TWI826445B - Conductor substrate, stretchable wiring substrate, and stretchable resin film for wiring substrate - Google Patents

Abstract

The present invention discloses a stretchable wiring substrate, which includes a stretchable resin film and a conductor layer provided on the stretchable resin film. The stretchable resin film contains rubber components and fillers. The rubber component can be cross-linked.

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 the wiring substrate.

In recent years, in the fields of wearable devices and health care-related devices, there has been a demand for stretchable electronic devices that can be used along curved surfaces or joints of the body and are less likely to cause poor connection even when put on and taken off. stretchable device). In order to produce 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 containing a thermoplastic elastomer.

[Prior art documents]

[Patent Document]

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

The stretchable wiring board is often exposed to high temperatures, for example, exceeding 100° C. during the installation of various electronic components during the manufacturing process of the stretchable element. However, it is clearly known that when a stretchable wiring board becomes high-temperature, it thermally expands significantly and becomes stable. Obstacles to creating stretchable elements. In addition, the stretchable resin film constituting the conventional stretchable wiring board has high viscosity especially at high temperatures, so there is also a problem with the handleability of the stretchable wiring board at high temperatures.

Therefore, an object of one aspect of the present invention is to provide a stretchable wiring board that has excellent stretchability, a small thermal expansion coefficient, low viscosity at high temperatures, and excellent handleability, and a method for obtaining the stretchable wiring board. Conductor substrate and stretchable resin film.

One aspect of the present invention provides a conductor substrate, which includes a stretchable resin film and a conductor layer disposed on the stretchable resin film. The stretchable resin film contains rubber components and fillers. The rubber component may be cross-linked.

According to the conductive substrate according to one aspect of the present invention, a stretchable wiring substrate can be obtained that has excellent stretchability, a small thermal expansion coefficient, low viscosity at high temperatures, and excellent handleability.

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

The conductor substrate has excellent stretchability and a small thermal expansion coefficient, has low viscosity at high temperatures, and has excellent handleability.

A further aspect of the present invention provides a stretchable resin film for wiring boards, which contains a rubber component and a filler. In other words, a further aspect of the present invention provides the use of a stretchable resin film for manufacturing a wiring substrate, the stretchable resin film containing a rubber component and a filler, and the rubber component can be cross-linked. The rubber is The points can be cross-linked.

The stretchable resin film can provide a stretchable wiring board that has excellent stretchability, a small thermal expansion coefficient, low viscosity at high temperatures, and excellent handleability.

According to one aspect of the present invention, it is possible to provide a stretchable wiring board that has excellent stretchability, a small thermal expansion coefficient, low viscosity at high temperatures, and excellent handleability.

1: Flexible wiring board

3: Stretchable resin film

5: Conductor layer

X: displacement amount

FIG. 1 is a plan view showing an embodiment of a stretchable wiring board.

FIG. 2 is a stress-strain curve showing a measurement example of recovery rate.

Several embodiments of the present invention will be described in detail below. 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 board 1 shown in FIG. 1 is a conductor board 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 rubber components and fillers. The rubber component makes it easy to impart stretchability to the stretchable resin film. The conductor layer 5 forms a wiring pattern including stretchable wave portions.

The stretchable resin film 3 may have stretchability such that, for example, the recovery rate after being stretched and deformed to a strain of 20% is 80% or more. The recovery rate is determined in a tensile test using a measurement sample of a stretchable resin film. Figure 2 is an application diagram showing an example of recovery rate measurement. Force-strain curve. The tensile stress is released at the time when the displacement (strain) When the difference between the position at the time when load application starts and X is set to Y, R calculated from 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 perspective of resistance to repeated use, the recovery rate may be above 80%, above 85%, or above 90%. Recovery rate is by definition capped at 100%.

The rubber component contains one or more than two types of rubber. The rubber contained in the rubber component may be a thermoplastic elastomer. Examples of thermoplastic elastomers include hydrogenated styrenic elastomers. The hydrogenated styrenic elastomer is an elastomer obtained by adding hydrogen to an unsaturated double bond of a styrenic elastomer having a soft segment containing an unsaturated double bond. Hydrogenated styrenic elastomers can also be expected to have effects such as improved weather resistance. Examples of hydrogenated styrene elastomers include styrene-ethylene-butylene-styrene block copolymer elastomer (SEBS (Styrene Ethylene Butylene Styrene)), sometimes also called "hydrogenated styrene butadiene rubber" ”).

