JP2005109134A - Flexible rigid wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new flexible rigid wiring board characterized by an adhesive used in it. <P>SOLUTION: The flexible rigid wiring board consists of a flexible wiring board and a rigid wiring board bonded by an adhesive layer between them. In the flexible rigid wiring board, the adhesive layer consists of the adhesive which forms a cured resin film having a coefficient of water absorption not larger than 0.5% when its thickness is 50 μm. In a method for manufacturing the flexible rigid wiring board, the rigid wiring board having the adhesive layer with above-mentioned features is formed by laminating a non-cured or semi-cured resin film on the rigid wiring board, and is laminated on the flexible wiring board and bonded thereto while it is heated and pressurized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flex-rigid wiring board composed of a flex part and a rigid part and a manufacturing method thereof, and more particularly to a holding-type flex-rigid wiring board in which two or more rigid parts are connected by a flex part. The present invention is particularly characterized by an adhesive that bonds the rigid portion and the flex portion.

  The flex-rigid wiring board is used in many electronic devices such as a digital camera, a digital video, and a mobile phone, particularly in response to miniaturization and high functionality of electronic devices.

  As a method for producing a flex-rigid circuit board, JP-A-10-27966 proposes an epoxy resin composition containing (A) an epoxy resin, (B) a novolac type phenol resin, and (C) an imidazole derivative as an adhesive as an adhesive. Has been. The rigid conductor layer of the flex-rigid circuit board had a minimum wiring width of about 100μm and a wiring spacing of about 100μm. However, with further enhancement of functionality, the wiring width / wiring spacing is less than 50 / 50μm. It has been requested. However, the conventional adhesive layer uses acrylic resin, phenol resin, rubber-based resin, polyamide resin, polyimide resin, etc. as well as the aforementioned epoxy resin. With adhesives using these resins, there was anxiety about migration resistance when the wiring interval became fine. In addition, as a function addition, there is a demand for providing a communication function such as wireless LAN and Bluetooth, and the insulating material used is required to have characteristics in a high frequency region.

  As an adhesive layer (bonding sheet) used to join the rigid part and flex part of a flex-rigid circuit board, Japanese Patent Application Laid-Open No. 2000-129228 discloses a high heat-resistant, low water-absorbing bonding with a water absorption rate of 2% or less for the entire sheet. A sheet has been proposed. However, the adhesive illustrated here is a polyimide resin or the like, and does not satisfy the migration resistance in fine wiring.

  As an adhesive for semiconductors with low water absorption, WO99 / 01519 contains a ring structure selected from (a) a cyclic olefin polymer and (b) an aromatic polymer having an aromatic ring repeating unit in the main chain. There is a proposal of an adhesive for semiconductor parts using a thermoplastic polymer as a base polymer. Certainly, it has low water absorption and is suitable as an adhesive for semiconductor components. However, in this application, after bonding the rigid part and the flex part, there is a process such as immersion in a solder bath, and there are multiple processes that are performed at a temperature higher than the glass transition temperature of the aforementioned polymer. In such an adhesive, there has been a problem that the insulation reliability is lowered due to a positional shift caused by the thermoplasticity of the resin.

Japanese Patent Laid-Open No. 10-27966 JP 2000-129228 A WO99 / 01519

  Therefore, the present invention is a flexible rigid wiring board in which a flexible wiring board and a rigid wiring board are bonded with an adhesive, and has high migration resistance even in the case of fine wiring, and also has insulation reliability and high temperature and high humidity conditions. Provided are a flexible rigid wiring board having excellent adhesion and a method for producing the same.

  As a result of various studies to solve the above problems, the present inventor, as an adhesive used for bonding a flexible wiring board and a rigid wiring board, a curable resin having a water absorption rate of 0.5% or less at a thickness of 50 μm When an adhesive that gives a film is used, it has been found that migration resistance is high even for fine wiring, and that the insulation reliability and adhesion are excellent even under high temperature and high humidity conditions, and the present invention has been completed.

Accordingly, the present invention provides a flexible wiring board in which a flexible wiring board and a rigid wiring board are bonded via an adhesive layer, and the adhesive layer has a water absorption of 0.5% or less when the thickness is 50 μm. Provided is a flexible rigid wiring board made of an adhesive that gives a film.
The adhesive preferably comprises a curable composition containing an alicyclic olefin polymer and a curing agent. The flexible wiring board is preferably such that a conductor layer is formed on both surfaces of one insulating layer, and both conductor layers are covered with a coverlay film. The rigid wiring board is coupled to, for example, both surfaces of a flexible wiring board.

