WO2023286872A1

WO2023286872A1 - Laminate and electronic device provided with laminate

Info

Publication number: WO2023286872A1
Application number: PCT/JP2022/027941
Authority: WO
Inventors: 雅弘滝澤; 陽祐広田; 亘冨士川; 潤白髪
Original assignee: 太陽インキ製造株式会社; Dic株式会社
Priority date: 2021-07-15
Filing date: 2022-07-15
Publication date: 2023-01-19
Also published as: KR20240037880A; TW202327876A; JPWO2023286872A1; CN117561164A

Abstract

Provided is a laminate in which adhesion of a plating layer can be maintained not only when in a normal state, but even after a long heat resistance test.　A laminate comprising a support and a primer layer, a metal particle layer, and a metal plating layer provided in the stated order on the support, wherein the primer layer includes a phenoxy resin having a weight-average molecular weight of 10,000 to 100,000.

Description

Laminates and electronic devices with laminates

The present invention relates to laminates, and more particularly to laminates that can be suitably used in electronic devices such as electromagnetic wave shields, printed wiring boards, integrated circuits, and organic transistors, and electronic devices using the laminates.

Due to the miniaturization and speeding up of electronic devices, printed wiring boards are required to be faster and have higher performance. In order to meet this demand, printed wiring boards with smooth surfaces and sufficiently thin conductive layers (metal layers) are being developed. It has been demanded. A flexible copper-clad laminate (hereinafter abbreviated as "FCCL") is known as a component of this printed wiring board. FCCL is mainly manufactured by bonding a heat-resistant polymer film and a copper foil together with an epoxy resin adhesive.

In FCCL using copper foil, an epoxy resin-based adhesive is applied to the surface of the rolled copper foil while it is pulled out, and then the copper foil is attached to a polymer film. cannot be thin enough. Furthermore, it is necessary to roughen the surface of the copper foil in order to improve the adhesion with the polymer film. (several tens of Gbps), there is a problem of transmission loss.

On the other hand, as a method for thinning the copper layer of FCCL, after forming a metal thin film on the surface of the polymer film by vapor deposition or sputtering, electrolytic copper plating, electroless plating, or a combination of both is applied on the metal thin film. Conventionally, a method of forming copper by a method has been proposed (for example, Patent Document 1). However, in this method, since vapor deposition or sputtering is used to form the metal thin film, large-scale vacuum equipment is required, and the size of the base material is limited due to the equipment.

Furthermore, as another method for thinning the copper layer of FCCL, for example, Patent Document 2 discloses that inorganic nanoparticles and a phthalocyanine-based ligand are used as a plating underlayer provided between a support and a metal plating layer. It has been proposed to improve the adhesion between the support and the plating layer by using a composition containing a solvent (dispersion medium). Further, in Patent Document 3, a layer containing a compound having an aminotriazine ring is provided as a primer layer on a support, and a metal nanoparticle layer is provided on the primer layer, whereby the support and the metal plating layer are formed. It has been proposed that the adhesion of Furthermore, in Patent Document 4, a metal particle layer containing metal particles and a reaction product of a specific epoxy compound and a blocked polyisocyanate is interposed between the support and the plating layer, thereby It has been proposed that the adhesion to is improved.

JP 2015-118044 A JP 2017-218664 A WO2019/013038 pamphlet Japanese Patent Application Laid-Open No. 2020-59185

All of the laminated structures proposed in Patent Documents 1 to 4 mentioned above improve the adhesion between the support and the plating layer in a normal state, that is, after the formation of the plating layer, in a room temperature environment. However, when the inventors of the present invention conducted a long-term heat resistance test, for example, at 150 ° C. for 300 hours, it was found that even if the adhesiveness was excellent in the normal state, the adhesion was significantly reduced after the long-term heat resistance test. It turned out that a new problem existed.

Therefore, an object of the present invention is to provide a laminate that can maintain the adhesion of the plating layer not only in normal conditions but also after a long-term heat resistance test.

In order to solve the above problems, the present inventors have found that by using a high-molecular-weight phenoxy resin in the primer layer, the elongation of the primer layer is increased and the elastic modulus is improved, so that the plating immediately after plating (normal state) It has been found that the layer adhesion can be improved. In addition, by using a high-molecular-weight phenoxy resin, deterioration such as decomposition of the polymer in the primer layer is suppressed during the long-term heat resistance test, so that the adhesion of the plating layer can be maintained even after the long-term heat resistance test. I have learned that I can. The present invention has been completed based on such findings. That is, the gist of the present invention is as follows.

[1] A laminate comprising a support, a primer layer, a metal particle layer and a metal plating layer on the support in this order, wherein the primer layer has a weight average molecular weight of 10,000 to 100,000. A laminate containing a phenoxy resin.
[2] The laminate according to [1], wherein the primer layer further contains an epoxy resin.
[3] The laminate according to [2], wherein the primer layer contains the phenoxy resin and the epoxy resin in a mass ratio of 90:10 to 10:90.
[4] The laminate according to any one of [1] to [3], wherein the primer layer further contains a compound having an aminotriazine ring.
[5] The laminate according to [4], wherein the compound having an aminotriazine ring is an aminotriazine-modified novolak resin.
[6] The laminate according to any one of [1] to [5], wherein the metal particle layer contains metal particles and a compound having a cationic group.
[7] The laminate according to [6], wherein the compound having a cationic group is a compound having a basic nitrogen atom-containing group.
[8] The laminate according to any one of [1] to [7], wherein the support is made of a flexible resin material.
[9] The laminate according to any one of [1] to [8], which is used for electronic equipment.
[10] The laminate according to [9], wherein the electronic device is selected from printed wiring boards and electromagnetic wave shields.
[11] An electronic device comprising the laminate according to any one of [1] to [10].

According to the present invention, in a laminate sequentially comprising a support, a primer layer, a metal particle layer, and a metal plating layer, by using a phenoxy resin having a weight average molecular weight of 10,000 to 100,000 as the primer layer, The adhesion of the metal plating layer can be maintained not only in the normal state but also after the long-term heat resistance test.

[Laminate]
A laminate according to the present invention comprises a support and, on the support, a primer layer, a metal particle layer and a metal plating layer in this order. Each element constituting the laminate of the present invention will be described below.

