Sclerotic resin laminate, dry film and cured product, electronic component

Abstract

To provide a curable resin laminate useful for forming an insulating layer which has low dielectric characteristics and excellent adhesion (peel strength) to a conductor layer.SOLUTION: The curable resin laminate includes a first resin layer and a second resin layer laminated on the first resin layer. The second resin layer has a thickness of 5-35% of the total thickness of the first resin layer and the second resin layer. A first curable composition contains (A1) a polyphenylene ether and a filler. A second curable composition contains (A2) a polyphenylene ether. The Young's modulus (YM2) of a cured product of the second resin layer is 3.0 GPs or less. The relationship between the Young's modulus (YM1) of a cured product of the first resin layer and the Young's modulus (YM2) of the cured product of the second resin layer is YM1>YM2. (A1) and (A2) have slopes calculated from conformation plots of less than 0.6.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a curable resin laminate useful for manufacturing an interlayer insulating layer in an electronic component such as a printed wiring board (hereinafter, also simply referred to as "wiring board"), a dry film having the curable resin laminate, and a cured product of the curable resin laminate obtained by using the curable resin laminate or the dry film, and an electronic component.

Background Art

[0002] In recent years, with the spread of high-capacity high-speed communication represented by the fifth-generation communication system (5G) and millimeter-wave radars for automotive ADAS (Advanced Driving Assistance System), the high-frequencyization of signals in electronic devices has been progressing.

[0003] For wiring boards incorporated in such electronic devices, a curable resin composition mainly composed of an epoxy resin or the like has been used as an insulating material. However, the cured product made of such a composition has a high relative permittivity (Dk) and a high dielectric loss tangent (Df), resulting in an increased transmission loss for signals in the high-frequency band and problems such as signal attenuation and heat generation. Therefore, polyphenylene ether having excellent low dielectric properties has attracted attention.

[0004] Non-Patent Document 1 proposes a polyphenylene ether with improved heat resistance by introducing an allyl group into the molecule of polyphenylene ether to form a thermosetting resin.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0006] However, when polyphenylene ether is used for applications such as an insulating film for a wiring board, for example, as an interlayer insulating material sandwiched between upper and lower conductor layers of a copper-clad laminate (CCL) or the like, there has been a problem that sufficient adhesion, so-called peel strength, with the copper foil used for such a conductor layer cannot be obtained.

[0007] Therefore, an object of the present invention is to provide a curable resin laminate useful for forming an insulating layer having low dielectric properties and excellent adhesion (peel strength) to a conductor layer.

Means for Solving the Problems

[0008] The present inventors have found that a multilayer structure in which the thickness configuration of each resin layer is in a specific range, and each resin layer contains a polyphenylene ether having a branched structure as a resin component, and further, by setting the Young's modulus of each resin layer as a cured product within a specific range, the above problems can be solved, and the present invention has been completed. That is, the present invention is as follows.

[0009] The present invention is a curable resin laminate having a first resin layer and a second resin layer laminated on at least one surface of the main surface of the first resin layer, wherein the second resin layer has a thickness of 5 to 35% with respect to the total thickness of the first resin layer and the second resin layer, the first resin layer contains (A1) polyphenylene ether and (B1) a filler, the second resin layer contains (A2) polyphenylene ether, and the Young's modulus (YM2) as a cured product is 3.0 GPa or less, the relationship between the Young's modulus (YM1) of the cured product of the first resin layer and the Young's modulus (YM2) of the cured product of the second resin layer is YM1 > YM2, The (A1) polyphenylene ether and the (A2) polyphenylene ether are polyphenylene ethers obtained from raw material phenols containing at least phenols satisfying condition 1 and having a slope calculated by a conformation plot of less than 0.6. It is a curable resin laminate characterized by this. (Condition 1) Having hydrogen atoms at the ortho and para positions

[0010] The present invention may be a dry film having the curable resin laminate. The present invention may be a cured product composed of the curable laminate. The present invention may be an electronic component having the cured product.

Effect of the Invention

[0011] According to the present invention, it is possible to provide a curable resin laminate useful for forming an insulating layer having low dielectric characteristics and excellent adhesion (peel strength) to a conductor layer.

Mode for Carrying Out the Invention

[0012] Hereinafter, a curable resin laminate which is a laminate structure including at least two resin layers will be described, but the present invention is not limited thereto.

[0013] When isomers exist in the described compounds, unless otherwise specified, all possible isomers can be used in the present invention.

[0014] In the present invention, phenols that can be used as raw materials for polyphenylene ether (PPE) and can become constituent units of polyphenylene ether are collectively referred to as "raw material phenols".

[0015] In the present invention, when expressing "ortho position" or "para position" etc. in the description of raw material phenols, unless otherwise specified, the position of the phenolic hydroxyl group is used as a reference (ipso position).

[0016] In the present invention, when simply expressed as "ortho-position" or the like, it means "at least one of the ortho-positions". Therefore, unless there is a particular contradiction, when simply expressed as "ortho-position", it may be interpreted as indicating either one of the ortho-positions or both of the ortho-positions.

[0017] In the present invention, a polyphenylene ether in which some or all of the functional groups (for example, hydroxyl groups) possessed by the polyphenylene ether are modified may sometimes be simply expressed as "polyphenylene ether". Therefore, when expressed as "polyphenylene ether", unless there is a particular contradiction, it includes both unmodified polyphenylene ether and modified polyphenylene ether.

[0018] In this specification, although mainly monohydric phenols are disclosed as raw material phenols, polyhydric phenols may be used as raw material phenols as long as the effects of the present invention are not inhibited.

[0019] In this specification, when the upper limit value and the lower limit value of a numerical range are separately described, all combinations of each lower limit value and each upper limit value within a non-contradictory range are substantially described.

[0020] In this specification, the solid content is used in the meaning of non-volatile components (components other than volatile components such as solvents).

[0021] Hereinafter, the configuration and components of the curable resin laminate, the effects of the curable resin laminate, the manufacturing method of the curable resin laminate, the uses of the curable resin laminate, etc. will be described.

[0022] Note that hereinafter, there may be cases where the components contained in the curable composition and the components contained in the curable resin layer which is the dried coating film of the curable composition are not distinguished and described.

[0023] <<<<<<Configuration and Components of Curable Resin Layer>>>>>> The curable resin laminate of the present invention has a first resin layer and a second resin layer laminated (directly) on at least one of the main surfaces of the first resin layer. The second resin layer has a thickness of 5 to 35% with respect to the total thickness of the first resin layer and the second resin layer. The first resin layer and the second resin layer contain polyphenylene ether. In addition, the first resin layer essentially contains a filler. The second resin layer may or may not contain a filler.