  The present invention also includes laminating an uncured or semi-cured resin film on a rigid wiring board, the adhesive layer comprising an adhesive that gives a cured resin film having a water absorption rate of 0.5% or less when the thickness is 50 μm. The rigid rigid wiring according to any one of claims 1 to 4, wherein the rigid wiring board formed and laminated with the flexible wiring board while being heated and pressed and bonded together. A method for manufacturing a board is provided.

  An example of the flexible rigid wiring board and the manufacturing method thereof of the present invention is schematically shown in FIG. For example, a flexible wiring board (D) in which a wiring pattern (7) is formed on both sides or one side of a flexible base film (6) and the surface thereof is covered with a coverlay (8), and a glass epoxy laminated board (3,4) The flexible rigid wiring board (E) of the present invention is formed by bonding the rigid wiring board (B) having the wiring pattern (2) formed on the surface thereof with the adhesive sheet (A). .

In this process, for example, an adhesive sheet (A) made of an uncured or semi-cured resin film is heat-pressed on the surface of the rigid wiring board (B) having the wiring pattern (2), and an adhesive layer (5 ′) Is formed, and then the flexible wiring board (C) is formed on the adhesive layer (5 ′) of the rigid wiring board (C) having the adhesive layer (5 ′). The rigid wiring board (C ′) and the flexible wiring board (D) are joined by overlapping and thermocompression bonding. By this thermocompression bonding, a flexible rigid wiring board (E) in which an adhesive layer (5) is formed between the rigid wiring board (B) and the flexible wiring board (D) can be obtained.
For laminating the adhesive sheet (A) on the rigid wiring board (B) or laminating the rigid wiring board (B) and the flexible wiring board (D), usually a pressure laminator, vacuum laminator, vacuum press roll laminator, etc. The stacking apparatus may be used. In particular, it is preferable to carry out under reduced pressure (preferably vacuum) from the viewpoint of wiring embedding and suppression of bubble generation. When reducing the pressure, the pressure is usually reduced to 100 kPa to 1 kPa, preferably 40 kPa to 10 Pa. The pressing force is generally 10 kPa to 20 MPa, preferably 100 kPa to 10 MPa. The pressure bonding temperature is usually 30 to 250 ° C, preferably 70 to 220 ° C. When laminating the adhesive sheet (A) on the rigid wiring board (B), it is performed at a low temperature so as not to be cured, and the rigid wiring board (C) having the adhesive layer (5 ') and the flexible wiring board (D). When laminating the layers, it is preferable to increase the temperature (150 ° C.) or higher so as to be cured. The electrical conductivity between the wiring pattern (2) of the rigid wiring board (B) and the wiring pattern (7) of the flexible wiring board (D) is ensured by a conventional through-hole means.

The adhesive layer (5) of the present invention is characterized by comprising an adhesive that gives a cured resin film having a water absorption of 0.5% or less when the thickness is 50 μm. The water absorption rate of the cured resin film is preferably 0.35% or less, and more preferably 0.2% or less. Here, the water absorption is the weight when a cured resin film having a thickness of 50 μm is formed using an adhesive, the film is dried in an oven at 105 ° C. for 2 hours, and then cooled to room temperature in a desiccator. _0, and then the sample was immersed into distilled water at 25 ° C., the weight at the time of and immediately weighed after wiping with a dry cloth pulled from the water after 24 hours as W _1, the following equation 1:
Water absorption (%) = [(W ₁ −W ₀ ) / W ₀ ] × 100 (Formula 1)
Ask for.

  Said water absorption can be adjusted to the said range by using the curable resin composition mentioned later.

Next, the adhesive constituting the features of the present invention will be described in detail.
In FIG. 1, the adhesive layer (5) is formed from an adhesive sheet (A). This adhesive sheet is a film-like or sheet-like molded product obtained using a curable composition, and is an uncured or semi-cured resin film. This curable composition contains an insulating polymer and a curing agent as described later. In forming this adhesive sheet, that is, a film-like or sheet-like molded product of the curable composition, the curable composition is dissolved in an organic solvent to obtain a varnish.

