Resin composition, and prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards using the same.

Abstract

To provide a resin composition that maintains excellent low dielectric properties (low dielectric loss tangent) in the cured product while producing less smear residue during wet desmear treatment. [Solution] A resin composition comprising a radical polymerizable group-containing ester compound (A) having one or more first units having a structure derived from polyphenylene ether with hydroxyl groups at both ends, and one or more second units having a structure derived from a bifunctional or trifunctional aromatic acid halide and bonded to the first units by ester bonds, and radical polymerizable groups added to each end of the ester bond-containing structure, and a curing agent (B) containing a compound having an unsaturated double bond.

Description

[Technical Field]

[0001] The present invention relates to a resin composition, and to prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards using the same. [Background technology]

[0002] In recent years, various electronic devices have seen advancements in mounting technologies, such as the high integration of semiconductor devices, high density of wiring, and multilayering, in response to the increasing amount of information processing required. Furthermore, wiring boards used in various electronic devices are required to be high-frequency compatible, such as millimeter-wave radar substrates in automotive applications. In order to increase the signal transmission speed, wiring boards used in various electronic devices are required to reduce signal transmission losses, and this is especially important for high-frequency compatible wiring boards. To meet this requirement, the substrate material that constitutes the base material of the wiring board used in various electronic devices is required to have low dielectric constant and dielectric loss tangent.

[0003] As such a base material, for example, a PPE-containing resin composition comprising PPE (polyphenylene ether), a crosslinking agent, and a filler has been reported (Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 2006-516297 [Overview of the project] [Problems that the invention aims to solve]

[0005] While PPE-containing resin compositions like the one described in Patent Document 1 exhibit excellent low dielectric properties, their high chemical resistance presents a problem when used as a substrate material: smear residue tends to remain after wet desmearing following drilling.

[0006] The present invention has been made in view of these circumstances, and aims to provide a resin composition that maintains excellent low dielectric properties (low dielectric loss tangent) in its cured product while producing less smear residue in wet desmear treatment. [Means for solving the problem]

[0007] A resin composition according to one aspect of the present invention is characterized by comprising a radical polymerizable group-containing ester compound (A) having an ester bond-containing structure comprising one or more first units having a structure derived from a polyphenylene ether having hydroxyl groups at both ends, and one or more second units having a structure derived from a bifunctional or trifunctional aromatic acid halide and bonded to the first unit by an ester bond, and radical polymerizable groups added to each end of the ester bond-containing structure, and a curing agent (B) comprising a compound having an unsaturated double bond. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition that has excellent low dielectric properties in its cured product and produces little smear residue in wet desmear treatment. Furthermore, by using the resin composition, it is possible to provide prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards that have excellent low dielectric properties and excellent processability, such as for drilling. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view showing the configuration of a prepreg according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing the configuration of a metal-clad laminate according to one embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing the configuration of a wiring board according to one embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing the structure of a resin-coated metal foil according to one embodiment of the present invention. [Figure 5]Figure 5 is a schematic cross-sectional view showing the structure of a resin-coated film according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] A resin composition according to an embodiment of the present invention (hereinafter also simply referred to as "resin composition") is characterized by comprising a radical polymerizable group-containing ester compound (A) having an ester bond-containing structure comprising one or more first units having a structure derived from a polyphenylene ether having hydroxyl groups at both ends, and one or more second units having a structure derived from a bifunctional or trifunctional aromatic acid halide and bonded to the first unit by an ester bond, and radical polymerizable groups added to each end of the ester bond-containing structure, and a curing agent (B) comprising a compound having an unsaturated double bond.

[0011] The above configuration provides a resin composition that exhibits excellent low dielectric properties (low dielectric loss tangent) and produces minimal smear residue during wet desmearing. Minimizing smear residue means excellent processability when used as a prepreg or various substrates. Furthermore, the resin composition of this embodiment also exhibits excellent adhesion (bonding properties) in its cured product. Therefore, the resin composition of this embodiment is useful for industrial applications.

[0012] The components of the resin composition according to this embodiment will be described in detail below.

[0013] (Radical polymerizable group-containing ester compound (A)) The resin composition of this embodiment contains a radical-polymerizable group-containing ester compound (A) having one or more first units having a structure derived from polyphenylene ether having hydroxy groups at both ends, and one or more second units having a structure derived from a bifunctional or trifunctional aromatic acid halide and bonded to the first unit by an ester bond, an ester bond-containing structure, and radical-polymerizable groups added to each end of the ester bond-containing structure. By containing such a radical-polymerizable group-containing ester compound (A), the resin composition of this embodiment has the above-described effects (low dielectric characteristics and few smear residues).

[0014] The radical-polymerizable group in the radical-polymerizable group-containing ester compound (A) preferably has at least one of the group represented by the following formula (1) or the group represented by the following formula (2).

Chemical formula

[0015]

Chemical formula

[0016] The radical-polymerizable group-containing ester compound (A) preferably contains an aromatic ester structure (a) represented by the following formula (3). It is considered that the above-described effects can be obtained more reliably in this way.

Chemical formula

[0017] In this embodiment, the radical polymerizable group-containing ester compound (A) preferably contains an aromatic ester structure (a) such that the concentration of ester groups bonded to the aromatic (aromatic ester group concentration) is 0.1 to 3 mmol / g. This is thought to allow for more reliable acquisition of excellent low dielectric properties.

[0018] In this embodiment, the "concentration of ester groups bonded to aromatic compounds" means the concentration shown by the following formula: Aromatic ester group concentration (mmol / g) = Number of ester groups / Molecular weight × 1000 Furthermore, the number of ester groups referred to here means the number of "ester groups bonded to aromatic compounds" shown in the shaded area of ​​the structure below. For example, in the structure below, the number of ester groups bonded to aromatic compounds is 2. [ka]

[0019] The concentration of the aromatic ester group is more preferably 0.5 to 2.0 mmol / g.

[0020] More specifically, the group represented by formula (1) above includes vinyl benzyl groups (ethenyl benzyl groups) such as p-ethenylbenzyl groups and m-ethenylbenzyl groups, vinylphenyl groups, and the like. More specifically, the group represented by formula (2) above includes, for example, acrylate groups and methacrylate groups.

[0021] The resin composition of this embodiment has the advantage of having at least one of the groups represented by formula (1) and formula (2) above, which improves reactivity with the curing agent (B) and makes it easier to obtain a resin cured product with high heat resistance.

