JP2005019965A - Flexible wiring board and flex-rigid wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible wiring board for repetitively bending portions and with excellent bending resistance, and a flex-rigid wiring board having the flexible wiring board. <P>SOLUTION: The flexible wiring board for repetitively bending portions consists of a base-film layer (I) on which wiring patterns are formed, a flexible insulating-material layer (II) that covers the layer (I), and a cover-film layer (III) that covers the layer (II). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flexible wiring board for repeated bending portions, and more particularly to a flex-rigid wiring board having a flexible wiring board for repeated bending portions having excellent bending resistance.

  A printed wiring board in which a rigid portion is formed on a part of a flexible printed wiring board on which a wiring pattern is formed is generally called a flex-rigid wiring board (FIG. 1). This flex-rigid circuit board has a relatively rigid rigid part on which electrical parts are mounted and a flexible part that can be bent (bent) to electrically connect between rigid parts or between a rigid part and electrical parts. It consists of and. Since this flex-rigid wiring board has a flexible part that can be bent, it has a high degree of freedom in spatial arrangement, and can also be installed across the movable part and the fixed part (FIG. 2).

In general, a flex-rigid wiring board is a flexible substrate obtained by directly attaching a cover film called a cover lay film in which an adhesive layer is applied on an insulating base material on which a pattern circuit is formed by a metal foil layer onto the metal foil layer. The substrate constituting the rigid part is bonded with an adhesive sheet. This insulating substrate is usually made of a flexible film such as polyimide resin or polyethylene terephthalate resin.
In the case of such a conventional flex-rigid wiring board, for example, when used as a substrate for a foldable mobile phone, the flexible part straddling the fold part is required to bend tens of thousands to hundreds of thousands of times. High bending resistance and flexibility are required. At this time, there is a problem that fatigue deterioration occurs particularly in the metal foil layer portion of the pattern circuit, cracks occur, and the pattern circuit is disconnected.

  For this reason, when used under severe bending conditions, an adhesive having a high elastic modulus and heat resistance is used to bond the metal foil layer and the insulating base material in order to suppress the occurrence of cracks and their progress. Although a method has been proposed, in this case, a problem arises that the flexible portion becomes hard and the flexibility is impaired.

  Moreover, when the constituent material including the insulating base material of the flex-rigid wiring board is not appropriate, it may become unsuitable for use due to cracks or breakage of the wiring board itself before the fatigue deterioration of the metal foil layer portion.

  Japanese Patent Application Laid-Open No. 7-2072111 describes a resist ink composition for flexible printed wiring boards, the cured film of which has excellent flexibility, folding resistance, adhesion, chemical resistance, and heat resistance. However, it is not intended to improve the bending resistance (see Patent Document 1).

  Japanese Patent Application Laid-Open No. 2000-109541 discloses a photosensitive thermosetting resin composition for solder resist that can be applied to both a rigid array substrate and a flexible wiring substrate. However, such a composition is not intended to improve the bending resistance of the flexible part (see Patent Document 2).

JP-A-7-207211 JP 2000-109541 A

  The present invention relates to a flexible wiring board having excellent resistance to repeated bending and a flex-rigid wiring board having the flexible wiring board portion, and in particular, there is no occurrence of cracks or disconnections in the metal foil constituting the pattern circuit even when subjected to repeated bending. Another object of the present invention is to provide a flex-rigid wiring board in which an interlayer insulating layer has high adhesive strength and does not peel off. Still another object of the present invention is to provide a flex-rigid wiring board having excellent strength, particularly breaking strength between a rigid portion and a flexible portion.

  According to the present invention, a flexible rigid wiring board in which an insulating base material, a metal foil layer forming a pattern circuit, and an insulating material are laminated in this order sacrifices the flexibility of the entire flexible printed wiring board by having a specific configuration. Therefore, it is possible to obtain a flex-rigid wiring board with improved bending resistance and a printed wiring board with excellent breaking strength. That is, the present invention relates to the following [1] to [14].

[1] Repeated bending comprising a base film layer (I) on which a wiring pattern is formed, a flexible insulating material layer (II) covering (I), and a cover film layer (III) covering (II) Flexible wiring board for parts.
[2] The flexible wiring board for repeated bending portions according to [1], wherein the cover film layer (III) is further coated with a flexible insulating material.
[3] The flexible for repeated bending portions according to [1] or [2], wherein the flexible insulating material layer (II) is a cured body of a heat and / or photocurable resin composition. Wiring board.

[4] The flexible wiring board for repeated bending portions according to [3], wherein the heat and / or photocurable resin composition contains a biphenol type epoxy resin.
[5] The flexible wiring board for repeated bending portions according to [4], wherein the heat and / or photocurable resin composition contains urethane acrylate.
[6] The flexible wiring board for repeated bending portions according to any one of [1] to [5], wherein the base film layer (I) is polyimide.

[7] The flexible wiring board for repeated bending portions according to any one of [1] to [6], wherein the cover film layer (III) is a polyimide film.
[8] The flexible wiring board for repeated bending portions according to [7], wherein the cover film layer (III) is a polyimide film with an adhesive.

[9] Repetitive bending comprising a base film layer (I) on which a wiring pattern is formed, a flexible insulating material layer (II) covering the (I), and a cover film layer (III) covering the (II) A flex-rigid wiring board having a flexible wiring board for parts.

[10] Repeated bending comprising a base film layer (I) on which a wiring pattern is formed, a flexible insulating material layer (II) covering (I), and a cover film layer (III) covering (II) A flex-rigid wiring board in which a rigid part is formed on a part of a flexible wiring board for part.

[11] The flex-rigid wiring board according to [10], wherein the cover film layer (III) constitutes a part of a rigid portion.
[12] The flex-rigid wiring board according to [10] or [11], wherein the rigid portion is formed so as to cover a part of the cover film layer (III).
[13] The flex-rigid wiring board according to any one of [9] to [12], in which a flexible insulating material is further coated on the cover film layer (III).

[14] A flex-rigid wiring board having the flexible wiring board for repeated bending portions according to any one of [1] to [8].