<Support>
As the support, any material can be used without particular limitation as long as it has mechanical strength that allows successive lamination of a primer layer, a metal particle layer, and a metal plating layer, which will be described later. Examples include polyimide resin and polyamide. Imid resin, polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polycarbonate resin, acrylonitrile-butadiene-styrene (ABS) resin, polystyrene, cycloolefin polymer, liquid crystal polymer, polyether ether ketone, polyphenylene sulfide resin , acrylic resins such as polyphenylsulfone, polyphenylene ether, polymethyl(meth)acrylate, polyvinylidene fluoride resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polyethylene resin, polypropylene resin, urethane resin, silicon, Silicon carbide, gallium nitride, sapphire, ceramics, glass, glass epoxy resin, glass polyimide, paper phenol, diamond-like carbon, alumina, polyester fiber, polyamide fiber, synthetic fiber such as polyaramid fiber, inorganic fiber such as carbon fiber, cellulose nano Examples include natural fibers such as fibers. These supports are preferably insulating ones, and porous ones can be used. Moreover, the support may be made of a single material, or may be a laminate of a plurality of materials.

Also, as the support, for example, a base material made of synthetic fibers such as polyester fibers, polyamide fibers, aramid fibers, etc., natural fibers such as cotton, hemp, etc. can be used. The fibers may be processed in advance.

As the support, a support made of polyimide resin, polyethylene terephthalate, polyethylene naphthalate, glass, cellulose nanofiber, etc., which is often used as a support for forming a conductive pattern such as an electric circuit, is generally used. preferable.

Among the above, the support is preferably made of a flexible resin material in order to impart flexibility to the laminate and obtain a bendable final product. Specifically, it is preferably in the form of a film or sheet formed by uniaxial or biaxial stretching. Examples of film-like or sheet-like supports include polyimide film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film and the like.

When the support is in the form of a film or a sheet, the thickness is not particularly limited. more preferably 1 to 200 μm.

In order to further enhance the adhesion to the primer layer described later, the surface of the support may, if necessary, have fine irregularities that do not lose its smoothness, or may have functional groups such as hydroxyl, carbonyl, and carboxyl groups. may be surface treated for the introduction of Examples thereof include plasma discharge treatment such as corona discharge treatment, dry treatment such as ultraviolet treatment, and wet treatment using an aqueous solution of water, an acid or an alkali, or an organic solvent.

<Primer layer>
The primer layer has the function of improving the adhesion between the support and the metal particle layer described later. In the present invention, the primer layer contains, as an essential component, a phenoxy resin having a weight average molecular weight in the range of 10,000 to 100,000. In the present invention, by using a high-molecular-weight phenoxy resin in the primer layer, the elongation of the polymer is improved, and furthermore the elastic modulus is improved, thereby improving the adhesion between the support and the metal plating layer. can. Furthermore, the use of a high-molecular-weight phenoxy resin can suppress deterioration such as decomposition of the polymer due to heat during the long-term heat resistance test, so the adhesion of the metal plating layer can be maintained even after the long-term heat resistance test.

A phenoxy resin is a polyhydroxy polyether obtained by reacting a dihydric phenol compound and epichlorohydrin or by reacting a dihydric epoxy compound and a dihydric phenol compound. Examples of dihydric phenol compounds include bisphenols. Examples of phenoxy resins include phenoxy resins having a bisphenol A structure (skeleton), phenoxy resins having a bisphenol F structure, phenoxy resins having a bisphenol S structure, phenoxy resins having a bisphenol M structure, phenoxy resins having a bisphenol P structure, Examples include phenoxy resins having a bisphenol Z structure. In addition, phenoxy resins having a skeletal structure such as a novolac structure, anthracene structure, fluorene structure, dicyclopentadiene structure, norbornene structure, naphthalene structure, biphenyl structure, and adamantane structure are also included. These phenoxy resins may be used singly or in combination of two or more. Among these, those having a bisphenol structure are preferred, and bisphenol A skeleton, bisphenol F skeleton, and bisphenol S skeleton are more preferred. Moreover, the terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group.

The weight average molecular weight of the phenoxy resin used in the present invention is in the range of 10,000 to 100,000. If the molecular weight is 10,000 or more, the plating adhesion after a long-term heat resistance test will be high. Since the viscosity of the working fluid becomes appropriate, the handling is improved. The weight average molecular weight of the phenoxy resin is preferably 20,000-50,000, more preferably 22,000-50,000. The weight average molecular weight of the phenoxy resin can be adjusted by the molar ratio of the epoxy resin and the phenol resin and the reaction time in the above reaction. In addition, in this specification, the weight average molecular weight employ|adopted the value converted into standard polystyrene measured by the gel permeation chromatography (GPC) mentioned later. For GPC measurement, a high-speed GPC device (HLC-8420GPC, manufactured by Tosoh Corporation) is used as a measurement device, and columns TSKgelG5000HxL / G4000HxL / G3000HxL / G2000HxL (manufactured by Tosoh Corporation) are used in series and used for elution. Tetrahydrofuran was used as a liquid, and the measurement was performed using an RI detector. In addition, phenoxy resin generally means a high molecular weight epoxy resin. It shall be distinguished from resin.

Commercially available phenoxy resins may be used, for example, Mitsubishi Chemical Corporation 1256, 4250 (both bisphenol A skeleton-containing phenoxy resins), 4275 (bis A/bis F mixed type), YL6794, YL7213, YL7290, YL7482, YL7553, YX8100 (phenoxy resin containing bisphenol S skeleton), X6954 (phenoxy resin containing bisphenolacetophenone skeleton, YX7200 (phenoxy resin containing cyclohexane skeleton), YP-70 (bisphenol F-type phenoxy resin), ZX-1356-2 (phenoxy resin containing bisphenol A and bisphenol F skeleton), YPB-40PXM40 (bromine-containing phenoxy resin), ERF-001M30 (phosphorus-containing phenoxy resin), FX-280, FX-293 , FX-310 (fluorene skeleton-containing phenoxy resin), PKHA, PKHB, PKHB+, PKHC, PKHH, PKHJ, PKFE manufactured by Gabriel Phenoxies.

In the present invention, the primer layer preferably contains an epoxy resin in combination with the phenoxy resin described above. The combined use of the phenoxy resin and the epoxy resin further improves the adhesion of the metal plating layer under normal conditions and after the long-term heat resistance test.

Epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, bisphenol A novolak type epoxy resin, alcohol ether type epoxy resin, tetrabromobisphenol. A-type epoxy resin, naphthalene-type epoxy resin, phosphorus-containing epoxy compound having a structure derived from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative, epoxy having a structure derived from dicyclopentadiene derivative Examples thereof include resins and epoxidized oils and fats such as epoxidized soybean oil. These epoxy resins may be used individually by 1 type, and may use 2 or more types together.

As the epoxy resin to be used in combination with the phenoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, cresol novolac type epoxy resin, and phenol novolac type epoxy resin can be used because they can further improve the adhesion of the metal plating layer. Aromatic epoxy resins such as bisphenol A novolac type epoxy resins are preferred, and bisphenol A type epoxy resins are particularly preferred.

