JP2003027028A - Adhesive composition, and substrate for flexible printed wiring and cover-lay film obtained by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly heat-resistant, halogen-free, flame-retardant adhesive composition without detriment to excellence in adhesion, flexibility, electric characteristics, and the like, and to provide also a substrate for a flexible printed wiring, and to prepare a cover-lay film obtained by using the adhesive composition. SOLUTION: The adhesive composition comprises 100 pts.wt. of a phosphorus- containing epoxy resin, 10-300 pts.wt. of a phosphorus-free epoxy resin, 10-400 pts.wt. of a butyral resin, 100-400 pts.wt. of a phenol resin, 10-200 pts.wt. of a reactive phosphorus-containing compound, 10-100 pts.wt. of a copolymer obtained by reacting an aromatic polymer with an organopolysiloxane represented by the formula (1): Ra R'b SiO(4-a-b)/2 (wherein R is hydrogen atom, amino group, epoxy group, a hydroxyl or carbonyl group-containing monovalent hydrocarbyl group, or an alkoxyl group; R' is a substituted or unsubstituted monovalent hydrocarbyl group; and (a) and (b) are each a positive number satisfying 0.001<=a<=1, 1<=b<=2 and 1<=a+b<=3) and 1-50 pts.wt. of a curing accelerator, and the total phosphorus content in the adhesive composition is 1.5-3.0 wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition used for producing a flexible printed wiring board or the like, a flexible printed wiring board using the same, and a coverlay film.

[0002]

2. Description of the Related Art A flexible printed wiring board is a coverlay for protecting a circuit by forming a circuit on a flexible printed wiring board in which an electrically insulating film and a metal foil are laminated and integrated via an adhesive. It is a film in which films are laminated and integrated. The coverlay film is a laminate of an electrically insulating film and a release paper via a semi-cured adhesive, and is used after the release paper is peeled off. The properties required for these flexible printed wiring boards, substrates for flexible printed wiring, and coverlay films are high adhesion between the electrically insulating film and the metal foil, heat resistance, solvent resistance, electrical characteristics, and dimensional stability. Properties such as heat resistance, long-term heat resistance, and flame retardancy. With the recent trend toward higher density and lighter weight of circuit boards, even in flexible printed wiring boards, finer patterns, higher densities and thinner films of circuits have been advanced. Therefore, not only high adhesion between the electrically insulating film and the metal foil, especially, high heat resistance, high flexibility, further, from the viewpoint of environmental issues, do not use brominated flame retardant,
There has been a demand for halogen-free materials.

In recent years, IC mounting by the COF (chip on film) method has been used for wiring of liquid crystal peripheral materials, and this method uses the conventional TAB (tape automatic bonding) method.
Compared with the method, the COF method is gradually being switched to because it has better bendability of the circuit board and does not require drilling. As a COF substrate material, IC
Since high heat resistance is required when mounting, a two-layer film in which a polyimide film with a glass transition point (Tg) of 200 ° C or higher is copper-plated, or a two-layer film formed by casting a polyimide solution on a copper foil Films (hereinafter these are referred to as "two-layer flexible printed wiring boards") have been used. However, these two-layer flexible printed wiring boards are different from those of the three-layer flexible printed wiring boards, which have been conventionally used, in which an electrically insulating film and a metal foil are bonded to each other via an adhesive. Since the yield is low and the manufacturing cost is high, the demand cannot be met. Therefore, as a substitute for the two-layer flexible printed wiring board, a conventionally used three-layer flexible printed wiring board having high heat resistance (high Tg) has been strongly demanded. Further, a cover layer film having a high heat resistance (high Tg) corresponding to a substrate for a two-layer flexible printed wiring is currently in a state where there is no material that can be sufficiently used, and an early commercialization is required.

Conventionally, as an adhesive used for a flexible printed wiring board, a composition obtained by combining various thermosetting resins and an elastomer compound has been used. For example,
Various adhesive compositions such as epoxy resin / polyester resin system, epoxy resin / acrylonitrile / butadiene copolymer system, epoxy resin / acrylic resin, etc. have been investigated. Then, in order to improve the heat resistance of these adhesive compositions, application of higher heat resistant epoxy resin or butyral / phenol resin, reduction of the elastomer component in the epoxy resin / elastomer compound system, and the like have been studied. However, the halogen-free adhesive composition used for flexible printed wiring boards has not yet been made (Japanese Patent Laid-Open No. 60-79080 and Japanese Patent Laid-Open No. 60-139770, Japanese Patent Laid-Open No. 60-139770, Kai 61-
108679, and JP 2001-15876 A). Further, it has been widely used to use thermoplastic silicone-modified polyimide or silicone-modified polyamide-imide as an adhesive used for flexible printed wiring boards (Japanese Patent Laid-Open No. 2000-226566, Japanese Patent Laid-Open No. 2-256666).
000-345035, JP 2000-2651.
49). However, these adhesives
Epoxy resin or the like is generally added to compensate for the decrease in adhesiveness, and therefore the flame retardancy of the polyimide may be impaired.

