JP4704082B2 - Adhesive composition and flexible printed wiring board using the same - Google Patents

Description

  The present invention relates to an adhesive composition and a flexible printed wiring board using the same, and more specifically, an adhesive composition for bonding an insulating film of a flexible printed wiring board and a metal foil and the use thereof. The present invention relates to a flexible printed wiring board.

  Generally, a flexible printed wiring board (flexible printed wiring board) uses an insulating film made of a heat resistant film such as a polyimide film as a base material, and a metal foil such as a copper foil is used as an adhesive on one or both sides of the insulating film. It is based on the structure that is bonded together. As such an adhesive, conventionally, a thermosetting adhesive such as an epoxy resin or an acrylic resin has been used. However, the thermosetting adhesives such as the epoxy resin have a problem that the adhesive layer is swollen in the soldering process because the thermal characteristics are remarkably inferior to those of the insulating film (polyimide film or the like).

  In order to solve such problems, it is proposed to use heat-resistant resins such as polyamideimide resins and bismaleimide resins with relatively low molecular weights as adhesives instead of conventional thermosetting adhesives such as epoxy resins. Has been.

  However, the adhesive layer using a heat-resistant resin such as the polyamide-imide resin is poor in flexibility and has a small elongation at break, so that when the flexible printed wiring board is folded and used, an insulating film or There are drawbacks such as insufficient adhesion to the metal foil. In addition, when using a heat-resistant resin such as the polyamide-imide resin as an adhesive, severe work conditions such as laminating an insulating film and a metal foil at high temperature and high pressure are required, so that workability is inferior. There are also difficulties.

Therefore, as a technique for imparting flexibility to the polyamide-imide resin, a technique for copolymerizing a polyamide-imide resin with carboxylic acid-terminated butadiene-acrylonitrile rubber, a technique for copolymerizing a polyamide-imide resin with a siloxane compound, and the like have been proposed. (For example, refer to Patent Document 1).
JP 2001-131525 A

  However, when the carboxylic acid both terminal butadiene-acrylonitrile rubber is copolymerized with the polyamide-imide resin as in Patent Document 1, the flexibility is somewhat improved, but the effect is small. Accordingly, since it is necessary to copolymerize carboxylic acid-terminated butadiene-acrylonitrile rubber in a large amount, the physical properties such as heat resistance and the like inherent in the polyamide-imide resin are impaired, and the adhesiveness is insufficient. It was. Moreover, the method of copolymerizing a siloxane compound with the polyamide-imide resin has a drawback that the cost is low and the economy is poor.

  The present invention has been made in view of such circumstances, and is excellent in workability and flexibility, and can improve heat resistance and adhesive force, and an adhesive composition and a flexible printed wiring board using the same The purpose is to provide.

In order to achieve the above object, the present invention comprises the following (A) and (B) as essential components, and the weight mixing ratio of (A) and (B) is (A) / (B) = the Ru der range of 50 / 50-80 / 20 adhesive composition to the first aspect. Moreover, this invention makes the 2nd summary the flexible printed wiring board formed using the said adhesive composition.

(A) A modified polyamideimide resin obtained by copolymerizing the following (a) to (c).
(A) An aromatic isocyanate compound.
(B) An aromatic tricarboxylic acid anhydride.
(C) Ca carboxylic acid both terminated polyamide.
(B) At least one epoxy resin of the following (d) and (e).
(D) An epoxy resin that is solid or semi-solid at normal temperature and has a softening point of 65 ° C. or lower.
(E) Epoxy resin that is liquid at room temperature.