The epoxy equivalent of the epoxy resin is preferably 100 to 5,000 g/equivalent, more preferably 120 to 2,000 g/equivalent, and 120 to 250 g/equivalent, because it can further improve adhesion. is more preferred.

When an epoxy resin is further included in addition to the phenoxy resin in the primer layer, the mixing ratio of the phenoxy resin and the epoxy resin is preferably 90:10 to 10:90, preferably 85:15 to 15:10 by mass. 80 is more preferred.

Also, in the present invention, the primer layer preferably contains a compound having an aminotriazine ring. A compound having an aminotriazine ring may be a low molecular weight compound or a higher molecular weight compound such as a resin.

Various additives having an aminotriazine ring can be used as the low-molecular-weight compound having an aminotriazine ring. Commercially available products include VT, VD-3 and VD-4 (all of which are from Shikoku Kasei Co., Ltd.), which are compounds having an aminotriazine ring and a hydroxyl group, and VD-5 (which is a compound having an aminotriazine ring and an ethoxysilyl group). Shikoku Kasei Co., Ltd.) and the like. These may be used individually by 1 type, and may be used together 2 or more types.

The amount of the low-molecular-weight compound having an aminotriazine ring is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the resin component.

Examples of resins having aminotriazine rings include resins in which aminotriazine rings are covalently introduced into the polymer chain of the resin. Specifically, an aminotriazine-modified novolak resin is preferred.

Aminotriazine-modified novolak resin is a novolac resin in which an aminotriazine ring structure and a phenol structure are bonded via a methylene group. Aminotriazine-modified novolak resins are prepared, for example, by combining aminotriazine compounds such as melamine, benzoguanamine and acetoguanamine; In the presence or absence of a weakly alkaline catalyst, a co-condensation reaction is carried out near neutrality, or an alkyl etherified product of an aminotriazine compound such as methyl-etherified melamine is reacted with a phenol compound.

The aminotriazine-modified novolac resin preferably has substantially no methylol groups. The aminotriazine-modified novolac resin may also contain molecules in which only the aminotriazine structure is methylene-bonded, molecules in which only the phenol structure is methylene-bonded, and the like, which are produced as by-products during the production of the aminotriazine-modified novolac resin. In addition, it may contain some unreacted raw materials.

Phenolic structures include, for example, phenol residues, cresol residues, butylphenol residues, bisphenol A residues, phenylphenol residues, naphthol residues, resorcin residues, and the like. In addition, the term "residue" as used herein means a structure in which at least one hydrogen atom bonded to a carbon atom of an aromatic ring is removed. For example, phenol means a hydroxyphenyl group.

Examples of triazine structures include structures derived from aminotriazine compounds such as melamine, benzoguanamine, and acetoguanamine.

The phenol structure and triazine structure may be used singly or in combination of two or more. Further, the phenol structure is preferably a phenol residue, and the triazine structure is preferably a melamine-derived structure, since the adhesion can be further improved.

In addition, the hydroxyl value of the aminotriazine-modified novolac resin is preferably 50 to 200 mgKOH/g, more preferably 80 to 180 mgKOH/g, because it can further improve adhesion.

The aminotriazine-modified novolak resin may be used singly or in combination of two or more. When an epoxy resin and an aminotriazine-modified novolak resin are used in combination, from the viewpoint of improving adhesion, the phenolic hydroxyl group (x) in the aminotriazine-modified novolak resin and the epoxy group (y) in the epoxy resin is preferably in the range of 0.1-5, more preferably in the range of 0.2-3.

The primer layer may further contain a cross-linking agent, if necessary, in addition to the epoxy resin and the compound having an aminotriazine ring described above. As a cross-linking agent, it is preferable to use a polyvalent carboxylic acid. Examples of polycarboxylic acids include trimellitic anhydride, pyromellitic anhydride, maleic anhydride, and succinic acid. These crosslinking agents may be used individually by 1 type, and may use 2 or more types together. Among these cross-linking agents, trimellitic anhydride is preferable because it can further improve adhesion.

A curing catalyst may also be used to promote the reaction between the epoxy group and various curing agents. Examples of the curing catalyst include tertiary amines, imidazole compounds, organic phosphines, and Lewis acid catalysts.

Tertiary amines include, for example, trimethylamine, triethylamine, tripropylamine, tributylamine, triamylamine, trihexylamine, trioctylamine, trilaurylamine, dimethylethylamine, dimethylpropylamine, dimethylbutylamine, dimethylamylamine, dimethylhexylamine, dimethylcyclohexylamine, dimethyloctylamine, dimethyllaurylamine, triallylamine, tetramethylethylenediamine, triethylenediamine (triethylenetetramine: TETA), N-methylmorpholine, 4,4'-(oxydi-2,1 -ethanediyl)bis-morpholine, N,N-dimethylbenzylamine, pyridine, picoline, dimethylaminomethylphenol, trisdimethylaminomethylphenol, triethanolamine, N,N'-dimethylpiperazine, tetramethylbutanediamine, bis( 2,2-morpholinoethyl) ether, bis(dimethylaminoethyl) ether, N,N′,N″-tris(dimethylaminopropyl)hexahydro-s-triazine, N,N′,N″-tris( dimethylaminoethyl)hexahydro-s-triazine, N,N',N''-tris(2-hydroxyethyl)hexahydro-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1' )]-ethyl-s-triazine, 1,8-diazabicyclo[5.4.0]undecene-1, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0 ] and undec-7-ene (DBU).

Examples of imidazole compounds include 1-benzyl-2-imidazole (1B2MZ), 2-ethyl-4-imidazole, 2-undelimidazole, 1,2-dimethylimidazole, 1-benzyl-2-phenylimidazole, 2- Methylimidazole, 2-ethyl-4-methylimidazole (2E4MZ), 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ), 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole (TBZ) and the like.

Examples of organic phosphines include triphenylphosphine (TPP), triphenylphosphine-triphenylborate, tris(p-methoxyphenyl)phosphine, tetraphenylphosphonium/tetraphenylborate, and the like.

Examples of Lewis acid catalysts include Lewis acid catalysts such as boron trifluoride amine complexes, boron trichloride amine complexes, and boron trifluoride ethylamine complexes.

Among these curing catalysts, it is preferable to use tertiary amines and imidazole compounds, and more preferably to use imidazole compounds, because the adhesion can be further improved. Moreover, these curing catalysts can be used alone or in combination of two or more. In addition, the preferred amount of the curing catalyst is 0.3 to 20 parts by mass, preferably 0.5 to 15 parts by mass, based on the total amount of 100 parts by mass of all the resins contained in the primer layer, in terms of solid content. part is more preferred.