Since the above-mentioned two-layer flexible printed wiring board has no flammable adhesive layer made of epoxy resin or the like, it has heat resistance and, as described below,
Shows flame retardancy without using halogen compounds. On the other hand, the conventional three-layer flexible printed wiring board and the corresponding coverlay film are added with a brominated epoxy resin chemically bonded to the adhesive composition in order to impart flame retardancy and self-extinguishing property. I've been However, with the recent growing concern about the environment, non-halogenation of the adhesive composition is required.

As a non-halogenating method for the adhesive composition, addition of a flame-retardant material containing phosphoric acid has been studied (see JP-A-2000-345035).
There is a disadvantage that flame retardancy is not imparted unless a large amount of flame retardant is added. In addition, in the three-layer flexible printed wiring board using the above adhesive composition, the electrical insulation between the formed circuits is deteriorated (especially when moisture is absorbed), and the phosphorus additive added to the adhesive layer is added. A resinous protrusion (dendrite) is generated, and in the worst case, the conductors are short-circuited due to the growth of dendrites and the circuit is destroyed.
However, satisfactory characteristics are not obtained at present. Therefore, a three-layer flexible printed wiring board using a highly heat-resistant and halogen-free flame-retardant adhesive composition that can replace the two-layer flexible printed wiring board, and a coverlay film corresponding thereto have been developed. The current situation is not.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to provide a high heat resistance and halogen-free difficulty without impairing the excellent adhesiveness, flexibility, electrical characteristics and the like of conventional adhesive compositions. It is intended to provide a flammable adhesive composition, and at the same time to provide a flexible printed wiring board and a coverlay film using the adhesive composition.

[0008]

Means for Solving the Problems The present invention includes the following (1) to
An adhesive composition comprising the component (7) and having a total phosphorus content of 1.5 to 3.0% by weight in the adhesive composition. (1) Phosphorus-containing epoxy resin 100 parts by weight (2) Phosphorus-free epoxy resin 10-300 parts by weight (3) Butyral resin 10-400 parts by weight (4) Phenolic resin 100-400 parts by weight (5) Reactive phosphorus-containing compounds 10 to 200 parts by weight (6) copolymer 10 to 100 parts by weight obtained by reacting an organopolysiloxane represented by the aromatic polymer and the following composition formula _{(1) R a R 'b} SiO (4 _{-ab) / 2} (1) (In the formula, R represents a hydrogen atom, an amino group, an epoxy group, a hydroxy group or a monovalent hydrocarbon group containing a carbonyl group or an alkoxy group, and R'is substituted or non-substituted. A substituted monovalent hydrocarbon group, a and b are positive numbers satisfying 0.001 ≦ a ≦ 1, 1 ≦ b ≦ 2, 1 ≦ a + b ≦ 3. The number is 2 to 1000, and the number of The number of functional groups R directly linked to elementary atoms is 1 or more.) (7) Curing accelerator 1 to 50 parts by weight, Further, the present invention provides an electrically insulating film and a metal foil via the above adhesive composition. Heat-resistant, halogen-free, flame-retardant flexible printed wiring substrate obtained by adhering the above, and high heat-resistance, halogen-free difficulty obtained by laminating an electrically insulating film and release paper via the adhesive composition. It is a flammable coverlay film.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Since the phosphorus-containing epoxy resin which is the above-mentioned component (1) constituting the adhesive composition of the present invention contains a phosphorus atom, it exhibits flame retardancy upon combustion, and is Unlike the conventional phosphorus-based additive, since the phosphorus atom is fixed by a chemical bond, it is possible to prevent deterioration of electrical insulation due to migration between conductors and generation of dendrites between conductors. The phosphorus-containing epoxy resin is
It means a polyfunctional epoxy resin incorporating a phosphorus atom by a chemical bond, as long as it has two or more epoxy groups in one molecule. Specifically, glycidyl ether-based epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, hexahydrophthalic acid glycidyl ester,
Glycidyl ester-based epoxy resin such as dimer acid glycidyl ester, triglycidyl isocyanurate, glycidyl amine-based epoxy resin such as tetraglycidyl diaminodiphenylmethane, epoxidized polybutadiene,
Examples thereof include those having a skeleton of a linear aliphatic epoxide resin such as epoxidized soybean oil. These phosphorus-containing epoxy resins may be synthesized by a known method, for example,
A method of adding diphenylphosphoric acid to the benzene ring of a bisphenol F type epoxy resin is exemplified (Japanese Patent Publication No. 6-5.
See Japanese Patent No. 3785 and Japanese Patent Laid-Open No. 2000-336145). Further, as a commercially available product, EXA9710 (manufactured by Dainippon Ink and Chemicals, Inc., trade name, epoxy equivalent 496
g / eq, phosphorus content 3%), and 9709 (manufactured by Dainippon Ink and Chemicals, Inc., trade name, epoxy equivalent 370 g / eq, phosphorus content 2.4% by weight). These phosphorus-containing epoxy resins can be used alone or in combination of two or more. The phosphorus-containing epoxy resin has a phosphorus content of 0.5 to 5% by weight, and particularly,
It is preferably 1.0 to 4.0% by weight.