That is, the present inventors have intensively studied in order to obtain an adhesive composition that is excellent in workability and flexibility and can improve heat resistance and adhesive strength. As a result, the aromatic isocyanate compound (a), anhydride of an aromatic tricarboxylic acid and (b), and mosquito carboxylic acid both ends polyamide (c) and by copolymerizing a modified polyamide-imide resin (A component) And an epoxy resin (component B) that is solid or semisolid at room temperature and has a softening point of 65 ° C. or lower and an epoxy resin (e) that is liquid at room temperature as an essential component It was found that the intended purpose can be achieved by the adhesive composition, and the present invention has been achieved. That is, the (a) the use - the copolymerization is allowed to become modified polyamideimide resin (A component) (c), the upper hear carboxylic acid both ends polyamide (c) is a soft segment specific role and ideas Therefore, flexibility can be imparted to the polyamide-imide resin. The upper hear carboxylic acid both ends polyamide (c) is relatively small because the flexibility can be imparted by, that without impairing the intrinsic heat-resistant polyamide-imide resin, moreover thermal bonding at a relatively low temperature of 200 ° C. or less Because it is possible, it is excellent in workability. In addition, when this modified polyamideimide resin (component A) is used in combination with an epoxy resin (component B) composed of at least one of the above (d) and (e), the modified polyamideimide resin ( Compared with the case where component A) is used alone, the adhesiveness is remarkably improved and the heat resistance is improved.

Thus, the adhesive composition of the present invention comprises a modified polyamideimide resin (component A) obtained by copolymerizing the above (a) to (c), and at least one of the above (d) and (e). An epoxy resin (component B) is used in combination. The adhesive composition of the present invention, since the upper hear carboxylic acid both ends polyamide (c) is used copolymerized modified polyamideimide resin (A component), together with an excellent flexibility, the modified polyamide Since the imide resin (component A) is excellent in solvent solubility and can be thermally bonded even at a relatively low temperature (for example, 200 ° C. or lower), it is excellent in workability. And since the specific epoxy resin (B component) is used together, the improvement effect of adhesiveness or heat resistance can also be acquired.

  Moreover, when the weight mixing ratio of the modified polyamideimide resin and the specific epoxy resin is within a predetermined range, the balance of physical properties such as flexibility, heat resistance, and adhesiveness is improved.

  And the flexible printed wiring board which uses the adhesive composition of the said invention is excellent in solder heat resistance, since the swelling of an adhesive bond layer etc. do not arise at a soldering process.

  Next, an embodiment of the present invention will be described.

The adhesive composition of the present invention comprises a modified polyamideimide resin (component A) obtained by copolymerizing the following (a) to (c) and a specific epoxy resin (component B) as essential components. is there.
(A) An aromatic isocyanate compound.
(B) An aromatic tricarboxylic acid anhydride.
(C) Ca carboxylic acid both terminated polyamide.

Here, in the present invention, the specific modified polyamideimide (PAI) resin (component A) introduces the structural unit derived from (c) as a soft segment in the molecular structure of the PAI resin. And the specific epoxy resin (component B) is at least one of the following (d) and (e), and these are the greatest features.
(D) An epoxy resin that is solid or semi-solid at normal temperature and has a softening point of 65 ° C. or lower.
(E) Epoxy resin that is liquid at room temperature.

  In the present invention, the aromatic isocyanate compound (a) used for forming the modified PAI resin (component A) is not particularly limited as long as it is a compound having an aromatic ring in the molecular structure. For example, diphenylmethane Diisocyanate (MDI), toluene diisocyanate (TDI), tolidine diisocyanate (TODI), xylylene diisocyanate (XDI), lysine diisocyanate (LDI), naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PPDI), tetramethylxylene diisocyanate (TMXDI) Etc. These may be used alone or in combination of two or more. Among these, MDI and TODI are preferably used in terms of reactivity, cost, and solubility.

  The anhydride (b) of the aromatic tricarboxylic acid is not particularly limited as long as it has an aromatic ring in the molecular structure and undergoes a condensation reaction with the aromatic isocyanate compound (a). , Trimellitic anhydride (trimellitic anhydride), naphthalene-1,2,4-tricarboxylic acid anhydride, and the like. These may be used alone or in combination of two or more. Among these, trimellitic anhydride (trimellitic anhydride) is preferably used in terms of reactivity, cost, solubility, and the like.

  In the present invention, an aromatic polycarboxylic acid dianhydride, an aromatic polycarboxylic acid, or the like may be used in combination with the aromatic tricarboxylic acid anhydride (b).