In addition, the primer layer may contain other resins as components other than those described above, if necessary. Other resins include, for example, urethane resins, acrylic resins, imide resins, amide resins, melamine resins, phenol resins, urea-formaldehyde resins, blocked polyisocyanates using phenol as a blocking agent, polyvinyl alcohol, polyvinylpyrrolidone, and the like. be done. These binder resins may be used individually by 1 type, and may use 2 or more types together.

In addition, when forming the primer layer, it is preferable to blend an organic solvent in addition to the above components in order to obtain a viscosity that facilitates coating on the support. Examples of organic solvents include toluene, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isopropyl alcohol.

The amount of the organic solvent used can be appropriately adjusted according to the coating method used when coating the support and the desired thickness of the primer layer.

Further, the coating solution for forming the primer layer may contain known additives such as film-forming aids, leveling agents, thickeners, water repellents, antifoaming agents, antioxidants, etc., as necessary. You may add and use it.

The primer layer can be formed by applying a coating liquid containing the above-described components to part or all of the surface of the support, and removing the organic solvent contained in the coating liquid by heating or drying. .

The coating method is not particularly limited, and conventionally known coating methods can be applied. Examples thereof include gravure, coating, screen, roller, rotary, spray, and capillary methods. .

After applying the coating liquid to the surface of the support, the method for removing the organic solvent contained in the coating film is generally, for example, drying with a dryer to volatilize the organic solvent. The drying temperature may be set within a range in which the organic solvent used can be volatilized and the support is not adversely affected by heat deformation or the like.

The thickness of the primer layer may be appropriately adjusted depending on the use of the laminate of the present invention, but it is preferably within a range that further improves the adhesion between the support and the metal particle layer described later, and the thickness of the primer layer is 10 nm. It is preferably ˜1 μm, more preferably 10 nm to 500 nm. The thickness of the primer layer can be adjusted by the amount of the coating liquid applied to the support.

From the viewpoint of adhesion with the metal particle layer described later, the surface of the primer layer may be treated, if necessary, by a plasma discharge treatment method such as a corona discharge treatment method, a dry treatment method such as an ultraviolet treatment method, water or an acidic or alkaline chemical solution. The surface treatment may be performed by a wet treatment method using an organic solvent or the like.

<Metal particle layer>
The metal particle layer is provided on the primer layer described above, and is a layer provided for forming the metal plating layer described later. The metal particle layer is preferably a layer containing a composite of metal particles and an organic compound. In the present invention, the metal particle layer more preferably contains metal particles and a compound having a cationic group.

The metals that make up the metal particles include transition metals and their compounds, and among these, ionic transition metals are preferred. Examples of ionic transition metals include copper, silver, gold, nickel, palladium, platinum, cobalt, etc. From the viewpoint of formability of the metal plating layer described later, silver is preferable. In the present invention, the term "metal particles" refers to particulate or fibrous particles made of the metals described above.

When using particulate metal, the average particle diameter is preferably 1 to 100 nm, more preferably 1 to 50 nm, from the viewpoint of further reducing the resistance value. In addition, in this specification, the average particle diameter means the volume average value (D50) measured by the dynamic light scattering method after diluting the metal particles with a good dispersion solvent. Also when fibrous metal is used, the fiber diameter is preferably 5 to 100 nm, more preferably 5 to 50 nm, from the viewpoint of further reducing the resistance value. Also, the fiber length is preferably 0.1 to 100 μm, more preferably 0.1 to 30 μm.

A compound having a cationic group can be preferably used as the organic compound used in combination with the metal particles. The compound having a cationic group disperses the metal particles satisfactorily, and reacts with the functional groups contained in the components of the primer layer, such as the epoxy groups contained in the epoxy resin, to form the primer layer and the metal particle layer. It is preferable in that it has a function of further improving the adhesion of the interface. Also, the compound having a cationic group may be a surface-treated metal particle contained in the metal particle layer.

As the compound having a cationic group, a compound having a basic nitrogen atom-containing group can be preferably used. For example, polyalkyleneimine such as polyethyleneimine and polypropyleneimine, a compound obtained by adding polyoxyalkylene to polyalkyleneimine, and the like are used. can do. A compound in which polyoxyalkylene is added to polyalkyleneimine is preferable because it can improve the water dispersion stability of metal particles.

As the polyoxyalkylene, for example, a random structure or block structure such as polyoxyethylene and poly(oxyethylene-oxypropylene) can be used. As the polyoxyalkylene, it is preferable to use one having an oxyethylene unit from the viewpoint of the water dispersion stability of the metal particles. It is preferred to use the one with

As a compound in which polyoxyalkylene is added to polyalkyleneimine, for example, a compound having a structure composed of polyethyleneimine and a polyoxyalkylene structure such as a polyethylene oxide structure can be used.

The polyethyleneimine and the polyoxyalkylene may be linearly bonded, or may be a main chain composed of polyethyleneimine and a side chain grafted with the polyoxyalkylene.

Specific examples of the compound in which polyoxyalkylene is added to polyalkyleneimine include a copolymer of polyethyleneimine and polyoxyethylene, a part of the imino groups present in the main chain, and ethylene oxide. A compound or the like obtained by the reaction can be used. They preferably have a block structure.

As the compound in which polyoxyalkylene is added to polyalkyleneimine, those obtained by reacting the amino group of polyalkyleneimine, the hydroxyl group of polyoxyethylene glycol, and the epoxy group of epoxy resin are used. You can also

As the polyalkyleneimine, commercially available products may be used. 1000 (above, Nippon Shokubai Co., Ltd.) can be used.

The metal particle layer may contain an epoxy resin in addition to the metal particles described above. As the epoxy resin, the same one as described in the primer layer can be used. However, when a compound having a basic nitrogen atom-containing group is used as the compound having a cationic group, the epoxy resin Aliphatic epoxy resins are preferably used, and alicyclic epoxy resins are more preferably used, from the viewpoint of suppressing reaction with a compound having a basic nitrogen atom-containing group.

Examples of aliphatic epoxy resins include neopentyl glycol diglycidyl ether, dimethylolcyclohexanediglycidyl ether, 1,4-cyclohexanediglycidyl ether, 1,3-cyclohexanediglycidyl ether, 1,2-cyclohexanediglycidyl ether, Acyclic fatty acids such as dimethylol dicyclopentadiene diglycidyl ether, hexahydrophthalic acid diglycidyl ester, hexahydroterephthalic acid diglycidyl ester, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether group epoxy resins, 3′,4′-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, ε-caprolactone-modified 3′,4′-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, limonene dioxide, Alicyclic epoxy resins such as dicyclopentadiene dioxide and hydrogenated bisphenol A type diglycidyl ether can be mentioned. These aliphatic epoxy resins may be used singly or in combination of two or more.

