TW202003665A - Conductor substrate, stretchable wiring board, and stretchable resin film for wiring board - Google Patents

Abstract

Disclosed is a stretchable wiring board which comprises a stretchable resin film and a conductor layer disposed on the stretchable resin film. The stretchable resin film comprises a rubber ingredient and a filler. The rubber ingredient may have been crosslinked.

Description

Conductor substrate, stretchable wiring substrate, and stretchable resin film for wiring substrate

The present invention relates to a conductor substrate, a stretchable wiring substrate, and a stretchable resin film for a wiring substrate.

In recent years, in the fields of wearable devices and health care-related devices, for example, it is required to be able to be used along the curved surface or joints of the body, and it is difficult to cause poor connection even when putting on and taking off (a flexible electronic device (possible Stretchable device (stretchable device). In order to manufacture such a stretchable element with high stretchability, a stretchable wiring board with high stretchability is required. Therefore, for example, Patent Document 1 proposes a stretchable flexible circuit board including a thermoplastic elastomer that can be stretched. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-187380

[Problems to be solved by the invention] The stretchable wiring board is often exposed to a high temperature exceeding 100°C, for example, in the process of manufacturing a stretchable element as various electronic parts are mounted. However, it is clear that when the stretchable wiring board becomes high in temperature, it expands greatly, which may hinder the stable manufacture of the stretchable element. In addition, the conventional stretchable resin film constituting the stretchable wiring board has high viscosity particularly at high temperature, and therefore the handleability of the stretchable wiring board at high temperature is also problematic.

Therefore, an object of one aspect of the present invention is to provide a stretchable wiring board having excellent stretchability, a small thermal expansion coefficient, low viscosity at high temperature, and excellent handling properties, and a method for obtaining the stretchable wiring board Conductor substrate and stretchable resin film. [Means to solve the problem]

An aspect of the present invention provides a conductor substrate including a stretchable resin film and a conductor layer provided on the stretchable resin film. The stretchable resin film contains a rubber component and a filler. The rubber component may be cross-linked.

According to the conductor substrate of one aspect of the present invention described above, it is possible to obtain a stretchable wiring substrate having excellent stretchability, a small thermal expansion coefficient, low viscosity at high temperatures, and excellent handling properties.

Another aspect of the present invention provides a stretchable wiring board including the conductor substrate, the conductor layer forming a wiring pattern.

The conductive substrate has excellent stretchability and a small thermal expansion coefficient, and has low viscosity at high temperatures and excellent handling properties.

A further aspect of the present invention provides a stretchable resin film for a wiring board, which contains a rubber component and a filler. In other words, still another aspect of the present invention provides the use of a stretchable resin film for manufacturing a wiring board. The stretchable resin film contains a rubber component and a filler, and the rubber component can be cross-linked. The rubber component may be cross-linked.

The stretchable resin film can provide a stretchable wiring board having excellent stretchability, a small coefficient of thermal expansion, low viscosity at high temperatures, and excellent handling properties. [Effect of invention]

According to an aspect of the present invention, it is possible to provide a stretchable wiring board having excellent stretchability, a small thermal expansion coefficient, low viscosity at high temperatures, and excellent handling properties.

Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

FIG. 1 is a plan view showing an embodiment of a stretchable wiring board. The stretchable wiring substrate 1 shown in FIG. 1 is a conductor substrate including a stretchable resin film 3 and a conductor layer 5 provided on the stretchable resin film 3 and forming a wiring pattern. The stretchable resin film 3 contains a rubber component and a filler. Mainly due to the rubber component, it is easy to impart stretchability to the stretchable resin film. The conductor layer 5 forms a wiring pattern that includes a stretchable waveform portion.

The stretchable resin film 3 may have stretchability such as a recovery rate of 80% or more after tensile deformation to a strain of 20%. This recovery rate was determined in a tensile test of a measurement sample using a stretchable resin film. FIG. 2 is a stress-strain curve showing an example of measurement of recovery rate. At the time when the displacement amount (strain) X was reached in the first tensile test, the tensile stress was opened to return the test piece to the initial position. Thereafter, the second tensile test was performed. When the difference between the position at the time when the load is started and X is set to Y, R calculated by the formula: R=(Y/X)×100 is defined as the recovery rate. The recovery rate can be measured by setting X to 50%, for example. From the viewpoint of durability against repeated use, the recovery rate may be 80% or more, 85% or more, or 90% or more. The upper limit of the recovery rate by definition is 100%.

The rubber component contains one kind or two or more kinds of rubber. The rubber contained in the rubber component may be a thermoplastic elastomer. Examples of thermoplastic elastomers include hydrogenated styrene elastomers. The hydrogenated styrene-based elastomer is an elastomer obtained by performing addition reaction of hydrogen and unsaturated double bonds of a styrene-based elastomer having a soft segment containing unsaturated double bonds. The hydrogenated styrene-based elastomer can also expect effects such as improved weather resistance. Examples of hydrogenated styrene elastomers include styrene-ethylene butene-styrene block copolymer elastomers (SEBS (Styrene Ethylene Butylene Styrene), sometimes called "hydrogenated styrene butadiene rubber" ").

The rubber component may include selected from acrylic rubber, isoprene rubber, butyl rubber, styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, silicone rubber, urethane rubber, chlorine At least one rubber in the group consisting of butadiene rubber, ethylene propylene rubber, fluororubber, vulcanized rubber, epichlorohydrin rubber, and chlorobutyl rubber.

From the viewpoint of avoiding damage to wiring due to moisture absorption or the like, the rubber component may include at least one rubber selected from styrene butadiene rubber, butadiene rubber, and butyl rubber. By using styrene butadiene rubber, the resistance of the stretchable resin film to various chemical liquids used in the plating step is improved, and the wiring substrate can be manufactured with good yield.