[0024] The curable resin laminate of the present invention is usually used such that the second resin layer contacts an object to be adhered, such as a copper foil (copper circuit). Therefore, in the case of a two-layer laminate composed of the first resin layer and the second resin layer, it is arranged to contact a substrate such as a wiring board on the first resin layer side of the resin layer, and the second resin layer is used to contact an object to be adhered such as a copper foil (copper circuit).

[0025] A base material film made of polyethylene terephthalate, polypropylene, or the like, or other resin layers may be laminated on the outer layer of the first resin layer and / or the second resin layer of the curable resin laminate of the present invention. In addition, two or more base material films or other layers may be provided.

[0026] It should be noted that the curable resin laminate of the present invention only needs to be a laminate that satisfies the above configuration. For example, it can also be a laminate composed of at least three layers laminated in the order of the second resin layer / the first resin layer / the second resin layer. When the curable resin laminate of the present invention has two second resin layers, within the range that satisfies the following conditions, the thickness, material, etc. of each second resin layer may be the same or different. (Condition) The combined thickness of the second resin layers is 10 to 70% of the combined thickness of the first resin layer and the second resin layer, and each resin layer is configured to satisfy the regulation of a predetermined Young's modulus as a cured product.

[0027] <<<<<Configuration>>>>> <<<Composition: First resin layer>>> The first resin layer of the present invention contains (A1) polyphenylene ether and (B1) filler.

[0028] According to another expression, the first resin layer is a dried coating film obtained from a first curable composition containing (A1) polyphenylene ether and (B1) filler.

[0029] The content ratio M of the (B1) filler with respect to the total solid content of the first resin layer (or the total solid content of the first curable composition) B1 is preferably 30% by mass or more. Further, the content ratio M of the (B1) filler B1 is more preferably 30 to 80% by mass, still more preferably 50 to 80% by mass, and particularly preferably 65 to 80% by mass from the viewpoint of reducing the thermal expansion.

[0030] The content ratio M of the (A1) polyphenylene ether with respect to the total solid content of the first resin layer (or the total solid content of the first curable composition) A1 is preferably 3 to 40% by mass, more preferably 5 to 30% by mass, still more preferably 7 to 25% by mass, and particularly preferably 9 to 20% by mass.

[0031] In addition, the first resin layer may contain (C1) other components.

[0032] (A1) Polyphenylene ether, (B1) filler, and (C1) other components will be described later.

[0033] The thickness T1 of the first resin layer is thicker than the thickness T2 of the second resin layer. For example, it is preferably 1 to 50 μm, more preferably 10 to 45 μm, still more preferably 20 to 30 μm, and particularly preferably 24 to 29 μm.

[0034] <<<Composition: Second resin layer>>> The second resin layer of the present invention contains (A2) polyphenylene ether.

[0035] In another expression, the second resin layer is a dried coating film obtained from a second curable composition containing (A2) polyphenylene ether.

[0036] The second resin layer may or may not contain (B2) filler.

[0037] When the second resin layer contains (B2) filler, the content rate (M B2 ) of (B2) filler with respect to the total solid content of the second resin layer (or the total solid content of the second curable composition) is preferably 40% by mass or less, and more preferably 35% by mass or less. Further, when the second resin layer contains filler, since it is excellent in the balance of low thermal expansibility and adhesion to the conductor layer, the content rate M B2 of (B2) filler is preferably 5 to 35% by mass, and more preferably 20 to 35% by mass.

[0038] Here, the relationship between the content rate (M B1 ) of the (B1) filler and the content rate (M B2 ) of the (B2) filler is preferably M B1 >M B2 . More specifically, the ratio (M B1 ) of the content rate M B2 of (B2) filler with respect to the total solid content of the second curable composition to the content rate M B2 / M B1 ) of (B1) filler with respect to the total solid content of the first curable composition is more preferably 50% or less, still more preferably 45% or less, and even more preferably 15% or less from the viewpoint of low dielectric property.

[0039] The content rate (M A2 ) of (A2) polyphenylene ether with respect to the total solid content of the second resin layer (or the total solid content of the second curable composition) is preferably 10 to 50% by mass, and more preferably 30 to 50% by mass.

[0040] Also, the second resin layer may contain (C2) other components.

[0041] (A2) polyphenylene ether, (B2) filler, and (C2) other components will be described later.

[0042] The thickness T2 of the second resin layer, and the ratio of the thickness T2 of the second resin layer to the total thickness (T1 + T2) of the thickness (T1) of the first resin layer and the thickness (T2) of the second resin layer, i.e., T2 / (T1 + T2), is 5 to 35%, preferably 10 to 25%, and more preferably 15 to 25%. By the ratio of the thickness T2 of the second resin layer being within the above range, stable adhesion to the conductor layer can be obtained.

[0043] The thickness T2 of the second resin layer is thinner than the thickness T1 of the first resin layer. For example, it is preferably 0.5 to 40 μm, more preferably 0.7 to 30 μm, still more preferably 1 to 20 μm, and particularly preferably 3 to 10 μm.

[0044] <<<<Configuration: Other Layers>>>> Examples of other layers include base films such as polyethylene terephthalate and polypropylene, and cover films for protecting the surface of the curable resin layer.

[0045] <<<<<Physical Properties>>>>> <<<<Young's Modulus>>>> The Young's modulus (YM1) of the cured product of the first resin layer is preferably greater than 2.0 GPa, more preferably greater than 3.0 GPa, still more preferably greater than 3.5 GPa, and particularly preferably greater than 5.0 GPa.

[0046] The Young's modulus (YM2) of the cured product of the second resin layer is 3.0 GPa or less, preferably 2.0 GPa or less.

[0047] Also, the relationship between the Young's modulus (YM1) of the cured product of the first resin layer and the Young's modulus (YM2) of the cured product of the second resin layer is YM1 > YM2.

[0048] More specifically, the Young's modulus difference (YM1 - YM2) between the Young's modulus (YM1) of the cured product of the first resin layer and the Young's modulus (YM2) of the cured product of the second resin layer is preferably 0.5 GPa or more, more preferably 1.0 GPa or more, and particularly preferably 1.5 GPa or more. The upper limit value of the Young's modulus difference (YM1 - YM2) is not particularly limited, but is, for example, 8 GPa, 6 GPa, or 5 GPa.

[0049] The Young's modulus of the cured product of the resin layer can be adjusted by changing the molecular structure, molecular weight, and content of the resin component (polyphenylene ether), changing the number of curing-reactive functional groups contained in the composition, or changing the filler content. Specifically, increasing the filler content rate in the resin layer tends to increase the Young's modulus.