[0022] In the radical polymerizable group-containing ester compound (A), the first unit having a structure derived from polyphenylene ether preferably has a polyphenylene ether chain in its molecule, and for example, it preferably has a repeating unit represented by the following formula (6) in its molecule.

[0023] [ka]

[0024] In formula (6), m represents a value between 1 and 100. Furthermore, R5 to R8 are independent of each other. That is, R5 to R8 may be the same group or different groups. Also, R5 to R8 represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Among these, hydrogen atoms and alkyl groups are preferred.

[0025] In R5 to R8, the functional groups listed are specifically as follows:

[0026] The alkyl group is not particularly limited, but for example, alkyl groups having 1 to 18 carbon atoms are preferred, and alkyl groups having 1 to 10 carbon atoms are more preferred. Specifically, examples include methyl groups, ethyl groups, propyl groups, hexyl groups, and decyl groups.

[0027] The alkenyl group is not particularly limited, but for example, an alkenyl group having 2 to 18 carbon atoms is preferred, and an alkenyl group having 2 to 10 carbon atoms is more preferred. Specifically, examples include vinyl groups, allyl groups, and 3-butenyl groups.

[0028] The alkynyl group is not particularly limited, but for example, an alkynyl group having 2 to 18 carbon atoms is preferred, and an alkynyl group having 2 to 10 carbon atoms is more preferred. Specifically, examples include the ethynyl group and the propa-2-in-1-yl group (propargyl group).

[0029] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, alkylcarbonyl groups having 2 to 18 carbon atoms are preferred, and alkylcarbonyl groups having 2 to 10 carbon atoms are more preferred. Specifically, examples include acetyl group, propionyl group, butyryl group, isobutyryl group, pivaloyl group, hexanoyl group, octanoyl group, and cyclohexylcarbonyl group.

[0030] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specifically, examples include acryloyl groups, methacryloyl groups, and crotonoyl groups.

[0031] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specifically, for example, a propioloyl group can be mentioned.

[0032] In the radical polymerizable group-containing ester compound (A), the second unit has a structure derived from a bifunctional or trifunctional aromatic acid halide and is bonded to the first unit by an ester bond.

[0033] The radical polymerizable group-containing ester compound (A) of this embodiment more preferably contains at least one selected from the radical polymerizable group-containing ester compound (A-1) represented by the following formula (4) and the radical polymerizable group-containing ester compound (A-2) represented by the following formula (5). This is thought to make it possible to more reliably obtain excellent low dielectric properties.

[0034] [ka] In formula (4), X1 and X2 are each independently selected from the group represented by formula (1) and the radical polymerizable group represented by formula (2). Y represents a linear, branched, or cyclic hydrocarbon having 20 or fewer carbon atoms. p is the average value of the number of repeating units and is a number of 1 or more, t is from 1 to 100, and u is from 1 to 100.

[0035] [ka] In formula (5), X1 and X2 are each independently selected from the group represented by formula (1) and the radical polymerizable group represented by formula (2). Y represents a linear, branched, or cyclic hydrocarbon having 20 or fewer carbon atoms. p is the average value of the number of repeating units and is a number of 1 or more, t is from 1 to 100, and u is from 1 to 100.

[0036] In the above formulas (4) and (5), Y can be, for example, a group represented by the following formula (7). [ka]

[0037] In formula (7) above, R9 and R 10 Each of these independently represents either a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (7) include a methylene group, a methylmethylene group, and a dimethylmethylene group, among which the dimethylmethylene group is preferred.

[0038] The number-average molecular weight of the radical polymerizable group-containing ester compound (A) in this embodiment is preferably 1,000 to 7,000. This is thought to make it possible to more reliably obtain the effects of the present invention, such as low dielectric properties and low smear residue. Furthermore, since the radical polymerizable group-containing ester compound (A) in this embodiment has a relatively low molecular weight, it is thought to have excellent moldability. A more preferred range for the number-average molecular weight is 1,000 to 5,000. Here, the number-average molecular weight can be measured by any general molecular weight measurement method, specifically, values ​​measured using gel permeation chromatography (GPC), etc.

[0039] Furthermore, the average number of radical polymerizable groups (groups represented by formula (1) or (2)) at the molecular terminals of the radical polymerizable group-containing ester compound (A) per molecule (number of terminal functional groups) is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal radical polymerizable groups is within this range, the cured product is expected to have excellent heat resistance, as well as excellent storage properties and fluidity of the resin composition.

[0040] The method for synthesizing the radical polymerizable group-containing ester compound (A) used in this embodiment is not particularly limited. Specifically, for example, it can be obtained by reacting a polyphenylene ether compound with an aromatic halide in the presence of a base catalyst, and then reacting the reaction product with a radical polymerizable group-containing substrate in the presence of a base catalyst.

[0041] (Hardening agent (B)) The curing agent (B) used in this embodiment is not particularly limited as long as it contains a compound having an unsaturated double bond and can react with the radical polymerizable group-containing ester compound (A) to cure the resin composition containing the radical polymerizable group-containing ester compound (A). Examples of such curing agents (B) include curing agents having at least one functional group in the molecule that contributes to the reaction with the radical polymerizable group-containing ester compound (A). Using such a curing agent (B) has the advantage of providing high heat resistance in addition to low dielectric properties.

[0042] Preferably, the curing agent (B) is a compound having two or more unsaturated double bonds in its molecule.

[0043] More specifically, examples include isocyanurate compounds having an isocyanurate group in the molecule, polyfunctional acrylate compounds having two or more acryloyl groups in the molecule, polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule, allyl compounds having an allyl group in the molecule, maleimide compounds having a maleimide group in the molecule, acenaphthylene compounds having an acenaphthylene structure in the molecule, and styrene derivatives.

[0044] Among these, it is preferable to use a curing agent containing an isocyanurate compound having an isocyanurate group in the molecule. Examples of the isocyanurate compound include compounds further having an alkenyl group in the molecule (alkenyl isocyanurate compounds), and for example, triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC) are preferred examples.

[0045] The curing agent (B) may be any of the compounds described above, either individually or in combination of two or more.

