Electroless plating primer composition, laminate using the same, and method for producing the same

Abstract

To provide an electroless plating primer composition that has preferable adhesion strength and adhesion reliability with respect to an insulating substrate without etching.SOLUTION: An electroless plating primer composition includes a (meth) acrylic resin (A), an epoxy resin (B) and a polyaddition-type epoxy resin hardening agent (C). The (meth) acrylic resin (A) includes a reactive group that is reactive with the polyaddition-type epoxy resin hardening agent (C).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an electroless plating primer composition, a laminate using the same, and a method for producing the same.

Background Art

[0002] Techniques for forming a metal plating on an insulating substrate such as a resin substrate are used when producing conductive films such as electromagnetic wave shields, decorative plating for the purpose of imparting design, and electronic components such as integrated circuits and resistors. In particular, when producing a printed wiring board used in electronic devices or the like, a technique for forming a plating is used when forming a conductive wiring pattern on an insulating substrate.

[0003] At that time, in order to improve the adhesion between the insulating substrate and the plating layer, it has been studied to impart an anchor effect by performing etching (roughening) to form fine irregularities on the surface of the insulating substrate. However, this etching not only complicates the process, but also has a problem that transmission loss is likely to decrease due to the skin effect in high-frequency compatible devices such as those for 5G.

[0004] On the other hand, methods for adhering an insulating substrate and a plating without performing etching have been studied. For example, a method is known in which a base layer containing an electroless plating catalyst is formed on the surface of an insulating substrate and then a plating is formed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in high-frequency compatible devices for 5G and the like, a low-dielectric substrate is used as the insulating substrate. Since it is more difficult to obtain adhesion to plating for the low-dielectric substrate, it has been required to enhance the adhesive strength of plating more than ever.

[0007] In addition, in the manufacturing process of printed wiring boards, not only various heat histories are applied, but also it is required that the adhesiveness between the insulating substrate and the wiring layer can be maintained well (adhesion reliability) even when used for a long time in the operating environment (high temperature) of the manufactured printed wiring board.

[0008] The present invention has been made in view of such circumstances, and an electroless plating primer composition having good adhesive strength and adhesion reliability to an insulating substrate without performing etching, a laminate using the same, and a manufacturing method thereof are provided.

Means for Solving the Problems

[0009] The electroless plating primer composition of the present invention contains a (meth)acrylic resin (A), an epoxy resin (B), and a polyaddition-type epoxy resin curing agent (C), and the (meth)acrylic resin (A) has a reactive group that reacts with the polyaddition-type epoxy resin curing agent (C).

[0010] The laminate of the present invention includes an insulating substrate, a primer layer containing a cured product of the electroless plating primer composition of the present invention disposed on the insulating substrate, and a metal plating layer disposed on the primer layer.

[0011] The manufacturing method of the laminate of the present invention includes a step of applying the electroless plating primer composition of the present invention to the surface of an insulating substrate, followed by drying and curing to form a primer layer, and a step of forming a metal plating layer by electroless plating on the primer layer.

Effects of the Invention

[0012] According to the present invention, it is possible to provide an electroless plating primer composition having good adhesive strength and adhesive reliability with respect to an insulating substrate without performing etching, a laminate using the same, and a method for producing the same.

Embodiment for Carrying Out the Invention

[0013] The present inventors have found that a cured product of a primer composition containing an epoxy resin (B), a polyaddition-type epoxy resin curing agent (C), and further containing a (meth)acrylic resin (A) that reacts with the curing agent (C) as a base resin not only has excellent adhesive strength with a plating film, but also can maintain good adhesive strength even when used at a high temperature for a certain period of time (excellent adhesive reliability).

[0014] The reason is not clear, but it is presumed as follows. The (meth)acrylic resin (A) (preferably an elastomer) not only has appropriate flexibility, but also can react with the epoxy resin (B) via the polyaddition-type epoxy resin curing agent (C) to form a crosslinked structure. Specifically, while incorporating the structure of the polyaddition-type epoxy resin curing agent (C), the (meth)acrylic resin (A) and the epoxy resin (B) can form an appropriate crosslinked structure. As a result, the obtained cured product has OH groups generated by an addition polymerization reaction and exhibits appropriate polarity, so that not only is it easy to obtain adhesive strength with the substrate, but also it has appropriate flexibility and heat resistance, and thus it is considered that it not only has excellent initial adhesive strength but also can maintain good adhesive strength even when exposed at a high temperature for a certain period of time. Hereinafter, the present invention will be described in detail.