As commercially available products of acrylic rubber, for example, "Nipol AR series" by Zeon Co., Ltd. and "Kurarity series" by Kuraray Co., Ltd. can be cited. . As a commercially available product of isoprene rubber, for example, "Nipol IR series" of Zeon Co., Ltd. can be cited. As a commercially available product of butyl rubber, for example, the "butyl (BUTYL) series" of JSR Co., Ltd. may be mentioned. Examples of commercially available products of styrene butadiene rubber include, for example, "Dynaron SEBS series", "Dynaron HSBR series" by JSR Corporation, and Kraton (Kraton) Polymers Japan Co., Ltd.'s "Kraton D polymer series" and Aronkasei Co., Ltd.'s "AR series". As a commercially available product of butadiene rubber, for example, "Nipol BR series" of Zeon Co., Ltd. can be cited. As a commercially available product of acrylonitrile butadiene rubber, for example, "JSR NBR series" of JSR Co., Ltd. may be mentioned. As a commercially available product of silicone rubber, for example, "KMP series" of Shin-Etsu Silicone Co., Ltd. can be cited. As a commercial item of ethylene propylene rubber, the "JSR EP series" of JSR Corporation is mentioned, for example. As a commercially available product of fluororubber, for example, "DAI-EL series" of Daikin Co., Ltd. may be mentioned. As a commercially available product of epichlorohydrin rubber, for example, the "Hydrin series" of Zeon Co., Ltd. can be cited.

The rubber component can also be produced by synthesis. For example, acrylic rubber can be obtained by reacting (meth)acrylic acid, (meth)acrylate, aromatic vinyl compound, cyanide vinyl compound, and the like.

The rubber component can be crosslinked by the reaction of the crosslinking group. By using the cross-linked rubber component, the heat resistance of the stretchable resin film tends to be easily improved. The crosslinking group may be any reactive group that can form the crosslinked structure by the reaction of crosslinking the molecular chain of the rubber component or the reaction of the molecular chain of the rubber component with the crosslinking component described below. Examples of the crosslinking group include (meth)acryloyl, vinyl, epoxy, styryl, amine, isocyanurate, urea, cyanate, and isocyanate. Group, mercapto group, hydroxyl group, carboxyl group and anhydride group.

The rubber component can be crosslinked by the reaction of at least one crosslinking group in an acid anhydride group or a carboxyl group. As an example of the rubber having an acid anhydride group, rubber partially modified with maleic anhydride can be cited. As a commercially available product of rubber partially modified with maleic anhydride, for example, there is a styrene-based elastomer "TufPrene (912)" manufactured by Asahi Kasei Corporation.

The rubber partially modified with maleic anhydride may be a hydrogenated styrene-based elastomer modified with maleic anhydride. As an example of the hydrogenated styrene elastomer modified with maleic anhydride, maleic anhydride modified styrene-ethylene butene-styrene block copolymer elastomer can be mentioned. Examples of commercially available hydrogenated styrene elastomers modified with maleic anhydride include “FG1901”, “FG1924” of Kraton Polymers Japan Co., Ltd., and Asahi Kasei Co., Ltd. The company's "TufTech M1911", "TufTech M1913", "TufTech M1943".

From the viewpoint of coating properties, the weight average molecular weight of the rubber component may be 20,000 to 200,000, 30,000 to 150,000, or 50,000 to 125,000. The weight average molecular weight (Mw) here refers to a standard polystyrene conversion value obtained by gel permeation chromatography (Gel Permeation Chromatography, GPC).

Based on the mass of components other than the filler in the stretchable resin film, the content of the rubber component in the stretchable resin film may be 30% by mass to 100% by mass, 50% by mass to 100% by mass, or 70% by mass to 100% by mass %. When the content of the rubber component is within this range, the stretchable resin film tends to have particularly excellent stretchability.

The stretchable resin film contains one or more fillers dispersed in the resin phase containing the rubber component. The filler may be an inorganic filler, an organic filler, or a combination of these. The filler may particularly include at least one inorganic filler selected from the group consisting of silica, glass, alumina, titanium oxide, carbon black, mica, and boron nitride.

The average particle size of the filler can be from 10 nm to 500 nm. If the average particle diameter of the filler is within this range, a further remarkable effect can be obtained in terms of reduction of the thermal expansion coefficient of the stretchable resin film and suppression of the viscosity of the stretchable resin film at high temperatures. From the same viewpoint, the average particle size of the filler may be 400 nm or less, 300 nm or less, 200 nm or less, 150 nm or less, or 80 nm or less. In this specification, the average particle diameter of the filler refers to the average value (average primary particle diameter) of the particle diameter determined by the laser diffraction/scattering method. The average particle diameter of the filler can be measured using, for example, a nanoparticle diameter distribution measuring device SALD-7500nano (Shimadzu Corporation).

The shape of the filler is not particularly limited, and the filler may have any shape such as substantially spherical, fibrous, and indefinite.

The surface of the filler can be modified with functional groups. Examples of functional groups that can be introduced on the surface of the filler include amine groups, phenylamine groups, and phenyl groups. The filler having a surface modified with functional groups can contribute to the improvement of the adhesion between the stretchable resin film and the conductor layer.

The content of the filler in the stretchable resin film may be 1 part by mass to 200 parts by mass relative to 100 parts by mass of the rubber component. If the content of the filler is within this range, a further remarkable effect can be obtained in terms of reduction of the thermal expansion coefficient of the stretchable resin film and suppression of the viscosity of the stretchable resin film at high temperatures. From the same viewpoint, the content of the filler may be 150 parts by mass or less or 100 parts by mass or less with respect to 100 parts by mass of the rubber component.