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

From the viewpoint of avoiding damage to wiring due to moisture absorption, etc., the rubber component may include styrene-butadiene rubber, butadiene rubber, and butyl rubber. At least one kind of 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 wiring substrates can be manufactured with good yield.

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

Rubber components can also be produced synthetically. For example, acrylic rubber can be obtained by reacting (meth)acrylic acid, (meth)acrylic acid ester, aromatic vinyl compound, cyanide vinyl compound, and the like.

The rubber component can be cross-linked through the reaction of cross-linking groups. By using a crosslinked rubber component, the heat resistance of the stretchable resin film tends to be easily improved. The cross-linking group may be a reactive group that can form a cross-linked structure by a reaction that cross-links the molecular chain of the rubber component or a reaction between the molecular chain of the rubber component and a cross-linking component described below. Examples of the crosslinking group include: (meth)acryl group, vinyl group, epoxy group, styrene group, amine group, isocyanurate group, urea group, cyanate group, and isocyanate group, mercapto group, hydroxyl group, carboxyl group and acid anhydride group.

The rubber component can be cross-linked by reaction of at least one cross-linking group among an acid anhydride group or a carboxyl group. Examples of rubber having an acid anhydride group include rubber partially modified with maleic anhydride. As a commercially available rubber partially modified with maleic anhydride, there is, for example, the styrenic elastomer "TufPrene 912" manufactured by Asahi Kasei Co., Ltd.

The rubber partially modified with maleic anhydride may be a hydrogenated styrenic elastomer modified with maleic anhydride. Examples of hydrogenated styrene-based elastomers modified with maleic anhydride include maleic anhydride-modified styrene-ethylene butylene-styrene block copolymer elastomers. Examples of commercially available hydrogenated styrenic elastomers modified with maleic anhydride include "FG1901" and "FG1924" of Kraton Polymers Japan Co., Ltd., Asahi Kasei Co., Ltd. The company's "TufTech (TufTech) M1911", "TufTech (TufTech)M1913", "TufTech (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 calculated by gel permeation chromatography (Gel Permeation Chromatography, GPC).

Based on the mass of components other than fillers in the stretchable resin film, the content of the rubber component in the stretchable resin film may be 30 mass% to 100 mass%, 50 mass% to 100 mass%, or 70 mass% to 100 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 a resin phase containing a rubber component. Fillers can be inorganic fillers, organic fillers, 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 10nm~500nm. If the average particle diameter of the filler is within this range, further significant effects can be obtained in reducing the thermal expansion coefficient of the stretchable resin film and suppressing the viscosity of the stretchable resin film at high temperatures. From the same point of view, 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 size of the filler is determined by laser diffraction. The average value of the particle diameter (average primary particle diameter) determined by the scattering method. The average particle size of the filler can be measured, for example, using a nanoparticle size distribution measuring device SALD-7500nano (manufactured by Shimadzu Corporation).

The shape of the filler is not particularly limited, and the filler may have any shape such as approximately spherical, fibrous, or irregular.

The surface of the filler can be modified with functional groups. Examples of the functional group that can be introduced onto the surface of the filler include an amino group, a phenylamino group, and a phenyl group. The filler having a functional group-modified surface can contribute to improving the adhesion between the stretchable resin film and the conductor layer.

The content of the filler in the stretchable resin film may be 1 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, further significant effects can be obtained in terms of reducing the thermal expansion coefficient of the stretchable resin film and suppressing 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 relative 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 crosslinking component. The cured product of the resin composition includes a cross-linked structure formed by the reaction of the cross-linked groups of the rubber component, the reaction of the cross-linked group of the rubber component and the cross-linked component, the polymerization reaction of the cross-linked component, or a combination thereof. . 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 can be contained in the resin composition used to form a stretchable resin film is a compound having one or more reactive groups. The cross-linking component may, for example, have a group selected from the group consisting of epoxy group, (meth)acrylyl group, vinyl group, styrene group, amine group, isocyanurate group, urea group, cyanate group, isocyanate group, and mercapto group. , hydroxyl and carboxyl groups Compounds consisting of at least one reactive group in the group. From the viewpoint of improving the heat resistance of the stretchable resin film, the crosslinking component may be a compound having a reactive group selected from an epoxy group, an amine group, a hydroxyl group, and a carboxyl group. In particular, a combination of a rubber having at least one of a maleic anhydride group or a carboxyl group and a compound having an epoxy group (epoxy resin) improves the heat resistance, low moisture permeability, and stretchability of the stretchable resin film. Particularly excellent effects can be obtained in terms of the adhesion between the flexible resin film and the conductive layer and the low viscosity of the cured stretchable resin film. If the heat resistance of the stretchable resin film is improved, for example, deterioration of the stretchable resin film in a heating step such as nitrogen reflux can be suppressed. If the cured stretchable resin film has low viscosity, the conductor substrate or the wiring substrate can be processed with good workability.