[0015] 1. Primer Composition The primer composition of the present invention contains a (meth)acrylic resin (A), an epoxy resin (B), and a polyaddition-type epoxy resin curing agent (C).

[0016] 1-1. (Meth)acrylic resin (A) (Meta)acrylic resin (A) has a group (reactive group) that reacts with the polyaddition-type epoxy resin curing agent (C), preferably an epoxy group. The (meta)acrylic resin (A) having such a reactive group can react with the epoxy resin (B) via the polyaddition-type epoxy resin curing agent (C), so that a suitable crosslinked structure is easily formed, and a cured product with a good balance of flexibility and heat resistance is easily obtained.

[0017] The (meta)acrylic resin (A) having an epoxy group is a polymer containing a structural unit derived from an epoxy group-containing unsaturated monomer (a1). The epoxy group-containing unsaturated monomer (a1) is preferably an epoxy group-containing (meta)acrylic acid ester. In the present invention, (meta)acrylic (acid) means acrylic (acid) or methacrylic (acid). Examples of the epoxy group-containing (meta)acrylic acid ester include glycidyl methacrylate.

[0018] The content of the structural unit derived from the epoxy group-containing unsaturated monomer (a1) is not particularly limited, but is preferably 0.5 to 5% by mass based on all the structural units constituting the (meta)acrylic resin (A). When the content of the structural unit derived from the epoxy group-containing unsaturated monomer (a1) is 0.5% by mass or more, a sufficient crosslinked structure is formed with the epoxy resin (B), and the heat resistance of the obtained cured product is easily enhanced. When it is 5% by mass or less, the flexibility is hardly impaired. From the same viewpoint, the content of the structural unit derived from the epoxy group-containing unsaturated monomer (a1) is more preferably 1 to 3% by mass based on all the structural units constituting the (meta)acrylic resin (A).

[0019] The (meta)acrylic resin (A) having an epoxy group preferably further contains a structural unit derived from an unsaturated monomer (a2) having a glass transition temperature (Tg) of the homopolymer of 90°C or higher. The unsaturated monomer (a2) having a Tg of the homopolymer of 90°C or higher can impart appropriate heat resistance to the (meta)acrylic resin (A) and enhance the adhesion reliability.

[0020] The unsaturated monomer (a2) with a Tg of the homopolymer of 90°C or higher is preferably an unsaturated monomer with a Tg of the homopolymer of 100 - 110°C. Examples of the unsaturated monomer (a2) with a Tg of the homopolymer of 90°C or higher include alkyl methacrylates such as methyl methacrylate (Tg 105°C), t-butyl methacrylate (Tg 107°C); unsaturated nitriles such as acrylonitrile (Tg 105°C), methacrylonitrile (Tg 115°C); aromatic monomers such as styrene (Tg 100°C), phenyl methacrylate (Tg 105°C), isobornyl acrylate (97°C), etc., and preferably acrylonitrile or methyl methacrylate. The values in parentheses indicate the Tg of the homopolymer.

[0021] The Tg of the homopolymer of the unsaturated monomer (a2) can be, for example, the Tg measured by DSC etc. after preparing the homopolymer after specifying the structure (type) of the monomer by NMR analysis etc., or the literature value (for example, polymerdatabase.com) of the Tg of the homopolymer of the specified monomer.

[0022] The content of the structural unit derived from the unsaturated monomer (a2) with a Tg of the homopolymer of 90°C or higher is preferably 9.5 - 30 mass% based on all the structural units constituting the (meth)acrylic resin (A). When the content of the structural unit derived from the unsaturated monomer (a2) is 9.5 mass% or more, it is easy to enhance the heat resistance of the obtained (meth)acrylic resin (A) and the adhesion reliability of the cured product of the primer composition. When it is 30 mass% or less, the flexibility is hardly impaired and the initial adhesiveness is hardly impaired. From the same viewpoint, the content of the structural unit derived from the unsaturated monomer (a2) with a Tg of the homopolymer of 90°C or higher is more preferably 14 - 25 mass% based on all the structural units constituting the (meth)acrylic resin (A).

[0023] In addition, the (meth)acrylic resin (A) having an epoxy group may further contain structural units derived from other monomers. Examples of other monomers include acrylic esters having 1 to 10 carbon atoms such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate; methacrylic esters having 2 to 10 carbon atoms other than the above such as ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate; vinyl esters such as vinyl acetate; unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid; (meth)acrylamides such as (meth)acrylamide, methyl (meth)acrylamide, ethyl (meth)acrylamide, propyl (meth)acrylamide, dimethyl (meth)acrylamide (DMAA). Among them, from the viewpoint of exhibiting appropriate flexibility and being more likely to further enhance the adhesive strength, the (meth)acrylic resin (A) preferably further contains structural units derived from acrylic esters (a3) having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms.