The stretchable resin film may be a cured product of a resin composition containing a rubber component and a filler. In this case, the resin composition may further contain a cross-linking component. The cured product of the resin composition includes a crosslinked structure formed by the reaction of the crosslinking groups of the rubber component, the reaction of the crosslinking groups of the rubber component and the crosslinking component, the polymerization reaction of the crosslinking component, or a combination of these . If the stretchable resin film is a cured product of the resin composition, the heat resistance of the stretchable resin film tends to be easily improved.

The crosslinking component that the resin composition for forming the stretchable resin film may contain is a compound having one or more reactive groups. The crosslinking component may be, for example, an epoxy group, (meth)acryloyl group, vinyl group, styryl group, amine group, isocyanurate group, urea group, cyanate group, isocyanate group, mercapto group , A compound of at least one reactive group in the group consisting of hydroxy and carboxy. From the viewpoint of improving the heat resistance of the stretchable resin film, the cross-linking component may be a compound having a reactive group selected from epoxy groups, amine groups, hydroxyl groups, and carboxyl groups. In particular, by combining a rubber having at least one of a maleic anhydride group or a carboxyl group and a compound (epoxy resin) having an epoxy group, the heat resistance, low moisture permeability, and expansion and contraction of the stretchable resin film A particularly excellent effect can be obtained in terms of the adhesion between the conductive resin film and the conductive layer and the low viscosity of the stretchable resin film after curing. If the heat resistance of the stretchable resin film is improved, for example, the deterioration of the stretchable resin film in the heating step such as nitrogen reflow can be suppressed. If the stretchable resin film after curing has low viscosity, the conductor substrate or the wiring substrate can be processed with good operability.

The epoxy group-containing compound that can be used as a crosslinking component may be a monofunctional, difunctional, or trifunctional polyfunctional epoxy resin. In order to obtain sufficient hardenability, the crosslinking component may contain a difunctional or trifunctional or more epoxy resin.

The epoxy resin may be selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, cresol At least one of a novolac-type epoxy resin and an epoxy resin having a fatty chain. Examples of commercially available epoxy resins with fatty chains include EXA-4816 manufactured by DIC Corporation.

Providing an epoxy resin with a hardened product having a high glass transition temperature can contribute to the reduction of the thermal expansion coefficient of the stretchable resin film and the suppression of viscosity at high temperatures. For example, an epoxy resin forming a hardened product having a glass transition temperature of 180° C. or higher or 200° C. or higher can be selected according to a reaction with a phenol novolak resin as a curing agent. Specific examples of such epoxy resins include dicyclopentadiene-type epoxy resins and naphthalene-type epoxy resins.

The crosslinking component may also contain a compound having a (meth)acryloyl group. The compound having a (meth)acryloyl group may be a (meth)acrylate. The compound having a (meth)acryloyl group may be a compound having one, two, or more than three (meth)acryloyl groups (for example, a monofunctional, difunctional, or trifunctional (meth)acrylate) ). In order to obtain sufficient hardenability, the crosslinking component may be a compound having two or more (meth)acryloyl groups.

Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, (meth) ) Third butyl acrylate, butoxyethyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (A Group) heptyl acrylate, octyl heptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, ( Tridecyl meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, stearic (meth)acrylate Ester, behenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxy(meth)acrylate Propyl ester, 2-hydroxybutyl (meth)acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) (Meth) acrylate, ethoxy polypropylene glycol (meth) acrylate and succinic acid mono(2-(meth)acryloyloxyethyl) ester and other aliphatic (meth) acrylate; (meth) Cyclopentyl acrylate, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, dicyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate, isocyanate (meth) acrylate Borneyl ester, tetrahydrophthalic acid mono(2-(meth)acryloyloxyethyl) ester and hexahydrophthalic acid mono(2-(meth)acryloyloxyethyl) ester and other fats Cyclic (meth)acrylate; benzyl (meth)acrylate, phenyl (meth)acrylate, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, (Naphthyl) (meth)acrylate, phenoxyethyl (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate , (Meth)acrylic acid-1-naphthoxyethyl, (meth)acrylic acid-2-naphthoxyethyl, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene Glycol (meth)acrylate, phenoxy polypropylene glycol (meth)acrylate, (meth)acrylic acid 2-hydroxy-3-phenoxypropyl ester, (meth)acrylic acid 2-hydroxy-3 -(O-phenylphenoxy)propyl ester, (meth)acrylic acid-2-hydroxy-3-(1-naphthyloxy)propyl ester and (meth)acrylic acid-2-hydroxy-3-(2-naphthalene Aromatic (meth)acrylates such as oxy)propyl ester; 2-tetrahydrofurfuryl (meth)acrylate, N-(meth)acryloyloxyethyl hexahydrophthalimide and Heterocyclic (meth)acrylates such as 2-(meth)acryloyloxyethyl-N-carbazole; and caprolactone modified forms of these compounds. Among these, from the viewpoint of compatibility with styrene-based elastomers, transparency and heat resistance, the aliphatic (meth)acrylate and the aromatic (meth)acrylate can be selected from Select monofunctional (meth)acrylate.