[0050] The Young's modulus of the cured product of the resin layer can be measured by the following method. A cured product of a resin layer with a thickness of 25 μm is cut out to a length of 8 cm and a width of 0.5 cm, and the Young's modulus is measured under the following conditions. Note that the Young's modulus is determined by the slope of the strain at a stress of 5 MPa to 10 MPa in the obtained stress-strain diagram. [Measurement Conditions] Testing machine: Tensile testing machine EZ-SX (manufactured by Shimadzu Corporation) Distance between chucks: 50 mm Testing speed: 1 mm / min Elongation calculation: (Tensile movement amount / Distance between chucks) × 100

[0051] <<<<<Components>>>>> The constituent components of the above-described first resin layer and second resin layer, namely, (A1) polyphenylene ether, (A2) polyphenylene ether, (B1) filler, (B2) filler, (C1) other components, and (C2) other components will be described.

[0052] <<<<Components: Polyphenylene ether (A1) and (A2)>>>> The (A1) polyphenylene ether contained in the first curable composition and the resin layer and the (A2) polyphenylene ether contained in the second curable composition and the resin layer may be the same component or different components. Here, the (A1) polyphenylene ether and the (A2) polyphenylene ether will be collectively described as polyphenylene ether (predetermined polyphenylene ether).

[0053] <<<Polyphenylene ether (predetermined polyphenylene ether)>>> The polyphenylene ether of the present invention is a polyphenylene ether having a branched structure, obtained from raw material phenols containing phenols satisfying at least condition 1 and obtained from raw material phenols containing phenols satisfying at least condition 1. Such a polyphenylene ether is referred to as a predetermined polyphenylene ether. (Condition 1) Having hydrogen atoms at the ortho and para positions

[0054] Since the phenols satisfying condition 1 {for example, phenols (A) and phenols (B) described later} have hydrogen atoms at the ortho position, when polymerized oxidatively with phenols, ether bonds can be formed not only at the ipso and para positions but also at the ortho position, so that a branched-chain structure can be formed.

[0055] Thus, a polyphenylene ether having a branched structure may be expressed as a predetermined polyphenylene ether branched polyphenylene ether.

[0056] Thus, in the predetermined polyphenylene ether, a part of its structure will be branched by a benzene ring in which at least three positions, namely the ipso, ortho, and para positions, are ether-bonded. This predetermined polyphenylene ether is considered to be, for example, a polyphenylene ether compound having at least a branched structure represented by formula (i) in the skeleton.

[0057]

Chemical formula

[0058] In formula (i), R a ~R k is a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms (preferably 1 to 12 carbon atoms).

[0059] Here, the raw material phenols constituting the predetermined polyphenylene ether may contain other phenols that do not satisfy Condition 1 as long as the effects of the present invention are not inhibited.

[0060] Examples of such other phenols include phenols (C) and phenols (D) described later, and phenols having no hydrogen atom at the para position. In particular, when phenols (C) and phenols (D) described later are oxidatively polymerized, ether bonds are formed at the ipso position and the para position, and polymerization proceeds linearly. Therefore, in order to increase the molecular weight of the polyphenylene ether, it is preferable to further contain phenols (C) and phenols (D) as the raw material phenols.

[0061] Further, the predetermined polyphenylene ether may have a functional group containing an unsaturated carbon bond. By having such a functional group, the crosslinkability-imparting effect and excellent reactivity make the various properties of the cured product better. In the present invention, the "unsaturated carbon bond" refers to an ethylenic or acetylenic carbon-carbon multiple bond (double bond or triple bond) unless otherwise specified. The functional group containing such an unsaturated carbon bond is not particularly limited, but is preferably an alkenyl group (e.g., vinyl group, allyl group), an alkynyl group (e.g., ethynyl group), or a (meth)acryloyl group. From the viewpoint of excellent curability, it is more preferably a vinyl group, an allyl group, or a (meth)acryloyl group, and from the viewpoint of excellent low dielectric properties, it is even more preferably an allyl group. These functional groups having an unsaturated carbon bond can have, for example, 15 or less, 10 or less, 8 or less, 5 or less, 3 or less, etc. carbon atoms. As a method for introducing a functional group containing such an unsaturated carbon bond into a predetermined polyphenylene ether, although not particularly limited, the following [Method 1] or [Method 2] can be mentioned.

[0062] [Method 1] Method 1 is As starting phenols, include phenols (A) that satisfy at least the following Condition 1 and the following Condition 2 (Form 1), or include a mixture of phenols (B) that satisfy at least the following Condition 1 and do not satisfy the following Condition 2 and phenols (C) that do not satisfy the following Condition 1 and satisfy the following Condition 2 (Form 2). (Condition 1) Having hydrogen atoms at the ortho and para positions (Condition 2) Having a hydrogen atom at the para position and having a functional group containing an unsaturated carbon bond

[0063] According to Method 1, a predetermined polyphenylene ether having a functional group containing an unsaturated carbon bond derived from the starting phenols can be obtained.

[0064] [Method 2] Method 2 is a method of modifying the terminal hydroxyl group of a branched polyphenylene ether with a functional group containing an unsaturated carbon bond to obtain a terminally modified polyphenylene ether.

[0065] According to Method 2, even when the starting phenols do not have a functional group containing an unsaturated carbon bond, a predetermined polyphenylene ether having a functional group containing an unsaturated carbon bond introduced therein can be obtained.

[0066] [Method 1] and [Method 2] may be carried out simultaneously.

[0067] <<The predetermined polyphenylene ether obtained by Method 1>> The predetermined polyphenylene ether obtained by Method 1 uses phenols {for example, either of phenols (A) and phenols (C)} that satisfy Condition 2 as at least the phenol raw material, and thus has crosslinkability by a hydrocarbon group containing at least an unsaturated carbon bond. When the predetermined polyphenylene ether has such a hydrocarbon group containing an unsaturated carbon bond, it is also possible to perform modification such as epoxidation using a compound that reacts with the hydrocarbon group and has a reactive functional group such as an epoxy group.

[0068] That is, the predetermined polyphenylene ether obtained by Method 1 is, for example, a polyphenylene ether having at least a branched structure represented by the following formula (i) in the skeleton, and is considered to be a compound having a hydrocarbon group containing at least one unsaturated carbon bond as a functional group. Specifically, at least one of R a ~R k in the above formula (i) is considered to be a compound having a hydrocarbon group having an unsaturated carbon bond.

[0069] In particular, in the above-mentioned Form 2, from an industrial and economic perspective, it is preferable that phenols (B) are at least any one of o-cresol, 2-phenylphenol, 2-dodecylphenol, and phenol, and phenols (C) are 2-allyl-6-methylphenol.