[0024] The content of the structural units derived from acrylic esters (a3) having 1 to 10 carbon atoms is preferably 65 to 90% by mass based on all the structural units constituting the (meth)acrylic resin (A). When the content of the structural units derived from the acrylic esters (a3) is within the above range, the (meth)acrylic resin (A) has high flexibility, so the adhesive strength and adhesive reliability of the resulting cured product can be further enhanced. From the same viewpoint, the content of the structural units derived from acrylic esters (a3) having 1 to 10 carbon atoms is more preferably 70 to 85% by mass based on all the structural units constituting the (meth)acrylic resin (A).

[0025] Examples of commercially available products of the (meth)acrylic resin (A) include "SG-80H", "SG-80H-3", "SG-P3" (epoxy group-containing acrylic ester copolymer).

[0026] (Meta)acrylic resin (A) preferably has appropriate flexibility and is more preferably an elastomer from the viewpoint of enhancing the adhesive strength. Specifically, the Tg of (meta)acrylic resin (A) is preferably 25°C or lower, and more preferably 0 to 15°C.

[0027] The glass transition temperature (Tg) of (meta)acrylic resin (A) can be measured by thermomechanical analysis (TMA). Specifically, for a sample of (meta)acrylic resin (A), using a thermomechanical analysis (TMA) apparatus, under a nitrogen atmosphere, in a tensile mode (49 mN), at a heating rate of 5°C / min, measurement is carried out to obtain a TMA curve. For the inflection point of the TMA curve caused by the glass transition, by extrapolating the curves before and after it, the value of the glass transition temperature (Tg) of (meta)acrylic resin (A) can be obtained.

[0028] The weight average molecular weight (Mw) of (meta)acrylic resin (A) is not particularly limited, but can be, for example, 100,000 to 500,000. When the Mw of the (meta)acrylic resin is within the above range, the film strength of the resulting cured product can be increased without impairing the coatability of the primer composition. The Mw of (meta)acrylic resin (A) is the weight average molecular weight in terms of standard polystyrene, measured by gel permeation chromatography (GPC).

[0029] The epoxy equivalent of (meta)acrylic resin (A) is not particularly limited, but can be, for example, 1800 to 18000 g / eq. When the epoxy equivalent of (meta)acrylic resin (A) is within the above range, the number of crosslinking points with the epoxy resin (B) can be appropriately increased, so that the heat resistance of the resulting cured product can be further enhanced. Thereby, the adhesive strength and adhesive reliability can be further enhanced. The epoxy equivalent can be measured in accordance with JIS K7236.

[0030] The content of the (meth)acrylic resin (A) can be 50 to 80% by mass based on the total of the (meth)acrylic resin (A), the epoxy resin (B), and the polyaddition-type epoxy resin curing agent (C). When the content of the (meth)acrylic resin (A) is 50% by mass or more, it is easy to enhance the adhesion reliability of the cured product of the primer composition, and when it is 80% by mass or less, the adhesive strength is less likely to be impaired. From the same viewpoint, the content of the (meth)acrylic resin (A) is more preferably 55 to 77% by mass based on the total of the (meth)acrylic resin (A), the epoxy resin (B), and the polyaddition-type epoxy resin curing agent (C).

[0031] 1-2. Epoxy resin (B) The type of the epoxy resin (B) is not particularly limited, but from the viewpoint of obtaining a cured product with high heat resistance and high adhesion reliability, it is preferably an epoxy resin having an aromatic structure (aromatic epoxy resin).

[0032] Examples of aromatic epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, bixylenol type epoxy resin, tris-phenol type epoxy resin, naphthol novolak type epoxy resin, phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin having an aromatic structure, glycidyl ester type epoxy resin having an aromatic structure, cresol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin having an aromatic structure, epoxy resin having a butadiene structure with an aromatic structure, alicyclic epoxy resin having an aromatic structure, heterocyclic epoxy resin, spiro ring-containing epoxy resin having an aromatic structure, cyclohexanedimethanol type epoxy resin having an aromatic structure, naphthylene ether type epoxy resin, trimethylol type epoxy resin having an aromatic structure, tetraphenylethane type epoxy resin, aminophenol type epoxy resin, etc. These may be epoxy resins that are liquid at 20°C (liquid epoxy resins) or epoxy resins that are solid at 20°C (solid epoxy resins). Further, the epoxy resin (B) may be used alone or in combination of two or more kinds.