An uncured or semi-cured resin film or sheet-shaped molded body (hereinafter sometimes simply referred to as “molded body” or “adhesive sheet”) is usually obtained by a solution casting method, a melt casting method, or the like. It is molded. In the case of molding by the solution casting method, the organic solvent is dried and removed after applying the varnish of the curable composition to the support.
Examples of the support used in the solution casting method include a resin film (carrier film) and a metal foil. As the resin film, a thermoplastic resin film is usually used. Specific examples include a polyethylene terephthalate film, a polypropylene film, a polyethylene film, a polycarbonate film, a polyethylene naphthalate film, a polyarylate film, and a nylon film.
Among these resin films (carrier films), a polyethylene terephthalate film and a polyethylene naphthalate film are preferable from the viewpoints of heat resistance, chemical resistance, peelability after lamination, and the like. Examples of the metal foil include copper foil, aluminum foil, nickel foil, chrome foil, gold foil, and silver foil. From the viewpoint of good conductivity and low cost, a copper foil, particularly an electrolytic copper foil or a rolled copper foil is preferred.

  The thickness of the support is not particularly limited, but is usually 1 μm to 150 μm, preferably 2 μm to 100 μm, more preferably 3 μm to 50 μm from the viewpoint of workability and the like.

  Examples of the coating method include dip coating, roll coating, curtain coating, die coating, and slit coating. The conditions for removing and drying the organic solvent are appropriately selected depending on the type of the organic solvent, the drying temperature is usually 20 to 300 ° C., preferably 30 to 200 ° C., and the drying time is usually 30 seconds to 1 hour, preferably Is 1 to 30 minutes.

  The thickness of the film or sheet is usually 0.1 to 150 μm, preferably 0.5 to 100 μm, more preferably 1.0 to 80 μm. In addition, when it is desired to obtain a film or a sheet alone, the film or sheet is formed on the support and then peeled off from the support.

  There is no special restriction | limiting in the method of obtaining a varnish, For example, it can obtain by mixing each component which comprises a curable composition, and an organic solvent. The mixing method of each component may be in accordance with ordinary methods, for example, stirring using a stirrer and a magnetic stirrer, high speed homogenizer, dispersion, planetary stirrer, twin screw stirrer, ball mill, three rolls, etc. And so on. The temperature at the time of mixing is in a range where the reaction by the curing agent does not affect the workability, and is preferably below the boiling point of the organic solvent used at the time of mixing from the viewpoint of safety.

  Examples of the organic solvent include aromatic hydrocarbon organic solvents such as toluene, xylene, ethylbenzene and trimethylbenzene; aliphatic hydrocarbon organic solvents such as n-pentane, n-hexane and n-heptane; cyclopentane and cyclohexane. Alicyclic hydrocarbon organic solvents such as; halogenated hydrocarbon organic solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; ketone organic solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone. it can. These organic solvents can be used alone or in combination of two or more.

Among these organic solvents, non-polar organic solvents such as aromatic hydrocarbon organic solvents and alicyclic hydrocarbon organic solvents and polar organic solvents such as ketone organic solvents A mixed organic solvent in which is mixed is preferable. The mixing ratio of these nonpolar organic solvents and polar organic solvents can be appropriately selected, but is usually 5:95 to 95: 5, preferably 10:90 to 90:10, more preferably 20:80 to weight ratio. The range is 80:20.
The amount of the organic solvent used is appropriately selected according to the purpose of controlling the thickness or improving the flatness, but the solid content concentration of the varnish is usually 5 to 70% by weight, preferably 10 to 65% by weight, more preferably Is in the range of 20-60% by weight.

The insulating polymer constituting the curable composition is not particularly limited as long as it has electrical insulating properties. In addition, it is preferable to use a polymer having a weight average molecular weight Mw of 10,000 to 1,000,000, preferably 50,000 to 500,000 as the insulating polymer, since it exhibits better migration resistance. The polymer having such a weight average molecular weight is present in a proportion of 20 parts by weight or more, preferably 30 parts by weight or more and 100 parts by weight or less, in 100 parts by weight of the insulating polymer component contained in the curable composition. Is desirable from the viewpoint of maintaining the smoothness of the electrical insulating layer b. As an insulating polymer other than a polymer having a weight average molecular weight Mw of 10,000 to 1,000,000, preferably 50,000 to 500,000, a polymer having a weight average molecular weight Mw less than the lower limit of the range or a weight average molecular weight Mw of the upper limit of the range It is possible to use a polymer in excess of.
In the present invention, the weight average molecular weight Mw is a weight average molecular weight in terms of polystyrene or polyisoprene measured by gel permeation chromatography (GPC).