  Examples of the dianhydride of the aromatic polyvalent carboxylic acid include, for example, benzene-1,2,4,5-tetracarboxylic acid (pyromellitic acid), benzophenone-3,3 ', 4,4'-tetracarboxylic acid. Diphenyl ether-3,3 ', 4,4'-tetracarboxylic acid, benzene-1,2,3,4-tetracarboxylic acid, biphenyl-3,3', 4,4'-tetracarboxylic acid, biphenyl-2 , 2 ', 3,3'-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid, naphthalene-1,4,5,8 -Tetracarboxylic acid, decahydronaphthalene-1,4,5,8-tetracarboxylic acid, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6 -Tetracarboxylic acid, 2 6-dichloronaphthalene-1,4,5,8-tetracarboxylic acid, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic acid, 2,3,6,7-tetrachloronaphthalene-1, 4,5,8-tetracarboxylic acid, phenanthrene-1,3,9,10-tetracarboxylic acid, perylene-3,4,9,10-tetracarboxylic acid, bis (2,3-dicarboxyphenyl) methane, Bis (3,4-dicarboxyphenyl) methane, 1,1-bis (2,3-dicarboxyphenyl) ethane, 1,1-bis (3,4-dicarboxyphenyl) ethane, 2,2-bis ( 2,3-dicarboxyphenyl) propane, 2,3-bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxy) Eniru) ether, ethylene glycol bis (anhydrotrimellitate), and propylene glycol bis (anhydrotrimellitate) and the like. These may be used alone or in combination of two or more.

Next, to introduce a soft segment part in PAI resin skeleton, upper hear carboxylic acid both terminated polyamide (hereinafter, referred to as "carboxylic acid both terminated polymer") (c) is a carboxylic acid on both ends of polyamides As long as it has, there is no particular limitation.

The carboxylic acid used to introduce the carboxylic acid at both ends of the upper Kipo polyamide is not particularly limited, for example, aliphatic carboxylic acids, and aromatic carboxylic acid. These may be used alone or in combination of two or more.

  Examples of the aliphatic carboxylic acid include adipic acid, sebacic acid, oxalic acid, succinic acid, corkic acid, azelaic acid, dodecanedicarboxylic acid, undecanedicarboxylic acid, maleic acid, fumaric acid and the like. Examples of the aromatic carboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, chlorophthalic acid, and nitrophthalic acid.

The carboxylic acid both terminated polymer (c) is, for example, at both ends of the synthesized polyamides according to the usual method, can be obtained by introducing the carboxylic acid as described above. It should be noted that the synthesis of the above Kipo polyamide is not particularly limited, for example, 4th Edition Experimental Chemistry 28 Polymer Synthesis (edited by the Chemical Society of Japan, 1992, Maruzen Co., Ltd.), the first 208 pages of the, second, It can be produced according to the methods described on pages 231 and 252 to 287.

  The carboxylic acid both-end polyester can be prepared, for example, as follows. That is, in a reaction vessel equipped with a heating device, a stirring device, a reflux device, a water separator, a distillation column and a thermometer, a dicarboxylic acid such as adipic acid or sebacic acid, methylpentanediol, nonanediol, methyloctanediol, etc. Diol is charged, and the temperature is raised to a predetermined temperature (usually about 220 ° C.) over a predetermined time (usually about 1 hour). Furthermore, after continuing the polycondensation reaction at a predetermined temperature (usually about 220 ° C.), the desired carboxylic acid-terminated polyester can be obtained by cooling to a predetermined temperature (usually about room temperature).

  In addition, carboxylic acid both terminal polyamide can also be suitably produced by introducing carboxylic acid into both terminals in accordance with the above-mentioned method for producing carboxylic acid both terminal polyester.

  The acid value of the carboxylic acid bi-terminal polymer (c) thus obtained is preferably in the range of 30 to 120 mgKOH / g, particularly preferably in the range of 38 to 112 mgKOH / g.

  Moreover, the number average molecular weight (Mn) of the carboxylic acid both terminal polymer (c) is preferably in the range of 900 to 3800, particularly preferably the number average molecular weight (Mn) is in the range of 1000 to 3000.