In the present invention, alicyclic epoxy resins are preferred, particularly from the viewpoint of the suppression of reaction with compounds having basic nitrogen atom-containing groups in the metal particle layer-forming coating solution and the compatibility with solvents described later. , 3′,4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and ε-caprolactone-modified 3′,4′-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate can be preferably used.

Commercially available epoxy resins may be used, for example, ADEKA RESIN EP-4080S, EP-4085S, EP-4088S (manufactured by ADEKA Corporation), Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085, Celoxide 8010, EHPE 3150, EPOLEAD PB 3600, EPOLEAD PB 4700 (manufactured by Daicel Corporation), Denacol EX-121, EX-211, EX-212, EX-212L, EX-214, Same EX-214L, Same as EX-216, Same as EX-216L, Same as EX-252, Same as EX-252L, Same as EX-321, Same as EX-321L, Same as EX-830, Same as EX-830L, Same as EX-850, Showfree EX-850L (manufactured by Nagase ChemteX Corporation), Showfree CDMDG, Showfree PETG (manufactured by Showa Denko KK), and the like.

The metal particle layer is formed by dissolving or dispersing the above components in an appropriate solvent to prepare a coating solution, coating the primer layer to form a coating film, and drying the coating film to remove the solvent. can be formed.

Solvents used in the coating solution for forming the metal particle layer include aqueous media such as distilled water, ion-exchanged water, pure water, and ultrapure water, as well as organic solvents such as alcohols, ethers, esters, and ketones. can do.

Examples of alcohols include methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, sec-butanol, tert-butanol, heptanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol. , pentadecanol, stearyl alcohol, allyl alcohol, cyclohexanol, terpineol, terpineol, dihydroterpineol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, Tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol Monobutyl ether and the like can be used.

The coating liquid can be used in combination with ketone solvents such as acetone, cyclohexanone, and methyl ethyl ketone to adjust physical properties. In addition, ester solvents such as ethyl acetate, butyl acetate, 3-methoxybutyl acetate, 3-methoxy-3-methyl-butyl acetate, etc., hydrocarbon solvents such as toluene, especially hydrocarbon solvents having 8 or more carbon atoms can be used. can be done.

Hydrocarbon solvents having 8 or more carbon atoms include nonpolar solvents such as octane, nonane, decane, dodecane, tridecane, tetradecane, cyclooctane, xylene, mesitylene, ethylbenzene, dodecylbenzene, tetralin, and trimethylbenzenecyclohexane. can also be used in combination depending on the Furthermore, mixed solvents such as mineral spirit and solvent naphtha can be used together.

Other solvents include, for example, 2-ethyl 1,3-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,4-butanediol, 2,3-butanediol, glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl Ether acetate, diethylene glycol monobutyl ether acetate and the like can be used.

The coating solution for forming the metal particle layer may contain surfactants, antifoaming agents, rheology modifiers, and the like as necessary from the viewpoint of improving the wettability and the like when applied to the primer layer. good.

The content of the metal particles contained in the coating solution for forming the metal particle layer is preferably 1 to 90% by mass, more preferably 5 to 60% by mass, more preferably 10% by mass, based on the total coating solution. More preferably, it is up to 40% by mass. Moreover, the content of the compound having a cationic group is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, relative to the entire coating liquid. In addition, when the metal particle layer is formed by coating and drying the coating liquid (that is, when the solvent is removed), the epoxy resin is preferably contained in the metal particle layer in an amount of 0.01 to 10% by mass. , more preferably 0.05 to 5% by mass.

The metal particle layer may be a layer provided on the entire surface of the primer layer, or may be a layer provided on part of the surface of the primer layer. In the case of forming the metal particle layer on a part of the surface of the primer layer, specifically, a fine line-shaped layer formed by drawing lines on the surface of the primer layer can be mentioned. The fine line-shaped layer is suitable when the laminate according to the present invention is used for a printed wiring board or the like. In this case, the width (line width) of the fine line-shaped layer (pattern) is generally about 0.01 to 200 μm, preferably about 0.01 to 150 μm.

The metal particle layer preferably has a thickness of 0.01 to 100 μm in order to form a conductive pattern with low resistance and excellent conductivity. Further, when the metal particle layer is in the form of thin wires, its thickness (height) is preferably in the range of 0.05 to 50 μm. The thickness of the metal particle layer can be adjusted by the amount of the coating liquid applied to the primer layer.

Examples of methods for applying the metal particle layer-forming coating solution to the primer layer include reverse printing such as letterpress reverse printing, inkjet printing, screen printing, offset printing, gravure printing, and spin coating. , a spray coating method, a bar coating method, a die coating method, a slit coating method, a roll coating method, a dip coating method, and the like. In the case of applying (printing) thin lines of approximately 0.01 to 100 μm, which is required when realizing high density electronic circuits, it is preferable to adopt an inkjet printing method.

<Metal plating layer>
The metal plating layer constituting the laminate of the present invention has a reliability that can maintain good conductivity without causing disconnection or the like for a long period of time, for example, when the laminate is used for a printed wiring board, an electromagnetic wave shield, or the like. This layer is provided for the purpose of forming a wiring pattern with a high density.

The metal plating layer is a layer formed on the metal particle layer described above, and the method of forming it is preferably a method of forming by plating. Examples of the plating treatment include wet plating methods such as electroplating and electroless plating, which can easily form a metal plating layer. Also, two or more of these plating methods may be combined. For example, after performing electroless plating, electroplating may be performed to form a metal plating layer.

In the electroless plating method, for example, by bringing an electroless plating solution into contact with the metal that constitutes the metal particle layer, a metal such as copper contained in the electroless plating solution is deposited to form an electroless plating layer consisting of a metal coating. is a method of forming Examples of electroless plating solutions include those containing metals such as copper, silver, gold, nickel, chromium, cobalt and tin, reducing agents, and solvents such as aqueous media and organic solvents.

Examples of reducing agents include dimethylaminoborane, hypophosphorous acid, sodium hypophosphite, dimethylamine borane, hydrazine, formaldehyde, sodium borohydride, and phenol.

As the electroless plating solution, monocarboxylic acids such as acetic acid and formic acid; dicarboxylic acid compounds such as malonic acid, succinic acid, adipic acid, maleic acid and fumaric acid; malic acid, lactic acid, glycolic acid and gluconate hydroxycarboxylic acid compounds such as acid and citric acid; amino acid compounds such as glycine, alanine, iminodiacetic acid, arginine, aspartic acid, and glutamic acid; Organic acids such as carboxylic acid compounds, soluble salts of these organic acids (sodium salts, potassium salts, ammonium salts, etc.), complexing agents such as amine compounds such as ethylenediamine, diethylenetriamine, and triethylenetetramine are used. be able to.