  As the insulating polymer, an alicyclic olefin polymer, an aromatic polyether polymer, a benzocyclobutene polymer, a cyanate ester polymer or a polyimide is preferable because it is easy to ensure a low water absorption rate. Polymers or aromatic polyether polymers are particularly preferred, and alicyclic olefin polymers are particularly preferred.

  An alicyclic olefin polymer is a polymer of an unsaturated hydrocarbon having an alicyclic structure. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of mechanical strength, heat resistance, and the like. In addition, the alicyclic structure may be monocyclic or polycyclic (condensed polycyclic, bridged ring, combination polycyclic, etc.). The number of carbon atoms constituting the alicyclic structure is not particularly limited, but it is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the range of mechanical strength and heat resistance. And various properties of formability and moldability are highly balanced. Moreover, the alicyclic olefin polymer used in the present invention is usually thermoplastic.

  The alicyclic olefin polymer preferably has a polar group. Examples of the polar group include a hydroxyl group, a carboxyl group, an alkoxyl group, an epoxy group, a glycidyl group, an oxycarbonyl group, a carbonyl group, an amino group, an ester group, and a carboxylic acid anhydride group. An anhydride group is preferred.

  The cycloaliphatic olefin polymer is usually subjected to addition polymerization or ring-opening polymerization of the alicyclic olefin, and hydrogenation of the unsaturated bond portion as necessary, or addition polymerization or ring-opening polymerization of the aromatic olefin. And hydrogenating the aromatic ring portion of the polymer. The alicyclic olefin polymer having a polar group is, for example, 1) by introducing a polar group into the alicyclic olefin polymer by a modification reaction, and 2) copolymerizing a monomer containing the polar group. It can be obtained by copolymerization as a component, or 3) by copolymerizing a monomer containing a polar group such as an ester group as a copolymerization component and then removing the ester group by hydrolysis or the like.

  Examples of the alicyclic olefin used to obtain the alicyclic olefin polymer include bicyclo [2.2.1] hept-2-ene (common name: norbornene), 5-methyl-bicyclo [2.2.1] hept- 2-ene, 5,5-dimethyl-bicyclo [2.2.1] hept-2-ene, 5-ethyl-bicyclo [2.2.1] hept-2-ene, 5-butyl-bicyclo [2.2.1] hept- 2-ene, 5-hexyl-bicyclo [2.2.1] hept-2-ene, 5-octyl-bicyclo [2.2.1] hept-2-ene, 5-octadecyl-bicyclo [2.2.1] hept-2- Ene, 5-ethylidene-bicyclo [2.2.1] hept-2-ene, 5-methylidene-bicyclo [2.2.1] hept-2-ene, 5-vinyl-bicyclo [2.2.1] hept-2-ene,

  5-propenyl-bicyclo [2.2.1] hept-2-ene, 5-methoxy-carbonyl-bicyclo [2.2.1] hept-2-ene, 5-cyano-bicyclo [2.2.1] hept-2-ene, 5-methyl-5-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene, 5-ethoxycarbonyl-bicyclo [2.2.1] hept-2-ene, bicyclo [2.2.1] hept-5-enyl- 2-methylpropionate, bicyclo [2.2.1] hept-5-enyl-2-methyloctanoate,

  Bicyclo [2.2.1] hept-2-ene-5,6-dicarboxylic anhydride, 5-hydroxymethylbicyclo [2.2.1] hept-2-ene, 5,6-di (hydroxymethyl) -bicyclo [2.2 .1] Hept-2-ene, 5-hydroxy-i-propylbicyclo [2.2.1] hept-2-ene, 5,6-dicarboxy-bicyclo [2.2.1] hept-2-ene, bicyclo [2.2 .1] hept-2-ene-5,6-dicarboxylic imide, 5-cyclopentyl-bicyclo [2.2.1] hept-2-ene, 5-cyclohexyl-bicyclo [2.2.1] hept-2-ene, 5 -Cyclohexenyl-bicyclo [2.2.1] hept-2-ene, 5-phenyl-bicyclo [2.2.1] hept-2-ene,

Tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene), tricyclo [4.3.0.1 ^2,5 ] dec-3-ene, tricyclo [4.4.0.1 ^2,5 ] undeca 3,7-diene, tricyclo [4.4.0.1 ^{2, 5]} undec-3,8-diene, tricyclo [4.4.0.1 ^{2, 5]} undec-3-ene, tetracyclo [7.4.0.1 ^10,13 .0 ^{2 , 7]} trideca -2,4,6,11- tetraene (alias: 1,4-methano -1,4,4a, 9a- tetrahydrofluorene), tetracyclo [8.4.0.1 ^11,14 .0 ^2,8] tetradeca −3,5,7,12,11-tetraene,

Tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene (trivial name: tetracyclododecene), 8-methyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca -3 - ene, 8-ethyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8-methylidene - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene , 8-ethylidene - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8-vinyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8 - propenyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8-methoxycarbonyloxy - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8- methyl-8-methoxycarbonyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8-hydroxymethyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3 Ene, 8-carboxy-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] dodeca -3-ene,

8-cyclopentyl-- tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8-cyclohexyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8- cyclohexenyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, 8-phenyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene, pentacyclo [6.5 .1.1 ^3,6 .0 ^2,7 .0 ^9,13] pentadeca-3,10-diene, pentacyclo [7.4.0.1 ^3,6 .1 ^10,13 .0 ^2,7] pentadeca-4,11-diene Norbornene monomers such as

  Cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano-1H -Monocyclic cycloalkenes such as indene and cycloheptene; vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane; alicyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene; .

Examples of the aromatic olefin include styrene, α-methylstyrene, divinylbenzene and the like.
The alicyclic olefin and / or aromatic olefin can be used alone or in combination of two or more.

  The alicyclic olefin polymer may be obtained by copolymerization of the alicyclic olefin and / or aromatic olefin and a copolymerizable monomer. Monomers copolymerizable with alicyclic olefins or aromatic olefins include ethylene; propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, and 3-methyl-1-pentene. 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1 -Hexene,

3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,
C3-C20 α-olefins such as 1-hexadecene, 1-octadecene, 1-eicosene; 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1 , 7-octadiene and the like; These monomers can be used alone or in combination of two or more.

  The polymerization method of alicyclic olefin or aromatic olefin, and the hydrogenation method performed as necessary are not particularly limited and can be performed according to a known method.

Specific examples of alicyclic olefin polymers include ring-opening polymers of norbornene monomers and hydrogenated products thereof, addition polymers of norbornene monomers, addition weights of norbornene monomers and vinyl compounds. Examples thereof include a polymer, a monocyclic cycloalkene polymer, an alicyclic conjugated diene polymer, a vinyl alicyclic hydrocarbon polymer and a hydrogenated product thereof, and an aromatic ring hydrogenated product of an aromatic olefin polymer. Among these, ring-opening polymers of norbornene monomers and hydrogenated products thereof, addition polymers of norbornene monomers, addition polymers of norbornene monomers and vinyl compounds, aromatic olefin polymers An aromatic ring hydrogenated product is preferable, and a hydrogenated product of a ring-opening polymer of a norbornene monomer is particularly preferable.
The alicyclic olefin polymers may be used alone or in combination of two or more.

  As a method for adjusting the Mw of the alicyclic olefin polymer, for example, in the ring-opening polymerization of the alicyclic olefin using a titanium-based or tungsten-based catalyst, a molecular weight modifier such as a vinyl compound or a diene compound is used. The method of adding about 0.1-10 mol% with respect to the whole quantity of a monomer is mentioned. At this time, a relatively high Mw polymer is obtained when the amount of the molecular weight modifier is small, and a relatively low Mw polymer is obtained when it is used in a large amount.

  Examples of vinyl compounds used as molecular weight regulators include α-olefin compounds such as 1-butene, 1-pentene, 1-hexene and 1-octene; styrene compounds such as styrene and vinyltoluene; ethyl vinyl ether, isobutyl vinyl ether, allyl glycidyl ether Ether-containing compounds such as halogen-containing vinyl compounds such as allyl chloride; oxygen-containing vinyl compounds such as allyl acetate, allyl alcohol, and glycidyl methacrylate; nitrogen-containing vinyl compounds such as acrylamide; Non-conjugated diene compounds such as 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 2-methyl-1,4-pentadiene, 2,5-dimethyl-1,5-hexadiene, etc. Conjugated diene compounds such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene;

  The glass transition temperature of the alicyclic olefin polymer can be appropriately selected depending on the purpose of use, but is usually 50 ° C. or higher, preferably 70 ° C. or higher, more preferably 100 ° C. or higher, and most preferably 125 ° C. or higher.