  The content of the structural unit derived from the carboxylic acid both-end polymer (c) is preferably 5% by weight or more, particularly preferably in the range of 5 to 65% by weight based on the whole modified PAI resin (component A). Is within. That is, if it is less than 5% by weight, it is difficult to obtain the effect of flexibility.

  The mixing ratio of the aromatic isocyanate compound (a) to the aromatic tricarboxylic acid anhydride (b) and the carboxylic acid both-end polymer (c) is (a) / [(b) + (c )]] = 0.9 / 1 to 1.4 / 1 is preferable, and (a) / [(b) + (c)] = 1/1 to 1.25 / 1 is particularly preferable. is there. That is, when the molar ratio of (a) is less than 0.9, the molecular weight of the resulting modified PAI resin (component A) is decreased, and the tensile fracture strain tends to decrease. This is because when the ratio exceeds 1.4, the tensile modulus of elasticity of the resulting modified PAI resin (component A) increases and the flexibility tends to deteriorate.

Here, the modified PAI resin (component A) obtained by copolymerizing the above (a) to (c) can be prepared, for example, as follows. That is, a reaction vessel equipped with a stirrer, a nitrogen introducing tube, a thermometer, and a cooling tube was prepared, and the aromatic isocyanate compound (a) and an aromatic tricarboxylic acid anhydride (b) such as trimellitic anhydride , mosquitoes carboxylic acid both terminated polymer and (c) a predetermined amount, N- methyl-2-pyrrolidone (NMP), N, N- dimethylformamide (DMF), N, N- dimethylacetamide (DMAC), .gamma. A polar solvent such as butyrolactone is charged and heated to a predetermined temperature (preferably 130 to 150 ° C.) over a predetermined time (preferably 1 to 2 hours) with stirring in a nitrogen stream. Next, after reacting at a predetermined temperature (preferably 130 to 150 ° C.) for a predetermined time (preferably about 3 to 5 hours), the modified PAI resin (component A) is prepared by stopping the reaction. Can do.

  The modified PAI resin (component A) preferably has a number average molecular weight (Mn) in the range of 5,000 to 100,000, particularly preferably Mn in the range of 10,000 to 50,000. That is, if the Mn of the modified PAI resin (component A) is less than 5,000, the tear strength is lowered and the durability deteriorates. Conversely, if the Mn of the modified PAI resin (component A) exceeds 100,000. This is because the viscosity of the solution increases and the workability tends to deteriorate. The number average molecular weight (Mn) can be measured by a gel permeation chromatograph (GPC) method.

Next, as the specific epoxy resin (component B) used together with the specific modified polyamideimide resin (component A), at least one of the following epoxy resins (d) and (e) is used.
(D) An epoxy resin that is solid or semi-solid at normal temperature and has a softening point of 65 ° C. or lower.
(E) Epoxy resin that is liquid at room temperature.

  In the present invention, the normal temperature generally refers to a temperature of about 25 ° C., and the semi-solid state refers to a solid water tank-like shape that is deformed when pressed with a finger. The softening point refers to the temperature at which the epoxy resin starts to soften, and refers to the temperature measured by the ring and ball method (JIS K 7234) or the like.

  In the specific epoxy resin (d), the softening point must be 65 ° C. or lower. That is, when the softening point exceeds 65 ° C., the heat laminating property is inferior.

  The epoxy equivalent of the specific epoxy resin (d) or the specific epoxy resin (e) is preferably in the range of 160 to 2000, particularly preferably in the range of 180 to 500.

  The specific epoxy resin (component B) is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, novolak Type epoxy resin, cresol novolac type epoxy resin, brominated epoxy resin, cycloaliphatic epoxy resin, heterocyclic epoxy resin and the like. These may be used alone or in combination of two or more.

Here, the weight mixing ratio of the specific modified polyamideimide resin (component A) and the specific epoxy resin (component B) is within the range of component A / component B = 50/50 to 80/20 , Preferably it is in the range of A component / B component = 60 / 40-75 / 25. That is, when the weight ratio of the A component is less than 50 (the weight ratio of the B component exceeds 50), the heat resistance tends to deteriorate, and conversely the weight ratio of the A component exceeds 80 (the B component This is because if the weight ratio is less than 20, the adhesiveness tends to deteriorate.