Examples of difunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. Ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate Ester, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate , 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1, 6-Hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate , 1,10-decanediol di(meth)acrylate, glycerol di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate and ethoxylated-2-methyl-1, Aliphatic (meth)acrylates such as 3-propanediol di(meth)acrylate; cyclohexanedimethanol (meth)acrylate, ethoxylated cyclohexanedimethanol (meth)acrylate, propoxy Cyclohexane dimethanol (meth)acrylate, ethoxylated propoxylated cyclohexane dimethanol (meth)acrylate, tricyclodecane dimethanol (meth)acrylate, ethoxy Tricyclodecane dimethanol (meth)acrylate, propoxylated tricyclodecane dimethanol (meth)acrylate, ethoxylated propoxylated tricyclodecane dimethanol (meth)acrylic acid Ester, ethoxylated hydrogenated bisphenol A di(meth)acrylate, propoxylated hydrogenated bisphenol A di(meth)acrylate, ethoxylated propoxylated hydrogenated bisphenol A bis(methyl) ) Acrylate, ethoxylated hydrogenated bisphenol F di(meth)acrylate, propoxylated hydrogenated bisphenol F di(meth)acrylate and ethoxylated propoxylated hydrogenated bisphenol F di( Alicyclic (meth)acrylates such as meth)acrylate; ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, ethoxylated Propoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate, propoxylated bisphenol F di(meth)acrylate, ethoxylated propylene Oxygenated bisphenol F di(meth)acrylate, ethoxylated bisphenol AF di(meth)acrylate, propoxylated bisphenol AF di(meth)acrylate, ethoxylated propoxy Bisphenol AF di(meth)acrylate, ethoxylated fluorene type di(meth)acrylate, propoxylated fluorene type di(meth)acrylate and ethoxylated propoxylated fluorene Aromatic (meth)acrylates such as type di(meth)acrylate; ethoxylated isocyanurate di(meth)acrylate, propoxylated isocyanurate di(meth)acrylate and Heterocyclic (meth)acrylates such as ethoxylated propoxylated isocyanurate di(meth)acrylates; modified caprolactones of these compounds; neopentyl Aliphatic epoxy (meth)acrylates such as alcohol epoxy (meth)acrylate; cyclohexanedimethanol epoxy (meth)acrylate, hydrogenated bisphenol A epoxy (meth) Groups) acrylates and hydrogenated bisphenol F-type epoxy (meth)acrylates and other alicyclic epoxy (meth)acrylates; resorcinol-type epoxy (meth)acrylates, bisphenols A type epoxy (meth) acrylate, bisphenol F type epoxy (meth) acrylate, bisphenol AF type epoxy (meth) acrylate and fluorene type epoxy (meth) acrylic Aromatic epoxy (meth)acrylates such as esters. From the viewpoint of compatibility with styrene-based elastomers, transparency and heat resistance, a difunctional can be selected from the aliphatic (meth)acrylate and the aromatic (meth)acrylate (Meth)acrylate.

Examples of trifunctional or higher polyfunctional (meth)acrylates include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, and propoxy Trimethylolpropane tri(meth)acrylate, ethoxylated propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol Tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated propoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxy Pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated propoxylated pentaerythritol tetra(meth)acrylate, di-trimethylolpropane tetraacrylate And dipentaerythritol hexa(meth)acrylate and other aliphatic (meth)acrylate; ethoxylated isocyanurate tri(meth)acrylate, propoxylated isocyanurate tri(meth)acrylic acid Heterocyclic (meth)acrylates such as esters and ethoxylated propoxylated isocyanurate tri(meth)acrylates; modified caprolactones of these compounds; phenol novolac epoxy groups Aromatic epoxy (meth)acrylates such as (meth)acrylates and cresol novolac epoxy (meth)acrylates. From the viewpoint of compatibility with styrene-based elastomers, transparency and heat resistance, a multifunctional can be selected from the aliphatic (meth)acrylate and the aromatic (meth)acrylate (Meth)acrylate.

The content of the cross-linking component in the resin composition used to form the stretchable resin film may be 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more, and may be 70 parts by mass or less with respect to 100 parts by mass of the rubber component. 60 parts by mass or less or 50 parts by mass or less. When the content of the cross-linking component is within the above range, there is a tendency that the adhesion to the conductor layer is improved while maintaining the characteristics of the stretchable resin film.

The resin composition used to form the stretchable resin film may further contain a curing agent, a curing accelerator, or both to achieve the polymerization reaction (hardening reaction) of the cross-linked component. A hardener is a compound that itself becomes a reaction matrix of a polymerization reaction (hardening reaction) that reacts with a cross-linking component. The hardening accelerator is a compound that functions as a catalyst for the hardening reaction. A compound having the functions of both a hardener and a hardening accelerator can also be used. The content of the curing agent and the curing accelerator may be 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the total of the rubber component and the cross-linking component.

When a compound (epoxy resin) having an epoxy group is used as a cross-linking component, as its hardener, a compound selected from aliphatic polyamines, polyaminoamides, polythiols, aromatic polyamines, At least one of the group consisting of acid anhydride, carboxylic acid, phenol novolac resin, ester resin, and dicyandiamide. As the hardener or hardening accelerator of the compound having an epoxy group, at least one selected from the group consisting of tertiary amine, imidazole, and phosphine can be used. From the viewpoint of storage stability and curability of the resin composition before curing, imidazole can be used. When the rubber component contains maleic anhydride-modified rubber, imidazole compatible with the rubber can be selected. The content of imidazole may be 0.1 to 10 parts by mass relative to 100 parts by mass of the total amount of the rubber component and the cross-linking component.

When a compound having a (meth)acryloyl group is used as a cross-linking component, as its hardener, a thermal radical polymerization initiator or a photo radical polymerization initiator can be used.