[0033] Also, from the viewpoint of obtaining a cured product with high heat resistance and high adhesion reliability, the aromatic epoxy resin preferably contains an aromatic epoxy resin having two or more epoxy groups in one molecule, and more preferably contains an aromatic epoxy resin having three or more epoxy groups in one molecule.

[0034] Examples of the aromatic epoxy resin having three or more epoxy groups in the molecule include naphthalene type tetrafunctional epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, trisphenol type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, tetraphenylethane type epoxy resin, and the like. Examples of commercially available products include "jER1031S" (tetraphenylethane type epoxy resin), "157S70" (bisphenol novolak type epoxy resin), and the like. These may be used alone or in combination of two or more.

[0035] The epoxy equivalent of the epoxy resin (B) is not particularly limited, but is preferably, for example, 140 to 300 g / eq. If the epoxy equivalent is within the above range, sufficient curing is possible without impairing the coatability of the primer composition. The epoxy equivalent can be measured by the same method as described above.

[0036] The weight average molecular weight (Mw) of the epoxy resin (B) is not particularly limited, but is preferably 1000 or less. The Mw of the epoxy resin (B) is the weight average molecular weight in terms of standard polystyrene measured by GPC in the same manner as described above.

[0037] The content of the epoxy resin (B) can be 3 to 25% by mass based on the total of the (meth)acrylic resin (A), the epoxy resin (B) and the polyaddition type epoxy resin curing agent (C). When the content of the epoxy resin (B) is 3% by mass or more, it is easy to increase the initial adhesive strength of the cured product of the primer composition, and when it is 25% by mass or less, the adhesive reliability is hardly impaired. From the same viewpoint, the content of the epoxy resin (B) is more preferably 5 to 24% by mass based on the total of the (meth)acrylic resin (A), the epoxy resin (B) and the polyaddition type epoxy resin curing agent (C).

[0038] In the primer composition of the present invention, the mass ratio MA / MB of the content MA of the (meth)acrylic resin (A) to the content MB of the epoxy resin (B) is not particularly limited, but from the viewpoint of the balance between the initial adhesion strength and adhesion reliability, it is preferably 100 / 5 to 100 / 50, and more preferably 100 / 7 to 100 / 40. When the mass ratio MA / MB is equal to or more than a certain value, it is easier to further improve the adhesion reliability, and when it is equal to or less than a certain value, the initial adhesiveness is less likely to be impaired.

[0039] 1-3. Polyaddition-type epoxy resin curing agent (C) The polyaddition-type epoxy resin curing agent (C) may have a group that undergoes an addition reaction with the reactive group of the (meth)acrylic resin (A) and the epoxy group of the epoxy resin (B). However, from the viewpoint of obtaining a primer composition with good adhesion reliability, it is preferably a phenolic curing agent or an acid anhydride curing agent.

[0040] The phenolic curing agent may be a novolak-type phenolic curing agent or a resol-type phenolic curing agent. Examples of novolak-type phenolic curing agents include phenol novolaks such as 2,6-bis[(2-hydroxyphenyl)methyl]-phenol, and cresol novolaks such as o-cresol novolak, m-cresol novolak, and p-cresol novolak. Examples of resol-type phenolic curing agents include straight type and alkylphenol type.

[0041] Examples of acid anhydride curing agents include didecenyl succinic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhimic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, ethylene glycol bistrimellitate, glycerol tristrimellitate, etc. Examples of commercially available products include Rickacid TBN-100 (manufactured by Shin Nippon Rika Co., Ltd.).

[0042] Among them, from the viewpoint of further enhancing the heat resistance of the cured product of the primer composition, a phenolic curing agent is preferable, and a resol type phenolic curing agent is more preferable. The polyaddition type epoxy resin curing agent (C) may be used alone or in combination of two or more.

[0043] The content of the polyaddition type epoxy resin curing agent (C) can be 5 to 35% by mass based on the total of the (meth)acrylic resin (A), the epoxy resin (B) and the polyaddition type epoxy resin curing agent (C). When the content of the polyaddition type epoxy resin curing agent (C) is 5% by mass or more, the reaction between the (meth)acrylic resin (A) and the epoxy resin (B) or the reaction between the epoxy resins (B) can occur sufficiently, so that the adhesion reliability of the cured product can be easily enhanced. When it is 35% by mass or less, the coatability is hardly impaired. From the same viewpoint, the content of the polyaddition type epoxy resin curing agent (C) is more preferably 7 to 30% by mass based on the total of the (meth)acrylic resin (A), the epoxy resin (B) and the polyaddition type epoxy resin curing agent (C).