  According to the present invention, it is possible to manufacture a flexible wiring board having excellent resistance to repeated bending and a flex-rigid wiring board having the flexible wiring board portion, and between repeated movable parts such as a folding mobile phone and a laptop computer. It is useful as a flexible printed wiring board to be connected.

  The present invention is for a repetitive bending portion comprising a base film layer (I) on which a wiring pattern is formed, a flexible insulating material layer (II) covering said (I), and a cover film layer covering said (II) The present invention relates to a flexible wiring board and a flex-rigid wiring board having the flexible wiring board.

  In the base film layer (I) on which the wiring pattern in the present invention is formed, an arbitrary conductive circuit pattern is formed on a flexible insulating substrate. There is no particular limitation on the flexible insulating substrate, polyimide film, polyethylene terephthalate film, polyethylene naphthalate film, polytetrafluoroethylene film, polyamide film, polyarylate film, polysulfone film, polyether sulfone film, polysulfide film, Known materials such as a polyetherimide film, a polyetherketone film, a polyamideimide film, and a liquid crystal polymer film can be used, and a polyimide film is preferable.

  Moreover, although the thickness is arbitrary, it is the range of 5-125 micrometers normally, Preferably it is the range of 10-75 micrometers, Most preferably, it is the range of 12-50 micrometers.

  The wiring pattern is an electric circuit formed of a conductive material (for example, copper foil), and is manufactured by an etching method or the like. The production method of the base film layer (I) on which the wiring pattern is formed is arbitrary, and after the patterning resist is applied to a commercially available copper-clad laminate, it is produced through steps of exposure, development, etching, and resist peeling.

  In applying the patterning resist, it is preferable that the surface of the copper clad laminate is previously subjected to roughening treatment such as microetching or blackening treatment. In such treatment, a hydrogen peroxide-based, sulfuric acid-based, persulfate-based or chlorine-based treatment agent can be used.

  The flexible insulating material layer (II) in the present invention is a layer made of an insulating material having flexibility, and has a function of protecting the wiring pattern by covering the (I). In addition, the flexible printed wiring board and the rigid-flex wiring board of the present invention together with the cover film layer (III) are also provided with resistance to repeated bending.

  The flexible wiring board for repeated bending portions according to the present invention is provided with appropriate rigidity and flexibility due to the presence of the flexible insulating material layer (II). As a result, excessive bending of the wiring pattern made of a metal material such as copper and peeling from the base film are suppressed, and resistance to repeated bending is improved.

The flexible insulating material layer (II) of the present invention preferably has a volume resistivity of 0.1 MΩ / cm ² or more from the viewpoint of insulation.

  The flexible insulating material layer (II) of the present invention has a tensile modulus (JIS K7217) of preferably 5 to 6,000 MPa, more preferably 100 to 4,000 MPa, and still more preferably 300 to 2,000 MPa from the viewpoint of flexibility. Range. In addition, when flexible insulating material layer (II) is a curable resin composition etc., said value is a value after hardening. The elastic modulus of the normal epoxy resin after curing is about 20,000 MPa, and the elastic modulus of the flexible insulating material layer (II) of the present invention is considerably low.

  The thickness of the flexible insulating material layer (II) of the present invention is usually in the range of 1 to 500 μm, preferably in the range of 5 to 200 μm, and most preferably in the range of 10 to 50 μm.

  The material constituting the flexible insulating material layer (II) may be a single compound or a composition composed of a plurality of compounds, and any material can be used. The flexible insulating material layer (II) is formed on the (I) by any method so as to cover the circuit pattern. Specifically, a flexible insulating material solution or dispersion is applied onto the substrate. Examples thereof include a method of drying after application, or a method of pressing a flexible material film on the substrate. It should be noted that any pressure bonding method can be used for pressure bonding, and any known apparatus can be used without any limitation. The conditions are also arbitrary. For example, preferable conditions may be adopted by appropriately adjusting the roll temperature, the roll pressure, and the like. Moreover, there is no restriction | limiting in the method of this application | coating, Arbitrary application methods, such as screen printing, a bar coat, a roll coat, a spray coat, a dip coat, a curtain coat, are possible, The application conditions can also employ | adopt the arbitrary conditions normally performed.

  The cover film layer (III) in the present invention is a resin film or metal foil layer formed so as to cover the above (II), and is further bent repeatedly on the flexible printed wiring board and the flex-rigid wiring board of the present invention. It imparts resistance to. The cover film layer (III) is formed by an arbitrary method so as to cover a part or the entire surface of the (II). For example, the cover film layer (III) can be formed by pressure bonding a commercially available coverlay film with a laminating press or a hot roll. it can.

  When manufacturing a flex-rigid circuit board, the cover film layer (III) can be formed only on a part of the (II) in order to reduce the amount of cover film used. It is desirable to laminate the cover film so as to cover a part of the portion where the rigid portion is formed. Thereby, it becomes easier to suppress the peeling of the cover film from the boundary portion between the rigid portion and the flexible portion and the disconnection of the copper circuit in the portion. In addition, the part formed in the site | part in which a rigid part is comprised among the laminated | stacked cover films will be integrated in a part of rigid part by a next process.

  Cover films used for the cover film layer (III) include polyimide film, polyethylene terephthalate film, polyethylene naphthalate film, polytetrafluoroethylene film, polyamide film, polyarylate film, polysulfone film, polyethersulfone film, polysulfide Films, polyetherimide films, polyetherketone films, polyamideimide films, liquid crystal polymer films, acrylic resin films, etc., and metal surfaces such as aluminum deposited on these surfaces to provide an electromagnetic shielding function, metals such as aluminum foil Arbitrary things, such as foil, can be used. Among these, a polyimide film is preferable, and these may be in the form of a coverlay film having an adhesive layer. In addition, when laminating the cover film, the cover film layer (III) may be adhered to the flexible insulating material layer (III) via an adhesive sheet, but when a flexible insulating material having adhesiveness is used, It is also possible to bond the cover film without using an adhesive sheet or an adhesive. In this case, it is possible to reduce the number of steps and the raw material cost, which is a preferable method.

  The cover film layer (III) can be further covered with the flexible insulating material layer (II), which not only further improves the bending resistance but also improves the moisture resistance. Furthermore, in manufacturing a flex-rigid wiring board by forming a rigid portion, it has the following advantages.