[0046] (Content ratio and content) In the resin composition of this embodiment, the content of the radical polymerizable group-containing ester compound (A) and the curing agent (B) is not particularly limited, but it is preferable that the ratio of the radical polymerizable group-containing ester compound (A) to the curing agent (B) is 90:10 to 50:50 by mass ratio. It is believed that low dielectric properties (especially low dielectric loss tangent) can be more reliably obtained by having the content ratio of the radical polymerizable group-containing ester compound (A) to the curing agent (B) in the resin composition within the above range. A more preferable range for the above content ratio is 80:20 to 60:40 by mass ratio.

[0047] In the resin composition of this embodiment, the content of the radical polymerizable group-containing ester compound (A) is about 50 to 90 parts by mass, and more preferably about 60 to 80 parts by mass, based on 100 parts by mass of the total resin components in the resin composition. Furthermore, the content of the curing agent (B) is about 10 to 50 parts by mass, and more preferably about 20 to 40 parts by mass, based on 100 parts by mass of the total resin components in the resin composition.

[0048] (Curing accelerator (C)) The resin composition according to this embodiment may further contain a curing accelerator (C). The curing accelerator (C) is not particularly limited as long as it can accelerate the curing reaction of the resin composition. Specifically, examples include peroxides, metal oxides, azo compounds, imidazole compounds, phosphorus-based curing accelerators, amine-based curing accelerators, and the like.

[0049] Examples of peroxides include α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexine, benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile.

[0050] Examples of metal oxides include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0051] Examples of azo compounds include 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(2-methylbutyronitrile).

[0052] Examples of phosphorus-based curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.

[0053] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine (DMAP), benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

[0054] Examples of imidazole compounds include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[ 2'-methylimidazolyl-(1')-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate adduct, 2-F Examples of imidazole compounds include phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline.

[0055] The reaction initiators described above may be used individually or in combination of two or more.

[0056] Among the curing accelerators (C), peroxides such as α,α'-di(t-butylperoxy)diisopropylbenzene are preferred. α,α'-di(t-butylperoxy)diisopropylbenzene has low volatility, so it does not volatilize during drying or storage, and has good stability. In addition, because α,α'-di(t-butylperoxy)diisopropylbenzene has a relatively high reaction initiation temperature, it can suppress the acceleration of the curing reaction at times when curing is not necessary, such as during prepreg drying. This suppression of the curing reaction can suppress the deterioration of the shelf life of the resin composition.

[0057] When the resin composition of this embodiment contains a curing accelerator (C), its content is not particularly limited, but is preferably 0.01 to 5.0 parts by mass, and more preferably 0.05 to 3.0 parts by mass, based on 100 parts by mass of the total of the radical polymerizable group-containing ester compound (A), curing agent (B), and curing accelerator (C).

[0058] (Inorganic fillers) The resin composition according to this embodiment may further contain an inorganic filler. Examples of inorganic fillers include those added to reduce the thermal expansion coefficient of the cured resin composition, or to enhance its heat resistance and flame retardancy, and are not particularly limited.

[0059] **Inorganic fillers that can be used in this embodiment** Specifically, examples of fillers include those made from at least one selected from the group consisting of silica, alumina, metal oxides such as titanium oxide, magnesium oxide and mica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, talc, aluminum borate, barium sulfate, aluminum nitride, boron nitride, barium titanate, strontium titanate, calcium titanate, aluminum titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and magnesium carbonate such as zirconium tungstate phosphate and anhydrous magnesium carbonate, and calcium carbonate, as well as boehmite-treated materials thereof. Among these materials, silica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, aluminum oxide, boron nitride, and barium titanate and strontium titanate are preferred, with silica being more preferred. The silica is not particularly limited and examples include crushed silica, spherical silica, and silica particles.

[0060] These inorganic fillers may be used individually or in combination of two or more types. Furthermore, while the inorganic fillers described above may be used as is, they may also be surface-treated with epoxysilane, vinylsilane, methacrylicsilane, phenylaminosilane, or aminosilane type silane coupling agents. These silane coupling agents can be added using an integral blending method, rather than being pre-surface-treated with the fillers.

[0061] If the resin composition of this embodiment contains an inorganic filler, its content is preferably 10 to 300 parts by mass, and more preferably 20 to 200 parts by mass, based on 100 parts by mass of the total mass of the radical polymerizable group-containing ester compound (A) and the curing agent (B).

[0062] (Other ingredients) The resin composition according to this embodiment may contain components other than those described above (other components) as necessary, as long as they do not impair the effects of the present invention. Other components contained in the resin composition according to this embodiment may further include, for example, resin components other than the radical polymerizable group-containing ester compound (A) and curing agent (B) described above, flame retardants, silane coupling agents, polymerization inhibitors, polymerization retardants, flame retardant aids, defoamers, leveling agents, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes and pigments, dispersants and lubricants and other additives.

[0063] Examples of other resin components include epoxy resins, phenolic resins, cyanate esters, and amine resins.

[0064] (Prepregs, resin-coated films, metal-clad laminates, wiring boards, and resin-coated metal foils) Next, we will describe prepregs for wiring boards, metal-clad laminates, wiring boards, and resin-coated metal foils using the resin composition of this embodiment.

[0065] Figure 1 is a schematic cross-sectional view showing an example of prepreg 1 according to an embodiment of the present invention.

[0066] As shown in Figure 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3. An example of this prepreg 1 is one in which the fibrous base material 3 is present within the resin composition or its semi-cured product 2. That is, this prepreg 1 comprises the resin composition or its semi-cured product and the fibrous base material 3 present within the resin composition or its semi-cured product 2.

[0067] In this embodiment, "semi-cured product" refers to a resin composition that has been partially cured to the extent that it can be further cured. In other words, a semi-cured product is a resin composition that has been partially cured (stage B). For example, when a resin composition is heated, its viscosity gradually decreases at first, then curing begins, and the viscosity gradually increases. In such a case, a semi-cured state would be the state between when the viscosity begins to increase and when it is not yet completely cured.

[0068] The prepreg obtained using the resin composition according to this embodiment may include a semi-cured product of the resin composition as described above, or it may include the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in stage B) and a fibrous substrate, or it may be a prepreg comprising the uncured resin composition (the resin composition in stage A) and a fibrous substrate. Specifically, for example, a resin composition may contain a fibrous substrate. The resin composition or its semi-cured product may be obtained by heat-drying the resin composition.

[0069] The resin composition according to this embodiment is often prepared in a varnish-like form and used as a resin varnish when manufacturing the prepreg, or resin-coated metal foil or metal-clad laminate described later. Such a resin varnish is prepared, for example, as follows.