[0044] Also, the content of the polyaddition type epoxy resin curing agent (C) depends on the equivalent of the epoxy resin (B), and can be, for example, 50 to 328% by mass with respect to the epoxy resin (B).

[0045] 1-4. Other Components The primer composition of the present invention may further contain other components other than the above as necessary. Examples of other components include a curing catalyst, a palladium catalyst, a solvent and the like.

[0046] (Curing Catalyst) The type of the curing catalyst is not particularly limited, and is appropriately selected according to the types of the (meth)acrylic resin (A) and the epoxy resin (B) having an epoxy group. Examples of the curing catalyst include an imidazole compound and an amine compound.

[0047] Examples of imidazole compounds include 2-ethyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, etc. Examples of amine compounds include trialkylamines such as triethylamine and tributylamine, and tris(dimethylaminomethyl)phenol, etc.

[0048] The content of the curing catalyst can be 0.7 to 1.1% by mass based on the total of (meth)acrylic resin (A), epoxy resin (B) and polyaddition-type epoxy resin curing agent (C). When the content of the curing catalyst is 0.7% by mass or more, the reaction between (meth)acrylic resin (A) and epoxy resin (B), or the reaction between epoxy resins (B) can occur sufficiently, so it is easy to enhance the adhesion reliability of the cured product. When it is 1.1% by mass or less, the coatability is hardly impaired.

[0049] (Palladium catalyst) The palladium catalyst, preferably palladium particles, can function as a nucleating agent for electroless plating. The palladium particles may be dispersed with a dispersant or the like.

[0050] The average particle diameter of the palladium particles is not particularly limited, but can be, for example, 2 to 10 nm. The average particle diameter of the palladium particles can be calculated by measuring the particle diameters of any 10 particles with a transmission electron microscope and taking their number average (as the number-based average diameter).

[0051] The content of the palladium catalyst can be 1 to 15% by mass based on the total of (meth)acrylic resin (A), epoxy resin (B) and polyaddition-type epoxy resin curing agent (C). When the content of the palladium catalyst is 1% by mass or more, it is easy to sufficiently enhance the adhesion to the electroless plating film of the obtained primer layer. When it is 15% by mass or less, the coatability and dispersion stability are hardly impaired.

[0052] (Solvent) The primer composition of the present invention may further contain a solvent (dispersion medium) if necessary. Such a solvent is preferably one capable of dispersing a palladium catalyst or its dispersion, and can be, for example, water or an aprotic polar solvent.

[0053] Examples of the aprotic polar solvent include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, and the like.

[0054] In addition, it may contain alcohols such as methanol and ethanol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monobutyl ether; aromatic carboxylic acid esters such as methyl benzoate, ethyl benzoate, and methyl salicylate; aromatic hydrocarbons such as toluene and xylene; glycol ether esters such as methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, methyl carbitol acetate, and butyl carbitol acetate; alkanol esters such as ethyl acetate and butyl acetate.

[0055] 1-5. Manufacturing method The primer composition of the present invention can be prepared by any method, and can be obtained, for example, by mixing the above components.

[0056] The palladium catalyst may be added as particles, or may be added in a state dispersed with a dispersant or the like (as a dispersion).

[0057] 2. Laminate The laminate of the present invention includes an insulating substrate, a primer layer containing a cured product of the primer composition of the present invention, and a metal plating layer.

[0058] (Insulating substrate) The type of the insulating substrate can be a resin substrate or an inorganic substrate such as ceramics or glass. Examples of materials constituting the resin substrate include polyester, (meth)acrylic resin, polycarbonate, polystyrene, polyvinyl chloride, polyamide, polyimide (such as MPI), polyetherimide, polyacetal, polyetheretherketone (PEEK), cyclic polyolefin (COC), polyolefin, polyphenylene sulfide (PPS), polysulfone, phenol resin, liquid crystal polymer (LCP), fluororesin, etc. Examples of ceramics constituting the inorganic substrate include alumina, etc.

[0059] Among them, when the laminate is a printed wiring board, particularly a printed wiring board used for high-frequency devices such as 5G, etc., the insulating substrate is more preferably a low dielectric constant insulating substrate (low dielectric substrate). Examples of materials of the low dielectric substrate include resins and glass with low dielectric constants such as polyimide (such as MPI), polyetheretherketone (PEEK), cyclic polyolefin (COC), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), fluororesin, etc., and preferably it can be polyphenylene sulfide (PPS).