In the electrolytic plating method, for example, the metal forming the metal particle layer or the surface of the electroless plated layer (coating) formed by the electroless treatment is energized while the electrolytic plating solution is in contact with the electroplating. In this method, a metal such as copper contained in a liquid is deposited on the surface of the metal particles constituting the metal particle layer placed on the cathode or on the surface of the electroless plated layer formed by electroless treatment to form an electrolytic plated layer. .

Examples of electrolytic plating solutions include those containing sulfides of metals such as copper, nickel, chromium, cobalt, and tin, sulfuric acid, and an aqueous medium. Specific examples include those containing copper sulfate, sulfuric acid, and an aqueous medium.

As for the method of forming the metal plating layer, the method of electroplating after electroless plating is preferable because it is easy to control the thickness of the metal plating layer to a desired thickness from a thin film to a thick film.

The film thickness of the metal plating layer is preferably 1 to 50 μm. The film thickness of the metal plating layer can be adjusted by controlling the treatment time, current density, amount of plating additive used, etc. in the plating process for forming the metal plating layer.

<Application of laminate>
In the laminate according to the present invention, the metal plating layer formed on the surface does not peel off under normal conditions, and even when placed at a high temperature of 150 ° C. for a long time, the adhesion of the metal plating layer is maintained. maintained. Therefore, formation of circuit forming substrates used for electronic circuits, integrated circuits, etc., formation of peripheral wiring constituting organic solar cells, electronic book terminals, organic EL, organic transistors, flexible printed circuit boards, RFID, etc., plasma display It can be suitably used for applications in which durability is particularly required, such as wiring for electromagnetic shielding. In particular, the conductive pattern subjected to the plating treatment can form a highly reliable wiring pattern that can maintain good conductivity without causing disconnection or the like for a long period of time. It can be used for electronic equipment applications such as FPC) and electromagnetic wave shielding.

As an embodiment of the present invention, a laminate in which a primer layer, a metal particle layer and a metal plating layer are sequentially provided on one surface of a support has been described as an example. A layered product may also be formed in which a primer layer, a metal particle layer and a metal plating layer are sequentially provided on the opposite side of the body.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

<Preparation of phenoxy resin>
Three types of phenoxy resins (P-1) to (P-3) were synthesized in the following manner.
[Synthesis Example 1: Phenoxy Resin (P-1)]
100 mass of bisphenol A type epoxy resin (Epiclon EXA-850CRP manufactured by DIC Corporation, solid content 100%, epoxy equivalent 173 g/eq) was placed in a reactor equipped with a stirrer, thermometer, nitrogen blowing tube, and cooling tube. 65 parts by mass of bisphenol A (the ratio of the number of moles of epoxy groups (E1) to the number of moles of phenolic hydroxyl groups (F1) (E1/F1) = 1.01), 15 parts of cyclohexanone as a reaction solvent, nitrogen The temperature was raised to 100° C. under the atmosphere. Then, after adding 0.1 part of methyltriphenylphosphonium bromide as a catalyst, the internal temperature was raised to 140°C. As the reaction progressed, the viscosity of the reaction solution began to increase. Therefore, 72 parts of cyclohexanone was appropriately added in several portions to carry out the reaction while keeping the torque of the stirrer constant. The reaction temperature was 140 to 145° C. when the non-volatile content was 80% or more, and thereafter the reaction temperature was reflux temperature. A sample was taken during the reaction and the average molecular weight was measured by GPC. The reaction was continued until the weight average molecular weight reached 20,000. After confirming the above molecular weight, the reaction was terminated. Next, cyclohexanone was added and stirred to obtain a phenoxy resin (P-1) having a solid content of 15% by mass.

[Synthesis Example 2: Phenoxy resin (P-2)]
100 mass of bisphenol A type epoxy resin (Epiclon EXA-850CRP manufactured by DIC Corporation, solid content 100%, epoxy equivalent 173 g/eq) was placed in a reactor equipped with a stirrer, thermometer, nitrogen blowing tube, and cooling tube. 65 parts by mass of bisphenol A (the ratio of the number of moles of epoxy groups (E1) to the number of moles of phenolic hydroxyl groups (F1) (E1/F1) = 1.01), 15 parts of cyclohexanone as a reaction solvent, nitrogen The temperature was raised to 100° C. under the atmosphere. Then, after adding 0.1 part of methyltriphenylphosphonium bromide as a catalyst, the internal temperature was raised to 140°C. As the reaction progressed, the viscosity of the reaction solution began to increase. Therefore, 72 parts of cyclohexanone was appropriately added in several portions to carry out the reaction while keeping the torque of the stirrer constant. The reaction temperature was 140 to 145° C. when the non-volatile content was 80% or more, and thereafter the reaction temperature was reflux temperature. A sample was taken during the reaction and the average molecular weight was measured by GPC. The reaction was continued until the weight average molecular weight reached 45,000. After confirming the above molecular weight, the reaction was terminated. Next, cyclohexanone was added and stirred to obtain a phenoxy resin (P-2) having a solid content of 15% by mass.

[Synthesis Example 3: Phenoxy Resin (P-3)]
100 mass of bisphenol A type epoxy resin (Epiclon EXA-850CRP manufactured by DIC Corporation, solid content 100%, epoxy equivalent 173 g/eq) was placed in a reactor equipped with a stirrer, thermometer, nitrogen blowing tube, and cooling tube. 65 parts by mass of bisphenol A (the ratio of the number of moles of epoxy groups (E1) to the number of moles of phenolic hydroxyl groups (F1) (E1/F1) = 1.01), 15 parts of cyclohexanone as a reaction solvent, nitrogen The temperature was raised to 100° C. under the atmosphere. Then, after adding 0.1 part of methyltriphenylphosphonium bromide as a catalyst, the internal temperature was raised to 140°C. As the reaction progressed, the viscosity of the reaction solution began to increase. Therefore, 72 parts of cyclohexanone was appropriately added in several portions to carry out the reaction while keeping the torque of the stirrer constant. The reaction temperature was 140 to 145° C. when the non-volatile content was 80% or more, and thereafter the reaction temperature was reflux temperature. A sample was taken during the reaction and the average molecular weight was measured by GPC. The reaction was continued until the weight average molecular weight reached 100,000. After confirming the above molecular weight, the reaction was terminated. Next, cyclohexanone was added and stirred to obtain a phenoxy resin (P-3) having a solid content of 15% by mass.