Examples of thermal radical polymerization initiators include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and methyl cyclohexanone peroxide; 1,1-bis (p. 1 Tributylperoxy) cyclohexane, 1,1-bis(third butylperoxy)-2-methylcyclohexane, 1,1-bis(third butylperoxy)-3 ,3,5-trimethylcyclohexane, 1,1-bis(third hexyl peroxy) cyclohexane and 1,1-bis(third hexyl peroxy)-3,3,5-tri Peroxyketals such as methylcyclohexane; hydroperoxides such as p-menthane hydroperoxide; α,α'-bis(third butylperoxy) diisopropylbenzene, dicumyl peroxide Compounds, tertiary butyl cumyl peroxide and di-tertiary butyl peroxide and other dialkyl peroxides; octyl peroxide, lauryl peroxide, stearyl peroxide and benzoic acid Diacyl peroxides such as acyl peroxide; bis(4-tert-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-peroxydicarbonate- Peroxycarbonates such as 2-ethylhexyl ester and di-3-methoxybutyl peroxycarbonate; third butyl peroxytrimethylacetate, third hexyl peroxytrimethylacetate, peroxide- 2-ethylhexanoic acid-1,1,3,3-tetramethylbutyl ester, 2,5-dimethyl-2,5-bis(2-ethylhexylperoxy) hexane, Oxidized 2-ethylhexanoic acid third hexyl ester, Peroxy-2-ethylhexanoic acid third butyl ester, Peroxyisobutyric acid third butyl ester, Isopropyl peroxymonocarbonate third hexyl ester, Peroxy Oxidized tert-butyl-3,5,5-trimethylhexanoate, tert-butyl laurate peroxide, tert-butyl peroxyisopropyl monocarbonate, tert-butyl-2-ethylhexyl monocarbonate Tributyl ester, tert-butyl peroxybenzoate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-bis(benzylperoxy) hexane and peracetic acid Peroxyesters such as third butyl ester; 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile) and 2,2'-azobis( 4-methoxy-2'-dimethylvaleronitrile) and other azo compounds. From the viewpoint of curability, transparency, and heat resistance, a thermal radical polymerization initiator can be selected from the diacyl peroxide, the peroxyester, and the azo compound.

Examples of photo radical polymerization initiators include: benzoin ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one; 1-hydroxycyclohexyl phenyl ketone, 2 -Hydroxy-2-methyl-1-phenylpropane-1-one and 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1- Α-hydroxyketones such as ketones; 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butane-1-one and 1,2-methyl-1-[4 -(Methylthio)phenyl]-2-morpholinylpropane-1-one and other α-amino ketones; 1-[4-(phenylthio)phenyl]-1,2-octanedione-2 -Oxime esters such as (benzyl)oxime; bis(2,4,6-trimethylbenzyl)phenyl phosphine oxide, bis(2,6-dimethoxybenzyl)-2 ,4,4-trimethylpentylphosphine oxide and 2,4,6-trimethylbenzyldiphenylphosphine oxide and other phosphine oxides; 2-(o-chlorophenyl)-4,5-diphenyl Imidazole dimer, 2-(o-chlorophenyl)-4,5-bis(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer Polymer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, etc. 2 ,4,5-Triarylimidazole dimer; benzophenone, N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone, N,N,N' , N'-tetraethyl-4,4'-diaminobenzophenone and 4-methoxy-4'-dimethylaminobenzophenone and other benzophenone compounds; 2-ethyl Anthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzoanthraquinone, 2,3-benzoanthraquinone, 2-phenylanthraquinone, 2,3- Diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthrenequinone, 2-methyl-1,4-naphthoquinone and 2,3-bis Quinone compounds such as methylanthraquinone; benzoin ethers such as benzoin methyl ether, benzoin ether and benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin and ethyl benzoin; benzyl compounds such as benzyl dimethyl ketal; 9-benzene Acridine compounds such as acridine and 1,7-bis(9,9'-acridinylheptane); N-phenylglycine; and coumarin.

The stretchable resin film or the resin composition used to form the stretchable resin film, in addition to the above components, may further include antioxidants, heat stabilizers, and ultraviolet absorbers within a range that does not significantly impair the effects of the present invention, if necessary. Agent, anti-hydrolysis agent, anti-yellowing agent, visible light absorber, colorant, plasticizer, flame retardant, leveling agent, etc.

The thickness of the stretchable resin film 3 may be 5 μm to 1000 μm. If the thickness of the stretchable resin film is within this range, sufficient strength as a stretchable base material can be easily obtained and drying can be performed sufficiently, so that the amount of residual solvent in the stretchable resin film can be reduced.

The surface roughness Ra value of the main surface of the stretchable resin film 3 on the side opposite to the conductor layer 5 may be 0.1 μm or more. When the Ra value is 0.1 μm or more, the viscosity of the surface of the stretchable resin film tends to further decrease. From the same viewpoint, the Ra value may be 0.2 μm or more, 0.3 μm or more, or 0.4 μm or more. The upper limit of the Ra value is not particularly limited, and from the viewpoint of the strength of the stretchable resin film, it may be 2.0 μm or less. The surface roughness Ra value can be measured using, for example, a step difference meter (manufactured by Kosaka Research Institute Co., Ltd., ET-200).

By providing irregularities to the stretchable resin film, the surface roughness Ra value of the stretchable resin film can be within the above range. As a method of imparting unevenness to the stretchable resin film, for example, an unevenness transfer substrate is used to transfer the unevenness pattern to the stretchable resin film in the B-stage state or the stretchable resin film after the curing reaction, and then the unevenness is transferred to the substrate Method of peeling; method of performing imprinting processing such as etching treatment and hot embossing processing on the hardened stretchable resin film; and method of crimping the roughened surface of the metal foil to the stretchable resin film and etching the metal foil .