  There is no particular limitation on the curing agent constituting the curable composition used in the present invention, and for example, an ionic curing agent, a radical curing agent, a curing agent having both ionic and radical properties, or the like is used. For example, nitrogen-based halogen-free isocyanurate-based curing agents containing allyl groups and epoxy groups such as 1-allyl-3,5-diglycidyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate Curing agent: bisphenol A bis (ethylene glycol glycidyl ether) ether, bisphenol A bis (diethylene glycol glycidyl ether) ether, bisphenol A bis (triethylene glycol glycidyl ether) ether,

  Polyhydric epoxy compounds such as glycidyl ether type epoxy compounds such as bisphenol A glycidyl ether type epoxy compounds such as bisphenol A bis (propylene glycol glycidyl ether) ether, alicyclic epoxy compounds, glycidyl ester type epoxy compounds; acid anhydrides And curing agents such as dicarboxylic acid derivatives such as carboxylic acid compounds and dicarboxylic acid compounds; polyol compounds such as diol compounds, triol compounds and polyhydric phenol compounds; Among these, a polyvalent epoxy compound is preferable, and a glycidyl ether type epoxy compound is particularly preferable from the viewpoint of improving crack resistance.

In order to accelerate the curing reaction between the alicyclic olefin polymer and the curing agent, a curing accelerator or a curing aid can also be used.
The curing accelerator is not particularly limited. When the curing agent is, for example, a polyvalent epoxy compound, a tertiary amine compound or a boron trifluoride complex compound is suitable. Among these, when a tertiary amine compound is used, the lamination property, insulation resistance, heat resistance, and chemical resistance to fine wiring are improved.

  Specific examples of tertiary amine compounds include chain tertiary amine compounds such as benzyldimethylamine, triethanolamine, triethylamine, tributylamine, tribenzylamine, dimethylformamide; pyrazoles, pyridines, pyrazines, pyrimidines , Indazoles, quinolines, isoquinolines, imidazoles, triazoles and the like. Among these, imidazoles, particularly substituted imidazole compounds having a substituent are preferable.

  Specific examples of the substituted imidazole compound include 2-ethylimidazole, 2-ethyl-4-methylimidazole, bis-2-ethyl-4-methylimidazole, 1-methyl-2-ethylimidazole, 2-isopropylimidazole, 2, Alkyl-substituted imidazole compounds such as 4-dimethylimidazole and 2-heptadecylimidazole; 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-ethylimidazole, 1 -Benzyl-2-phenylimidazole,

  Benzimidazole, 2-ethyl-4-methyl-1- (2′-cyanoethyl) imidazole, 2-ethyl-4-methyl-1- [2 ′-(3 ″, 5 ″ -diaminotriazinyl) ethyl] imidazole And an imidazole compound substituted with a hydrocarbon group containing a ring structure such as an aryl group or an aralkyl group. Among these, imidazole having a substituent containing a ring structure is preferable from the viewpoint of compatibility with the alicyclic olefin polymer, and 1-benzyl-2-phenylimidazole is particularly preferable.

  A hardening accelerator is used individually or in combination of 2 or more types. The amount of the curing accelerator is appropriately selected according to the purpose of use, but is usually 0.001 to 30 parts by weight, preferably 0.01 to 10 parts by weight, more preferably 0.03 to 100 parts by weight with respect to 100 parts by weight of the insulating polymer. 5 parts by weight.

  A curing aid is used as necessary. Examples of curing aids include oxime and nitroso curing aids such as quinonedioxime, benzoquinonedioxime, and p-nitrosophenol; maleimide curing aids such as N, Nm-phenylenebismaleimide; diallyl phthalate, Allyl-based curing aids such as triallyl cyanurate and triallyl isocyanurate; Methacrylate-based curing aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; Vinyl-based curing aids such as vinyltoluene, ethylvinylbenzene and divinylbenzene Agents; tertiary amine compounds such as 1-benzyl-2-phenylimidazole and the like. In addition, a peroxide that functions as a curing aid for the curing agent having an allyl group can also be used.