The phosphorus-free epoxy resin which is the above-mentioned component (2) constituting the adhesive composition of the present invention improves the adhesiveness of the adhesive composition, and the adhesive composition on the electrically insulating film. Improves the thermocompression bonding property between the electrically insulating film and the metal foil or the printed circuit after being applied and semi-cured. The phosphorus-free epoxy resin may be one having two or more epoxy groups in one molecule and not containing phosphorus and halogen atoms. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin,
Glycidyl ether-based epoxy resin such as phenol novolac type epoxy resin, glycidyl ester-based epoxy resin such as hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, triglycidyl isocyanurate, glycidylamine-based epoxy resin such as tetraglycidyl diaminodiphenylmethane, epoxy Examples thereof include linear aliphatic epoxide resins such as modified polybutadiene and epoxidized soybean oil. A polyfunctional epoxy resin that incorporates naphthalene, dicyclopentadiene, etc.
It is preferable from the viewpoint of improving heat resistance.

The amount of the non-phosphorus-containing epoxy resin compounded is 10 to 300 parts by weight, preferably 50 to 2 parts by weight, relative to 100 parts by weight of the phosphorus-containing epoxy resin which is the component (1).
It is 00 parts by weight. If the compounding amount of the phosphorus-free epoxy resin is less than 10 parts by weight, the adhesiveness may decrease,
If it is more than 300 parts by weight, the flame retardancy becomes insufficient.

The glass transition point (Tg) of the cured product of the butyral resin which is the component (3) constituting the adhesive composition of the present invention is not so high as around 100 ° C.,
It acts as a binder in the adhesive composition and imparts a certain degree of flexibility to the cured product of the adhesive composition. The butyral resin may be any butyralized polyvinyl alcohol, and may actually be a random copolymer of a butyral group, an acetyl group, and a vinyl alcohol group. Examples of commercially available products include S-REC B (trade name, manufactured by Sekisui Chemical Co., Ltd.).

The blending amount of the butyral resin is 1 with respect to 100 parts by weight of the phosphorus-containing epoxy resin which is the component (1).
It is 0 to 400 parts by weight, preferably 50 to 300 parts by weight. If the amount of the butyral resin is less than 10 parts by weight, the flexibility of the cured product of the adhesive composition is lowered, and the fluidity of the adhesive at the time of curing is increased. If it is more than 400 parts by weight, the heat resistance is lowered. You

The phenol resin which is the component (4) constituting the adhesive composition of the present invention is a curing component of the adhesive, and when used in combination with the above butyral resin, it is effective in improving heat resistance and the like. . As a phenolic resin,
Specific examples thereof include phenol novolac resin, cresol novolac resin, phenol / cresol copolymer novolac resin, trishydroxyphenylmethane type phenol resin, naphthalene type phenol resin, cyclopentadiene type phenol resin, and phenol aralkyl resin. The blending amount of the phenol resin is the same as in (1) above.
100 to 400 parts by weight, preferably 50 to 300 parts by weight, relative to 100 parts by weight of the phosphorus-containing epoxy resin as a component.
Parts by weight. If the compounding amount of the phenolic resin is less than 100 parts by weight, the heat resistance of the obtained adhesive decreases, and
If it is more than the weight part, the flexibility of the adhesive is impaired.

The reactive phosphorus-containing compound which is the above-mentioned component (5) constituting the adhesive composition of the present invention is different from the conventional non-reactive phosphorus-based flame-retardant material when the adhesive composition is prepared. Alternatively, since it reacts with other components in the after-baking process after temporary adhesion, it retains the same flame retardant effect as conventional phosphorus-based flame retardant materials, while significantly improving the electrical characteristics including ion migration characteristics. Can be made. The reactive phosphorus-containing compound may be any organic compound containing a phosphorus atom and having reactivity. However, the phosphorus-containing epoxy resin which is the component (1) is not included. In particular,
HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, manufactured by Sankosha, trade name), HCA with hydroquinone added to HCA-
HQ (manufactured by Sanko Co., trade name), MR-200 (2-methacryloyl-oxyethyl acid phosphate, manufactured by Daihachi Chemical Co., trade name), MR-260 (diphenyl-2-methacryloyl-oxyethyl phosphate Daihachi) Manufactured by Kagaku Co., Ltd.) and the like. The reactive phosphorus-containing compound used is preferably one having a phosphorus content in the range of 6 to 30% by weight. The compounding amount of the reactive phosphorus atom-containing compound is the phosphorus-containing epoxy resin 10 which is the component (1).
The amount is 10 to 200 parts by weight, preferably 30 to 150 parts by weight, relative to 0 parts by weight. If the compounding amount of the reactive phosphorus atom-containing compound is less than 10 parts by weight, the flame retardancy of the resulting adhesive decreases, and if it is more than 200 parts by weight, the unreacted component may cause deterioration of the hygroscopic property.