[0060] The thickness of the insulating substrate is not particularly limited, but it can be, for example, 12.5 to 50 μm.

[0061] (Primer layer) The primer layer contains a cured product of the primer composition of the present invention.

[0062] The thickness of the primer layer only needs to be such that the adhesive strength between the metal plating layer and the insulating substrate can be ensured, and it is not particularly limited, but it is preferably thinner than the thickness of the metal plating layer. In particular, since the cured product of the primer composition of the present invention exhibits good adhesive strength, the thickness of the primer layer can be made sufficiently thin. Specifically, the thickness of the primer layer can be, for example, 0.05 to 0.5 μm.

[0063] (Metal plating layer) The metal plating layer is a layer obtained by bringing the surface of the primer layer into contact with an electroless plating solution, and contains metals such as copper, platinum, gold, silver, nickel, chromium, cobalt, tin, etc. The metal plating layer preferably contains a metal selected from the group consisting of copper, platinum, gold, silver, and nickel, and more preferably contains copper or an alloy thereof.

[0064] The thickness of the metal plating layer can be appropriately set according to the application. For example, when used in a printed wiring board, it can be, for example, 0.01 to 50 μm, preferably 0.1 to 10 μm, and more preferably 0.1 to 2 μm.

[0065] The metal plating layer may be patterned into a predetermined shape. The metal plating layer formed in a pattern can function as a wiring pattern for, for example, a printed wiring board.

[0066] 3. Method for manufacturing the laminate The laminate of the present invention can be obtained through the following steps: 1) a step of applying the primer composition of the present invention to the surface of an insulating substrate, followed by drying and curing to form a primer layer; and 2) a step of subjecting the surface of the primer layer to electroless plating to form a metal plating layer.

[0067] Regarding the step of 1) The primer composition of the present invention is applied to the surface of the insulating substrate.

[0068] The method for applying the primer composition is not particularly limited, and can be carried out, for example, by a gravure printing method, a flexographic printing method, an inkjet method, a dipping method, a spraying method, a spin coating method, a roll coating method, a reverse coating method, a screen printing method, etc.

[0069] Next, the applied primer composition is dried and cured to obtain a primer layer.

[0070] The drying and curing temperature may be such that it can cure the (meth)acrylic resin (A) and epoxy resin (B) in the primer composition, for example, it can be 60 to 400 °C, preferably about 80 to 150 °C. The drying time depends on the drying temperature, but for example, it can be about 0.1 to 60 minutes, preferably about 10 to 30 minutes.

[0071] Regarding the step of 2) Next, the surface of the primer layer on the insulating substrate is brought into contact with an electroless plating solution to form an electroless plating film (metal plating layer). Since the primer layer contains a palladium catalyst, electroless plating can be efficiently performed.

[0072] The electroless plating solution may contain the aforementioned metal, a reducing agent, water and / or a water-soluble organic solvent. The conditions for electroless plating can be set according to the composition of the electroless plating solution. For example, the temperature of an electroless copper plating bath is usually about 25 to 45 °C. The treatment time depends on the application, but when forming a metal plating layer with a thickness of about 0.3 to 0.4 μm, for example, it can be about 10 to 20 minutes.

[0073] The metal plating layer may be formed over the entire surface of the primer layer or in a pattern.

[0074] For example, in this step, when forming the metal plating layer in a pattern, a plating resist corresponding to the desired pattern is formed on the surface of the primer layer, and the portion where the plating resist is not formed is electroless plated to form a metal plating layer. Then, by dissolving and removing the plating resist with a chemical solution or the like, a metal plating layer (desired conductive pattern) formed in a pattern can be obtained (full additive method).

[0075] Alternatively, in this step, when forming the metal plating layer uniformly, in the step of 3) described later, a second metal plating layer may be further formed in a pattern on the metal plating layer (semi-additive method).

[0076] Regarding the step of 3) As described above, a plating resist corresponding to a desired pattern may be formed on the surface of the metal plating layer (seed layer) formed by electroless plating on the entire surface of the primer layer, and the portion where the plating resist is not formed may be electroplated to further form a second metal plating layer. Thereafter, the plating resist can be dissolved and removed with a chemical solution or the like to obtain a metal plating layer (desired conductive pattern) formed in a pattern shape.

[0077] In this way, the printed wiring board as a laminate can be manufactured by the semi-additive method or the full-additive method. Thereby, a wiring pattern with a fine pitch can be formed. The primer composition of the present invention is particularly effective in the method for manufacturing a laminate using these methods.