(1) In forming the rigid portion, the flexible insulating material (II) can be used in place of the bonding sheet, and after heating a member such as a copper-clad laminate or a prepreg in a semi-cured state, heating is performed. For example, the flexible insulating material can be cured and the copper-clad laminate can be bonded simultaneously.

(2) A part or all of the part where the flexible part and the rigid part are formed is coated with (II) and cured, and then the part where the rigid part is formed is further coated with (II) as an adhesive. Alternatively, a rigid portion can be formed instead of the bonding sheet. At this time, the flexible insulating material (II) coated on the cover film layer (III) and the flexible insulating material (II) applied as an adhesive for forming the rigid portion are the same type of materials, and the adhesion reliability between the layers. A flex-rigid wiring board with excellent resistance can be obtained.

(3) After forming the rigid part on the cover film (III) by an arbitrary method, the conductor of the outermost layer of the rigid part and the remaining flexible part are simultaneously covered with the flexible insulating material (II), thereby producing the manufacturing process. Can be reduced. In this method, not only the rigid part and the flexible part, but also the end face of the rigid part can be coated with the flexible insulating material at the same time, and a highly flexible flex-rigid wiring board with respect to moisture resistance can be manufactured at low cost. In general, there is a step at the boundary between the rigid part and the flexible part, and the applied flexible insulating material (II) accumulates at this step, so that stress concentration at the boundary is alleviated and excellent in reliability. Flex rigid wiring boards can also be provided.

  Although the flexible wiring board for repeated bending portions of the present invention is composed of the above (I), (II) and (III), other arbitrary layers may be formed on these layers. Further, the layers (II) and (III) may be formed on the opposite side of the above (I), and the layers may be further multilayered.

  Next, the flex-rigid wiring board of the present invention will be described. The flex-rigid wiring board of the present invention is obtained by connecting a rigid wiring board to the flexible wiring board made of (I), (II) and (III), or on a part of the flexible wiring board. It can be manufactured by forming.

  More specifically, a solder resist is applied to the flexible printed wiring board composed of the above (I), (II) and (III) except for the portion constituting the flexible portion. Thereafter, a member such as a prepreg is laminated on the solder resist, or a rigid wiring board on which a wiring pattern is formed in advance is mounted, and a through hole, an interstitial via hole, a circuit pattern, etc. are formed thereon by an arbitrary method. Thus, a rigid part is formed. Although the solder resist used here is arbitrary, it is preferable to use the same thing as the flexible insulating material of said (II) as a solder resist. In addition, when attaching a member such as a prepreg, it may be adhered via an adhesive sheet or the like, but when the above (II) is in an adhesive state before curing, it is directly adhered without using an adhesive sheet. It is also possible. In this case, it is possible to reduce the number of steps and the raw material cost, which is a preferable method.

  In the flex-rigid wiring board of the present invention thus obtained, as shown in FIG. 1, the flexible wiring board portion has an upper end 4 connected to the rigid portion and a side end 5 intersecting with the upper end 4 and the upper end and the side end. It is possible to improve the breaking strength between the rigid wiring board and the flexible wiring board by making the angle α crossing with the acute angle. In particular, it is preferable in terms of breaking strength that the portion 3 where the upper end 4 intersects the side end 5 is an arc. The radius of curvature of the arc is arbitrary, but is preferably 1.0 mm or more because the breaking strength is particularly improved.

  In the present invention, there are various advantages in achieving the configuration of the present invention, and good flex resistance can be obtained. Therefore, it is preferable to use a specific material for the flexible insulating material used above. . Hereinafter, the flexible insulating material preferably used in the present invention will be described.

  The flexible insulating material may be a curable resin or a resin composition such as a thermosetting resin or a photosensitive resin, or may be any non-curable resin such as a thermoplastic resin. . Of these, curable resins are preferred. The curable resin preferably contains a photosensitive resin composition in terms of positional accuracy when the base film layer is coated. When the flexible insulating material is a curable composition as described above, the flexible insulating material layer (II) is a cured product (cured body) of the flexible insulating material.

  The thermosetting resin composition itself is a resin composition that is cured by heat or a curing agent, and known ones can be used without limitation. More specifically, epoxy acrylate resins, unsaturated polyester resins, alkyd resins obtained by adding unsaturated carboxylic acids to polyvalent epoxy compounds such as epoxy resins, phenol resins, urea resins, melamine resins, diallyl phthalate resins, epoxy resins, etc. It is. As such a thermosetting resin composition, known ones can be used, but the glass transition temperature (TMA method, JIS K7197) after curing is in the range of 0 to 200 ° C, more preferably in the range of 20 to 150 ° C, particularly 30. What is in the range of -100 degreeC is preferable at the point of a softness | flexibility and bending resistance.

  Known curing agents for these thermosetting resins can be used, and amines and acid anhydrides can be used for epoxy resins. For those with ethylenically unsaturated bonds such as epoxy acrylate resins and unsaturated polyester resins, organicization such as dibenzoyl peroxide, dilauroyl peroxide, dicumyl peroxide, di-t-butyl peroxide, etc. An oxide or an azo compound such as azobisisobutyronitrile can be used.

  As the photosensitive resin composition of the present invention, known ones can be used without limitation, and a composition comprising a curable resin (A-1), a photopolymerization initiator (B), and a diluent (C) is exemplified. The As such a photosensitive resin composition, known ones can be used, but the glass transition temperature after curing (TMA method, JIS K7197) is in the range of 0 to 200 ° C., further 20 to 150 ° C., particularly 30 to 100 ° C. Those within the range are preferable in terms of flexibility and bending resistance.

Further, the photosensitive resin composition of the present invention may further contain a non-polymerizable resin (A-2).
When a photosensitive resin composition is used as the flexible insulating material, the curable resin (A-1) is obtained by adding an unsaturated carboxylic acid to a polyvalent epoxy compound such as an epoxy resin, (meth) acrylic acid -What added the unsaturated epoxy compound to the carboxyl group of the methacrylic acid ester copolymer can be used, Preferably it is unsaturated group containing polycarboxylic acid resin (A '). Examples of the non-polymerizable resin (A-2) include a copolymer of (meth) acrylic acid and methacrylic acid ester.