The epoxy group-containing compound that can be used as a cross-linking component can be a monofunctional, difunctional, or trifunctional or higher multifunctional epoxy resin. In order to obtain sufficient curability, the cross-linking component may contain a bifunctional or trifunctional or higher epoxy resin.

The epoxy resin may be, for example, selected from the group consisting of bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, phenol novolak-type epoxy resin, naphthalene-type epoxy resin, dicyclopentadiene-type epoxy resin, and cresol At least one kind of novolak-type epoxy resin and epoxy resin having an aliphatic chain. Examples of commercially available epoxy resins having an aliphatic chain include EXA-4816 manufactured by DIC Co., Ltd.

Epoxy resins that provide hardened materials with high glass transition temperatures can contribute to reducing the thermal expansion coefficient of stretchable resin films and suppressing viscosity at high temperatures. For example, an epoxy resin that forms a cured product having a glass transition temperature of 180° C. or higher or 200° C. or higher can be selected based on the reaction with a phenol novolac resin as a hardener. do Specific examples of such epoxy resins include dicyclopentadiene-type epoxy resin and naphthalene-type epoxy resin.

The cross-linking component may include a compound having a (meth)acrylyl group. The compound having a (meth)acrylyl group may be a (meth)acrylate. The compound having a (meth)acrylyl group may be a compound having one, two, or three or more (meth)acrylyl groups (for example, a monofunctional, difunctional, or trifunctional or higher (meth)acrylate ). In order to obtain sufficient curability, the cross-linking component may be a compound having two or more (meth)acrylyl groups.

Examples of the monofunctional (meth)acrylate include: (methyl)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, (meth)acrylate )Terth-butyl acrylate, (meth)butoxyethyl acrylate, (meth)isoamyl acrylate, (meth)hexyl acrylate, (meth)-2-ethylhexyl acrylate, (meth)acrylate Heptyl (meth)acrylate, octylheptyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, ( Tridecyl methacrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (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, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate Aliphatic (meth)acrylates such as acrylic acid ester, ethoxy polypropylene glycol (meth)acrylate and succinic acid mono(2-(meth)acryloyloxyethyl) ester; (meth) Cyclopentyl acrylate, cyclohexyl (meth)acrylate, (meth)acrylate Dicyclopentyl acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, mono(2-(meth)acryloxyethyl) tetrahydrophthalate and alicyclic (meth)acrylates such as hexahydrophthalic acid mono(2-(meth)acryloyloxyethyl) ester; benzyl (meth)acrylate, phenyl (meth)acrylate Ester, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, (meth)acrylate p-Cunylphenoxyethyl acrylate, o-phenylphenoxyethyl (meth)acrylate, 1-naphthyloxyethyl (meth)acrylate, 2-naphthoxyethyl (meth)acrylate Ethyl ester, phenoxy polyethylene glycol (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, phenoxy polypropylene glycol (meth)acrylate, (meth)acrylate 2-hydroxy-3-phenoxypropyl acrylate, (meth)acrylic acid-2-hydroxy-3-(o-phenylphenoxy)propyl ester, (meth)acrylic acid-2-hydroxy-3-(meth)acrylate Aromatic (meth)acrylates such as 1-naphthyloxy)propyl ester and (meth)acrylic acid-2-hydroxy-3-(2-naphthyloxy)propyl ester; (meth)acrylic acid-2-tetrahydrogen Heterocyclic (methyl) compounds such as furfuryl ester, N-(meth)acryloxyethyl hexahydrophthalimide and 2-(meth)acryloxyethyl-N-carbazole Acrylates; and caprolactone modifications of these compounds. Among these, from the viewpoint of compatibility with styrenic elastomer, transparency and heat resistance, the aliphatic (meth)acrylate and the aromatic (meth)acrylate can be selected. Select monofunctional (meth)acrylates.