The viscosity of the surface of the stretchable resin film can be 0.7 gf/mm ² or less (6.9 kPa or less), 0.5 gf/mm ² or less (4.9 kPa or less) or 0.4 gf/mm ² or less (3.9 kPa or less at 30°C) ). The viscosity value of the surface of the stretchable resin film can be 4.5 gf/mm ² or less (44 kPa or less) or 4.0 gf/mm ² or less (39 kPa or less) at 200°C. The lower limit of the viscosity value is not particularly limited, and can be 0 gf/mm ² (0 kPa). The viscosity value can be measured using, for example, an adhesion tester ("TACII" manufactured by Rhesca Co., Ltd.).

The elastic coefficient (tensile elastic coefficient) of the stretchable resin film may be 0.1 MPa or more and 1000 MPa or less. If the elastic coefficient is 0.1 MPa or more and 1000 MPa or less, the handling property and flexibility as a base material tend to be particularly excellent. From this viewpoint, the elastic coefficient may be 0.3 MPa or more and 100 MPa or less or 0.5 MPa or more and 50 MPa or less.

The elongation at break of the stretchable resin film may be 100% or more. If the elongation at break is 100% or more, there is a tendency that sufficient stretchability is easily obtained. From this viewpoint, the elongation at break may be 150% or more, 200% or more, 300% or more, or 500% or more. The upper limit of the elongation at break is not particularly limited, but is usually about 1000% or less.

The stretchable resin film may be supplied in the state of a laminated film including a carrier film and a stretchable resin film provided on the carrier film.

The carrier film is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate; and polycarbonate Esters; Polyolefins such as polyethylene and polypropylene; Polyamides; Polyamides; Polyamides and amides; Polyether amides; Polyether sulfides; Polyether sulfones; Polyether ketones; Polyphenylene ethers; Polyphenylene sulfide; polyarylate; polyphenols; and liquid crystal polymers. From the viewpoint of flexibility and toughness, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyamido, Films of polyimide, polyamidimide, polyphenylene oxide, polyphenylene sulfide, polyarylate, or polysulfide are used as carrier films.

The thickness of the carrier film is not particularly limited, and may be 3 μm to 250 μm. If the thickness of the carrier film is 3 μm or more, the carrier film tends to have sufficient film strength. If the thickness of the carrier film is 250 μm or less, sufficient flexibility tends to be easily obtained. From the above viewpoint, the thickness of the carrier film may be 5 μm to 200 μm or 7 μm to 150 μm. From the viewpoint of improving the releasability from the stretchable resin film, a film that has been subjected to a mold release treatment with a silicone-based compound, a fluorine-containing compound, or the like can be used as necessary.

The laminated film may further have a protective film covering the stretchable resin film.

The protective film is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene . From the viewpoint of flexibility and toughness, films of polyesters such as polyethylene terephthalate or polyolefins such as polyethylene and polypropylene can be used as protective films. From the viewpoint of improving the peelability from the stretchable resin film, the protective film may be subjected to a mold release treatment with a silicone compound, a fluorine-containing compound, or the like.

The thickness of the protective film can be appropriately changed according to the target flexibility, and can be 10 μm to 250 μm. If the thickness of the protective film is 10 μm or more, the protective film tends to have sufficient film strength. If the thickness of the protective film is 250 μm or less, the protective film tends to have sufficient flexibility. From the above viewpoint, the thickness of the protective film may be 15 μm to 200 μm or 20 μm to 150 μm.

The conductor layer 5 included in the stretchable wiring substrate 1 (or conductor substrate) may be, for example, a conductor foil or a conductor plating film.

The conductor foil may be metal foil. Examples of metal foils include copper foil, titanium foil, stainless steel foil, nickel foil, permalloy foil, 42 alloy foil, cobalt foil, nichrome foil, beryllium copper foil, phosphorus Bronze foil, brass foil, nickel silver alloy foil, aluminum foil, tin foil, lead foil, zinc foil, solder foil, iron foil, tantalum foil, niobium foil, molybdenum foil, zirconium foil, gold foil, silver foil, palladium foil, nickel alloy (Monel) foil, Inconel foil (Inconel) foil and Hastelloy foil. From the viewpoint of an appropriate elastic coefficient and the like, the conductor foil may be selected from copper foil, gold foil, nickel foil, and iron foil. From the viewpoint of wiring formability, the conductor foil may be copper foil. The copper foil can easily form wiring patterns by photolithography without compromising the characteristics of the stretchable resin substrate. The copper foil is not particularly limited, and for example, electrolytic copper foil and rolled copper foil used in copper-clad laminates and flexible wiring boards can be used.

The conductor plating film may be a film formed by a general plating method used in an additive method or a semi-additive method. For example, after the plating catalyst imparting treatment for adhering palladium, the stretchable resin film is immersed in an electroless plating solution, and electroless plating with a thickness of 0.3 μm to 1.5 μm is deposited on the entire surface of the primer layer Layer (conductor layer). If necessary, further electroplating (electrical plating) can be performed to adjust the thickness. As the electroless plating solution used in electroless plating, any electroless plating solution can be used without particular limitation. Regarding electroplating, a general method can also be used, and there is no particular limitation. From the viewpoint of cost and resistance value, the conductor plating film (electroless plating film, plating film) may be a copper plating film.

The thickness of the conductor layer is not particularly limited, and may be 1 μm to 50 μm. If the thickness of the conductor layer is 1 μm or more, the wiring pattern can be formed more easily. If the thickness of the conductor layer is 50 μm or less, etching and processing are particularly easy.

The stretchable wiring substrate can be manufactured by, for example, a method including: preparing a conductor substrate having a stretchable resin film and a conductor layer provided on the stretchable resin film; and forming a wiring pattern on the conductor layer.