[0078] The laminate of the present invention can be used for circuit forming substrates used in electronic circuits, integrated circuits, etc., organic EL elements, organic transistors, flexible printed boards, transparent electrodes used in RFID, touch panels, electromagnetic wave shielding materials, etc. Among them, it can be preferably used for applications that require durability at high temperatures. For example, it can be used for applications generally called copper-clad laminates (CCL: Copper Clad Laminate) such as flexible printed boards (FPC), tape automated bonding (TAB), chip-on-film (COF), and printed wiring boards (PWB).

[0079] In particular, since the laminate of the present invention has a primer layer containing a cured product of the primer composition of the present invention, the adhesive strength and adhesive reliability of the metal plating layer can be enhanced without etching the surface of the insulating base material. Also, since etching is not required, the smoothness of the surface of the primer layer is high, and the skin effect is less likely to occur. Therefore, the laminate of the present invention can be preferably used for printed wiring boards (PWB) used in devices for high frequencies such as 5G.

Examples

[0080] Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited thereby in any way.

[0081] 1. Preparation of Electroless Plating Primer Composition <Materials> (1) Base Resin Taisa Resin SG-80H (manufactured by Nagase ChemteX Corporation, acrylic ester / glycidyl methacrylate / acrylonitrile copolymer, epoxy equivalent 9100 g / eq, Mw: 350,000, Tg: 11 °C) Urethane-modified polyester copolymer (manufactured by Toyobo Co., Ltd., Baylon UR-3200) jER4275 (manufactured by Mitsubishi Chemical Corporation, phenoxy resin, Tg 68 °C, epoxy equivalent 8400 - 9200 g / eq)

[0082] (2) Epoxy Resin jER1031S (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin, epoxy equivalent 200 g / eq, Mw: 800)

[0083] (3) Curing Agent Phenolite TD-2131 (manufactured by DIC Corporation, novolak-type phenolic curing agent (phenol novolak), hydroxyl equivalent 104 g / eq, Tg 78 - 82 °C) Phenolite TD-2620 (manufactured by DIC Corporation, resol-type phenolic curing agent (alkylphenol) Ricacid TBN-100 (manufactured by Shin Nippon Rika Co., Ltd., acid anhydride-based curing agent) Amicure PN-23 (manufactured by Ajinomoto Fine-Techno Co., Inc., amine adduct-based curing agent)

[0084] (4) Curing Catalyst 2E4MZ (2-ethyl-4-methylimidazole)

[0085] (5) Palladium Catalyst Pd nanopowder (ML-001N manufactured by Ioxus Inc., average particle diameter 5 nm)

[0086] <Preparation of Primer Compositions 1 - 26> As shown in Table 1 or 2, each component was mixed to prepare primer compositions 1 to 26.

[0087] 2. Preparation and Evaluation of Laminates [Examples 1 to 6, Comparative Examples 1 to 20] (Formation of Primer Layer) As an insulating substrate, a polyphenylene sulfide (PPS) film with a thickness of 50 μm was prepared. On one side of this film, the primer composition in Table 1 or 2 was applied using a bar coater, dried in a drying oven at 120 °C for 5 minutes, and then further heated at 150 °C for 30 minutes to cure, forming a primer layer with a thickness of 0.5 μm.

[0088] (Electroless Plating) The film formed with the above primer layer was immersed in an electroless plating bath for electroless plating. The electroless copper plating bath used was Surcup PSY manufactured by Kamamura Kogyo Co., Ltd. (Cu concentration 2 to 3 g / L, 35 °C for 10 minutes), and the plating was carried out so that the plating thickness was 0.2 μm.

[0089] (Evaluation) The adhesion strength and adhesion reliability of the plating of the obtained laminate were evaluated by the following methods.

[0090] (Adhesion Strength) The adhesion of the plating film of the obtained laminate was measured by a 90° peel test. Specifically, it was measured at room temperature under the condition of a peel rate of 25 mm / min. And the adhesion strength was evaluated according to the following criteria. 〇: Adhesion strength is 5 N / cm or more △: Adhesion strength is 2 N / cm or more and less than 5 N / cm ×: Adhesion strength is less than 2 N / cm It was judged to be good if it was △ or more.

[0091] (Adhesion Reliability) The obtained laminate was stored in an air oven at 150 °C for 168 hours. Then, the adhesion strength of the plating film was evaluated by the same method and criteria as above.

[0092] The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 8 are shown in Table 1, and the evaluation results of Comparative Examples 9 to 20 are shown in Table 2. The content (% by mass) of the palladium catalyst in the table indicates the amount based on the entire primer composition.