[0070] Hereinafter, phenols (A) to (D) will be described in more detail.

[0071] Phenols (A) are, as described above, phenols that satisfy both Condition 1 and Condition 2, that is, phenols having hydrogen atoms at the ortho and para positions and having a functional group containing an unsaturated carbon bond, and are preferably phenols (a) represented by the following formula (1).

[0072]

Chemical formula

[0073] In formula (1), R1 to R3 are a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms. However, at least one of R1 to R3 is a hydrocarbon group having an unsaturated carbon bond. From the viewpoint of facilitating polymerization during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

[0074] Examples of the phenols (a) represented by formula (1) include o-vinylphenol, m-vinylphenol, o-allylphenol, m-allylphenol, 3-vinyl-6-methylphenol, 3-vinyl-6-ethylphenol, 3-vinyl-5-methylphenol, 3-vinyl-5-ethylphenol, 3-allyl-6-methylphenol, 3-allyl-6-ethylphenol, 3-allyl-5-methylphenol, 3-allyl-5-ethylphenol, etc. The phenols represented by formula (1) may be used alone or in combination of two or more.

[0075] As described above, the phenols (B) are phenols that satisfy condition 1 and do not satisfy condition 2, that is, phenols having hydrogen atoms at the ortho and para positions and not having a functional group containing an unsaturated carbon bond, and are preferably phenols (b) represented by the following formula (2).

[0076]

Chemical formula

[0077] In formula (2), R4 to R6 are a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms. However, R4 to R6 do not have an unsaturated carbon bond. From the viewpoint of facilitating polymerization during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

[0078] Examples of the phenols (b) represented by the formula (2) include phenol, o-cresol, m-cresol, o-ethylphenol, m-ethylphenol, 2,3-xylenol, 2,5-xylenol, 3,5-xylenol, o-tert-butylphenol, m-tert-butylphenol, o-phenylphenol, m-phenylphenol, 2-dodecylphenol, and the like. As the phenols represented by the formula (2), only one kind may be used, or two or more kinds may be used.

[0079] As described above, the phenols (C) do not satisfy Condition 1 and satisfy Condition 2, that is, they are phenols having a hydrogen atom at the para position, not having a hydrogen atom at the ortho position, and having a functional group containing an unsaturated carbon bond, and are preferably phenols (c) represented by the following formula (3).

[0080] [Chemical formula]

[0081] In the formula (3), R7 and R 10 are hydrocarbon groups having 1 to 15 carbon atoms, and R8 and R9 are a hydrogen atom or hydrocarbon groups having 1 to 15 carbon atoms. However, at least one of R7 to R 10 is a hydrocarbon group having an unsaturated carbon bond. From the viewpoint of facilitating polymerization into a polymer during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

[0082] Examples of the phenols (c) represented by the formula (3) include 2-allyl-6-methylphenol, 2-allyl-6-ethylphenol, 2-allyl-6-phenylphenol, 2-allyl-6-styrylphenol, 2,6-divinylphenol, 2,6-diallylphenol, 2,6-diisopropenylphenol, 2,6-dibutenylphenol, 2,6-diisobutenylphenol, 2,6-diisopentenylphenol, 2-methyl-6-styrylphenol, 2-vinyl-6-methylphenol, 2-vinyl-6-ethylphenol, and the like. Only one kind of the phenols represented by the formula (3) may be used, or two or more kinds may be used.

[0083] As described above, the phenols (D) are phenols having a hydrogen atom at the para-position, not having a hydrogen atom at the ortho-position, and not having a functional group containing an unsaturated carbon bond, and are preferably the phenols (d) represented by the following formula (4).

[0084]

Chemical formula

[0085] In the formula (4), R 11 and R 14 are hydrocarbon groups having 1 to 15 carbon atoms and not having an unsaturated carbon bond, and R 12 and R 13 are a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms and not having an unsaturated carbon bond. From the viewpoint of facilitating polymerization into a polymer during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

[0086] Examples of the phenols (d) represented by the formula (4) include 2,6-dimethylphenol, 2,3,6-trimethylphenol, 2-methyl-6-ethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-n-butylphenol, 2-methyl-6-phenylphenol, 2,6-diphenylphenol, 2,6-ditolylphenol, etc. As the phenols represented by the formula (4), only one kind may be used, or two or more kinds may be used.

[0087] Here, in the present invention, examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an alkynyl group, etc., and preferably an alkyl group, an aryl group, an alkenyl group. Examples of the hydrocarbon group having an unsaturated carbon bond include an alkenyl group, an alkynyl group, etc. These hydrocarbon groups may be linear or branched.

[0088] <<Predetermined polyphenylene ether obtained by Method 2>> The predetermined polyphenylene ether obtained by Method 2 is a terminally modified branched polyphenylene ether.

[0089] Such a terminally modified branched polyphenylene ether has a branched structure and the terminal hydroxyl group is modified, so that it is soluble in various solvents, and a cured product with further reduced low dielectric characteristics can be obtained. In addition, since the terminally modified branched polyphenylene ether has an unsaturated carbon bond arranged at the terminal position, its reactivity becomes extremely good, and the overall performance of the obtained cured product becomes better.

[0090] When modifying the terminal hydroxyl group with a modifying compound, usually, an ether bond or an ester bond is formed between the terminal hydroxyl group and the modifying compound.

[0091] Here, the modifying compound includes a functional group having an unsaturated carbon bond and is not particularly limited as long as it can react with a phenolic hydroxyl group in the presence or absence of a catalyst.

[0092] Preferable examples of the compound for modification include organic compounds represented by the following formula (11).

[0093]

Chemical formula

[0094] In formula (11), R A , R B , and R C are each independently hydrogen or a hydrocarbon group having 1 to 9 carbon atoms, R D is a hydrocarbon group having 1 to 9 carbon atoms, and X is a group capable of reacting with a phenolic hydroxyl group such as F, Cl, Br, I, or CN.

[0095] From another perspective, preferable examples of the compound for modification include organic compounds represented by the following formula (11-1).

[0096]

Chemical formula

[0097] In formula (11-1), R is a vinyl group, an allyl group, or a (meth)acryloyl group, and X is a group capable of reacting with a phenolic hydroxyl group such as F, Cl, Br, or I.

[0098] That the terminal hydroxyl group of the branched polyphenylene ether has been modified can be confirmed by comparing the hydroxyl value of the branched polyphenylene ether with that of the terminally modified branched polyphenylene ether. Note that a part of the terminally modified branched polyphenylene ether may remain as an unmodified hydroxyl group.