  In addition to the A component and B component, the adhesive composition of the present invention includes a curing accelerator, a flame retardant, a silane coupling agent, a heat aging inhibitor, a leveling agent, an antifoaming agent, an inorganic filler, and the like. Additives may be appropriately blended as necessary.

  Examples of the curing accelerator include imidazole derivatives and aromatic carboxylic acids. These may be used alone or in combination of two or more.

  The imidazole derivative is not particularly limited, and examples thereof include 2-methylimidazole, 2-ethyl-4-methylimidazole (2E4MZ), 2-undecylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl- 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6- (2-methyl-1-imidazolyl) -ethyl-1,3,5-triazine, 2,4 -Diamino-6- (2-undecyl-1-imidazolylethyl) -1,3,5-triazine, 2,4-diamino-6- (2-ethyl-4-methyl-1-imidazolylethyl) -1,3 , 5-triazine and the like. These may be used alone or in combination of two or more.

  The aromatic carboxylic acid is not particularly limited, and examples thereof include benzoic acid, 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid, 1,2,3- Examples thereof include benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid (trimellitic acid: TMA), 1,3,5-benzenetricarboxylic acid and the like. These may be used alone or in combination of two or more.

  The blending ratio of the curing accelerator is not particularly limited, but is preferably in the range of 0.01 to 2.0 parts with respect to 100 parts by weight (hereinafter abbreviated as “part”) of the total amount of components A and B. Particularly preferably, it is in the range of 0.1 to 1.5 parts.

  The adhesive composition of the present invention can be obtained by mixing and stirring the above-described components, and is usually used after being dissolved in a solvent. As the solvent, those which can dissolve the above-mentioned components are preferably used. Specifically, methanol, ethanol, i-propyl alcohol, n-propyl alcohol, i-butyl alcohol, n-butyl alcohol , Benzyl alcohol, ethylene glycol methyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diacetone alcohol and other alcohol solvents, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone and other ketone solvents , Aromatic solvents such as toluene, xylene, ethylbenzene, mesitylene, methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate Ester solvents such as 3-methoxybutyl acetate, chlorine solvents such as chloroform, carbon tetrachloride, dichloromethane, trichloromethane, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide (DMAC), N-methyl- Examples include 2-pyrrolidone (NMP). These may be used alone or in combination of two or more.

  And as mentioned above, when using the adhesive composition of this invention melt | dissolving in a solvent, it is preferable that the resin solid content density | concentration is set to 3 to 80 weight%, More preferably, it is 10-50. It is in the range of wt%. That is, when the concentration exceeds 80% by weight, the viscosity of the solution becomes too high, so that it is difficult to uniformly apply to an object to be coated such as a resin film, and conversely less than 3% by weight is desired. This is because it becomes difficult to form a coating film having a thickness.

  The use of the adhesive composition of the present invention is not particularly limited, and for example, it is used for flexible printed wiring boards, electromagnetic wave shielding materials and the like.

  Next, as the flexible printed wiring board of the present invention, for example, as shown in FIG. 1, a metal foil 3 is formed on one side of the insulating film 1 via an adhesive layer 2, and the insulating film 1 is formed. There is a double-sided metal foil-clad laminate in which a metal foil 5 is formed on the other surface of the metal foil 5 with an adhesive layer 4 interposed therebetween.

  In the present invention, the adhesive layers 2 and 4 are formed using the above-described adhesive composition of the present invention, and this is the greatest feature.

  The material for forming the insulating film 1 is not particularly limited, and examples thereof include polyimide, polyester, polyether ketone, polyphenylene sulfide, aramid, polycarbonate, and polyether sulfone. Moreover, the thickness of the insulating film 1 is not particularly limited, but usually a thickness in the range of 7.5 to 125 μm is used.

  The metal foils 3 and 5 are not particularly limited, and examples thereof include a copper foil and an aluminum foil. A copper foil is preferably used. Further, the thickness of the metal foils 3 and 5 is not particularly limited, but usually a thickness in the range of 9 to 105 μm is used.