[0070] First, each component of the resin composition that is soluble in an organic solvent is added to the organic solvent and dissolved. Heating may be used as needed during this process. Then, components that are not soluble in the organic solvent (e.g., inorganic fillers) are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, etc., until a predetermined dispersion state is reached, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the radical polymerizable group-containing ester compound (A) and curing agent (B), etc., and does not inhibit the curing reaction. Specifically, examples include toluene and methyl ethyl ketone (MEK).

[0071] A method for producing the prepreg 1 of this embodiment using the varnish-like resin composition of this embodiment is, for example, to impregnate a fibrous substrate 3 with the resin varnish-like resin composition 2 and then dry it.

[0072] Specific examples of fibrous base materials used in the manufacture of prepregs include glass cloth, aramid cloth, polyester cloth, LCP (liquid crystal polymer) nonwoven fabric, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. When glass cloth is used, a laminate with excellent mechanical strength can be obtained, and flattened glass cloth is particularly preferred. The glass cloth used in this embodiment is not particularly limited, but examples include low dielectric constant glass cloths such as E glass, S glass, NE glass, Q glass, and L glass. Specifically, the flattening process can be carried out, for example, by continuously pressing the glass cloth with a press roll at an appropriate pressure to flatten the yarn. The thickness of the fibrous base material can generally be 0.01 to 0.3 mm.

[0073] The resin varnish (resin composition 2) is impregnated into the fibrous substrate 3 by dipping, coating, etc. This impregnation can be repeated multiple times as needed. Furthermore, it is possible to repeat the impregnation using multiple resin varnishes with different compositions and concentrations to finally adjust to the desired composition (content ratio) and resin amount.

[0074] A fibrous substrate 3 impregnated with resin varnish (resin composition 2) is heated under desired heating conditions, for example, at 80°C or higher and 180°C or lower for 1 minute or more and 10 minutes or less. Heating causes the solvent to evaporate from the varnish, reducing or removing the solvent to obtain a prepreg 1 in a pre-cured state (Stage A) or a semi-cured state (Stage B).

[0075] Furthermore, as shown in Figure 4, the resin-coated metal foil 31 of this embodiment has a structure in which a resin layer 32 containing the above-mentioned resin composition or a semi-cured product of the resin composition and a metal foil 13 are laminated together. That is, the resin-coated metal foil of this embodiment may be a resin-coated metal foil comprising a resin layer containing the resin composition before curing (the resin composition in stage A) and a metal foil, or it may be a resin-coated metal foil comprising a resin layer containing a semi-cured product of the resin composition (the resin composition in stage B) and a metal foil.

[0076] One method for producing such resin-coated metal foil 31 is to apply a resin varnish-like resin composition, as described above, to the surface of a metal foil 13 such as copper foil, and then dry it. Examples of such application methods include bar coaters, comma coaters, die coaters, roll coaters, gravure coaters, and the like.

[0077] The metal foil 13 can be any metal foil used in metal-clad laminates, wiring boards, etc., for example, copper foil and aluminum foil.

[0078] Furthermore, as shown in Figure 5, the resin-coated film 41 of this embodiment has a structure in which a resin layer 42 containing the above-mentioned resin composition or a semi-cured product of the resin composition and a film support substrate 43 are laminated together. That is, the resin-coated film of this embodiment may be a resin-coated film comprising the resin composition before curing (the resin composition in stage A) and a film support substrate, or it may be a resin-coated film comprising a semi-cured product of the resin composition (the resin composition in stage B) and a film support substrate.

[0079] As a method for producing such a resin-coated film 41, for example, a resin varnish-like resin composition as described above can be applied to the surface of a film support substrate 43, and then the solvent can be evaporated from the varnish to reduce the amount of solvent, or the solvent can be removed, thereby obtaining a resin-coated film in a pre-cured state (Stage A) or a semi-cured state (Stage B).

[0080] Examples of the film support substrate include electrically insulating films such as polyimide film, PET (polyethylene terephthalate) film, polyethylene naphthalate film, polyester film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, aramid film, polycarbonate film, and polyarylate film.

[0081] In addition, in the resin-coated film and resin-coated metal foil of this embodiment, similar to the prepreg described above, the resin composition or its semi-cured product may be obtained by drying or heat-drying the resin composition.

[0082] The thickness of the metal foil 13 and the film support substrate 43 can be set appropriately according to the desired purpose. For example, the metal foil 13 can be approximately 0.2 to 70 μm thick. If the thickness of the metal foil is, for example, 10 μm or less, a carrier-equipped copper foil with a release layer and carrier may be used to improve handling. The resin varnish is applied to the metal foil 13 and the film support substrate 43 by coating, and this can be repeated multiple times as needed. In this case, it is also possible to repeatedly coat using multiple resin varnishes with different compositions and concentrations to finally adjust to the desired composition (content ratio) and amount of resin.

[0083] The drying or heat drying conditions in the manufacturing method of the resin-coated metal foil 31 and resin-coated film 41 are not particularly limited, but after applying the resin varnish-like resin composition to the metal foil 13 or film support substrate 43, the resin is heated under desired heating conditions, for example, at 50 to 180°C for about 0.1 to 10 minutes, to volatilize the solvent from the varnish and reduce or remove the solvent, thereby obtaining the resin-coated metal foil 31 or resin-coated film 41 in a pre-cured state (A stage) or a semi-cured state (B stage).

[0084] The resin-coated metal foil 31 and the resin-coated film 41 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited as long as it can be peeled off without damaging the form of the resin composition, but for example, polyolefin film, polyester film, TPX film, films formed by providing a release agent layer on these films, and paper obtained by laminating these films onto a paper substrate can be used.

[0085] As shown in Figure 2, the metal-clad laminate 11 of this embodiment is characterized by having an insulating layer 12 containing a cured product of the resin composition or a cured product of the prepreg described above, and a metal foil 13. The metal foil 13 used in the metal-clad laminate 11 can be the same as the metal foil 13 described above.

[0086] Furthermore, the metal-clad laminate 11 of this embodiment can also be made using the resin-coated metal foil 31 or resin-coated film 41 described above.

[0087] As a method for producing a metal-clad laminate using the prepreg 1, resin-coated metal foil 31, or resin-coated film 41 obtained as described above, one or more sheets of the prepreg 1, resin-coated metal foil 31, or resin-coated film 41 are stacked, and then metal foil 13 such as copper foil is stacked on both sides or one side of the stack. This is then heated and pressurized to create a laminate that is metal-clad on both sides or on one side. The heating and pressurizing conditions can be appropriately set depending on the thickness of the laminate to be manufactured and the type of resin composition, but for example, the temperature can be set to 170-230°C, the pressure to 1.5-5.0 MPa, and the time to 60-150 minutes.