[0093] [Table 1]

[0094] [Table 2]

[0095] As shown in Table 1, it can be seen that the laminates of Examples 1 to 6 all have good adhesive strength and adhesive reliability without performing etching.

[0096] On the other hand, it can be seen that the laminates of Comparative Examples 1 and 2 using a primer composition containing a polyamine-based curing agent (catalyst type curing agent) are inferior in at least adhesive reliability. Since the growth reaction by the polyamine-based curing agent is a sequential polymerization reaction, unlike the addition polymerization reaction, it does not generate OH groups. Therefore, the resulting crosslinked product has no OH groups and low polarity, so it is difficult to obtain adhesive strength with the substrate, and it is considered that adhesive reliability could not be obtained because it also does not have a heat-resistant structure. In addition, it can be seen that the laminates of Comparative Examples 3 to 8 using a primer composition not containing a base resin are low in both initial adhesive strength and adhesive reliability.

[0097] Also, as shown in Table 2, it can be seen that the laminates of Comparative Examples 9 to 20 using a primer composition using polyester urethane or phenoxy resin as the base resin all have low adhesive reliability. It is considered that this is because the OH groups of the resulting crosslinked product are few (degree of polarity), the reactivity with the epoxy resin curing agent (C) is low, and it is difficult to obtain a crosslinked product with a sufficient crosslink density, so sufficient adhesiveness with the substrate could not be obtained.

Industrial Applicability

[0098] According to the present invention, it is possible to provide an electroless plating primer composition having good adhesion strength and adhesion reliability to an insulating substrate. Therefore, it is suitable for a laminate for obtaining a printed wiring board, particularly a printed wiring board used for high-frequency compatible devices such as 5G.

Claims

1. A (meth)acrylic resin (A), an epoxy resin (B), and a polyaddition-type epoxy resin curing agent (C), wherein the (meth)acrylic resin (A) has an epoxy group that reacts with the polyaddition-type epoxy resin curing agent (C), a electroless plating primer composition.

2. The (meth)acrylic resin (A) includes a structural unit derived from an epoxy group-containing unsaturated monomer (a1) and a structural unit derived from an unsaturated monomer (a2) having a Tg of a homopolymer of 90°C or higher, The electroless plating primer composition according to Claim 1.

3. The unsaturated monomer (a2) having a Tg of a homopolymer of 90°C or higher is acrylonitrile or methyl methacrylate, The electroless plating primer composition according to Claim 2.

4. The (meth)acrylic resin (A) is an elastomer, The electroless plating primer composition according to any one of Claims 1 to 3.

5. The epoxy resin (B) includes an aromatic epoxy resin having 3 or more epoxy groups in one molecule, The electroless plating primer composition according to any one of Claims 1 to 4.

6. The mass ratio MA / MB of the content MA of the (meth)acrylic resin (A) to the content MB of the epoxy resin (B) is 100 / 5 to 100 / 50, The electroless plating primer composition according to any one of Claims 1 to 5.

7. The polyaddition-type epoxy resin curing agent (C) is a phenolic curing agent or an acid anhydride curing agent, The electroless plating primer composition according to any one of Claims 1 to 6.

8. With respect to the total of the (meth)acrylic resin (A), the epoxy resin (B), and the polyaddition-type epoxy resin curing agent (C), the (meth)acrylic resin (A) is 50 to 80% by mass, the epoxy resin (B) is 3 to 25% by mass, the polyaddition-type epoxy resin curing agent (C) is 5 to 35% by mass, and The electroless plating primer composition according to any one of Claims 1 to 7.

9. Further including a palladium catalyst, The electroless plating primer composition according to any one of Claims 1 to 8.

10. An insulating substrate, a primer layer including a cured product of the electroless plating primer composition according to any one of Claims 1 to 9 disposed on the insulating substrate, and a metal plating layer disposed on the primer layer and a laminate.

11. The insulating substrate contains a resin with a low dielectric constant selected from the group consisting of polyimide, polyetheretherketone, cyclic polyolefin, polyphenylene sulfide, liquid crystalline polymer, and fluororesin. The laminate according to claim 10.

12. The thickness of the primer layer is 0.05 to 0.5 μm. The laminate according to claim 10 or 11.

13. A step of applying the electroless plating primer composition according to any one of claims 1 to 9 to the surface of the insulating substrate, followed by drying and curing to form a primer layer. A step of forming a metal plating layer by electroless plating on the primer layer. including A method for manufacturing a laminate.

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