[0099] Regarding the reaction temperature, reaction time, presence or absence of a catalyst, and type of catalyst during modification, etc., they can be designed appropriately. Two or more types of compounds may be used as the compound for modification.

[0100] When the predetermined polyphenylene ether as described above is used as a component of the curable composition, it may be used alone or in combination of two or more kinds.

[0101] In addition, the ratio of phenols satisfying Condition 1 to the total of raw material phenols used in the synthesis of the predetermined polyphenylene ether is preferably 1 to 50 mol%.

[0102] Also, it is not necessary to use phenols satisfying the above Condition 2, but when used, the ratio of phenols satisfying Condition 2 to the total of raw material phenols is preferably 0.5 to 99 mol%, and more preferably 1 to 99 mol%.

[0103] <<Physical properties and characteristics of the predetermined polyphenylene ether>> <Degree of branching> The branched structure (degree of branching) of the predetermined polyphenylene ether can be confirmed based on the following analysis procedure.

[0104] (Analysis procedure) Prepare chloroform solutions of polyphenylene ether at intervals of 0.1, 0.15, 0.2, and 0.25 mg / mL, and then create a graph of the refractive index difference and concentration while feeding the solution at 0.5 mL / min, and calculate the refractive index increment dn / dc from the slope. Next, measure the absolute molecular weight under the following apparatus operating conditions. Referring to the chromatogram of the RI detector and the chromatogram of the MALS detector, obtain a regression line by the least squares method from the logarithmic graph of the molecular weight and the radius of gyration (conformation plot), and calculate its slope.

[0105] (Measurement conditions) Apparatus name: HLC8320GPC Mobile phase: Chloroform Column: TOSOH TSKguardcolumnHHR-H + TSKgelGMHHR-H (2 pieces) + TSKgelG2500HHR Flow rate: 0.6 mL / min. Detector: DAWN HELEOS (MALS detector) +Optilab rEX (RI detector, wavelength 254 nm) Sample concentration: 0.5 mg / mL Sample solvent: The same as the mobile phase. Dissolve 5 mg of the sample in 10 mL of the mobile phase Injection volume: 200 μL Filter: 0.45 μm STD reagent: Standard polystyrene Mw 37,900 STD concentration: 1.5 mg / mL STD solvent: The same as the mobile phase. Dissolve 15 mg of the sample in 10 mL of the mobile phase Analysis time: 100 min

[0106] In resins with the same absolute molecular weight, the greater the progress of the branching of the polymer chain, the smaller the distance (radius of gyration) from the center of gravity to each segment. Therefore, the slope of the logarithmic plot of the absolute molecular weight and the radius of gyration obtained by GPC-MALS indicates the degree of branching, and the smaller the slope, the more the branching has progressed. In the present invention, the smaller the slope calculated by the above conformation plot, the more branched the polyphenylene ether, and the larger the slope, the less branched the polyphenylene ether.

[0107] In the predetermined polyphenylene ether constituting the curable composition of the present invention, the slope is less than 0.6, preferably 0.55 or less, 0.50 or less, 0.45 or less, 0.40 or less, or 0.35 or less. When the slope is within this range, it is considered that the polyphenylene ether has sufficient branching. The lower limit of the slope is not particularly limited, but for example, it is 0.05 or more, 0.10 or more, 0.15 or more, or 0.20 or more.

[0108] Note that the slope of the conformation plot can be adjusted by changing the temperature, catalyst amount, stirring speed, reaction time, oxygen supply amount, and solvent amount during the synthesis of polyphenylene ether. More specifically, increasing the temperature, increasing the catalyst amount, increasing the stirring speed, lengthening the reaction time, increasing the oxygen supply amount, and / or decreasing the solvent amount tend to lower the slope of the conformation plot (make the polyphenylene ether more prone to branching).

[0109] <Molecular weight of a predetermined polyphenylene ether> The predetermined polyphenylene ether constituting the curable composition of the present invention preferably has a number average molecular weight of 2,000 to 30,000, more preferably 5,000 to 30,000, still more preferably 8,000 to 30,000, and particularly preferably 8,000 to 25,000. By setting the molecular weight within such a range, the film-forming property of the curable composition can be improved while maintaining the solubility in the solvent. Further, the predetermined polyphenylene ether constituting the curable composition of the present invention preferably has a polydispersity index (PDI: weight average molecular weight / number average molecular weight) of 1.5 to 20.

[0110] In the present invention, the number average molecular weight and the weight average molecular weight are measured by gel permeation chromatography (GPC) and converted using a calibration curve prepared using standard polystyrene.

[0111] <Hydroxyl value of a predetermined polyphenylene ether> The hydroxyl value of the predetermined polyphenylene ether constituting the curable composition of the present invention is preferably 15.0 or less, more preferably 2 or more and 10 or less, and still more preferably 3 or more and 8 or less in the range where the number average molecular weight (Mn) is 2,000 to 30,000.

[0112] Note that when the predetermined polyphenylene ether is the predetermined polyphenylene ether obtained by Method 2, the hydroxyl value may be lower than the above-described numerical values.

[0113] <Solubility of a Predetermined Polyphenylene Ether in a Solvent> 1 g of the predetermined polyphenylene ether constituting the curable composition of the present invention is soluble at 25°C, preferably in 100 g of cyclohexanone (more preferably in 100 g of cyclohexanone, DMF, and PMA). Here, the fact that 1 g of the polyphenylene ether is soluble in 100 g of a solvent (for example, cyclohexanone) means that when 1 g of the polyphenylene ether and 100 g of the solvent are mixed, turbidity and precipitation cannot be visually confirmed. It is more preferable that this predetermined polyphenylene ether is soluble in 1 g or more of 100 g of cyclohexanone at 25°C.

[0114] The predetermined polyphenylene ether constituting the curable composition of the present invention has a branched structure, which improves its solubility in various solvents, as well as the dispersibility and compatibility of the components in the composition. As a result, each component of the composition can be uniformly dissolved or dispersed, enabling the formation of a uniform cured product. Consequently, this cured product has extremely excellent mechanical properties and the like. In particular, the predetermined polyphenylene ethers can crosslink with each other. As a result, the mechanical properties and low thermal expansion properties of the resulting cured product are even better.

[0115] <<Method for Producing a Predetermined Polyphenylene Ether>> The predetermined polyphenylene ether constituting the curable composition of the present invention can be produced by applying a conventionally known method for synthesizing polyphenylene ether (such as polymerization conditions, the presence or absence of a catalyst, and the type of catalyst), except that specific raw phenols are used.

[0116] Next, an example of the method for producing this predetermined polyphenylene ether will be described.