The component (6) constituting the adhesive composition of the present invention is a copolymer obtained by reacting an aromatic polymer with the organopolysiloxane represented by the composition formula (1). As the aromatic polymer, various ones can be used. For example, the following [Chemical formula 1],
An epoxy resin or a phenol resin having a structure shown in [Chemical Formula 2] can be given.

[0017]

[Chemical 1]

[0018]

[Chemical 2]

Further, the following [Chemical formula 3], [Chemical formula 4] and [Chemical formula 5]
It is also possible to use an alkenyl group-containing epoxy resin or phenol resin having the structure shown in.

[0020]

[Chemical 3]

[0021]

[Chemical 4]

[0022]

[Chemical 5]

In the above [Chemical formula 1] to [Chemical formula 5],
R ⁴ is a hydrogen atom or a methyl group, R ⁵ is a hydrogen atom or a methyl group, R ⁶ is a hydrogen atom or a glycidyl group, n is 0 or a natural number, preferably an integer of 0 to 50, particularly preferably 1 to 20. It is an integer, and m is 0 or a natural number, preferably an integer of 0 to 50, particularly preferably 0 or 1. p,
q is a natural number, preferably p + q is an integer of 2 to 50, more preferably 2 to 20.

On the other hand, the above-mentioned organopolysiloxane is represented by the following composition formula (1). R _a R ′ _b SiO _{(4-ab) / 2} (1) In the formula, R represents a hydrogen atom, an amino group, an epoxy group, a hydroxy group or a monovalent hydrocarbon group containing a carbonyl group or an alkoxy group, and R 'Represents a substituted or unsubstituted monovalent hydrocarbon group, and a and b are 0.001 ≦ a ≦ 1 and 1 ≦ b ≦
It is a positive number that satisfies 2, 1 ≦ a + b ≦ 3. The number of silicon atoms in one molecule is 2 to 1,000, and the number of functional groups R directly bonded to the silicon atom in one molecule is 1 or more.
In this case, as the amino group-containing monovalent hydrocarbon group of R,
The following are exemplified.

[0025]

[Chemical 6]

Examples of the epoxy group-containing monovalent hydrocarbon group for R include the following.

[0027]

[Chemical 7]

Examples of the hydroxy group-containing monovalent hydrocarbon group for R include the following.

[0029]

[Chemical 8]

Examples of the carboxyl-containing monovalent hydrocarbon group for R include —C _x H _2x COOH (x = 0 to 10).

As the alkoxy group of R, a methoxy group,
Examples thereof include those having 1 to 4 carbon atoms such as ethoxy group and n-propoxy group. The substituted or unsubstituted monovalent hydrocarbon group for R ′ preferably has 1 to 10 carbon atoms. For example, alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, and decyl group. , Alkenyl groups such as vinyl group, allyl group, propenyl group and butenyl group, aryl groups such as phenyl group and tolyl group, aralkyl groups such as benzyl group and phenylethyl group. Among these, a group not containing an aliphatic unsaturated bond, for example, an alkyl group, an aryl group or an aralkyl group is preferable, and a methyl group or a phenyl group is particularly preferable.

Further, in the composition formula (1), a,
b is the value described above, but preferably 0.01≤a≤0.
1, 1.8 ≦ b ≦ 2, 1.85 ≦ a + b ≦ 2.1, the number of silicon atoms is preferably 10 to 400, more preferably 2
0 to 210.

As the organopolysiloxane represented by the above composition formula (1), for example, the following structural formula [Chemical formula 9],
[Chemical formula 10] can be mentioned.

[0034]

[Chemical 9]

[0035]

[Chemical 10]

In the above [formula 9] and [formula 10], R '
Represents a substituted or unsubstituted monovalent hydrocarbon group, preferably a methyl group or a phenyl group, as in the case of the above composition formula (1), and x contains an amino group, an epoxy group, a hydroxy group or a carboxyl group. Represents a monovalent hydrocarbon group
O to 1000, preferably an integer of 8 to 400, q is 0 to 2
0, preferably an integer of 0 to 5 is shown. Specific examples include the following diorganopolysiloxanes.

[0037]

[Chemical 11]

The molecular weight of the organopolysiloxane represented by the above composition formula (1) is not particularly limited,
100 to 70,000 is desirable. This is because when the organopolysiloxane has a molecular weight of 100 to 70,000, the obtained copolymer of the component (6) is blended with other components of the adhesive composition to give the copolymer with the copolymer. This is because the union is not compatible with each other, a fine sea-island structure is formed, and while maintaining the physical properties of the matrix, it is possible to simultaneously exert the effects such as flexibility unique to siloxane. When the molecular weight of the organopolysiloxane is less than 100, the copolymers are compatible with each other in the matrix, the sea-island structure disappears, the flexibility of the cured product of the adhesive composition is reduced, and the molecular weight is more than 70,000. If it is large, the sea-island structure becomes large, and the heat resistance of the cured product of the adhesive composition may decrease.