Other components can be blended with the curable composition according to the present invention as desired.
For example, flame retardants, soft polymers, heat stabilizers, weathering stabilizers, anti-aging agents, leveling agents, antistatic agents, slip agents, anti-blocking agents, anti-fogging agents, lubricants, dyes, pigments, natural oils, synthetic oils Waxes, emulsions, fillers, ultraviolet absorbers and the like can be used as other components. The blending ratio is appropriately selected within a range that does not impair the object of the present invention.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the examples, parts and% are based on mass unless otherwise specified.
The evaluation methods performed in this example are as follows.
(1) Molecular weight (Mw, Mn)
It was measured as a polystyrene equivalent value by gel permeation chromatography (GPC) using toluene as a solvent.

(2) Hydrogenation rate and (anhydrous) maleic acid residue content Hydrogenation rate (hydrogenation rate) relative to the number of moles of unsaturated bonds in the polymer before hydrogenation and the total number of monomer units in the polymer The ratio of the number of moles of (anhydrous) maleic acid residue relative to was measured by ¹ H-NMR spectrum.
(3) Glass transfer temperature (Tg)
It was measured by differential scanning calorimetry (DSC method).

(4) Measurement of water absorption of 50μm thick film After drying a sample (cured resin film) molded into a 50μm thick film in an oven at 105 ° C for 2 hours, the weight when cooled to room temperature in a desiccator W ₀ , and then this sample was immersed in distilled water at 25 ° C., and after 24 hours, it was pulled up from water and wiped with a dry cloth. It was.
Water absorption rate (%) = [(W ₁ −W ₀ ) / W ₀ ] × 100 (Formula 1)

(5) Evaluation of insulation reliability A comb-shaped electrode pattern having a wiring thickness of 18 μm, a wiring width of 25 μm, a distance between wirings of 25 μm, and a length of 1 cm was formed on the inner layer side of the rigid part, and a 50 μm thick adhesive layer was laminated and cured. A measurement sample was prepared and allowed to stand for 1000 hours in a constant temperature and humidity chamber maintaining 85 ° C. and 85% RH while applying a DC voltage of 40V. Even when 1000 hours passed, the electrical resistance of 10 ⁹ ohms or more was evaluated as “◯”, 10 ⁸ ohms or more and less than 10 ⁹ ohms as △, and less than 10 ⁸ ohms as ×

(6) Adhesion evaluation after humidification at high temperature Wiring after leaving the rigid and flex parts connected and cured / adhered in a constant temperature and humidity chamber maintained at 85 ° C and 85% RH for 168 hours. The peel strength test was performed in accordance with JIS C 5016, and the 180 ° peel test was performed. × less than 0.1 kN / m, △ 0.3 kN / m greater than 0.1 kN / m, 0.3 Those exceeding kN / m were marked with ○.

Example 1.
Ethyl 8 - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodeca-3-ene ring-opening polymerization and then subjected to hydrogenation reaction, the number average molecular weight (Mn) = 31,200, weight average molecular weight (Mw ) = 55,800 and a hydrogenated polymer having Tg = about 140 ° C. was obtained. The hydrogenation rate of the obtained polymer was 99% or more.
100 parts of the obtained polymer, 40 parts of maleic anhydride and 5 parts of dicumyl peroxide were dissolved in 250 parts of t-butylbenzene and reacted at 140 ° C. for 6 hours. The obtained reaction product solution was poured into 1000 parts of isopropyl alcohol to solidify the reaction product to obtain a maleic acid-modified hydrogenated polymer. This modified hydrogenated polymer was vacuum-dried at 100 ° C. for 20 hours. The molecular weight of this modified hydrogenated polymer was Mn = 33,200, Mw = 68,300, and Tg was 170 ° C. The (anhydrous) maleic acid residue content was 25 mol%.

  100 parts of the modified hydrogenated polymer, 40 parts of bisphenol A bis (propylene glycol glycidyl ether) ether, 5 parts of 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] benzotriazole, 1 0.1 part of benzyl-2-phenylimidazole and 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4, as antioxidant 1 part of 6 (1H, 3H, 5H) -trione, 10 parts of liquid polybutadiene (trade name Nisseki Polybutadiene B-1000, manufactured by Nippon Petrochemical Co., Ltd.) as a resin soluble in the oxidizing treatment liquid, and 222 parts of xylene and It was dissolved in a mixed solvent consisting of 56 parts of cyclopentanone to obtain a varnish.