Examples of the difunctional (meth)acrylate 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 Acrylates, ethoxylated polypropylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol Alcohol 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 Aliphatic (meth)acrylates such as meth)acrylate, tricyclodecane dimethanol (meth)acrylate and ethoxylated-2-methyl-1,3-propanediol di(meth)acrylate ; Cyclohexane dimethanol (meth)acrylate, ethoxylated cyclohexanedimethanol (meth)acrylate, propoxylated cyclohexanedimethanol (meth)acrylate, ethoxylated propylene Oxylated cyclohexanedimethanol (meth)acrylate, tricyclodecane dimethanol (meth)acrylate, ethoxylated tricyclodecane dimethanol (meth)acrylate, propoxylated tricyclohexanedimethanol (meth)acrylate Cyclodecanedimethanol (meth)acrylate, ethoxylated propoxylated tricyclodecane dimethanol (meth)acrylate, ethoxylated hydrogenated bisphenol A di(meth)acrylate, propoxylated Oxylated hydrogenated bisphenol A di(meth)acrylate, ethoxylated propoxylated hydrogenated bisphenol A di(meth)acrylate, ethoxylated hydrogenated bisphenol F di(meth)acrylate , propoxylated hydrogenated bisphenol F di(meth)acrylate and ethoxylated propoxylated hydrogenated bisphenol F di(meth)acrylate and other alicyclic (meth)acrylates; ethoxy 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 propoxylated bisphenol F di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate Phenol AF di(meth)acrylate, propoxylated bisphenol AF di(meth)acrylate, ethoxylated propoxylated bisphenol AF di(meth)acrylate, ethoxylated Aromatic (meth)acrylates such as fluorene-based di(meth)acrylate, propoxylated fluorene-based di(meth)acrylate, and ethoxylated propoxylated fluorene-based di(meth)acrylate Esters; ethoxylated isocyanuric acid di(meth)acrylate, propoxylated isocyanuric acid di(meth)acrylate and ethoxylated propoxylated isocyanuric acid di(meth)acrylate ) Heterocyclic (meth)acrylates such as acrylates; caprolactone modified forms of these compounds; aliphatic epoxy (meth)acrylates such as neopentyl glycol epoxy (meth)acrylates Esters; alicyclic rings such as cyclohexanedimethanol-type epoxy (meth)acrylate, hydrogenated bisphenol A-type epoxy (meth)acrylate, and hydrogenated bisphenol F-type epoxy (meth)acrylate. Formula epoxy (meth)acrylate; resorcinol-type epoxy (meth)acrylate, bisphenol A-type epoxy (meth)acrylate, bisphenol F-type epoxy (meth)acrylate ) acrylate, bisphenol AF type epoxy (meth)acrylate and fluorene type epoxy (meth)acrylate and other aromatic epoxy (meth)acrylates. From the viewpoint of compatibility with styrene-based elastomer, transparency, and heat resistance, the difunctional acrylate 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, propoxylate 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, ethoxylated Pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated propoxylated quaternary Aliphatic (meth)acrylates such as pentaerythritol tetra(meth)acrylate, di-trimethylolpropane tetraacrylate and dipentaerythritol hexa(meth)acrylate; ethoxylated isocyanuric acid triacrylate Heterocyclic (meth)acrylate, propoxylated isocyanurate tri(meth)acrylate, ethoxylated propoxylated isocyanurate tri(meth)acrylate, etc. Acrylic esters; caprolactone modified forms of these compounds; aromatic epoxy (meth)acrylates such as phenol novolak type epoxy (meth)acrylate and cresol novolac type epoxy (meth)acrylate. base) acrylate. From the viewpoint of compatibility with styrene-based elastomer, transparency, and heat resistance, a polyfunctional polyester may be selected from the aliphatic (meth)acrylate and the aromatic (meth)acrylate. (meth)acrylate.

The content of the crosslinking component in the resin composition for forming 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 relative to 100 parts by mass of the rubber component, and may be 70 parts by mass or less. 60 parts by mass or less or 50 parts by mass or less. When the content of the crosslinking component is within the above range, the adhesive force with the conductor layer tends to increase while maintaining the characteristics of the stretchable resin film.

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

To use a compound with an epoxy group (epoxy resin) as a cross-linking component In this case, as the hardener, aliphatic polyamine, polyamine amide, polythiol, aromatic polyamine, acid anhydride, carboxylic acid, phenol novolac resin, ester resin and dicyandiamine can be used. (dicyandiamide) at least one of the group consisting of. As the hardener or hardening accelerator of the compound having an epoxy group, at least one selected from the group consisting of tertiary amines, imidazole, and phosphine can be used. From the viewpoint of storage stability and curability of the resin composition before curing, imidazole can be used. In the case where the rubber component includes rubber modified by maleic anhydride, an imidazole compatible with the rubber may 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-linked component.