As a method of reacting the aromatic polymer with the organopolysiloxane to obtain the copolymer of the component (6), a known method is adopted. Specifically, the aromatic polymer and the organopolysiloxane are mixed in toluene, heated and reacted at 100 ° C. for 12 hours in a nitrogen atmosphere and aged, and then the toluene is distilled off under normal pressure and the temperature is reduced to 150 ° C. under vacuum. A crude product was prepared by stripping the mixture in 1 hour, and the crude product was dissolved in a small amount of toluene, washed in a large amount of hexane, and purified to obtain a copolymer of the component (6). To be The method for synthesizing the copolymer is not limited to the above method. The blending amount of this copolymer is 10 to 100 parts by weight, preferably 20 to 60 parts by weight, based on 100 parts by weight of the phosphorus-containing epoxy resin which is the component (1). The amount of copolymer is 1
If it is less than 0 parts by weight, the flexibility of the cured product of the adhesive composition may be reduced, and if it is more than 100 parts by weight, the heat resistance may be reduced.

An organic phosphorus compound can be used as the curing accelerator which is the component (7) constituting the adhesive composition of the present invention. Specifically, triphenylphosphine, tributylphosphine, tri (p-toluyl) phosphine, tri (p-methoxyphenyl) phosphine, tri (p-ethoxyphenyl) phosphine, triphenylphosphine / triphenylborate, tetra Examples thereof include triorganophosphines such as phenylphosphonium and tetraphenylborate, quaternary phosphonium salts, and the like, and these can be used alone or in combination of two or more kinds. Various imidazole compounds are also used as the curing accelerator. For example,
2-methylimidazole, 2-ethylimidazole, 2
-Ethyl-4-methylimidazole, an ethylisocyanate compound of this compound, 2-phenylimidazole,
2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2
-Phenyl-4,5-dihydroxymethylimidazole and the like can be mentioned, and of these, they can be used alone or in combination of two or more. Further, as curing accelerators, tetraphenylborates of tertiary amines such as triethylene ammonium triphenylborate, zinc borofluoride, tin borofluoride, borofluorides such as nickel borofluoride, tin octylate, Examples thereof include octylates such as zinc octylate, and these can be used alone or in combination of two or more kinds.

The compounding amount of the curing accelerator is 1 to 5 relative to 100 parts by weight of the phosphorus-containing epoxy resin which is the component (1).
It is 0 parts by weight, preferably 5 to 20 parts by weight. When the compounding amount of the curing accelerator is less than 1 part by weight, the adhesive composition is not sufficiently cured, and when it is more than 10 parts by weight, the storage stability of the adhesive composition is deteriorated.

The total phosphorus content in the adhesive composition of the present invention is 1.5 to 3.0% by weight, preferably 1.8 to 2.7.
The phosphorus-containing component is blended so as to have a weight percentage. When the total phosphorus content in the adhesive composition is less than 1.5% by weight, sufficient flame retardancy cannot be obtained, and when it exceeds 3.0% by weight, the heat resistance of the cured adhesive is high. There is a risk that the

Other resins and additives may be added to the adhesive composition of the present invention, in addition to the above components (1) to (7), as long as the various properties are not deteriorated. Examples thereof include aluminum hydroxide, magnesium hydroxide, silicon dioxide, various compounds containing nitrogen / phosphorus as a flame retardant aid (melamine phosphate, various phosphazene compounds, etc.).
Additives containing both nitrogen / phosphorus components are effective as flame retardant aids. Further, the adhesive composition of the present invention can be used in combination with a curing agent used for an epoxy resin.
Examples thereof include aliphatic amine curing agents, alicyclic amine curing agents, aromatic amine curing agents, acid anhydride curing agents, dicyandiamide, and boron trifluoride amine complex salts.
These curing agents also have a great influence on the migration property of metal ions, which is the subject of the present invention, and when an amine having a particularly high activity is used, the migration resistance decreases, so that an aromatic amine such as 4,4 is used. The use of'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane is preferred. In addition, these can also be used individually or in combination of 2 or more types.

The adhesive composition of the present invention comprises the above (1) to
It is produced by mixing the component (7) using a pot mill, a ball mill, a homogenizer, a super mill or the like. When applied to an object, a solvent is added to the adhesive composition to prepare an adhesive solution. Examples of the solvent include methanol, ethanol, acetone, 10-methyl ethyl ketone, toluene, trichloroethylene, 1,4-dioxane, 1,3-dioxolane and the like. The solid content concentration in the adhesive solution is suitably 10 to 45% by weight, preferably 20 to 35% by weight. If the solid content concentration exceeds 45% by weight, the applicability deteriorates due to the increase in the viscosity of the adhesive solution and the decrease in the compatibility between the solid content and the solvent, and the workability deteriorates. On the other hand, if the solid content concentration is less than 10% by weight, coating unevenness is likely to occur, and the amount of solvent removed increases, resulting in problems such as environmental and economic deterioration.