  The unsaturated group-containing polycarboxylic acid resin (A ′) is a resin having at least one polymerizable unsaturated group and carboxyl group in one molecule. For example, an unsaturated carboxylic acid is added to a polyvalent epoxy compound such as an epoxy resin. , An acid anhydride further reacted, a product obtained by adding an unsaturated epoxy compound to a part of the carboxyl group of the (meth) acrylic acid-methacrylic acid ester copolymer, styrene and maleic anhydride, Examples include compounds obtained by adding an unsaturated hydroxy compound to a compound containing an acid anhydride group, such as a copolymer with itaconic anhydride. Among these, an unsaturated group-containing polycarboxylic acid resin which is a reaction product of an addition product of an epoxy resin (a) and an unsaturated group-containing monocarboxylic acid (b) and succinic anhydride (c) is preferable.

  Specific examples of the unsaturated group-containing monocarboxylic acid (b) include, for example, acrylic acid, a dimer of acrylic acid, methacrylic acid, β-styrylacrylic acid, β-furfurylacrylic acid, crotonic acid, α- Cyclocinnamic acid, cinnamic acid, and half-esters that are a reaction product of a saturated or unsaturated dibasic acid anhydride and a (meth) acrylate derivative having one hydroxyl group in one molecule, or a saturated or unsaturated dibasic The half ester which is the reaction material of an acid and an unsaturated group containing monoglycidyl compound is mentioned. Half esters include, for example, succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, itaconic anhydride, methylendomethylenetetrahydroanhydride. Saturated and unsaturated dibasic acid anhydrides such as phthalic acid, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, glycerin di (meth) acrylate , Trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, (meth) acrylate of phenylglycidyl ether Half esters obtained by reacting equimolar amounts of (meth) acrylate derivatives having one hydroxyl group in one molecule, or saturated or unsaturated dibasic acids (for example, succinic acid, maleic acid, Adipic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, itaconic acid, fumaric acid, etc.) and an unsaturated group-containing monoepoxy compound (for example, glycidyl (meth) acrylate) are reacted in an equimolar ratio. Half esters and the like. These unsaturated group-containing monocarboxylic acids (b) can be used alone or in combination. A particularly preferred unsaturated group-containing monocarboxylic acid is acrylic acid.

  The urethane (meth) acrylate compound having a carboxyl group is preferably obtained by reacting (meth) acrylate (α), polyol (β) and polyisocyanate (γ) having a hydroxyl group.

  The (meth) acrylate (α) having a hydroxyl group is a compound constituting both ends of a urethane (meth) acrylate compound having a carboxyl group, and specific compounds include 2-hydroxyethyl (meth) acrylate, hydroxy Propyl (meth) acrylate, hydroxybutyl (meth) acrylate, caprolactone or alkylene oxide adduct of each of the above (meth) acrylates, glycerin mono (meth) acrylate, glycerin di (meth) acrylate, glycidyl methacrylate-acrylic acid adduct, tri Methylolpropane mono (meth) acrylate, trimethylol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylol Ropantori (meth) acrylate, trimethylolpropane - alkylene oxide adduct - di (meth) acrylate.

  These (meth) acrylates (α) having a hydroxyl group can be used alone or in combination of two or more. Among these, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate are preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.

  Polyol (β) is a compound constituting a repeating unit of a urethane (meth) acrylate compound having a carboxyl group together with polyisocyanate (γ), and a polymer polyol (β1) and a dihydroxyl compound having a carboxyl group (β2) Is mentioned.

  Examples of the polymer polyol (β1) used in the present invention include polyether diols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, polyester polyols obtained from esters of polyhydric alcohols and polybasic acids, hexamethylene carbonate, And polylactone diols such as polycarbonate diols, polycaprolactone diols, polybutyrolactone diols containing units derived from pentamethylene carbonate as constituent units. These polymer polyols (β1) can be used singly or in combination of polyether diols, polyester polyols, polycarbonate diols and polylactone diols. Moreover, what gave the carboxyl group to the polymer polyol may be used. The number average molecular weight of these polymer polyols (β1) is preferably 200 to 2,000 from the viewpoint of flexibility.

  The category of the dihydroxyl compound (β2) having a carboxyl group used in the present invention includes a branched or straight-chain dihydroxy aliphatic carboxylic acid having at least two alcoholic hydroxyl groups, and includes dimethylolpropionic acid and Dimethylol butanoic acid is preferred.

  Specific examples of the polyisocyanate (γ) used in the present invention include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and diphenylmethylene diisocyanate. Nert, (o, m, or p) -xylene diisocyanate, methylene bis (cyclohexyl isocyanate), trimethylhexamethylene diisocyanate, cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene range And diisocyanates such as isocyanate and 1,5-naphthalenediisocyanate. These polyisocyanates can be used alone or in combination of two or more.

  The urethane (meth) acrylate compound having a carboxyl group used in the present invention is composed of units derived from (meth) acrylate (α) having a hydroxyl group at the terminal, and the repeating units therebetween are polyol (β) and polyisocyanate. Nert (γ) is linked by a urethane bond, and — (ORbO—OCNHRcNHCO) n— [wherein ORbO is a dehydrogenated residue of polyol (β) and Rc is a dehydrogenation of polyisocyanate (γ). Represents an isocyanate residue. However, n representing the number of repeating units is preferably about 1 to 200, and more preferably 2 to 30.

  Further, the repeating unit represents a plurality of types when at least one of polyol (β) and polyisocyanate (γ) is used, but the repeating regularity in the repeating unit. Can be appropriately selected according to the purpose, such as complete randomness, block or localization.

  The method for producing a urethane (meth) acrylate compound having a carboxyl group used in the present invention from a (meth) acrylate (α), a polyol (β) and a polyisocyanate (γ) having a hydroxyl group is particularly limited. Although it is not a thing, as a preferable manufacturing method, (meth) acrylate (α) having a hydroxyl group, polyol (β) and polyisocyanate (γ) are mixed together and reacted, (Γ) The component is reacted to form a urethane isocyanate prepolymer containing one or more isocyanate groups per molecule, and then the urethane isocyanate prepolymer is reacted with the component (α) (Α) component and (γ) component are reacted to contain one or more isocyanate groups per molecule And a method of reacting the prepolymer with the component (β) after forming a urethane isocyanate prepolymer.