[0117] The predetermined polyphenylene ether can be produced, for example, by preparing a polymerization solution containing specific phenols, a catalyst, and a solvent (polymerization solution preparation step), passing oxygen through at least the solvent (oxygen supply step), and oxidatively polymerizing the phenols in the polymerization solution containing oxygen (polymerization step).

[0118] Hereinafter, the polymer solution preparation step, the oxygen supply step, and the polymerization step will be described. It should be noted that each step may be carried out continuously, or a part or all of one step and a part or all of another step may be carried out simultaneously, or one step may be interrupted and another step may be carried out during that time. For example, the oxygen supply step may be carried out during the polymer solution preparation step or the polymerization step. Further, the method for producing polyphenylene ether of the present invention may include other steps as necessary. Examples of other steps include a step of extracting the polyphenylene ether obtained by the polymerization step (for example, a step of performing reprecipitation, filtration, and drying), and the above-described modification step and the like.

[0119] <Polymer solution preparation step> The polymer solution preparation step is a step of mixing each raw material containing phenols to be polymerized in the polymerization step described later to prepare a polymer solution. Examples of the raw materials for the polymer solution include raw material phenols, a catalyst, and a solvent.

[0120] (Catalyst) The catalyst is not particularly limited, and any appropriate catalyst used in the oxidative polymerization of polyphenylene ether may be used.

[0121] Examples of the catalyst include amine compounds, metal amine compounds composed of heavy metal compounds such as copper, manganese, and cobalt and amine compounds such as tetramethylethylenediamine. In particular, in order to obtain a copolymer having a sufficient molecular weight, it is preferable to use a copper-amine compound in which a copper compound is coordinated with an amine compound. Only one type of catalyst may be used, or two or more types may be used.

[0122] The content of the catalyst is not particularly limited, but may be, for example, 0.1 to 0.6 mol% with respect to the total of the raw material phenols in the polymer solution.

[0123] Such a catalyst may be dissolved in an appropriate solvent in advance.

[0124] (Solvent) The solvent is not particularly limited, and any suitable solvent used in the oxidative polymerization of polyphenylene ether may be used. It is preferable to use a solvent capable of dissolving or dispersing phenolic compounds and catalysts.

[0125] Specific examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; halogenated aromatic hydrocarbons such as chloroform, methylene chloride, chlorobenzene, dichlorobenzene, and trichlorobenzene; nitro compounds such as nitrobenzene; methyl ethyl ketone (MEK), cyclohexanone, tetrahydrofuran, ethyl acetate, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), propylene glycol monomethyl ether acetate (PMA), diethylene glycol monoethyl ether acetate (CA), and the like. The solvent may be used alone or in combination of two or more.

[0126] In addition, the solvent may contain water or a solvent compatible with water.

[0127] The content of the solvent in the polymerization solution is not particularly limited and may be adjusted as appropriate.

[0128] (Other raw materials) The polymerization solution may contain other raw materials as long as the effects of the present invention are not impaired.

[0129] <Oxygen supply step> The oxygen supply step is a step of introducing an oxygen-containing gas into the polymerization solution.

[0130] The aeration time of the oxygen gas and the oxygen concentration in the oxygen-containing gas used can be appropriately changed according to the atmospheric pressure, temperature, and the like.

[0131] <Polymerization step> The polymerization step is a step of oxidatively polymerizing phenols in the polymerization solution in a situation where oxygen is supplied to the polymerization solution.

[0132] Although the specific polymerization conditions are not particularly limited, for example, stirring may be performed under the conditions of 25 to 100°C for 2 to 24 hours.

[0133] In the production of a predetermined polyphenylene ether through the steps as described above, by referring to Method 1 or Method 2 described above, a specific method for introducing a functional group containing an unsaturated carbon bond into the branched polyphenylene ether can be understood. That is, a predetermined polyphenylene ether having a functional group containing an unsaturated carbon bond can be obtained by specifying the types of raw phenols or by further providing a step (modification step) for modifying the terminal hydroxyl group after the polymerization step.

[0134] <<<<Component: Fillers (B1) and (B2)>>>> The (B1) filler contained in the first curable composition and the resin layer of the present invention and the (B2) filler contained in the second curable composition and the resin layer may be the same component or different components. Here, the (B1) filler and the (B2) filler will be collectively described as fillers.

[0135] Examples of the filler include inorganic fillers and organic fillers. Examples of the inorganic filler include metal oxides such as silica, alumina, and titanium oxide; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; clay minerals such as talc and mica; fillers having a perovskite-type crystal structure such as barium titanate and strontium titanate; boron nitride, aluminum borate, barium sulfate, calcium carbonate, etc. can be used. As the organic filler, fluororesin fillers such as polytetrafluoroethylene (PTFE), tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc.; hydrocarbon resin fillers such as cycloolefin polymer (COP), cycloolefin copolymer (COC), etc. can be used.

[0136] Among them, considering low dielectric loss tangent and low thermal expansivity, the filler component is preferably silica. Hereinafter, silica, which is a preferred form of the filler component, will be described.

[0137] <<Silica>> The average particle size of silica is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. Here, the average particle size can be determined as the median diameter (d50, volume basis) by cumulative distribution from the measured values of the particle size distribution by the laser diffraction / scattering method using a commercially available laser diffraction / scattering type particle size distribution measuring device.

[0138] It is also possible to use silica with different average particle sizes in combination. When aiming for high filling of silica, for example, silica with an average particle size of 1 μm or more can be used in combination with nano-order fine silica with an average particle size of less than 1 μm.

[0139] Silica may be surface-treated with a coupling agent. By treating the surface with a silane coupling agent, the dispersibility with polyphenylene ether can be improved. Also, the affinity with an organic solvent can be improved.

[0140] As the silane coupling agent, for example, an epoxy silane coupling agent, a mercapto silane coupling agent, a vinyl silane coupling agent, etc. can be used. As the epoxy silane coupling agent, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, etc. can be used. As the mercapto silane coupling agent, for example, γ-mercaptopropyltriethoxysilane, etc. can be used. As the vinyl silane coupling agent, for example, vinyltriethoxysilane, etc. can be used.

[0141] The usage amount of the silane coupling agent may be, for example, 0.1 to 5 parts by mass, or 0.5 to 3 parts by mass with respect to 100 parts by mass of silica.

[0142] <<<<Component: Other components (C1) and (C2)>>>> The first curable composition and the resin layer may contain (C1) other components, and the second curable composition and the resin layer may contain (C2) other components. (C1) Other components and (C2) other components may be the same components or different components. Here, (C1) other components and (C2) other components will be described together as other components.