A conductor substrate having a conductor foil as a conductor layer can be obtained by, for example, a method including applying a varnish of a resin composition for forming a stretchable resin film to the conductor foil, or laminating the conductor foil to form On the stretchable resin film on the carrier film. The coating film of the resin composition for forming the stretchable resin film is dried, and the formed resin layer is cured by heating or light irradiation, whereby the stretchable resin film can be formed.

A conductor substrate having a conductor plating film as a conductor layer can be obtained by, for example, the following method: on a stretchable resin film formed on a carrier film by a general plating method used in an additive method or a semi-additive method Form a conductor plating film.

The method for forming a wiring pattern on the conductor layer may include, for example, a step of forming an etching resist on the conductor layer of the conductor substrate; exposing the etching resist, and developing the exposed etching resist to form a covered conductor The step of resist pattern of a part of the layer; the step of removing the conductive layer of the portion not covered by the resist pattern with an etching solution; and the step of removing the resist pattern.

Alternatively, the method of forming a wiring pattern on the conductor layer may also include the steps of forming a plating resist on the conductor layer of the conductor substrate; exposing the plating resist and performing the exposure on the plating resist Step of developing to form a resist pattern covering a part of the conductor layer; step of forming a conductor plating film on the part of the conductor layer not covered by the resist pattern by electroless plating or electroplating; removing the resist pattern And removing the portion of the conductor layer that is not covered by the conductor plating film formed by the plating.

By mounting various electronic components on a wiring board, a stretchable element can be obtained. [Example]

Hereinafter, the present invention will be further specifically described by citing examples. However, the present invention is not limited to these embodiments.

1. Raw materials As a raw material for producing a stretchable resin film, the following materials are prepared. (A) Rubber composition • Maleic anhydride modified styrene-ethylene butene-styrene block copolymer elastomer (trade name "FG1924GT", manufactured by Kraton polymers Japan Co., Ltd.) (B) Cross-linked components ·Dicyclopentadiene type epoxy resin (trade name "Epiclon HP7200H", manufactured by DIC (stock)) (C) Hardening accelerator ·1-Benzyl-2-methylimidazole (trade name "1B2MZ", manufactured by Shikoku Chemicals Co., Ltd.) (D) Filler ·Silica dioxide filler slurry SE2050 (trade name "SE2050KNK", manufactured by Admatechs Co., Ltd., with an average particle size of 500 nm, spherical silica particles modified with phenylamine surface modification, dioxide Methyl isobutyl ketone dispersion liquid with a silicon concentration of 70% by mass) ·Silica dioxide filler slurry C40 (trade name "C40", manufactured by CIK Nanotec Co., Ltd., surface-modified silicon dioxide particles with phenylamine group, average particle diameter 100 nm, dioxide Methyl Isobutyl Ketone (MIBK) dispersion with a silicon concentration of 65% by mass) ·Silica dioxide filler slurry C120 (trade name "C120", manufactured by CIK Nanotec Co., Ltd., surface-modified silicon dioxide particles with phenylamine group, average particle diameter 30 nm, dioxide MIBK dispersion with a silicon concentration of 30% by mass) ·Silica dioxide filler slurry F19 (trade name "F19", manufactured by CIK Nanotec Co., Ltd., phenyl surface-modified silica particles, average particle diameter 100 nm, silica concentration 70% by mass of MIBK dispersion liquid) (E) Solvent ·Toluene (Carrier film/protective film) · Released polyethylene terephthalate (PET) film (trade name "Purex (Purex) A31", manufactured by Teijin DuPont Films Co., Ltd., thickness 25 μm)

2. Laminated film with stretchable resin film Example 1 Modified 100 parts by mass of maleic anhydride with styrene-ethylene butene-styrene block copolymer elastomer (FG1924GT), 200 parts by mass of silica filler slurry (SE2050) and 50 parts by mass of toluene Mix well while stirring. 25 parts by mass of dicyclopentadiene-type epoxy resin (HP7200H) and 3.75 parts by mass of 1-benzyl-2-methylimidazole (1B2MZ) were added to the obtained mixture, and the mixture was further stirred to obtain a resin Varnish. The obtained resin varnish was coated on the release treatment surface of the carrier film using a blade coater ("SNC-350" manufactured by Kangjing Precision Machinery Co., Ltd.). In a dryer ("MSO-80TPS" manufactured by Erye Science Co., Ltd.), the coating film was dried by heating at 100°C for 20 minutes to form a resin layer with a thickness of 100 μm. On the formed resin layer, a release film PET film similar to the carrier film was attached as a protective film with the release surface facing the resin layer side as a protective film to obtain a laminated film. By heating the laminated film at 180° C. for 60 minutes to cure the resin layer, a laminated film having a stretchable resin film (cured product of the resin layer) is obtained.

Example 2 A resin varnish was prepared in the same manner as in Example 1 except that 200 parts by mass of silica filler paste (SE2050) was replaced with 108 parts by mass of silica filler paste (C40) containing 70 parts by mass of filler. . Using the obtained resin varnish, a laminate film having a stretchable resin film was obtained by the same method as in Example 1.

Example 3 A resin varnish was prepared in the same manner as in Example 1, except that 200 parts by mass of silica filler slurry (SE2050) was replaced with 233 parts by mass of silica filler slurry (C120) containing 70 parts by mass of filler. . Using the obtained resin varnish, a laminate film having a stretchable resin film was obtained by the same method as in Example 1.

Example 4 A resin varnish was prepared in the same manner as in Example 1, except that 200 parts by mass of silica filler slurry (SE2050) was replaced with 100 parts by mass of silica filler slurry (F19) containing 70 parts by mass of filler. . Using the obtained resin varnish, a laminate film having a stretchable resin film was obtained by the same method as in Example 1.