The varnish is applied to a polyethylene naphthalate film (carrier film) of 300mm square with a thickness of 40μm using a die coater, and then dried in a nitrogen oven at 120 ° C for 10 minutes to form a carrier film with a resin thickness of 50μm. An attached adhesive sheet was obtained.
Next, the carrier film of the obtained adhesive sheet with a carrier film was peeled off (A in FIG. 1), and then cured in a nitrogen oven at 170 ° C. for 1 hour to obtain a film-like molded product. The water absorption rate of this molded product was measured. The results are shown in Table 1.

  As shown in FIG. 1B, the conductor layer on one side of the glass-based epoxy copper clad laminate was processed into a comb electrode pattern having a thickness of 18 μm, a wiring width of 25 μm, a wiring interval of 25 μm, and a wiring length of 1 cm. The above-mentioned adhesive sheet with a carrier film was overlaid on the substrate so that the resin surface was inside. Using this as a primary press, the pressure was reduced to 200 Pa using a vacuum laminator provided with heat-resistant rubber press plates at the top and bottom, and thermocompression bonded at a temperature of 110 ° C. and a pressure of 0.5 MPa for 60 seconds. Next, using a vacuum laminator equipped with a heat-resistant rubber press plate at the top and bottom with a metal press plate as a secondary press, the pressure is reduced to 200 Pa, and thermocompression bonded at a temperature of 140 ° C. and 1.0 MPa for 60 seconds to form an adhesive sheet Laminated. Next, only the polyethylene naphthalate film was peeled off from the laminated substrate and heated in a nitrogen oven at a temperature of 170 ° C. for 60 minutes to cure the adhesive sheet (C in FIG. 1). The insulation reliability was evaluated using this substrate. The results are shown in Table 1.

  Only the polyethylene naphthalate film was peeled off from the substrate A described above, and a flex portion (double-sided flexible wiring board) as shown in FIG. Next, using a heating and pressurizing apparatus, heating was performed at a temperature of 170 ° C. and a pressure of 2.9 MPa for 60 minutes to perform pressure bonding and curing (see E in FIG. 1). Using this substrate, adhesion evaluation after high temperature humidification was performed. The results are shown in Table 1.

Comparative Example 1. Epoxy Adhesive In place of 100 parts of the modified hydrogenated polymer used in Example 1, 80 parts of epoxy resin (trade name: Epicoat 1000: manufactured by Yuka Shell Epoxy Co., Ltd .: Mw = 1,300) and polyamide Evaluation was performed in the same manner as in Example 1 except that 40 parts of resin macromethol 6217 (Henkel Hakusui Co., Ltd.) was used. The evaluation results are shown in Table 1.

Comparative Example 2 Polyimide Adhesive In place of 100 parts of the modified hydrogenated polymer used in Example 1, 55 parts of polyimide siloxane, 30 parts of epoxy resin (trade name: Epicoat 807: manufactured by Yuka Shell Epoxy Co., Ltd.), The same as Example 1 except that 18 parts of curing agent 1 (trade name: H-1: manufactured by Meiwa Kasei Co., Ltd.) and 0.1 part of curing agent 2 (2-phenylimidazole) were used as the curing agent, and THF was used as the solvent. And evaluated. The evaluation results are shown in Table 1.

FIG. 1 schematically shows an example of the manufacturing process of the flexible rigid wiring board of the present invention.

Claims (5)

  In a flexible rigid wiring board in which a flexible wiring board and a rigid wiring board are bonded via an adhesive layer, an adhesive that gives a cured resin film having a water absorption of 0.5% or less when the adhesive layer has a thickness of 50 μm A flexible rigid wiring board comprising:   The flexible rigid wiring board according to claim 1, wherein the adhesive is made of a curable composition containing an alicyclic olefin polymer and a curing agent.   The flexible rigid wiring board according to claim 1 or 2, wherein the flexible wiring board has a conductor layer formed on both surfaces of one insulating layer, and the conductor layers are both covered with a coverlay film.   The flexible rigid wiring board according to claim 1, wherein the rigid wiring board is bonded to both surfaces of the flexible wiring board.   The adhesive layer is formed by laminating an uncured or semi-cured resin film on a rigid wiring board made of an adhesive that gives a cured resin film having a water absorption rate of 0.5% or less when the thickness is 50 μm. The method for producing a flexible rigid wiring board according to claim 1, wherein the rigid wiring board having the adhesive layer is laminated and bonded to the flexible wiring board while being heated and pressed.

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