[0088] Alternatively, the metal-clad laminate 11 may be manufactured by forming a film-like resin composition on a metal foil 13 and then heating and pressurizing it, without using a prepreg 1 or the like.

[0089] As shown in Figure 3, the wiring board 21 of this embodiment has an insulating layer 12 containing a cured product of the resin composition or a cured product of the prepreg described above, and wiring 14.

[0090] The resin composition of this embodiment is suitably used as a material for the insulating layer of a wiring board. As a method for manufacturing the wiring board 21, for example, a wiring board 21 can be obtained by etching the metal foil 13 on the surface of the metal-clad laminate 11 obtained above to form circuits (wirings), thereby providing a conductor pattern (wirings 14) as a circuit on the surface of the laminate. As a method for forming circuits, in addition to the method described above, for example, the semi-additive method (SAP: Semi Examples include circuit formation using additive processes and modified semi-additive processes (MSAP).

[0091] The prepregs, resin-coated films, and resin-coated metal foils obtained using the resin composition of this embodiment possess excellent low dielectric properties and adhesion (bonding) in their cured products, while also suppressing smear residue in wet desmear treatment. As a result, they offer excellent drilling and other processability, making them extremely useful for industrial applications. Furthermore, metal-clad laminates and wiring boards equipped with an insulating layer containing the cured product of the resin composition of this embodiment have the advantages of low dielectric properties, adhesion (bonding), and excellent processability.

[0092] As described above, this specification discloses various aspects of technology, the main technologies among them are summarized below.

[0093] A resin composition according to a first aspect of the present invention is a resin composition comprising a radical polymerizable group-containing ester compound (A) having an ester bond-containing structure comprising one or more first units having a structure derived from a polyphenylene ether having hydroxyl groups at both ends, and one or more second units having a structure derived from a bifunctional or trifunctional aromatic acid halide and bonded to the first unit by an ester bond, and radical polymerizable groups added to each end of the ester bond-containing structure, and a curing agent (B) comprising a compound having an unsaturated double bond.

[0094] A resin composition according to a second aspect of the present invention is the resin composition according to the first aspect, wherein the radical polymerizable group has at least one of the group represented by formula (1) or the group represented by formula (2).

[0095] A third aspect of the present invention is a resin composition according to the first or second aspect, wherein the aromatic ester structure comprises an aromatic ester structure (a) represented by the above formula (3).

[0096] A fourth aspect of the present invention is a resin composition in which, in the third aspect of the present invention, the concentration of the ester group bonded to the aromatic in the aromatic ester structure (a) is 0.1 to 3 mmol / g.

[0097] A resin composition according to a fifth aspect of the present invention is a resin composition according to any of the second to fourth aspects, wherein the radical polymerizable group-containing ester compound (A) comprises at least one selected from the radical polymerizable group-containing ester compound (A-1) represented by formula (4) and the radical polymerizable group-containing ester compound (A-2) represented by formula (5).

[0098] The resin composition according to the sixth aspect of the present invention is a resin composition according to any of the first to fifth aspects, wherein the number average molecular weight of the radical polymerizable group-containing ester compound (A) is 1000 to 7000.

[0099] The resin composition according to the seventh aspect of the present invention is a resin composition according to any of the first to sixth aspects, further comprising a curing accelerator (C).

[0100] The eighth aspect of the present invention is a resin composition according to any of the first to seventh aspects, wherein the mass ratio ((A):(B)) of the radical polymerizable group-containing ester compound (A) to the curing agent (B) is 90:10 to 50:50.

[0101] A prepreg according to the ninth aspect of the present invention comprises a resin composition according to any of the first to eighth aspects or a semi-cured product of the resin composition, and a fibrous substrate.

[0102] A resin-coated film according to the tenth aspect of the present invention comprises a resin layer containing a resin composition according to any of the first to eighth aspects or a semi-cured product of the resin composition, and a support film.

[0103] A resin-coated metal foil according to the 11th aspect of the present invention comprises a resin layer containing a resin composition according to any of the 1st to 8th aspects or a semi-cured product of the resin composition, and a metal foil.

[0104] A metal-clad laminate according to the twelfth aspect of the present invention comprises an insulating layer containing a cured product of any of the first to eighth aspects of the resin composition or a cured product of the ninth aspect of the prepreg, and a metal foil.

[0105] A wiring board according to the 13th aspect of the present invention comprises an insulating layer containing a cured resin composition of any of the 1st to 8th aspects or a cured prepreg of the 9th aspect, and wiring.

[0106] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited thereto. [Examples]

[0107] First, the components used in preparing the resin composition in this embodiment will be described.

[0108] (Radical polymerizable group-containing ester compound (A)) First, as the raw material polyphenylene ether compound, we used "NORYL SA90" manufactured by SABIC. "NORYL SA90" is a polyphenylene ether with hydroxyl groups at both ends, with a number-average molecular weight of 1600 and a hydroxyl group equivalent of 840 g / eq.

[0109] The mole counts shown in the following examples are calculated from the functional group equivalents of the reacting functional groups. For example, in the case of SA90 mentioned above, the hydroxyl group equivalent is 840 g / eq, and if SA90 has a bifunctional structure, its molecular weight is 1680, and the mole count was calculated based on this molecular weight. The mole counts for other raw materials were similarly calculated from the functional group equivalents.

[0110] Synthesis of radical polymerizable group-containing ester compound 1 (a): 149.6 g of toluene and 100.8 g (0.06 mol) of SA90 were added to a 1 L flask equipped with a stirrer, condenser, and thermometer, and dissolved at 50-60°C. After dissolution, the mixture was cooled to room temperature, and 7.59 g of triethylamine was added. (b): In a separate container, 6.09 g (0.03 mol) of terephthalate chloride was dissolved in 93.44 g of methyl ethyl ketone. (c): While controlling the temperature to 40°C or below, solution (b) was added dropwise to solution (a) using a dropping funnel and allowed to react at room temperature for 2 hours. (d): After the reaction in (c), 7.59 g of triethylamine was added, and then, while controlling the temperature to 40°C or below, 7.84 g (0.075 mol) of methacrylate chloride was added dropwise using a dropping funnel, and the mixture was allowed to react at room temperature for 2 hours. (e): After the reaction in (d), 201.6 g of toluene, 100.8 g of isopropyl alcohol, and 100.8 g of water were added and heated, then stirred at 60°C for 30 minutes to stop the reaction, and then separated by standing. (f): Then, 20 g of isopropyl alcohol and 80 g of water were added to the upper layer, stirred at 60°C for 30 minutes, and then allowed to stand and separate. The upper layer of (g):(f) was added dropwise to 2326 g of methanol, the resulting solid was filtered using a Kiriyama funnel, and dried in a vacuum dryer at 60°C for 24 hours to obtain 90 g of solid.