[Synthesis Example 4: Modified Novolac Resin C]
750 parts by weight of phenol, 75 parts by weight of melamine, 346 parts by weight of 41.5% by weight formalin, and 1.5 parts by weight of triethylamine were added to a flask equipped with a thermometer, condenser, fractionating tube, and stirrer. The temperature was raised to 100°C with caution. After reacting at 100° C. for 2 hours under reflux, the temperature was raised to 180° C. over 2 hours while removing water under normal pressure. Next, unreacted phenol was removed under reduced pressure to obtain an aminotriazine-modified novolak resin as novolak resin C. The hydroxyl equivalent weight was 120 g/equivalent.

<Preparation of coating solution for forming primer layer>
[Preparation Example 1: Preparation of Primer Layer Forming Coating Solution (1)]
The phenoxy resin (P-1) obtained in Synthesis Example 1 was diluted with cyclohexanone so that the nonvolatile content was 2% by mass, and mixed uniformly to obtain a primer layer forming coating solution (1). got

[Preparation Example 2: Preparation of primer layer-forming coating solution (2)]
The phenoxy resin (P-2) obtained in Synthesis Example 2 was diluted with cyclohexanone so that the nonvolatile content was 2% by mass, and mixed uniformly to obtain a primer layer forming coating solution (2). got

[Preparation Example 3: Preparation of primer layer-forming coating liquid (3)]
The phenoxy resin (P-3) obtained in Synthesis Example 3 was diluted with cyclohexanone so that the nonvolatile content was 2% by mass, and mixed uniformly to obtain a primer layer forming coating solution (3). got

[Preparation Example 4: Preparation of primer layer-forming coating solution (4)]
533 parts by mass of the phenoxy resin (P-1) obtained in Synthesis Example 1, and 17 parts by mass of epoxy resin A (“EPICLON 850-S” manufactured by DIC Corporation; bisphenol A type epoxy resin, epoxy group equivalent: 188 g/equivalent). , Novolak resin B (DIC Corporation "PHENOLITE TD-2131", hydroxyl equivalent 104 g / equivalent) 3 parts by mass, and Shikoku Kasei Co., Ltd. as a curing catalyst 1 "TBZ" 0.5 parts by mass were mixed, and cyclohexanone was mixed. was used to dilute the non-volatile matter to 2% by mass, and mixed uniformly to obtain a primer layer-forming coating liquid (4).

[Preparation Example 5: Preparation of primer layer-forming coating liquid (5)]
267 parts by mass of the phenoxy resin (P-2) obtained in Synthesis Example 2, and 60 parts by mass of epoxy resin A ("EPICLON 850-S" manufactured by DIC Corporation; bisphenol A type epoxy resin, epoxy group equivalent: 188 g/equivalent). , And, as a curing catalyst 1, 0.5 parts by mass of “TBZ” manufactured by Shikoku Kasei Co., Ltd. is mixed, diluted with cyclohexanone so that the nonvolatile content is 2% by mass, and mixed uniformly to form a primer layer. A forming coating liquid (5) was obtained.

[Preparation Example 6: Preparation of primer layer-forming coating solution (6)]
133 parts by mass of the phenoxy resin (P-2) obtained in Synthesis Example 1, and 70 parts by mass of epoxy resin A ("EPICLON 850-S" manufactured by DIC Corporation; bisphenol A type epoxy resin, epoxy group equivalent: 188 g/equivalent). , 10 parts by mass of the modified novolak resin C obtained in Synthesis Example 4, and 5 parts by mass of "2E4MZ" manufactured by Shikoku Kasei Co., Ltd. as a curing catalyst 2, are mixed, and cyclohexanone is used so that the nonvolatile content is 2% by mass. By diluting and mixing uniformly, a primer layer-forming coating liquid (6) was obtained.

[Preparation Example 7: Preparation of primer layer-forming coating liquid (7)]
67 parts by mass of the phenoxy resin (P-3) obtained in Synthesis Example 3, and 76 parts by mass of epoxy resin A ("EPICLON 850-S" manufactured by DIC Corporation; bisphenol A type epoxy resin, epoxy group equivalent: 188 g/equivalent). , Novolak resin B (DIC Corporation "PHENOLITE TD-2131", hydroxyl equivalent 104 g / equivalent) 14 parts by weight, and Shikoku Kasei Co., Ltd. as curing catalyst 1 "TBZ" 0.5 parts by weight were mixed, and cyclohexanone was mixed. was used to dilute the non-volatile matter to 2% by mass, and mixed uniformly to obtain a primer layer-forming coating liquid (7).

[Preparation Example 8: Preparation of Primer Layer Forming Coating Solution (8)]
After mixing 65 parts by mass of modified novolak resin C obtained in Synthesis Example 4 with 35 parts by mass of epoxy resin A (“EPICLON 850-S” manufactured by DIC Corporation; bisphenol A type epoxy resin, epoxy group equivalent weight: 188 g/equivalent), The mixed resin solution of the aminotriazine-modified novolac resin and the epoxy resin was obtained by diluting with methyl ethyl ketone so that the non-volatile content was 2% by mass and mixing uniformly.

<Preparation of coating solution for forming metal particle layer>
Under a nitrogen atmosphere, chloroform (30 ml) containing 9.6 parts by weight of p-toluenesulfonyl chloride was added to a mixture containing 20 parts by weight of methoxypolyethylene glycol (number average molecular weight of 2,000), 8.0 parts by weight of pyridine and 20 ml of chloroform. The solution was added dropwise for 30 minutes with ice-cooling and stirring, then stirred at a bath temperature of 40° C. for 4 hours, and mixed with 50 ml of chloroform.
Next, the obtained product is washed with 100 ml of 5% by mass hydrochloric acid aqueous solution, then with 100 ml of saturated sodium bicarbonate aqueous solution, then with 100 ml of saturated saline solution, dried with anhydrous magnesium sulfate, and filtered. , concentrated under reduced pressure, washed several times with hexane, filtered and dried at 80° C. under reduced pressure to obtain methoxypolyethylene glycol having a p-toluenesulfonyloxy group.

5.39 parts by mass of methoxypolyethylene glycol having a p-toluenesulfonyloxy group, 20 parts by mass of polyethyleneimine (manufactured by Aldrich, molecular weight 25,000), 0.07 parts by mass of potassium carbonate and 100 ml of N,N-dimethylacetamide are mixed. and stirred at 100° C. for 6 hours under a nitrogen atmosphere.
Next, 300 ml of a mixed solution of ethyl acetate and hexane (volume ratio of ethyl acetate/hexane=1/2) was added, and the mixture was vigorously stirred at room temperature, and the solid product was filtered. The solid was washed with 100 ml of a mixed solution of ethyl acetate and hexane (volume ratio of ethyl acetate/hexane=1/2) and then dried under reduced pressure to obtain a compound in which polyethyleneimine was bound to polyethylene glycol. rice field.