The flexible printed wiring board of the present invention comprises:
It is formed by adhering an electrically insulating film and a metal foil via the adhesive composition, and the metal foil can be used by being provided on one side or both sides of the electrically insulating film. Examples of the electrically insulating film include a polyimide film, a polyester film, a polyvalanic acid film, a polyphenylene sulfide film, an aramid film, and the like. Among them, the polyimide film is preferable. The thickness of the electrically insulative film may be a suitable thickness if necessary, but is preferably 10 to 125 μm. It is also possible to perform surface treatment on one side or both sides of the electrically insulating film, and examples of the surface treatment include low temperature plasma treatment, corona discharge treatment, and sandblast treatment.

Examples of the metal foil include copper foil, aluminum foil, iron foil and the like, and copper foil is particularly preferable. The thickness of the metal foil may be set appropriately if necessary, but is preferably 5 to 70 μm.

Examples of the method for producing the flexible printed wiring board of the present invention include the following methods. First, an adhesive solution prepared by mixing a predetermined solvent with an adhesive composition prepared in advance is applied to an electrically insulating film by using a reverse roll coater, a comma coater or the like.
Then, the electrically insulating film is passed through an in-line dryer and treated at 80 ° C. to 160 ° C. for 2 to 10 minutes to remove the solvent of the adhesive solution and dried to be in a semi-cured state. After that, use a heating roll to apply a line pressure of metal foil to the adhesive coated surface.
Approximately 200 N / cm and a temperature of 60 to 180 ° C. for thermocompression bonding.
You may heat to further cure the adhesive agent of the obtained laminated film, and the heating temperature in that case is 80-200.
C., heating time is 1 to 24 hours. The thickness of the coating film of the adhesive composition in the flexible printed wiring board of the present invention may be 5 to 45 μm in a dry state, and preferably 5 to 30 μm.

The cover lay film of the present invention is a laminate of an electrically insulating film and a release paper with the semi-cured adhesive composition interposed therebetween. The coverlay film is used by forming a circuit on a flexible printed wiring board and then laminating and integrating the circuit to protect the circuit. When used, the release paper is peeled off for flexible printed wiring. Laminate on the circuit side of the board. In addition, what laminated | stacked and integrated the coverlay film on the circuit surface of the board | substrate for flexible printed wiring may be generically called a flexible wiring board. As the electrically insulating film of the coverlay film, those described above can be used in the flexible printed wiring board. The release paper that can be used includes polyethylene film on one or both sides of the base paper, 4
-Methyl-1-pentene-α-olefin copolymer (hereinafter referred to as TPX) film, or polypropylene film bonded, one side or both sides of base paper coated with polyvinylidene chloride, one side of these release papers Alternatively, a silicone release agent may be applied to both surfaces, and the like, which can be appropriately selected and used depending on the conditions at the time of drilling.

The coverlay film of the present invention is, for example,
It is manufactured as follows. First, an organic solvent solution of the adhesive composition of the present invention is applied to an electrically insulating film so as to have a thickness of 10 to 60 μm in a dry state, and then dried to remove the solvent to obtain an adhesive composition. It is in a semi-cured state. In this case, you may heat at the temperature of 50 degreeC-150 degreeC for a short time as needed. Next, the semi-cured electrical insulating film with an adhesive is superposed on the release paper,
Temperature of 20 to 120 ° C due to roll lamination, etc.
The cover lay film of the present invention is produced by laminating under a linear pressure of 2 to 200 N / cm and winding in a roll.

[0050]

EXAMPLES Next, examples of the present invention will be given, but the present invention is not limited to these examples. [Example 1] An adhesive solution having a solid content of 25% was prepared using the adhesive composition shown in the column of Example 1 in Table 1 and using methyl ethyl ketone as a solvent. And the thickness is 2
5 μm, 200 mm × 200 mm polyimide film: Kapton (trade name, manufactured by DuPont Toray Co., Ltd.) was coated with the above adhesive solution using an applicator so that the thickness after drying was 20 μm, and 120 ° C. for 10 minutes. The adhesive solution was heated to a semi-cured state to obtain a polyimide film with an adhesive. Next, on the adhesive-coated surface of this adhesive-attached polyimide film, a copper foil having a thickness of 35 μm and a size of 200 mm × 200 mm: B
HN (manufactured by Japan Energy Co., rolled copper foil, trade name) is overlaid, heated and pressure-bonded under the conditions of temperature 150 ° C and linear pressure 100N / cm, and further heat-cured at 170 ° C for 10 hours to produce flexible printed wiring. A substrate for use was prepared. Measure the characteristics of this flexible printed wiring board by the following methods,
The results are shown in Table 3.