[0111] The obtained solid was ester compound 1 represented by the following formula (8). When its molecular weight was determined by the GPC method described above, its number-average molecular weight was 4700 and its weight-average molecular weight was 12000. FT-IR measurement revealed that 1740 cm³ of the aromatic ester group was present. -1 and 1264cm -1 An absorption peak was observed. 1 1H-NMR measurements revealed signals originating from double bonds at 5.32 ppm and 5.71 ppm. The aromatic ester group concentration was 0.55 mmol / g.

[0112] [ka] (In the formula, t = 1 to 100, u = 1 to 100, and p = the average value of the number of repeating units, which is a number greater than or equal to 1)

[0113] Synthesis of radical polymerizable group-containing ester compound 2 (a): 68.84 g of methyl ethyl ketone and 22.33 g (0.11 mol) of terephthalate chloride were added to a 1 L flask equipped with a stirrer, condenser, and thermometer, and dissolved. (b): In a separate container, 92.4 g (0.055 mol) of SA90 was added to 160.63 g of toluene and dissolved at 50-60°C. After dissolution, the mixture was cooled to room temperature, and then 13.91 g of triethylamine was added. (c): While controlling the temperature to 40°C or below, solution (b) was added dropwise to solution (a) using a dropping funnel and allowed to react at room temperature for 2 hours. (d): After the reaction in (c), 13.91 g of triethylamine was added, and then, while controlling the temperature to below 40°C, 16.97 g (0.1265 mol) of vinylbenzyl alcohol was added dropwise using a dropping funnel, and the mixture was allowed to react at room temperature for 2 hours. (e): After the reaction in (d), 184.8 g of toluene, 92.4 g of isopropyl alcohol, and 92.4 g of water were added and heated, then stirred at 60°C for 30 minutes to stop the reaction, and then separated by standing. (f): Subsequently, 23.36 g of isopropyl alcohol and 200.2 g of water were added to the upper layer, stirred at 60°C for 30 minutes, and then allowed to stand and separate. The upper layer of (g):(f) was added dropwise to 2589.84 g of methanol, the resulting solid was filtered using a Kiriyama funnel, and dried in a vacuum dryer at 60°C for 24 hours to obtain 104 g of solid.

[0114] The obtained solid was ester compound 2 represented by the following formula (9). When its molecular weight was determined by the GPC method described above, its number-average molecular weight was 3800 and its weight-average molecular weight was 7800. FT-IR measurement revealed that 1740 cm³ of the aromatic ester group was present. -1 and 1264cm -1 An absorption peak was observed. 1 1H-NMR measurements revealed signals originating from double bonds at 5.39 ppm and 5.78 ppm. The aromatic ester group concentration was 1.81 mmol / g.

[0115] [ka] (In the formula, t = 1 to 100, u = 1 to 100, and p = the average value of the number of repeating units, which is a number greater than or equal to 1)

[0116] • Polyphenylene ether compound 1 having a methacryloyl group at the terminal (SA9000, manufactured by SABIC Innovative Plastics, weight-average molecular weight 2000)

[0117] Synthesis of polyphenylene ether compound 2 having vinylbenzyl groups at the end. Modified polyphenylene ether compound 2 was obtained by reacting polyphenylene ether with chloromethylstyrene. Specifically, first, 200 g of polyphenylene ether (SA90, manufactured by SABIC Innovative Plastics, with an intrinsic viscosity (IV) of 0.083 dl / g, 1.9 terminal hydroxyl groups, and a weight molecular weight of Mw1700), 30 g of a mixture of p-chloromethylstyrene and m-chloromethylstyrene in a mass ratio of 50:50 (chloromethylstyrene: CMS, manufactured by Tokyo Chemical Industry Co., Ltd.), 1.227 g of tetra-n-butylammonium bromide as a phase transfer catalyst, and 400 g of toluene were charged into a 1 liter three-necked flask equipped with a temperature controller, a stirrer, a cooling device, and a dropping funnel, and the mixture was stirred. The mixture was then stirred until the polyphenylene ether, chloromethylstyrene, and tetra-n-butylammonium bromide dissolved in the toluene. During this process, the mixture was gradually heated until the liquid temperature reached 75°C. Then, an aqueous solution of sodium hydroxide (20 g sodium hydroxide / 20 g water) was added dropwise to the solution over 20 minutes as an alkali metal hydroxide. After that, the mixture was stirred at 75°C for 4 hours. Next, the contents of the flask were neutralized with 10% by mass hydrochloric acid, and then a large amount of methanol was added. This caused a precipitate to form in the liquid in the flask, that is, the products contained in the reaction mixture in the flask were reprecipitated. This precipitate was then removed by filtration, washed three times with a methanol-water mixture in a mass ratio of 80:20, and then dried under reduced pressure at 80°C for 3 hours.

[0118] The obtained solid, 1The sample was analyzed by 1H-NMR (400 MHz, CDCl3, TMS). NMR analysis revealed peaks originating from ethenylbenzyl at 5–7 ppm. This confirmed that the obtained solid was a vinyl benzylated polyphenylene ether at its molecular ends.

[0119] Furthermore, the molecular weight distribution of the modified polyphenylene ether was measured using GPC. The weight-average molecular weight (Mw) was calculated from the obtained molecular weight distribution, and the result was 2300.