Example 5 Change the blending amount of silica filler slurry (SE2050), dicyclopentadiene-type epoxy resin (HP7200H) and 1-benzyl-2-methylimidazole (1B2MZ) as shown in Table 1, except for this In the same manner as in Example 1, a resin varnish was prepared. Using the obtained resin varnish, a laminate film having a stretchable resin film was obtained by the same method as in Example 1.

Comparative example 1 Modified 100 parts by mass of maleic anhydride with styrene-ethylene butene-styrene block copolymer elastomer (FG1924GT), 25 parts by mass of dicyclopentadiene-type epoxy resin (HP7200H) and 3.75 parts by mass One part of 1-benzyl-2-methylimidazole (1B2MZ) was mixed with 50 parts by mass of toluene, and the mixture was stirred to obtain a resin varnish. Using the obtained resin varnish, a laminate film having a stretchable resin film was obtained by the same method as in Example 1.

Comparative Example 2 and Comparative Example 3 Change the blending amount of maleic anhydride modified styrene-ethylene butene-styrene block copolymer elastomer (FG1924GT) and dicyclopentadiene epoxy resin (HP7200H) as shown in Table 1, except Other than this, the resin varnish and the laminated film were obtained in the same manner as in Comparative Example 1.

3. Evaluation Coefficient of Thermal Expansion (CTE) Using a sample of the stretchable resin film obtained from the laminated film, the thermal expansion coefficient of the stretchable resin film at 0° C. to 120° C. was measured by a thermomechanical analysis (TMA) method under the following conditions. Device: SS6000 (Seiko instruments) Co., Ltd. Sample size: length 10 mm × width 3 mm Load: 0.05 Mpa Temperature: 0℃～120℃ Heating rate: 5℃/min

Tensile modulus of elasticity Prepare a test strip of a stretched resin film with a length of 40 mm and a width of 10 mm and the carrier film and the protective film removed. The tensile test of this test piece was performed using an autograph ("EZ-S" of Shimadzu Corporation) to obtain a stress-strain curve. From the obtained stress-strain curve, the tensile modulus of elasticity at room temperature is determined. The tensile test was carried out under the conditions of a distance between the chucks of 20 mm and a tensile speed of 50 mm/min. The tensile elastic coefficient is obtained from the slope of the stress-strain curve in the range of stress 0.5 N to 1.0 N.

Recovery rate Prepare a test strip of a stretched resin film with a length of 40 mm and a width of 10 mm and the carrier film and the protective film removed. The recovery rate of the test piece was measured by a tensile test using a microforce tester (Illinois Tool Works Inc. "Instron 5948"). At the time when the displacement amount (strain) X is reached in the first tensile test, the tensile stress is released to return the test piece to the initial position, and thereafter, the second tensile test is performed. When the difference between the position at the time when the load is applied and X is Y, the value of R calculated by the formula: R=(Y/X)×100 is recorded as the recovery rate. In this embodiment, the strain X is set to 50%.

Viscosity The protective film was removed from the laminated film, and the adhesion value of the surface of the exposed stretchable resin film was measured using an adhesion tester ("TACII" manufactured by Rhesca Co., Ltd.). The measurement conditions were set as: constant load mode, immersion speed of 120 mm/min, test speed of 600 mm/min, load of 100 gf, load holding time of 1 second, temperature of 30°C or 200°C.

[Table 1]

Table 1 shows the formulation amounts of the components of the curable resin composition used to form the stretchable resin film and the evaluation results of the stretchable resin film. The numerical values in parentheses related to the filler in the table are the amount of solid components (filler) in the slurry.

As shown in the table, it was confirmed that the stretchable resin film of the example containing the filler has excellent stretchability and a small thermal expansion coefficient, and has low viscosity at high temperature and excellent handling properties. Even if it is a stretchable resin film containing no filler, the crosslinking component is increased as in Comparative Example 3, whereby the viscosity at high temperature can be reduced, but this case has a problem in that the coefficient of thermal expansion is large.

1‧‧‧Stretchable wiring board 3‧‧‧Stretchable resin film 5‧‧‧Conductor layer X‧‧‧Displacement

FIG. 1 is a plan view showing an embodiment of a stretchable wiring board. FIG. 2 is a stress-strain curve showing an example of measurement of recovery rate.

1‧‧‧Stretchable wiring board

3‧‧‧Stretchable resin film

5‧‧‧Conductor layer

X‧‧‧Displacement

Claims (9)

A conductor substrate, including: Stretchable resin film; and A conductor layer provided on the stretchable resin film; and The stretchable resin film contains a rubber component and a filler, and the rubber component may be cross-linked. The conductor substrate as described in item 1 of the patent application, wherein the average particle size of the filler is 10 nm to 500 nm. The conductive substrate according to claim 1 or claim 2, wherein the stretchable resin film contains a cured product of a curable resin composition containing the rubber component, the filler, and a cross-linking component. The conductor substrate according to item 3 of the patent application range, wherein the rubber component is crosslinked by reaction with the crosslinking component. A stretchable wiring board comprising the conductor substrate according to any one of the first to fourth patent application ranges, the conductor layer forming a wiring pattern. A stretchable resin film for a wiring board, which contains a rubber component and a filler, and the rubber component can be cross-linked. The stretchable resin film for a wiring board as described in Item 6 of the patent application range, wherein the average particle diameter of the filler is 10 nm to 500 nm. The stretchable resin film for a wiring board as described in Item 6 or Item 7 of the patent application range contains a cured product of a curable resin composition containing the rubber component, the filler, and a cross-linking component. The stretchable resin film for a wiring board according to item 8 of the patent application range, wherein the rubber component is crosslinked by reaction with the crosslinking component.

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