[0143] Examples of the other components include conventionally known additives that can be blended into the first curable composition and the second curable composition. More specifically, it is preferable to contain a peroxide, a crosslinking type curing agent, an elastomer, a maleimide compound, etc.

[0144] In addition, the other components may contain, within a range that does not impair the effects of the present invention, a flame retardancy improver (such as a phosphorus-based compound), cellulose nanofibers, a polymer component (resin components such as cyanate ester resin, epoxy resin, phenol novolak resin, organic polymers such as non-branched polyphenylene ether, polyimide, polyamide, etc.), a dispersant, a thermosetting catalyst, a thickener, an antifoaming agent, an antioxidant, a rust preventive agent, an adhesion imparting agent, and other components. These may be used alone or in combination of two or more.

[0145] <<<Peroxide>>> When the above-described predetermined polyphenylene ether has an unsaturated carbon bond, the curable composition or the curable resin laminate preferably contains a peroxide.

[0146] Examples of the peroxide include methyl ethyl ketone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)butane, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-butene, acetyl peroxide, octanoyl peroxide, lauroyl peroxide, benzoyl peroxide, m-toluoyl peroxide, diisopropyl peroxydicarbonate, t-butylene peroxybenzoate, di-t-butyl peroxide, t-butyl peroxyisopropyl monocarbonate, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, and the like. The peroxide may be used alone or in combination of two or more.

[0147] Among these, the peroxide preferably has a half-life temperature of 130°C to 180°C from the viewpoints of ease of handling and reactivity. Since such a peroxide has a relatively high reaction start temperature, it is difficult to promote curing at a time when curing is not required such as during drying, and it does not deteriorate the storage stability of the curable composition containing polyphenylene ether. Also, since it has low volatility, it does not volatilize during drying or storage and has good stability.

[0148] The content in the peroxide curable composition or the curable resin laminate is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, and particularly preferably 0.1 to 10% by mass based on the total amount of the peroxide and the total solid content of the curable composition or the curable resin laminate. By setting the total amount of the peroxide within this range, the effect at low temperature can be made sufficient while preventing the deterioration of the film quality when forming a coating film.

[0149] Also, if necessary, it may contain azo compounds such as azobisisobutyronitrile and azobisisovaleronitrile, and radical initiators such as dicumyl and 2,3-diphenylbutane.

[0150] <<<Crosslinking hardener>>> When the predetermined polyphenylene ether has an unsaturated carbon bond, it is preferable that the curable composition or the curable resin laminate contains a crosslinking hardener.

[0151] As the crosslinking hardener, those having good compatibility with polyphenylene ether are used. Examples include polyfunctional vinyl compounds such as divinylbenzene, divinylnaphthalene, and divinylbiphenyl; vinylbenzyl ether compounds synthesized from the reaction of phenol and vinylbenzyl chloride; allyl ether compounds synthesized from the reaction of styrene monomer, phenol, and allyl chloride; and triallyl isocyanurate. As the crosslinking hardener, triallyl isocyanurate having particularly good compatibility with polyphenylene ether is preferable. Specifically, triallyl isocyanurate (hereinafter, TAIC (registered trademark)) and triallyl cyanurate (hereinafter, TAC) are particularly preferable. These exhibit low dielectric characteristics and can enhance heat resistance. In particular, TAIC (registered trademark) is preferable because of its excellent compatibility with polyphenylene ether.

[0152] In addition, as the crosslinking hardener, a (meth)acrylate compound (methacrylate compound and acrylate compound) may be used. In particular, it is preferable to use a 3- to 5-functional (meth)acrylate compound. As the 3- to 5-functional methacrylate compound, trimethylolpropane trimethacrylate or the like can be used, while as the 3- to 5-functional acrylate compound, trimethylolpropane triacrylate or the like can be used. When these crosslinking hardeners are used, the heat resistance can be enhanced. The crosslinking hardener may be used alone or in combination of two or more.

[0153] When the components in the curable composition or curable resin laminate containing a predetermined polyphenylene ether contain a hydrocarbon group having an unsaturated carbon bond, particularly, a cured product excellent in dielectric properties can be obtained by curing with a crosslinking hardener.

[0154] In the curable composition or curable resin laminate, the blending ratio of the predetermined polyphenylene ether and the crosslinking hardener (for example, trialkenyl isocyanurate) is preferably 20:80 to 90:10, more preferably 30:70 to 90:10, as the solid content ratio (predetermined polyphenylene ether: crosslinking hardener). By setting such a range, a cured product excellent in low dielectric properties and heat resistance can be obtained.

[0155] <<<Maleimide compound>>> The maleimide compound is not particularly limited as long as it contains at least one maleimide group in one molecule.

[0156] Examples of the maleimide compound include (1) monofunctional aliphatic / alicyclic maleimide, (2) monofunctional aromatic maleimide, (3) polyfunctional aliphatic / alicyclic maleimide, (4) polyfunctional aromatic maleimide. can be mentioned.

[0157] <<(1) Monofunctional aliphatic / alicyclic maleimide>> Examples of the monofunctional aliphatic / alicyclic maleimide (1) include N-methylmaleimide, N-ethylmaleimide, and the reaction product of maleimidecarboxylic acid disclosed in JP-A-11-302278 and tetrahydrofurfuryl alcohol.

[0158] <<(2) Monofunctional aromatic maleimide>> Examples of the monofunctional aromatic maleimide (2) include N-phenylmaleimide, N-(2-methylphenyl)maleimide, and the like.

[0159] <<(3) Polyfunctional aliphatic / alicyclic maleimide>> Examples of the polyfunctional aliphatic / alicyclic maleimide (3) include N,N'-methylenebismaleimide, N,N'-ethylenebismaleimide, maleimide ester compounds having an isocyanurate skeleton obtained by dehydrative esterification of tris(hydroxyethyl)isocyanurate and aliphatic / alicyclic maleimidecarboxylic acid, maleimide urethane compounds having an isocyanurate skeleton obtained by urethanization of tris(carbamatehexyl)isocyanurate and aliphatic / alicyclic maleimide alcohol, etc., isocyanur skeleton polymaleimides, isophorone bisurethane bis(N-ethylmaleimide), triethylene glycol bis(maleimideethyl carbonate), aliphatic / alicyclic polymaleimide ester compounds obtained by dehydrative esterification of aliphatic / alicyclic maleimidecarboxylic acid and various aliphatic / alicyclic polyols, or by transesterification of aliphatic / alicyclic maleimidecarboxylic acid ester and various aliphatic / alicyclic polyols, aliphatic / alicyclic polymaleimide ester compounds obtained by ring-opening ether reaction of aliphatic / alicyclic maleimidecarboxylic acid and various aliphatic / alicyclic polyepoxides, aliphatic / alicyclic polymaleimide urethane compounds obtained by urethanization reaction of aliphatic / alicyclic maleimide alcohol and various aliphatic / alicyclic polyisocyanates, and the like.