[Examples 2 to 4] A flexible printed wiring board was prepared under the same conditions and methods as in Example 1 except that the adhesive compositions shown in the columns of Examples 2 to 4 in Table 1 were used. It was made. The characteristics of these flexible printed wiring boards were measured by the following methods, and the results are shown in Table 3.

Example 5 Using the formulation of the adhesive composition shown in the column of Example 5 in Table 1, the mixture was stirred and mixed with methyl ethyl ketone as a solvent to prepare an adhesive solution having a solid content concentration of 25%. Then, the above adhesive solution is applied to a Kapton (the same as above) having a thickness of 25 μm and 200 mm × 200 mm so that the thickness after drying becomes 30 μm, and the temperature is set to 80 ° C. for 1
The adhesive was semi-cured by heating for 0 minutes to obtain a coverlay film. Next, the adhesive-coated surface of this coverlay film and the glossy surface of 200 mm × 200 mm BHN (same as above) are overlapped, and thermocompression bonded under the conditions of a temperature of 170 ° C., a pressure of 5 MPa, and a duration of 30 minutes to prepare a laminate , And used as a sample for evaluation. The characteristics of this laminate were measured by the following methods, and the results are shown in Table 3.

[0053]

[Table 1] In Table 1, EXA-9710 (manufactured by Dainippon Ink and Chemicals,
Brand name, phosphorus content 3% by weight, epoxy equivalent 496 g / e
q), HP-4032 (Dainippon Ink and Chemicals, trade name, naphthalene type bifunctional epoxy resin, epoxy equivalent 150g / e
q), HP-7200 (Dainippon Ink and Chemicals, trade name, dicyclopentadiene type epoxy resin, epoxy equivalent 260
g / eq), KS-1 (butyral resin S-REC KS-1, manufactured by Sekisui Chemical Co., Ltd., trade name, degree of polymerization ~ 550, hydroxyl group about 25 mol
%), BX-1 (butyral resin S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd., trade name, degree of polymerization ~ 1700, hydroxyl group about 33 mol
%), LA7054 (manufactured by Dainippon Ink and Chemicals, Inc., trade name,
Triazine-based phenol resin, hydroxyl equivalent 125g / e
q), MEH7851SS (manufactured by Meiwa Kasei Co., Ltd., trade name, phenolic resin, hydroxyl group equivalent 200 g / eq), HCA (manufactured by Sanko Co., trade name,
Reactive phosphorus-containing flame retardant, phosphorus content about 15% by weight), CPHO
-HQ (Nippon Chemical Industry Co., Ltd., trade name, reactive phosphorus-containing flame retardant, phosphorus content about 11.6% by weight), DDS (4,4'-diaminodiphenyl sulfone), 2E-4MZ-CN (Shikoku Chemicals) Made, trade name, imidazole type curing accelerator), TPP (triphenylphosphine), Kisuma 5 (Kyowa Chemical Industry Co., Ltd., trade name, magnesium hydroxide particle system 0.6-1.0μ
m) and MPP-A (manufactured by Sanwa Chemical Co., Ltd., trade name, melamine phosphate, phosphorus content 15% by weight). Further, the siloxane copolymer represents the number of parts by weight per 100 parts by weight of the phosphorus-containing epoxy resin.

In Table 1, [Chemical formula 12] is as shown below.

[Chemical 12]

[Comparative Examples 1 to 5] A flexible printed wiring board was prepared under the same conditions and methods as in Example 1 except that the adhesive compositions shown in the columns of Comparative Examples 1 to 5 in Table 2 were used. It was made. The characteristics of these flexible printed wiring boards were measured by the following methods, and the results are shown in Table 3.

[0056]

[Table 2] In Table 2, PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd., trade name, phosphorus-based flame retardant, phosphorus content 9% by weight), EK154 (manufactured by Japan Epoxy Resin Co., Ltd., trade name, phenol novolac type multifunctional epoxy) Resin, epoxy equivalent is 178 g / eq). Others are the same as in the case of Table 1.

