example 2 and Comparative Example 3 not containing the phosphorus compound of general formula (1), and Comparative Example 4 not containing the resin having an imide bond resulted in certain characteristics being unsatisfactory.

(Industrial applicability)

The adhesive composition of the present invention is excellent in adhesion, heat resistance, flame retardancy, handleability, and insulation reliability by combining a resin having an imide bond and a specific phosphorus compound, and is used in adhesive films, coverlay films, copper-clad laminates, etc. It is suitable and very useful.

Claims (11)

An adhesive composition comprising a resin having an imide bond and a phosphorus compound represented by general formula (1).

(R ₁ to _{R 4} in General Formula (1) is any of the following General Formulas (2) to (4), and at least one of R ₁ to R ₄ is General Formula (2). General Formula (2) * in -(4) represents a site directly bonded to the aromatic ring of General Formula (1), and each of plural Xs in General Formula (1) and (3) is independently CH ₂ or C. (CH ₃ ) ₂ , and each Y in the formulas (1) and (3) is independently hydrogen or a hydroxyl group. However, in the formula (1), at least one of the Ys is a hydroxyl group. R ₅ in general formula (4) is hydrogen or an alkyl group having 1 to 10 carbon atoms.

The adhesive composition according to claim 1, wherein the resin having the imide bond is a polyimide resin, polyamidoimide resin, polyetherimide resin, polyesterimide resin, or polycarbonateimide resin. The adhesive composition according to claim 1 or 2, which contains trimellitic anhydride as a copolymerization component of the resin having an imide bond. The adhesive composition according to claim 1 or 2, which contains acrylonitrile butadiene rubber modified with carboxyl groups at both ends as a copolymerization component of the resin having an imide bond. The adhesive composition according to claim 1 or 2, further comprising an epoxy resin. The adhesive composition according to claim 5, wherein the epoxy resin is liquid at 25°C and has two or more epoxy groups per molecule. The adhesive composition according to claim 1 or 2, which is used in printed wiring board applications. An adhesive film comprising the adhesive composition according to claim 1. A coverlay film characterized by using the adhesive film according to claim 8. A copper-clad laminate using the adhesive film according to claim 8. A flexible printed wiring board using the coverlay film according to claim 9 or the copper-clad laminate according to claim 10.