  A photoinitiator (B) is a compound which has the capability to start superposition | polymerization of an unsaturated bond by irradiation, such as an ultraviolet-ray, A well-known thing can be used. For example, benzoins such as benzoin, benzoin methyl ether, benzoin isopropyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxy Acetophenones such as cyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, N, N-dimethylaminoacetophenone, 2-methylanthraquinone, 2-ethylanthraquinone , 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, anthraquinones such as 2-aminoanthraquinone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthate , Thioxanthones such as 2-chlorothioxanthone and 2,4-diisopropylthioxanthone, ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal, benzophenone, methylbenzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdiethylamino Benzophenones such as benzophenone, Michler's ketone, 4-benzoyl-4′-methyldiphenyl sulfide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like can be used. These can be used alone or in combination of two or more, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (manufactured by Ciba-Geigy, Irgacure 907) A combination of 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., Kayacure DETX), 2-isopropylthioxanthone or 4-benzoyl-4′-methyldiphenyl sulfide is preferred.

  Further, the photopolymerization initiator (B) includes tertiary amines such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl 4-dimethylaminobenzoate, triethylamine, and triethanolamine. Photosensitizers such as the above can be used alone or in combination of two or more.

  The proportion of the photopolymerization initiator (B) used in the photosensitive resin composition is arbitrary, but is usually 0.5 to 20% by mass, and preferably 1 to 10% by mass.

  As the diluent (C), a known solvent and / or photopolymerizable monomer can be used. Typical solvents include ketones such as ethyl methyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene, methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol and propylene glycol monomethyl. Glucol ethers such as ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether, esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, ethanol, propanol, ethylene Alcohols such as glycol and propylene glycol, aliphatic hydrocarbons such as octane and decane, petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and sorbet It may be mentioned petroleum-based solvents such as Tonafusa. Moreover, water can also be used as a solvent for reducing flammability. When water is used as a solvent, the carboxyl group of the component (A ′) is substituted with amines such as trimethylamine and triethylamine, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide. By making a salt with a (meth) acrylate compound having a tertiary amino group such as N, N-dimethyl (meth) acrylamide, acryloylmorpholine, N-isopropyl (meth) acrylamide, N-methylolacrylamide, and the like (A ′) It is preferred that the components are dissolved in water.

  Specific examples of the photopolymerizable monomer include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, glycols such as ethylene glycol, methoxytetraethylene glycol, and polyethylene glycol. Mono- or di (meth) acrylates, (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, and aminoalkyls such as N, N-dimethylaminoethyl (meth) acrylate (Meth) acrylates, hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, tris-hydroxyethyl isocyanurate and other polyhydric alcohols or Ethylene oxide or propylene oxide adduct polyhydric (meth) acrylates, phenoxyethyl (meth) acrylate, bisphenol A 'polyethoxydi (meth) acrylate and other phenolic ethylene oxide or propylene oxide adduct (meth) Acrylates, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, glycidyl ether (meth) acrylates such as triglycidyl isocyanurate, ε-caprolactone modified (meth) acrylates such as caprolactone-modified tris (acryloxyethyl) isocyanurate And melamine (meth) acrylate.

  The said diluent (C) is used individually or in mixture of 2 or more types. 5-80 mass% is preferable in the said composition, and, as for the quantity of the diluent (C) contained in the photosensitive resin composition of this invention, Most preferably, it is 10-70 mass%.

  As the photosensitive resin composition in the present invention, those usually used as a solder resist are particularly preferred. For example, an unsaturated group-containing polycarboxylic acid resin (A ′) which is a reaction product of an addition product of the epoxy resin (a) and the unsaturated group-containing monocarboxylic acid (b) and succinic anhydride (c), What contains a hardening component (D) in addition to a photoinitiator (B) and a diluent (C) is preferable.

  Specific examples of the curing component (D) include those that do not have an unsaturated double bond and that are cured by heat, ultraviolet rays, or the like, and the component (A ′) that is the main component in the flexible insulating material. It may react with a carboxyl group or the like by heat or ultraviolet light. Specifically, for example, an epoxy compound having one or more epoxy groups in one molecule (for example, Epicoat 1009, 1031 manufactured by Nippon Epoxy Resin Co., Ltd., Epicron N- manufactured by Dainippon Ink & Chemicals, Inc.) 3050, N-7050, Dow Chemical Co., Ltd., DER-642U, DER-673MF, etc. Bisfer A type epoxy resin, Toto Kasei Co., Ltd., ST-2004, ST-2007, etc. Hydrogenated bisphenol A type Epoxy resin, manufactured by Toto Kasei Co., Ltd., bisphenol F type epoxy resin such as YDF-2004, YDF-2007, manufactured by Sakamoto Pharmaceutical Co., Ltd., SR-BBS, SR-TBA-400, manufactured by Toto Kasei Co., Ltd. Brominated bisphenol A type epoxy resins such as YDB-600 and YDB-715, manufactured by Nippon Kayaku Co., Ltd., EPPN-201, EOC -103, EOCN-1020, novolak type epoxy resins such as BREN, manufactured by Dainippon Ink and Chemicals, bisphenol A novolak type epoxy resin such as Epicron N-880, manufactured by Yuka Shell Co., Ltd., YL-931 Amino group-containing epoxy resins such as YL-933, manufactured by Dainippon Ink and Chemicals, Epicron TSR-601, manufactured by Asahi Denka Co., Ltd., rubber-modified epoxy resins such as R-1415-1, Nippon Kayaku ( Co., Ltd., EBPS-200, Dainippon Ink & Chemicals Co., Ltd., Epiclon EXA-1514 and other bisphenol S type epoxy resins, Nippon Oil & Fats Co., Ltd., Bremer DGT and other diglycidyl terephthalates, Nissan Chemical Co., Ltd. Manufactured by, triglycidyl isocyanurate such as TEPIC, manufactured by Yuka Shell Co., Ltd., xylenone such as YX-4000 Type epoxy resin (biphenol type epoxy resin), Yuka Shell Co., Ltd., bisphenol type epoxy resin such as YL-6056, Daicel Chemical Industries, Ltd., alicyclic epoxy resin such as Celoxide 2021, etc. ), Melamine derivatives (eg, hexamethoxymelamine, hexabutoxylated melamine, condensed hexamethoxymelamine, etc.), urea compounds (eg, dimethylol urea, etc.), bisphenol A compounds (eg, tetramethylol / bisphenol A, etc.) ), And oxazoline compounds.