[0120] Furthermore, the number of terminal functionalities in modified polyphenylene ethers was measured as follows: First, the modified polyphenylene ether was accurately weighed. Let the weight be X (mg). Then, this weighed modified polyphenylene ether was dissolved in 25 mL of methylene chloride, and 100 μL of an ethanol solution of 10% by mass of tetraethylammonium hydroxide (TEAH) (TEAH:ethanol (volume ratio) = 15:85) was added to the solution. The absorbance (Abs) at 318 nm was then measured using a UV spectrophotometer (UV-1600, Shimadzu Corporation). From the measurement results, the number of terminal hydroxyl groups of the modified polyphenylene ether was calculated using the following formula. Residual OH amount (μmol / g) = [(25×Abs) / (ε×OPL×X)]×106 Here, ε represents the extinction coefficient, which is 4700 L / mol·cm. OPL is the cell path length, which is 1 cm.

[0121] Furthermore, the calculated residual OH amount (number of terminal hydroxyl groups) of the modified polyphenylene ether was almost zero, indicating that the hydroxyl groups of the polyphenylene ether before modification were almost completely modified. From this, it was found that the decrease from the number of terminal hydroxyl groups of the polyphenylene ether before modification corresponds to the number of terminal hydroxyl groups of the polyphenylene ether before modification. In other words, the number of terminal hydroxyl groups of the polyphenylene ether before modification corresponds to the number of terminal functional groups of the modified polyphenylene ether. That is, the number of terminal functional groups was 1.8. This will be referred to as "Polyphenylene Ether Compound 2". Here, the number of terminal hydroxyl groups refers to the average number of phenolic hydroxyl groups at the molecular ends per polyphenylene ether molecule.

[0122] • Polyarylate compounds (a) 232.59 g of toluene and 98 g (0.07 mol) of polyarylate resin (Unitika Ltd.'s "Unifiner® V575", number average molecular weight 1400, functional group equivalent 210 g / eq.) were added to a 1 L flask equipped with a stirrer, condenser, and thermometer, and dissolved at 50-60°C. After dissolution, the mixture was cooled to room temperature, and then 17.71 g of triethylamine was added. (b) While controlling the temperature to 40°C or below, 18.29 g (0.175 mol) of methacrylate chloride was added dropwise to the solution from (a) using a dropping funnel, and the mixture was allowed to react at room temperature for 2 hours. After the reaction in (c)(b), 98 g of toluene, 98 g of isopropyl alcohol, and 98 g of water were added and heated, then stirred at 60°C for 30 minutes to stop the reaction, and then allowed to stand and separate. (d) Then, 20 g of isopropyl alcohol and 80 g of water were added to the upper layer, stirred at 60°C for 30 minutes, and then allowed to stand and separate. The upper layer of (e)(d) was added dropwise to 2106.36 g of methanol, and the resulting solid was filtered using a Kiriyama funnel. The solid was dried in a vacuum dryer at 60°C for 24 hours to obtain 84 g of solid. The obtained solid is an ester compound (number average molecular weight 1400) that does not contain polyphenylene ether-derived structures.

[0123] (Hardening agent (B)) • TAIC: Triallyl isocyanurate (TAIC manufactured by Nippon Chemical Corporation)

[0124] (Curing accelerator (C)) • Peroxide initiator: PBP (1,3-bis(butylperoxyisopropyl)benzene) (Perbutyl P manufactured by NOF Corporation)

[0125] (Inorganic fillers) • Vinylsilane-treated silica MEK slurry: SC2050-MNU (manufactured by Admatex Co., Ltd.)

[0126] <Examples 1-2, Comparative Examples 1-3>

[0127] [Preparation method] (Resin varnish) First, the resin components (radical polymerizable group-containing ester compound (A), curing agent (B), curing accelerator (C), etc.) were added to toluene solvent in the mixing ratios (parts by mass) shown in Table 1 below, so that the solid content concentration was 30-50% by mass, and then mixed. An inorganic filler was added to the mixture, and after stirring for 30-60 minutes, the mixture was dispersed using a bead mill to obtain a resin varnish.

[0128] (Preparation of evaluation samples 1-3) • Resin-coated metal foil First, each of the varnishes obtained above was applied to an ultrathin metal foil with a carrier foil (manufactured by Mitsui Mining & Smelting Co., Ltd., ultrathin copper foil with carrier foil, product name "MT18FL", ultrathin copper foil thickness 1.5 μm, carrier foil thickness 18 μm), and then heated and dried at 80°C to 120°C for about 1 to 5 minutes to produce a resin-coated metal foil (resin-coated copper foil) with a resin layer thickness of about 20 μm.

[0129] • Evaluation boards 1 and 2 Two of the resin-coated metal foils obtained above were stacked with their resin layers facing each other, and vacuum-formed under conditions of 1 to 4 MPa pressure for 1.5 to 2 hours while increasing the temperature to 180 to 220°C at a rate of 2 to 5°C / min, thereby producing a double-sided metal-clad laminate (double-sided copper-clad laminate) with an insulating layer thickness of approximately 40 μm.

[0130] Subsequently, the carrier foil was removed from the above double-sided metal-clad laminate. Then, the copper foil was further removed by etching (unclad plate), which was used as evaluation substrate 1. After removing the carrier foil from the above double-sided metal-clad laminate, the copper foil was plated by electrolytic copper plating, increasing the thickness of the metal layer from 1.5 μm (copper foil thickness) to 35 μm, which was used as evaluation substrate 2.

[0131] • Evaluation board 3 The copper foil surface of a double-sided metal-clad laminate (double-sided copper-clad laminate) was roughened with a roughening solution, Multibond MB-100 (manufactured by MacDermid Japan Co., Ltd.), to prepare a roughened double-sided metal-clad laminate. A four-layer board was manufactured by layering the resin-coated metal foil described above onto both sides of the obtained laminate with resin layers facing each other, and then vacuum forming it under the same conditions as for evaluation board 1. Subsequently, the carrier foil was removed from the four-layer board, and the copper foil was further removed by etching to obtain evaluation board 3.

[0132] Using the evaluation boards 1 to 3 prepared as described above, evaluation tests were conducted using the method shown below.

[0133] <Evaluation Test>

[0134] (Dielectric properties: Dielectric loss tangent (Df)) The dielectric loss tangent at 10 GHz was measured using the cavity resonator perturbation method with the aforementioned evaluation substrate 1. Specifically, the dielectric loss tangent (Df) of the evaluation substrate at 10 GHz was measured using a network analyzer (N5230A manufactured by Keysight Technologies, Inc.). In this test, a Df of 0.0030 or less was considered a passing grade.