138.8 parts by mass of an aqueous solution containing 0.592 parts by mass of a compound in which polyethylene glycol is bound to polyethyleneimine obtained was mixed with 10 parts by mass of silver oxide, and the mixture was stirred at 25°C for 30 minutes. Then, 46 parts by mass of dimethylethanolamine was gradually added while stirring, and the mixture was stirred at 25°C for 30 minutes. Subsequently, 15.2 parts by mass of a 10% by mass ascorbic acid aqueous solution was gradually added with stirring, and stirring was continued for 20 hours to obtain a silver dispersion.

A mixed solvent of 200 ml of isopropyl alcohol and 200 ml of hexane was added to the resulting silver dispersion, and after stirring for 2 minutes, centrifugal concentration was performed at 3000 rpm for 5 minutes. After removing the supernatant, a mixed solvent of 50 ml of isopropyl alcohol and 50 ml of hexane was added to the precipitate, stirred for 2 minutes, and concentrated by centrifugation at 3000 rpm for 5 minutes. After removing the supernatant, 20 parts by mass of water was added to the precipitate, and the mixture was stirred for 2 minutes to remove the organic solvent under reduced pressure. After further adding 10 parts by mass of water and stirring and dispersing, the dispersion was left in a freezer at -40°C for one day and night to freeze. The time treatment gave cationic silver particles consisting of flaky masses with a gray-green metallic luster.

The obtained powder of cationic silver particles is dispersed in a mixed solvent of 45 parts by mass of ethylene glycol and 55 parts by mass of deionized water to form a metal particle layer containing 5% by mass of cationic silver particles. A coating solution was prepared.

<Production of laminates (1) to (8)>
On the surface of a polyimide film (“Kapton 150EN-A” manufactured by Toray DuPont Co., Ltd.; thickness 38 μm), each primer layer forming coating solution (1) to (8) obtained above is applied to a desktop small coater ( Using a K printing prober (RK Print Coat Instrument Co., Ltd.), coating was performed so that the coating thickness after drying was 300 nm. Then, a primer layer was formed on the surface of the polyimide film by drying at 155° C. for 5 minutes using a hot air dryer.
Subsequently, the coating solution for forming a metal particle layer obtained above was applied to the surface of the primer layer using a bar coater so that the coating thickness after drying was 100 nm. A metal particle layer was then formed by drying at 140° C. for 5 minutes.

The metal particle layer formed as described above is set on the cathode side, the phosphorous copper is set on the anode side, and electrolytic plating is performed for 18 minutes at a current density of 2 A/dm ² using an electrolytic plating solution containing copper sulfate. A copper plating layer (film thickness: 8 μm) was formed on the metal particle layer. As an electrolytic plating solution, 70 g/L of copper sulfate, 200 g/L of sulfuric acid, 50 mg/L of chloride ion, and 5 ml/L of additive (Top Lucina SF-M, Okuno Chemical Industry Co., Ltd.) were used.
Thus, laminates (1) to (8) were obtained in which the support, the primer layer, the metal particle layer, and the metal plating layer were sequentially laminated. The number of the primer layer forming coating liquid corresponds to the number of the laminate, for example, the primer layer forming coating liquid (1) corresponds to the laminate (1).

<Adhesion evaluation (under normal conditions)>
For each laminate obtained above, the peel strength was measured using 4000Plus manufactured by Nordson DAGE in a room temperature environment. The lead width used for measurement was 5 mm, and the peel angle was 90°. In addition, the peel strength tends to show a higher value as the thickness of the metal plating layer increases. In this specification, the peel strength was measured based on the measurement value at a thickness of 8 μm of the metal plating layer.
Adhesion was evaluated according to the following criteria from the measured peel strength before heating.
A: The value of peel strength is 600 N/m or more.
B: The peel strength value is 450 N/m or more and less than 600 N/m.
C: The peel strength value is 250 N/m or more and less than 450 N/m.
D: The peel strength value is less than 250 N/m.
The evaluation results were as shown in Table 1 below.

<Adhesion evaluation (long-term heat resistance test)>
Each laminate obtained above was stored in a dryer set at 150° C. for 300 hours and heated. After heating, each laminate was cooled to room temperature, and the peel strength was measured in the same manner as above.
Using the measured peel strength values before and after heating, the retention rate before and after heating was calculated, and the degree of retention of heat resistance was evaluated according to the following criteria.
A: The retention rate is 80% or more.
B: The retention rate is 60% or more and less than 80%.
C: The retention rate is 30% or more and less than 60%.
D: The retention rate is less than 30%.
The evaluation results were as shown in Table 1 below.

As is clear from the adhesion evaluation results shown in Table 1, the laminates (laminates (1) to (7)) using a phenoxy resin having a specific molecular weight as the primer layer are all good at normal conditions. The peel strength is 450 N/m or more, and even after the long-term heat resistance test, it has a retention rate of 80% or more of the peel strength in the normal state. In other words, it can be seen that the adhesion evaluation is excellent both in the normal state and after the long-term heat resistance test.

On the other hand, in the laminate (laminate (8)) in which the phenoxy resin was not used as the primer layer, although the peel strength was high under normal conditions, the retention rate was only 8% after the long-term heat resistance test, indicating stable adhesion. have no gender. That is, it can be seen that the adhesion evaluation after the long-term heat resistance test is inferior to that of the examples.

Claims

A laminate comprising a support, a primer layer, a metal particle layer and a metal plating layer on the support in this order, wherein the primer layer is a phenoxy resin having a weight average molecular weight of 10,000 to 100,000. A laminate comprising:
The laminate according to claim 1, wherein the primer layer further contains an epoxy resin.
The laminate according to claim 2, wherein the primer layer contains the phenoxy resin and the epoxy resin in a mass ratio of 90:10 to 10:90.
The laminate according to claim 1, wherein the primer layer further contains a compound having an aminotriazine ring.
The laminate according to claim 4, wherein the compound having an aminotriazine ring is an aminotriazine-modified novolac resin.
The laminate according to claim 1, wherein the metal particle layer contains metal particles and a compound having a cationic group.
The laminate according to claim 6, wherein the compound having a cationic group is a compound having a basic nitrogen atom-containing group.
The laminate according to claim 1, wherein the support is made of a flexible resin material.
The laminate according to any one of claims 1 to 8, which is used in electronic equipment.
The laminate according to claim 9, wherein the electronic device is selected from printed wiring boards and electromagnetic wave shields.
An electronic device comprising the laminate according to any one of claims 1 to 8.