  The double-sided metal foil-clad laminate of the present invention shown in FIG. 1 can be produced, for example, as follows. That is, after producing the adhesive composition of this invention like the above, this is melt | dissolved in a solvent and adhesive solution (adhesive varnish) is prepared. And after apply | coating the said adhesive solution (adhesive varnish) to the single side | surface of the prepared insulating film 1 by the roll coater method, it heat-drys (usually about 180 degreeC x about 4 minutes), and the single side | surface of the insulating film 1 Then, the adhesive layer 2 is formed. Next, the metal foil 3 is bonded to the surface of the adhesive layer 2 by thermal lamination. Next, after the adhesive layer 4 is formed on the other surface of the insulating film 1 in the same manner, the metal foil 5 is bonded to the surface of the adhesive layer 4 using a heating roll or the like. Next, this is heat-cured (usually about 80 to 160 ° C. × 4 hours), and the adhesive layers 2 and 4 are cured, whereby a double-sided metal foil-clad laminate can be obtained (see FIG. 1). ).

  The method of applying the adhesive solution (adhesive varnish) is not limited to the roll coater method, and can be performed by various methods such as a die coater, a comma coater, and a knife coater. Moreover, the thickness of the adhesive layers 2 and 4 is not particularly limited, but is preferably set in the range of 1 to 100 μm, and more preferably in the range of 5 to 50 μm.

  The heating method for curing the adhesive layers 2 and 4 is not particularly limited, and can be performed by various methods such as a dryer such as an oven or a heating press. In this case, the adhesive composition of the present invention is excellent in workability because it can be thermally bonded (heat cured) even at a relatively low temperature of 200 ° C. or lower.

  Next, examples will be described together with comparative examples.

  First, prior to Examples and Comparative Examples, the following materials were prepared or prepared.

[Preparation of polyamide-modified PAI resin varnish]
In a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a cooling tube, 49.5 g (0.03 mol) of carboxylic acid double-ended polyamide resin (manufactured by Fuji Kasei Kogyo Co., Ltd., TXM-74B3 base) and MDI ( Mitsui Takeda Chemical Co., Ltd. Cosmonate PH) 30.0 g (0.12 mol), trimellitic anhydride (Mitsubishi Gas Chemical Co., Ltd.) 17.3 g (0.09 mol), and NMP solvent 226 g were charged. The temperature was raised to 150 ° C. over 2 hours with stirring in a nitrogen stream, and the reaction was allowed to proceed at 150 ° C. for about 3 hours. Thereafter, an NMP solvent was added so that the final solid content concentration was 25% by weight to prepare a polyamide-modified PAI resin varnish.

[Preparation of unmodified PAI resin varnish]
An unmodified PAI resin varnish (solid content concentration: 25% by weight) was prepared in the same manner as above except that a carboxylic acid double-ended polyamide resin (manufactured by Fuji Kasei Kogyo Co., Ltd., TXM-74B3 base) was not added.

[Epoxy resin a]
Semi-solid phosphorus-containing epoxy resin at room temperature (Dai Nippon Ink Co., Ltd., EXA-9951) (softening point: 51 ° C., epoxy equivalent: 302)

[Epoxy resin b]
Phosphorus-containing epoxy resin that is liquid at normal temperature (FX289Z-1 manufactured by Tohto Kasei Co., Ltd.) (epoxy equivalent: 226)

[Epoxy resin c]
Cresol novolak type epoxy resin (Dainippon Ink & Chemicals, N-660) solid at normal temperature (softening point: 66 ° C., epoxy equivalent: 208)

[Curing accelerator]
Trimellitic acid (F-TMA, manufactured by Mitsubishi Gas Chemical Company)