  In addition, urethane acrylate having a urethane skeleton and a polymerizable unsaturated bond in one molecule (for example, U-4HA, U-15HA, U-108A, UA-122P, U-200AX, UA- manufactured by Shin-Nakamura Chemical Co., Ltd.) 4100, UA-4400, UA-340P, UA-2235PE, UA-160TM, UA-6100, etc.) can also be used.

  Among these, an epoxy compound having one or more epoxy groups in one molecule is preferable, a bisphenol type or biphenol type epoxy resin is preferable, and a biphenol type epoxy resin is most preferable.

  The purpose of use of the curing component (D) is to further improve various properties such as adhesion, heat resistance and plating resistance. The curing component (D) is used alone or as a mixture of two or more, and the amount of the curing component (D) contained in the composition of the present invention is preferably 1 to 50% by mass, particularly preferably in the composition. Is 3 to 45% by mass.

When using an epoxy compound in the said hardening component (D), in order to improve characteristics, such as adhesiveness, chemical resistance, and heat resistance, it is preferable to use an epoxy resin hardening | curing agent together. Specific examples of such epoxy resin curing agents, such as imidazole derivatives (Shikoku Chemicals _{Co., 2MZ, 2E4MZ, C 11 Z} , C 17 Z, 2PZ, 1B2MZ, 2MZ-CN, 2E4MZ-CN, C _{11 Z-CN, 2PZ-CN} , 2PHZ-CN, 2MZ-CNS, 2E4MZ-CNS, 2PZ-CNS, 2MZ-A'ZINE, 2E4MZ-A'ZINE, C 11 Z-A'ZINE, 2MA'-OK, 2P4MHZ, 2PHZ, 2P4BHZ, etc.); guanamines such as acetoguanamine, benzoguanamine; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, polybasic hydrazide These organic acid salts and / or Epoxy adduct; boron trifluoride amine complex; Echirujiamino -S- triazine, 2,4-diamino -S- triazine, triazine derivatives such as 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), tetramethyl Tertiary amines such as guanidine and m-aminophenol; Polyphenols such as polyvinylphenol, polyvinylphenol bromide, phenol novolac and alkylphenol novolac; Organic phosphines such as tributylphosphine, triphenylphosphine and tris-2-cyanoethylphosphine; Phosphonium salts such as tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide, hexadecyltributylphosphonium chloride; benzyltrimethylammonium Roraido, quaternary ammonium salts such as phenyl tributylammonium chloride; the polybasic acid anhydride;

  Diphenyliodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, manufactured by Ciba Geigy, Irgacure 261, manufactured by Asahi Denka Co., Ltd., Optoma-SP Photocatalytic polymerization catalyst such as -170; styrene-maleic anhydride resin; known equimolar reaction product of phenyl isocyanate and dimethylamine, equimolar reaction product of organic polyisocyanate such as tolylene diisocyanate, isophorone diisocyanate and dimethylamine, etc. Conventional curing agents or curing accelerators are used alone or in admixture of two or more. The amount of the epoxy resin curing agent used is preferably 0.01 to 25 parts by mass, particularly preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the epoxy compound.

  The flexible insulating material in the present invention may further include barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, talc, if necessary for the purpose of improving properties such as adhesion and hardness. Known inorganic fillers such as clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica powder can be used. The amount of use is preferably 0 to 60% by mass, particularly preferably 5 to 40% by mass in the flexible insulating material.

  Furthermore, if necessary, known and commonly used colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, hydroquinone, hydroquinone monomethyl ether, tert-butyl Known and conventional polymerization inhibitors such as catechol, pyrogallol and phenothiazine, known and conventional thickeners such as asbestos, olben, benton and montmorillonite, defoamers and / or leveling agents such as silicones, fluorines and polymers , Imidazole-based, thiazole-based, triazole-based, and well-known and conventional additives such as adhesion-imparting agents such as silane coupling agents can be used, but those that do not contain silicone in terms of adhesion to the cover film Prefer Good.

  In addition, copolymers of ethylenically unsaturated compounds such as acrylic acid esters, known and conventional binder resins such as polyester resins synthesized from polyhydric alcohols and polybasic acid compounds, and polyester (meth) acrylates, Photopolymerizable oligomers such as polyurethane (meth) acrylate and epoxy (meth) acrylate can also be used without departing from the spirit of the present invention.

  The composition for the flexible insulating material can be produced by any method, and the composition can be produced by a known method such as blending the blending components in the above ratio and uniformly mixing with a roll mill or the like.

Manufacture and evaluation method of flexible wiring board test piece
1) Manufacture of flexible wiring board test piece A flexible wiring board test piece for a bending test or the like was manufactured according to the following steps. FIG. 3 shows a schematic diagram of the test piece. The test piece is a rectangle of 150 mm × 15 mm, and the wiring pattern portion is about 110 mm × 10 mm. The line / space of the wiring pattern portion is 0.1 / 0.1 mm, and has two electrodes on one end. The repeated bending test is performed by repeatedly bending the longitudinal direction of the test piece. If one part of the wiring is disconnected during the test, the current flowing between the electrodes is interrupted, and the disconnection can be detected.

Step 1 : After crimping a dry film resist on a commercially available copper-clad laminate (R-F775, manufactured by Matsushita Electric Works Co., Ltd., a laminated copper film having a thickness of 18 μm on one side of a polyimide film having a thickness of 25 μm) A base film layer (I) (11 in FIG. 4) on which a wiring pattern was formed was manufactured through steps of photomask exposure, development, etching, and peeling.