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

Examples of thermal radical polymerization initiators include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and methyl cyclohexanone peroxide; 1,1-bis (th Tributylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)-2-methylcyclohexane, 1,1-bis(tert-butylperoxy)-3 ,3,5-trimethylcyclohexane, 1,1-bis(third hexylperoxy)cyclohexane and 1,1-bis(third hexylperoxy)-3,3,5-tri Peroxyketals such as methylcyclohexane; hydroperoxides such as p-menthane hydroperoxide; α,α'-bis(tert-butylperoxy)diisopropylbenzene, dicumyl peroxide Dialkyl peroxides such as tert-butylcumyl peroxide and di-tert-butyl peroxide; octyl peroxide, lauryl peroxide, stearyl peroxide and benzyl peroxide Dihydryl peroxides such as hydroxyl peroxide; peroxydicarbonate bis(4-tert-butylcyclohexyl) ester, peroxy Peroxycarbonates such as di-2-ethoxyethyl dicarbonate, di-2-ethylhexyl peroxydicarbonate and di-3-methoxybutyl peroxycarbonate; peroxytrimethylacetic acid Tributyl ester, tert-hexyl peroxytrimethylacetate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5 -Bis(2-ethylhexylperoxy)hexane, tert-hexyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, peroxyisobutyric acid tert-butyl ester, tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, isopropyl peroxide tert-butyl monocarbonate, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-butyl peroxybenzoate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2, Peroxyesters such as 5-bis(benzoylperoxy)hexane and tert-butyl peracetate; 2,2'-azobisisobutyronitrile, 2,2'-azobis(2, Azo compounds such as 4-dimethylvaleronitrile) and 2,2'-azobis(4-methoxy-2'-dimethylvaleronitrile). From the viewpoint of hardening, transparency, and heat resistance, the thermal radical polymerization initiator can be selected from the dicarboxylic peroxide, the peroxyester, and the azo compound.

Examples of the photoradical polymerization initiator include benzoin ketals such as 2,2-dimethoxy-1,2-diphenylethan-1-one; 1-hydroxycyclohexyl phenyl ketone, 2 -Hydroxy-2-methyl-1-phenylpropan-1-one and 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1- Ketones and other α-hydroxyketones; 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butan-1-one and 1,2-methyl-1-[4 -(Methylthio)phenyl]-2-morpholinylpropane-1-one and other α-aminoketones; 1-[4-(phenylthio)phenyl]-1,2-octanedione-2 -Oxime esters such as (benzyl)oxime; bis(2,4,6-trimethylbenzyl)phenylphosphine oxide, bis(2,6-dimethoxybenzyl)-2 ,4,4-trimethylpentylphosphine oxide and 2,4,6-trimethylbenzoyldiphenyl Phosphine oxides such as phosphine oxide; 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer polymer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer and 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer p-methoxyphenyl)-4,5-diphenylimidazole dimer and other 2,4,5-triarylimidazole dimer; benzophenone, N,N,N',N'-tetramethyl Base-4,4'-diaminobenzophenone, N,N,N',N'-tetraethyl-4,4'-diaminobenzophenone and 4-methoxy-4' -Dimethylaminobenzophenone and other benzophenone compounds; 2-ethylanthraquinone, 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 - Quinone compounds such as phenanthrenequinone, 2-methyl-1,4-naphthoquinone and 2,3-dimethylanthraquinone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether; benzoin, methyl benzoin and ethyl benzoin Benzoin compounds such as benzoin; benzyl compounds such as benzyl dimethyl ketal; acridine compounds such as 9-phenylacridine and 1,7-bis(9,9'-acridinylheptane); N-benzene glycine; and coumarin.

In addition to the above components, the stretchable resin film or the resin composition used to form the stretchable resin film may further contain antioxidants, heat stabilizers, and ultraviolet absorbers as necessary within the range that does not significantly impair the effects of the present invention. Agents, anti-hydrolysis agents, anti-yellowing agents, visible light absorbers, colorants, plasticizers, flame retardants, leveling agents, etc.

The thickness of the stretchable resin film 3 may be 5 μm to 1000 μm. When the thickness of the stretchable resin film is within this range, sufficient strength as a stretchable base material can be easily obtained and sufficient drying can be performed. Therefore, 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 point of view, 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, but 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 a step meter (ET-200, manufactured by Kosaka Laboratory Co., Ltd.), for example.