[0135] (Dielectric properties: Change in Df after water absorption (ΔDf)) After immersing the above-mentioned evaluation substrate 1 in water at 23°C for 24 hours, the water on the surface of the test piece was wiped off, and the dielectric loss tangent (Df-II) of the evaluation substrate at 10 GHz was measured using the same method as described above. Using the Df value obtained above, ΔDf was calculated from the following formula. ΔDf = (Df-II) - (Df) In this test, if ΔDf is 0.0030 or less, it is considered qualified.

[0136] (Desmear etching rate) A 50 mm × 50 mm test piece was taken out from the above evaluation substrate, dried in a constant temperature dryer at a temperature of 130°C for 30 minutes, and then cooled in a dry desiccator at room temperature for 120 minutes. Then, the initial weight was measured with an electronic balance. Then, etching was performed in the following procedure: 1. Swelling: Swelling Dip Securigant P (500 mL / L) + Sodium hydroxide (3 g / L), 60°C, 5 minutes 2. Hot water wash 3. Micro-etching: Concentrate Compact CP580 (580 mL / L) + Sodium hydroxide (40 g / L), 80°C, 10 minutes 4. Hot water wash 5. Neutralization: Reduction Solution Securigant P500 (100 mL / L) + Sulfuric acid (98%) (50 mL / L), 40°C, 5 minutes 6. Water wash After performing the above etching, the test piece was dried with a dryer, then dried in a constant temperature dryer at a temperature of 130°C for 30 minutes, and then cooled in a dry desiccator at room temperature for 120 minutes. Then, the weight after treatment was measured with an electronic balance. From the initial weight and the weight after treatment obtained above, the weight reduction amount due to the desmear treatment was determined, and by dividing this by the treatment area, the etching rate (mg / cm 2 ) was calculated. In this test, those with an etching rate of 0.100 or more are considered qualified. The values shown in the table are the average values (n = 3) obtained from 3 samples respectively.

[0137] (Peel strength) The copper foil was peeled off evaluation substrate 2, and the peel strength was measured in accordance with JIS C 6481. Specifically, the evaluation substrate was made 10 mm wide and long, and the copper foil was peeled off at a speed of 50 mm / min using a tensile testing machine, and the peel strength (kN / m) at that time was measured. In this test, a value of 0.6 kN / m or higher was considered acceptable.

[0138] The results above are summarized in Table 1.

[0139] [Table 1]

[0140] (Consideration) As is clear from the results in Table 1, the cured products (insulating layers) of the resin compositions in the examples of the present invention all exhibited low dielectric loss tangent and excellent adhesion (peel strength), and also produced little smear residue during the desmear treatment.

[0141] On the other hand, Comparative Examples 1 and 2, which used polyphenylene ether compounds without an aromatic ester structure, showed poor processability with a large amount of smear residue during desmearing. Comparative Example 2 also showed poor adhesion. Meanwhile, the results from Comparative Example 3, which used a polyarylate compound, confirmed that low dielectric properties and adhesion cannot be obtained simply by having an ester structure. [Explanation of symbols]

[0142] 1 Prepreg 2. Resin composition or semi-cured resin composition 3. Fibrous base material 11 Metal-clad laminate 12 Insulating layer 13 Metal foil 14 Wiring 21 Wiring board 31 Resin-coated metal foil 32, 42 Resin layer 41 Resin-coated film 43 Support film

Claims

1. A radical polymerizable group-containing ester compound (A) having one or more first units having a structure derived from a polyphenylene ether with hydroxyl groups at both ends, and one or more second units having a structure derived from a bifunctional or trifunctional aromatic acid halide and bonded to the first units by ester bonds, and radical polymerizable groups added to each end of the ester bond-containing structure, A resin composition comprising a curing agent (B) containing a compound having an unsaturated double bond.

2. The resin composition according to claim 1, wherein the radical polymerizable group has at least one of the groups represented by the following formula (1) or the group represented by the following formula (2). 【Chemistry 1】 (In formula (1), R １ R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. ２ (This represents an alkylene group with 1 to 10 carbon atoms.) 【Chemistry 2】 (In formula (2), R ３ (This represents a hydrogen atom or an alkyl group.)

3. The resin composition according to claim 1, wherein the radical polymerizable group-containing ester compound (A) comprises an aromatic ester structure (a) represented by the following formula (3). 【Transformation 3】

4. The resin composition according to claim 3, wherein the concentration of ester groups bonded to aromatics in the aromatic ester structure (a) is 0.1 to 3 mmol / g.

5. The resin composition according to claim 2, wherein the radical polymerizable group-containing ester compound (A) comprises at least one selected from the radical polymerizable group-containing ester compound (A-1) represented by the following formula (4) and the radical polymerizable group-containing ester compound (A-2) represented by the following formula (5). 【Chemistry 4】 (In formula (4), X1 and X2 are each independently selected from the group represented by formula (1) and the radical polymerizable group represented by formula (2). Y represents a linear, branched, or cyclic hydrocarbon having 20 or fewer carbon atoms. p is the average value of the number of repeating units and is a number of 1 or more, t is from 1 to 100, and u is from 1 to 100.) 【Transformation 5】 (In formula (5), X1 and X2 are each independently selected from the group represented by formula (1) and the radical polymerizable group represented by formula (2). Y represents a linear, branched, or cyclic hydrocarbon having 20 or fewer carbon atoms. p is the average value of the number of repeating units and is a number of 1 or more, t is from 1 to 100, and u is from 1 to 100.)

6. The resin composition according to claim 1, wherein the number average molecular weight of the radical polymerizable group-containing ester compound (A) is 1,000 to 7,000.

7. The resin composition according to claim 1, comprising a curing accelerator (C).

8. The resin composition according to claim 1, wherein the mass ratio ((A):(B)) of the radical polymerizable group-containing ester compound (A) to the curing agent (B) is 90:10 to 50:

50.

9. A prepreg comprising a resin composition according to any one of claims 1 to 8 or a semi-cured product of the resin composition, and a fibrous substrate.

10. A resin-coated film having a resin layer containing the resin composition according to any one of claims 1 to 8 or a semi-cured product of the resin composition, and a support film.

11. A resin-coated metal foil comprising a resin layer containing the resin composition according to any one of claims 1 to 8 or a semi-cured product of the resin composition, and a metal foil.

12. A metal-clad laminate having an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 8, and a metal foil.

13. A metal-clad laminate having an insulating layer containing a cured prepreg according to claim 9, and a metal foil.

14. A wiring board having an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 8, and wiring.

15. A wiring board having an insulating layer containing a cured prepreg according to claim 9, and wiring.

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