Step 2 : On the base film layer (I) obtained in Step 1 above, a predetermined flexible insulating material composition is applied by screen printing (using a 100 mesh polyester screen) so as to cover the circuit pattern, Next, the coating film was dried for 30 minutes in a hot air dryer at 80 ° C., and then exposed entirely with ultraviolet rays (ultra-high pressure mercury lamp, main wavelength 365 nm, 400 mJ / cm ² ) to form a flexible insulating material layer (II) having a thickness of 40 μm. (12 in FIG. 4) was produced.

Step 3 : On the entire surface of the flexible printed wiring board manufactured in Step 2 above, a polyimide coverlay film (T-type, 25 μm thick polyimide film manufactured by Toray Industries, Inc.) as a cover film layer (III) (13 in FIG. 4) And an adhesive having a thickness of 8 μm were laminated and pressure-bonded (160 ° C., 4.3 N / cm, 60 minutes) to manufacture a flexible wiring board.

Step 4 : The same flexible insulating material composition as that used in Step 2 is applied to the entire surface of the flexible printed wiring board manufactured in Step 3 by screen printing, and the thickness is 40 μm by the same operation as in Step 2. Layer (14 in FIG. 4) was formed (see FIG. 4). Thereafter, post-curing was performed at 150 ° C. for 30 minutes.

2) Synthesis of unsaturated group-containing polycarboxylic acid resin 371 parts of bisphenol A type epoxy resin having an epoxy equivalent of 650, a softening point of 81.1 ° C., and a melt viscosity (150 ° C.) of 12.5 poise was added to 925 parts of epichlorohydrin and 462 parts of dimethyl sulfoxide. After 5 parts were dissolved, 58.5 parts of 98.5% NaOH was added over 100 minutes at 70 ° C. with stirring. After the addition, the reaction was further carried out at 70 ° C. for 3 hours. Next, most of the excess unreacted epichlorohydrin and dimethyl sulfoxide were distilled off under reduced pressure, and the reaction product containing the by-product salt and dimethyl sulfoxide was dissolved in 750 parts of methyl isobutyl ketone, and further 10 parts of 30% NaOH was added to 70 ° C. For 1 hour. After completion of the reaction, washing was performed twice with 200 g of water. After separation of oil and water, methyl isobutyl ketone is recovered by distillation from the oil layer, epoxy having an epoxy equivalent of 287, a hydrolyzable chlorine content of 0.07%, a softening point of 64.2 ° C., and a melt viscosity (150 ° C.) of 0.71 Pa · s. 340 g of resin was obtained.

  2870 parts (10 equivalents) of the epoxy resin obtained according to the above, 720 parts (10 equivalents) of acrylic acid, 2.8 parts of methylhydroquinone, and 1943.5 parts of carbitol acetate were heated and stirred at 90 ° C., and the reaction mixture was stirred. Dissolved. Next, the reaction solution was cooled to 60 ° C., charged with 16.6 parts of triphenylphosphine, heated to 100 ° C., and reacted for about 32 hours to obtain a reaction product having an acid value of 1.0 mgKOH / g. Next, 783 parts (7.83 mol) of succinic anhydride and 421.6 parts of carbitol acetate were added thereto, heated to 95 ° C., reacted for about 6 hours, the solvent was distilled off, and the acid value was 100 mgKOH / g of unsaturated group-containing polycarboxylic acid resin was obtained.

3) Adhesion test In accordance with JIS K5400, 100 1-mm square goblets were made on a flexible wiring board test piece for a bending test or the like, and a peeling test was performed using a cellophane tape. Observed the peeling state of the goblet and evaluated it according to the following criteria:

◎: No more than 91 crushed eyes;
○: 81-90 goblets that did not peel;
(Triangle | delta): The thing of 50-80 eyes which did not peel; and x: The thing of less than 50 things which did not peel.

4) Bending resistance test Using a commercially available MIT flexibility evaluation tester (manufactured by Tester Sangyo Co., Ltd.), the number of bending until cracking and disconnection was measured (curvature of the bending surface). (Radius 2.0 mm, refraction cycle: 175 / min, refraction angle: 135 degrees on both sides, load 4.5 N).

5) Glass transition temperature Tg
The TMA method (thermomechanical analysis method, JIS K7197) was used to set the discontinuity of the linear expansion coefficient to Tg. The measuring device used was TMA-SS6100 type, manufactured by Seiko Instruments Inc.

Examples 1 and 2
Using each of the components described in Table 1 below, a flexible wiring board test piece was prepared according to the above. The results are shown in Table 1 below:

Comparative Example 1
1) Production of the flexible wiring board test piece was performed in the same manner as in Example 1 except that the step 2 was not performed.

Examples 3 and 4
The procedure was the same as in Example 1 except that the step 4 was not performed. The results are shown in Table 1.

Comparative Example 2
The same procedure as in Example 1 was performed except that the steps 3 and 4 were not performed. The results are shown in Table 1.

Examples 5-8
In Example 1, it carried out similarly except having used the thing of Table 1 as each component. The results are shown in Table 1.

Examples 9-13
In Example 1, it carried out similarly except having used the thing of Table 2 as each component. However, hot air drying and ultraviolet light exposure were not performed in Step 2 and Step 4. In Step 2, curing was performed at 150 ° C. for 30 minutes after coating. The results are shown in Table 2 below:

Manufacture and evaluation of flex-rigid circuit boards
6) Production of flex-rigid wiring board A flex-rigid wiring board having the shape shown in FIG. 1 was produced according to the following steps.
Step 1 : After crimping a dry film resist on a commercially available copper-clad laminate (R-F775, manufactured by Matsushita Electric Works Co., Ltd., a laminated copper film having a thickness of 18 μm on one side of a polyimide film having a thickness of 25 μm) The base film layer (I) (11 in FIG. 5) having a wiring pattern formed on one side was manufactured through steps of photomask exposure, development, etching, and peeling.

Step 2 : On the base film layer (I) obtained in Step 1 above, a predetermined flexible insulating material composition is applied by screen printing (using a 100 mesh polyester screen) so as to cover the circuit pattern, Next, the coating film was dried for 30 minutes in a hot air dryer at 80 ° C., and then exposed entirely with ultraviolet rays (ultra-high pressure mercury lamp, main wavelength 365 nm, 400 mJ / cm ² ) to form a flexible insulating material layer (II) having a thickness of 40 μm. (12 in FIG. 5) was produced.