By providing unevenness to the stretchable resin film, the surface roughness Ra value of the stretchable resin film can be within the above range. An example of a method for imparting unevenness to a stretchable resin film is to use an unevenness transfer substrate 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 transfer the unevenness transfer substrate to the stretchable resin film. A method of peeling off; a method of subjecting the hardened stretchable resin film to an embossing process such as etching or hot embossing; and a method of pressing the roughened surface of the metal foil onto the stretchable resin film and etching the metal foil. .

The surface viscosity value of the stretchable resin film can be 0.7gf/mm ² or less (below 6.9kPa), 0.5gf/mm ² or less (below 4.9kPa), or 0.4gf/mm ² or less (below 3.9kPa) at 30°C. ). The surface viscosity value of the stretchable resin film may 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, but may be 0gf/mm ² (0kPa). The viscosity value can be measured using an adhesion testing machine ("TACII" manufactured by Rhesca Co., Ltd.), for example.

The elastic coefficient (tensile elastic coefficient) of the stretchable resin film can be 0.1MPa Above and below 1000MPa. When the elastic coefficient is 0.1 MPa or more and 1000 MPa or less, the base material tends to have particularly excellent handleability and flexibility. From this point of view, 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 stretchable resin film may have an elongation at break of 100% or more. When the elongation at break is 100% or more, sufficient stretchability tends to be easily obtained. From this perspective, the elongation at break may be above 150%, above 200%, above 300%, or above 500%. 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 a laminated film state 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; polycarbonate ester; polyolefins such as polyethylene and polypropylene; polyamide; polyimide; polyamide imine; polyether imine; polyether sulfide; polyether sulfide; polyether ketone; polyphenylene ether; Polyphenylene sulfide; polyarylate; polyurethane; and liquid crystal polymers. From the viewpoint of softness and strength, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyamide, Films of polyimide, polyimide, polyphenylene ether, polyphenylene sulfide, polyarylate or polystyrene are used as carrier films.

The thickness of the carrier film is not particularly limited and can range from 3 μm to 250 μm. When 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 softness can be easily obtained. sexual orientation. From the above point of view, the thickness of the carrier film may be 5 μm ~ 200 μm or 7 μm ~ 150 μm. From the viewpoint of improving the peelability from the stretchable resin film, a film in which the base film has been subjected to a release treatment using a silicone compound, a fluorine-containing compound, or the like may be used if 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; and polyolefins such as polyethylene and polypropylene. . From the viewpoint of flexibility and strength, 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 can be subjected to a release treatment using a silicone compound, a fluorine-containing compound, or the like.

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

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

The conductor foil can be a 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 foil 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, Monel 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. Copper foil can easily form wiring patterns through photolithography without impairing the properties of the stretchable resin base material. The copper foil is not particularly limited, and for example, electrolytic copper foil and rolled copper foil used in copper-clad laminates, flexible wiring boards, and the like can be used.

The conductor plating film may be a film formed by a common plating method used in an additive method or a semi-additive method. For example, after performing a plating catalyst application process to adhere palladium, the stretchable resin film is immersed in an electroless plating solution to deposit electroless plating with a thickness of 0.3 μm to 1.5 μm on the entire surface of the primer. layer (conductor layer). If necessary, further electroplating (electroplating) can be performed to adjust to the required thickness. As the electroless plating liquid used for electroless plating, any electroless plating liquid can be used without particular limitation. Regarding electroplating, ordinary methods can also be used and are not particularly limited. From the viewpoint of cost and resistance value, the conductor plating film (electroless plating film, electroplating film) may be a copper plating film.

The thickness of the conductor layer is not particularly limited and can 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. When the thickness of the conductor layer is 50 μm or less, etching and processing are particularly easy.

A stretchable wiring board can be manufactured, for example, by a method including preparing a conductive board 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 conductive substrate having a conductor foil as a conductor layer can be obtained, for example, by applying a varnish of a resin composition for forming a stretchable resin film to the conductor foil, or laminating the conductor foil to form a stretchable resin film. on a stretchable resin film on a carrier film. A stretchable resin film can be formed by drying a coating film of a resin composition for forming a stretchable resin film and curing the formed resin layer by heating or irradiating light.

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

The method of forming a wiring pattern on a conductor layer may include, for example: 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 covering conductor. forming a resist pattern on a portion of the conductor layer; using an etching solution to remove a portion of the conductor layer that is not covered by the resist pattern; and removing the resist pattern.