(Measurement of characteristics) 1. Peel strength A sample was prepared according to JIS C 6481 so as to have a width of 1 mm, and the adhesive strength when peeled off to the copper foil side at a speed of 50 mm / min in the 90 ° direction was measured. 2. Solder heat resistance In accordance with JIS C 6481, the sample was cut into 25 mm square pieces, floated on the flow solder for 30 seconds, and the maximum temperature at which swelling and peeling did not occur was measured. 3. Flame-retardant The flexible printed wiring board obtained in each example and the cover lay film to which the copper foil was pressure bonded were treated with UL94 using an adhesive / polyimide film obtained by chemically treating and removing the copper foil.
The flame-retardant grade was measured according to the flame-retardant standard. 4. Folding resistance According to JIS C 6471, after printing the specified circuit on the flexible printed wiring boards of Examples 1 to 4, combined with the cover lay film of Example 5, 160 ° C, 50 kg / cm
^A sample was pressed for ² × 30 minutes. Similarly, the flexible printed wiring boards obtained in Comparative Examples 1 to 4 and the coverlay film of Comparative Example 5 were combined to form a sample, and evaluation was performed at a radius of curvature of 0.38 mm and 25 ° C. When the average value at n = 5 was 200 times or more, the result was ◯, and when it was less than 200, the result was x. 5. A comb-shaped pattern with 100 μm between migration resistance test lines was prepared and the temperature was set to 130
It is applied for 250 hours at a temperature of 85 ° C., a humidity of 85% and a voltage of 100 V, the sample before and after application is observed with a magnifying glass, the generation state of migration occurring between lines is inspected, and evaluated according to the following criteria. ○: No precipitate is formed between the lines △: Precipitate is slightly seen in the circuit part but does not fill the space between the lines ×: Precipitate is formed over the entire line and there is no trace of thermal deterioration Seen 6. Measurement of glass transition point of cured adhesive material Dynamic viscoelasticity measurement was performed using a sample with the same composition (polyimide film / adhesive layer) as the one subjected to flame retardancy test, and the maximum value of tan δ obtained is shown. The temperature was defined as the glass transition temperature of the cured adhesive. The measurement conditions are as follows. Measuring instrument: Rheometric Scientific F.E., viscoelasticity analyzer, RSA-II (trade name) Measuring mode: Distance between pulling chucks: 35 mm Measuring temperature: 0-300 ° C Temperature rising rate: 2.5 C / min Perturbation frequency: 5 Hz Sample size: 10 mm (width) x 50 mm (length)

[0058]

[Table 3]

(Evaluation) As can be seen from the results in Table 3, Examples 1 to 5 according to the present invention show excellent flame retardancy and high heat resistance (high Tg), and peel strength, solder heat resistance, and heat resistance. Also in terms of bendability and migration resistance, the results are equal to or higher than those of Comparative Examples 1 to 5.

[0060]

EFFECTS OF THE INVENTION According to the present invention, various properties such as adhesiveness, flexibility, and electrical properties are balanced, and flame retardancy, heat resistance, and
A halogen-free adhesive composition having excellent migration resistance can be obtained, and by using the same, a halogen-free flexible printed wiring board and a coverlay film having excellent properties can be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B32B 27/26 B32B 27/26 27/30 27/30 Z 27/38 27/38 27/42 101 27 / 42 101 C08G 81/00 C08G 81/00 C09J 129/14 C09J 129/14 161/06 161/06 183/10 183/10 H05K 3/38 H05K 3/38 E (72) Inventor Sakae Yoshiyoshi Ibaraki No. 1 Towada, Kamisu-cho, Kashima-gun, Shin-Etsu Chemical Co., Ltd., PVC Technology Research Institute (72) Inventor, Nobuhiro Iku, No. 1 Hitomi, Osamu, Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Toshio Shiobara 1 Hitomi, Oita, Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Co., Ltd. Silicon Electronic Materials Research Laboratory F-term (reference) 4F100 AA19 AH08B AK23B AK3 3B AK49 AK52B AK52J AK53B AL01B AL05B AL06B BA03 BA07 BA10A BA10C CA02B CB00B DG10A EC18 EH46 EJ42 GB43 JG04C JL14A YY00B 4J031 AA44 EC41 EC11 EC21 EC11 EC21 EC11 EC11 EC11 EC12 EC01 AF13 EC01 AF13 EC01 AF13 4 LA06 LA08 LA09 MA02 MA10 NA20 5E343 AA02 AA12 AA33 BB05 BB24 BB67 CC03 CC06 CC07 DD51 EE21 GG02

Claims (3)

[Claims] 1. An adhesive composition comprising the following components (1) to (7) and having a total phosphorus content of 1.5 to 3.0% by weight in the adhesive composition. (1) Phosphorus-containing epoxy resin 100 parts by weight (2) Phosphorus-free epoxy resin 10-300 parts by weight (3) Butyral resin 10-400 parts by weight (4) Phenolic resin 100-400 parts by weight (5) Reactive phosphorus-containing compounds 10 to 200 parts by weight (6) copolymer 10 to 100 parts by weight obtained by reacting an organopolysiloxane represented by the aromatic polymer and the following composition formula _{(1) R a R 'b} SiO (4 _{-ab) / 2} (1) (In the formula, R represents a hydrogen atom, an amino group, an epoxy group, a hydroxy group or a monovalent hydrocarbon group containing a carbonyl group or an alkoxy group, and R'is substituted or non-substituted. A substituted monovalent hydrocarbon group, a and b are positive numbers satisfying 0.001 ≦ a ≦ 1, 1 ≦ b ≦ 2, 1 ≦ a + b ≦ 3. The number is 2 to 1000, and the number of The number of functional groups R directly bonded to atom is 1 or more.) (7) curing accelerator 1-50 weight parts 2. A substrate for flexible printed wiring, comprising an electrically insulating film and a metal foil bonded together via the adhesive composition according to claim 1. 3. A coverlay film obtained by laminating an electrically insulating film and a release paper with the adhesive composition according to claim 1 interposed therebetween.