Step 3 : Next, on the entire surface of the flexible printed wiring board manufactured in Step 2 above, a polyimide coverlay film (T type, 25 μm in thickness, manufactured by Toray Industries, Inc.) as a cover film layer (III) (13 in FIG. 5). The polyimide film was coated with an adhesive having a thickness of 8 μm) and pressure-bonded (160 ° C., 4.3 N / cm, 60 minutes) to produce a flexible wiring board.
Step 4 : Thereafter, a 100 μm thick prepreg for a multilayer laminate and 18 μm thick copper foil are laminated on both sides of a part of the flexible printed wiring board manufactured in Step 3 above, and bonded at 180 ° C. by a heating press. A rigid part was formed.

Step 5: After having formed a circuit pattern by etching the metal layer of the rigid portion produced in step 4 (Fig. 5 15), by screen printing by applying to a thickness of 40μm solder resist ( In FIG. 5, 16) a flex-rigid wiring board was manufactured (see FIG. 5).

Examples 14-16
The composition of each component and the structure of each layer of the flexible part are the same as those in Example 3. The shape of the part 3 where the lower end 4 of the rigid part 1 in FIG. Flex-rigid wiring boards having arcs of 5 mm, 1.5 mm and 2.0 mm were produced by the above method. The rigid part of the obtained wiring board was fixed horizontally by a clamp, the flexible part was arranged so as to be perpendicular to the rigid part, and the load required for breaking was measured by applying a load to the flexible part. The loads that led to breakage between the rigid part and the flexible part were 120 gf, 600 gf, and 720 gf, respectively.

Comparative Examples 3-5
In the manufacture of the flex-rigid wiring board, a flex-rigid wiring board having the same radius of curvature as 0.5 mm, 1.5 mm, and 2.0 mm was used in the same manner as in Examples 15 to 17 except that the step 2 was not performed. Manufactured. The loads that led to breakage between the rigid part and the flexible part were 50 gf, 120 gf, and 180 gf, respectively.

Examples 17-19
The composition of each component and the structure of each layer of the flexible part was set as Example 1, and the same procedure as in Examples 14 to 16 except that Step 4-1 was performed instead of Step 4 was performed. Flex rigid wiring boards with arcs of .5 mm and 2.0 mm were manufactured. The loads that led to breakage between the rigid part and the flexible part were 150 gf, 720 gf, and 830 gf, respectively.

Step 4-1: on both sides over the entire surface of the flexible printed wiring board manufactured in step 3, a predetermined flexibility insulative material composition was applied by screen printing (100 a polyester mesh screen), and then a coating film After drying for 30 minutes in a hot air dryer at 80 ° C., the whole surface is exposed with ultraviolet rays (ultra-high pressure mercury lamp, main wavelength 365 nm, 400 mJ / cm ² ), and a flexible insulating material having a thickness of 40 μm on the cover film layer (III) Layer (II) was prepared.
A prepreg for a multilayer laminated board having a thickness of 100 μm and a copper foil having a thickness of 18 μm were laminated on both surfaces of a part of the flexible printed wiring board thus manufactured, and adhered at 180 ° C. by a heating press to form a rigid portion. .

The top view of a flex-rigid wiring board. The side view at the time of bending a flex-rigid wiring board. The schematic diagram (plane) of the flexible wiring board test piece of Example 1. FIG. The schematic diagram (cross section) of the flexible wiring board test piece of Example 1. FIG. Schematic diagram (cross section) of flex-rigid wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 '... Rigid part 2 ... Flexible part 3 ... Crossing part 4 ... Lower end line 5 of a rigid part ... Side edge line 6 of a flexible part ... Pattern circuit 7 ... Electrode part 11 ... Base film layer (I) (copper foil circuit) (Including pattern part)
12 ... Flexible insulating material layer (II)
13 ... Cover film layer (III)
14 ... Flexible insulating material layer 15 ... Hardened material layer of prepreg (including copper foil circuit pattern part)
16 ... Solder resist layer

Claims (14)

  Flexible for repeated bends comprising a base film layer (I) on which a wiring pattern is formed, a flexible insulating material layer (II) covering (I), and a cover film layer (III) covering (II) Wiring board.   The flexible wiring board for repeated bending portions according to claim 1, wherein a flexible insulating material is further coated on the cover film layer (III).   The flexible wiring board for repeated bending portions according to claim 1 or 2, wherein the flexible insulating material layer (II) is a cured body of heat and / or a photocurable resin composition.   The flexible wiring board for repeated bending portions according to claim 3, wherein the heat and / or photocurable resin composition contains a biphenol type epoxy resin.   The flexible wiring board for repeated bending portions according to claim 4, wherein the heat and / or photocurable resin composition contains urethane acrylate.   The flexible wiring board for repeated bending portions according to any one of claims 1 to 5, wherein the base film layer (I) is polyimide.   The flexible wiring board for repeated bending portions according to any one of claims 1 to 6, wherein the cover film layer (III) is a polyimide film.   The flexible wiring board for repeated bending portions according to claim 7, wherein the cover film layer (III) is a polyimide film with an adhesive.   Flexible for repeated bends comprising a base film layer (I) on which a wiring pattern is formed, a flexible insulating material layer (II) covering (I), and a cover film layer (III) covering (II) A flex-rigid wiring board having a wiring board.   Flexible for repeated bends comprising a base film layer (I) on which a wiring pattern is formed, a flexible insulating material layer (II) covering (I), and a cover film layer (III) covering (II) A flex-rigid wiring board in which a rigid part is formed on a part of the wiring board.   The flex-rigid wiring board according to claim 10, wherein the cover film layer (III) constitutes a part of a rigid portion.   The flex-rigid wiring board according to claim 10 or 11, wherein the rigid portion is formed so as to cover a part of the cover film layer (III).   The flex-rigid wiring board according to any one of claims 9 to 12, wherein a flexible insulating material is further coated on the cover film layer (III).   A flex-rigid wiring board having the flexible wiring board for repeated bending portions according to any one of claims 1 to 8.

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