Alternatively, the method of forming a wiring pattern on a conductor layer may also include: forming a plating resist on the conductor layer of the conductor substrate; exposing the plating resist; and conducting the exposed plating resist. The step of developing to form a resist pattern covering a portion of the conductor layer; the step of forming a conductor coating on the portion of the conductor layer not covered by the resist pattern by electroless plating or electroplating; removing the resist pattern and the step of removing the portion of the conductor layer that is not covered by the conductor coating formed by the electroplating.

By mounting various electronic components on the wiring board, stretchable elements can be obtained pieces.

[Example]

Hereinafter, an Example is given and this invention is demonstrated further concretely. However, the present invention is not limited to these examples.

1.Raw materials

As raw materials for producing a stretchable resin film, the following materials are prepared.

(A) Rubber component

． Maleic anhydride modified styrene-ethylene butylene-styrene block copolymer elastomer (trade name "FG1924GT", manufactured by Kraton Polymers Japan Co., Ltd.)

(B) Cross-linking component

． Dicyclopentadiene-type epoxy resin (trade name "EPICLON (EPICLON) HP7200H", manufactured by DIC Co., Ltd.)

(C) Hardening accelerator

． 1-Benzyl-2-methylimidazole (trade name "1B2MZ", manufactured by Shikoku Chemical Co., Ltd.)

(D)Packing

． Silica filler slurry SE2050 (trade name "SE2050KNK", manufactured by Admatechs Co., Ltd., average particle size 500nm, spherical silica particles surface-modified with phenylamine groups, silica concentration 70 mass% methyl isobutyl ketone dispersion)

． Silica filler slurry C40 (trade name "C40", CIK Nanotec (CIK Manufactured by Nanotec Co., Ltd., silica particles surface-modified with phenylamine groups, average particle diameter 100nm, silica concentration 65% by mass, methyl isobutyl ketone (Methyl Isobutyl Ketone, MIBK) dispersion)

． Silica filler slurry C120 (trade name "C120", manufactured by CIK Nanotec Co., Ltd., silica particles surface-modified with phenylamine groups, average particle size 30nm, silica concentration 30 mass% MIBK dispersion)

． Silica filler slurry F19 (trade name "F19", manufactured by CIK Nanotec Co., Ltd., phenyl surface-modified silica particles, average particle size 100nm, silica concentration 70 mass % MIBK dispersion)

(E)Solvent

． Toluene

(carrier film/protective film)

． Release-treated polyethylene terephthalate (PET) film (trade name "Purex A31", manufactured by Teijin DuPont Films Co., Ltd., thickness 25 μm)

2. Laminated film with stretchable resin film

Example 1

100 parts by mass of maleic anhydride modified styrene-ethylene butylene-styrene block copolymer elastomer (FG1924GT), 200 parts by mass of silica filler slurry (SE2050) and 50 parts by mass of toluene Stir to combine evenly. 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 Stir and obtain resin varnish. The obtained resin varnish was applied to the release-processed surface of the carrier film using a blade coater ("SNC-350" manufactured by Yasui Seiki Co., Ltd.). The coating film was dried by heating at 100° C. for 20 minutes in a dryer ("MSO-80TPS" manufactured by Futaba Science Co., Ltd.) to form a resin layer with a thickness of 100 μm. On the formed resin layer, a release-processed PET film identical to the carrier film was attached as a protective film with the release-processed surface facing the resin layer, thereby obtaining a laminated film. The laminated film was heated at 180° C. for 60 minutes to harden the resin layer, thereby obtaining a laminated film having a stretchable resin film (cured product of the resin layer).

Example 2

A resin varnish was prepared in the same manner as in Example 1, except that 200 parts by mass of the silica filler slurry (SE2050) was replaced with 108 parts by mass of the silica filler slurry (C40) containing 70 parts by mass of the filler. . Using the obtained resin varnish, a laminated film having a stretchable resin film was obtained in the same manner 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 the silica filler slurry (SE2050) was replaced with 233 parts by mass of the silica filler slurry (C120) containing 70 parts by mass of the filler. . Using the obtained resin varnish, a laminated film having a stretchable resin film was obtained in the same manner as in Example 1.

Example 4

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

Example 5

Change the compounding amounts of silica filler slurry (SE2050), dicyclopentadiene-type epoxy resin (HP7200H) and 1-benzyl-2-methylimidazole (1B2MZ) as shown in Table 1, except that , prepare a resin varnish in the same manner as Example 1. Using the obtained resin varnish, a laminated film having a stretchable resin film was obtained in the same manner as in Example 1.