[Examples 1-4, Comparative Examples 1-3]
The materials shown in Table 1 and Table 2 below are proportioned in the proportions shown in the table, and N, N-dimethylacetamide (DMAC) is added so that the solid content concentration is 25% by weight. Was made. Next, each adhesive varnish was applied to one side of the prepared 12.5 μm-thick polyimide film (insulating film) using a roll coater so that the thickness after drying was 10 μm, and then dried by heating (at 180 ° C. 4 minutes), an adhesive layer was formed on one side of the insulating film. Next, a rolled copper foil (thickness: 18 μm) was bonded to the surface of the adhesive layer by heat lamination with a heating roll at 120 ° C. Then, after forming an adhesive layer in the same manner on the other surface of the insulating film, a rolled copper foil (thickness: 18 μm) is pasted on the surface of the adhesive layer using a heating roll adjusted to a temperature of 120 ° C. Combined. Next, this was heat-cured (160 ° C. × 4 hours) to cure the adhesive layer, thereby producing a double-sided metal foil-clad laminate (see FIG. 1).

  Using the double-sided copper-clad laminates of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown together in Tables 1 and 2 below.

[Thermal laminating properties]
The external appearance of the adhesive layer in each double-sided copper-clad laminate was visually observed. The case where no abnormality such as floating or swelling was observed was marked with ○, and the case where abnormality was seen was marked with ×.

[Initial adhesive strength]
Using each double-sided copper-clad laminate, the initial adhesive strength (N / cm) was measured in accordance with JIS C 6471.

[Solder heat resistance]
Each double-sided copper-clad laminate was tested for solder heat resistance under the conditions of solder bath temperature: 260 ° C. and 280 ° C. and immersion time: 1 minute in accordance with JIS C 6471. Then, the presence or absence of appearance abnormality such as swelling and peeling of the adhesive layer was visually observed, and those having no appearance abnormality such as swelling and peeling were confirmed, while those having appearance abnormality such as swelling and peeling were confirmed. X.

[Tensile modulus]
A copper foil (thickness 18 μm) was prepared, and each adhesive varnish was roll-applied to the surface so that the thickness after drying was 10 μm, and then dried at 180 ° C. for 4 minutes to form a coating film on the surface of the copper foil. (Adhesive layer) was formed. Then, the copper foil was removed by etching, and the tensile property test of the coating film was performed according to JIS K7127, and the tensile elastic modulus was measured. The tensile modulus is an index of flexibility, and the smaller this value, the better the flexibility.

From the above results, all of the products of the examples used the polyamide-modified PAI resin and also used a specific epoxy resin, and thus were excellent in thermal laminating property, initial adhesive strength, solder heat resistance, and flexibility .

  On the other hand, the product of Comparative Example 1 uses an unmodified PAI resin and does not use a specific epoxy resin in combination, and therefore has poor heat laminating properties, adhesiveness, and flexibility. In addition, since the product of Comparative Example 1 was inferior in heat laminating properties, evaluation of solder heat resistance could not be performed. The product of Comparative Example 2 uses a modified PAI resin, but since a specific epoxy resin is not used in combination, the adhesiveness and solder heat resistance are inferior. The comparative example 3 product was inferior in heat laminating property and adhesiveness. In addition, since the comparative example 3 product was inferior in heat laminating property, evaluation of solder heat resistance was not able to be performed.

  The adhesive composition of the present invention is suitably used, for example, as an adhesive composition for bonding an insulating film of a flexible printed wiring board and a metal foil.

It is a block diagram which shows an example of the double-sided metal foil clad laminated board using the adhesive composition of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating film 2 Adhesive layer 3 Metal foil 4 Adhesive layer 5 Metal foil

Claims (2)

The following (A) and (B) are essential components, and the weight mixing ratio of the above (A) and (B) is within the range of (A) / (B) = 50/50 to 80/20 An adhesive composition characterized by that.
(A) A modified polyamideimide resin obtained by copolymerizing the following (a) to (c).
(A) An aromatic isocyanate compound.
(B) An aromatic tricarboxylic acid anhydride.
(C) Ca carboxylic acid both terminated polyamide.
(B) At least one epoxy resin of the following (d) and (e).
(D) An epoxy resin that is solid or semi-solid at normal temperature and has a softening point of 65 ° C. or lower.
(E) Epoxy resin that is liquid at room temperature. The flexible printed wiring board characterized by comprising using the adhesive composition of claim 1 Symbol placement.

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