Comparative example 1

100 parts by mass of maleic anhydride-modified styrene-ethylene butylene-styrene block copolymer elastomer (FG1924GT), 25 parts by mass of dicyclopentadiene-type epoxy resin (HP7200H) and 3.75 parts by mass parts of 1-benzyl-2-methylimidazole (1B2MZ) and 50 parts by mass of toluene were mixed, and the mixture was stirred to obtain a resin varnish. Using the obtained resin varnish, a laminated film having a stretchable resin film was obtained in the same manner as in Example 1.

Comparative Example 2 and Comparative Example 3

Change the blending amounts of maleic anhydride-modified styrene-ethylene butylene-styrene block copolymer elastomer (FG1924GT) and dicyclopentadiene-type epoxy resin (HP7200H) as shown in Table 1, except Except for this, a resin varnish and a 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 using the thermomechanical analysis (TMA) method under the following conditions.

Device: SS6000 (Seiko Instruments Co., Ltd.)

Sample size: length 10mm x width 3mm

Load: 0.05Mpa

Temperature: 0℃~120℃

Heating rate: 5℃/min

Tensile elastic coefficient

A short strip-shaped test piece of a stretchable resin film with a carrier film and a protective film removed was prepared with a length of 40 mm and a width of 10 mm. A tensile test was performed on the test piece using an autograph ("EZ-S" manufactured by Shimadzu Corporation) to obtain a stress-strain curve. The tensile elastic coefficient at room temperature was obtained from the obtained stress-strain curve. The tensile test was conducted under the conditions of a distance between chucks of 20mm and a tensile speed of 50mm/min. The tensile elastic coefficient is calculated from the slope of the stress-strain curve in the stress range of 0.5N to 1.0N.

recovery rate

A short strip-shaped test piece of a stretchable resin film with a carrier film and a protective film removed was prepared with a length of 40 mm and a width of 10 mm. The recovery rate of the test piece was measured by a tensile test using a microforce tester (Illinois Tool Works Inc. "Instron 5948"). Open the tensile stress at the time when the displacement (strain) X is reached in the first tensile test The test piece is returned to the initial position, and then the second tensile test is performed. At this time, when the difference between the position at the time when the load is applied and The value of R calculated by X)×100 is recorded as the recovery rate. In this example, the strain X is set to 50%.

Stickiness value

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

Table 1 shows the compounding amounts of each component of the curable resin composition used to form the stretchable resin film and the evaluation results of the stretchable resin film. and fill in the table The numerical value in parentheses related to the material is the blending amount of the solid component (filler) in the slurry.

As shown in the table, it was confirmed that the stretchable resin film of the Example containing a filler has excellent stretchability and a small thermal expansion coefficient, has low viscosity at high temperatures, and is excellent in handleability. Even if it is a stretchable resin film that does not contain fillers, the viscosity at high temperatures can be reduced by increasing the crosslinking component as in Comparative Example 3. However, in this case, there is a problem in that the thermal expansion coefficient is large.

1‧‧‧Flexible wiring board

3‧‧‧Stretchable resin film

5‧‧‧Conductor layer

X‧‧‧Displacement

Claims (4)

A conductor substrate, which includes: a stretchable resin film; and a conductor layer provided on the stretchable resin film; and the stretchable resin film includes a curable resin composition containing a rubber component, a filler, and a cross-linked component. Hardened material, the rubber component is cross-linked by reaction with the cross-linking component, the rubber component includes rubber having at least one of a maleic anhydride group or a carboxyl group, the cross-linking component includes a Epoxy compound, the average particle size of the filler is 10nm~200nm. The conductor substrate as described in Item 1 of the patent application, wherein the conductor layer is a metal foil or a conductor coating. A stretchable wiring substrate includes the conductor substrate as described in Item 1 or Item 2 of the patent application, and the conductor layer forms a wiring pattern. A stretchable resin film for a wiring board, wherein the stretchable resin film contains a cured product of a curable resin composition containing a rubber component, a filler, and a crosslinked component, and the rubber component is formed by contact with the crosslinked component. cross-linked by reaction, the rubber component includes a rubber having at least one of a maleic anhydride group or a carboxyl group, and the cross-linking component includes a compound having an epoxy group, The average particle size of the filler is 10nm~200nm.