[0160] Specifically, examples thereof include aliphatic bismaleimide compounds represented by the following general formula (X1) and general formula (X2), which are obtained by subjecting a maleimide alkyl carboxylic acid or a maleimide alkyl carboxylic acid ester having an alkyl group with 1 to 6 carbon atoms, more preferably a linear alkyl group, to a dehydration esterification reaction or a transesterification reaction with polyethylene glycol having a number average molecular weight of 100 to 1000 and / or polypropylene glycol having a number average molecular weight of 100 to 1000 and / or polytetramethylene glycol having a number average molecular weight of 100 to 1000.

[0161] JPEG0007705268000008.jpg35151(In the formula, m represents an integer of 1 to 6, n represents a value of 2 to 23, and R1 represents a hydrogen atom or a methyl group.)

[0162] JPEG0007705268000009.jpg37150(In the formula, m represents an integer of 1 to 6, and p represents a value of 2 to 14.)

[0163] <<(4) Polyfunctional aromatic maleimide>> Examples of the polyfunctional aromatic maleimide (4) include N,N'-(4,4'-diphenylmethane)bismaleimide, bis-(3-ethyl-5-methyl-4-maleimidophenyl)methane, 2,2'-bis-(4-(4-maleimidophenoxy)propane, N,N'-(4,4'-diphenyloxy)bismaleimide, N,N'-p-phenylenebismaleimide, N,N'-m-phenylenebismaleimide, N,N'-2,4-tolylene bismaleimide, N,N'-2,6-tolylene bismaleimide, aromatic polymaleimide ester compounds obtained by subjecting maleimide carboxylic acid and various aromatic polyols to dehydration esterification or subjecting maleimide carboxylic acid esters and various aromatic polyols to transesterification reactions, aromatic polymaleimide ester compounds obtained by subjecting maleimide carboxylic acid and various aromatic polyepoxides to ring-opening etherification reactions, aromatic polymaleimide urethane compounds obtained by subjecting maleimide alcohol and various aromatic polyisocyanates to urethanization reactions, and the like.

[0164] Among these, the maleimide compound is preferably polyfunctional. The maleimide compound preferably has a bismaleimide skeleton. The maleimide compound can be used alone or in combination of two or more.

[0165] The weight average molecular weight of the maleimide compound is not particularly limited, but can be 100 or more, 200 or more, 500 or more, 750 or more, 1,000 or more, 2,000 or more, or 100,000 or less, 50,000 or less, 10,000 or less, 5,000 or less, 4,000 or less, 3,500 or less.

[0166] The content of the maleimide compound can typically be 0.5 to 50% by mass, 1 to 40% by mass, or 1.5 to 30% by mass based on the total solid content in the curable composition or the curable resin laminate. From another perspective, in the curable composition or the curable resin laminate, the blending ratio of the predetermined polyphenylene ether and the maleimide compound can be 9:91 to 99:1, 17:83 to 95:5, or 25:75 to 90:10 as the solid content ratio. When the curable composition or the curable resin laminate contains a maleimide compound and a crosslinking curing agent, the blending ratio of the maleimide compound and the crosslinking curing agent is preferably 80:20 to 10:90, more preferably 70:30 to 20:80 as the solid content ratio (maleimide compound: crosslinking curing agent). By setting such a range, a cured product excellent in low dielectric characteristics and heat resistance can be obtained.

[0167] <<<Elastomer>>> Examples of elastomers include diene synthetic rubbers such as polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, polychloroprene rubber, nitrile rubber, ethylene-propylene rubber; non-diene synthetic rubbers such as ethylene-propylene rubber, butyl rubber, acrylic rubber, polyurethane rubber, fluororubber, silicone rubber, epichlorohydrin rubber; natural rubber, styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, silicone-based elastomers, etc.

[0168] From the viewpoints of compatibility with polyphenylene ether and dielectric properties, at least a part of the elastomer is preferably a styrene-based elastomer. Examples of styrene-based elastomers include styrene-butadiene copolymers such as styrene-butadiene-styrene block copolymer, styrene-butadiene-butylene-styrene block copolymer; styrene-isoprene copolymers such as styrene-isoprene-styrene block copolymer; styrene-ethylene-butylene-styrene block copolymer, styrene-ethylene-propylene-styrene block copolymer, etc. Styrene-based elastomers having no unsaturated carbon bonds such as styrene-ethylene-butylene-styrene block copolymer are preferred because the resulting cured product has particularly good dielectric properties.

[0169] The content ratio of the styrene block in the styrene-based elastomer is preferably 10 to 70% by mass, 30 to 60% by mass, or 40 to 50% by mass. The content ratio of the styrene block can be determined from the integral ratio of the spectrum measured by H-NMR. 1 It can be determined from the integral ratio of the spectrum measured by H-NMR.

[0170] Here, as raw material monomers of the styrene-based elastomer, not only styrene but also styrene derivatives such as α-methylstyrene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene are included.

[0171] The content ratio of the styrenic elastomer in 100% by weight of the elastomer may be, for example, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass.

[0172] The elastomer may have a functional group (including a bond) that reacts with other components.

[0173] For example, it may have an unsaturated carbon bond as a reactive functional group. By configuring the elastomer in this way, it can be cross-linked to the unsaturated carbon bond (for example, the unsaturated carbon bond possessed by branched polyphenylene ether), and there are effects such as reducing the risk of bleed-out.

[0174] The elastomer may be modified using (meth)acrylic acid, maleic acid, their anhydrides or esters, etc. Further, it may be obtained by adding water to the residual unsaturated bonds of the diene-based elastomer.

[0175] The number average molecular weight of the elastomer may be 1,000 to 150,000. When the number average molecular weight is at least the lower limit value, it is excellent in low thermal expansibility, and when it is at most the upper limit value, it is excellent in compatibility with other components.

[0176] The content of the elastomer in the curable composition or the curable resin laminate may be 10 to 300 parts by mass with respect to 100 parts by mass of the predetermined polyphenylene ether. Alternatively, the content of the elastomer may be 3 to 65% by mass based on the total solid content in the curable composition or the curable resin laminate. When within the above range, good tensile properties, adhesion, and heat resistance can be realized in a well-balanced manner.

[0177] <<<<<<Effect of the curable resin laminate>>>>>> The curable resin laminate of the present invention is arranged on an object to be adhered (such as a copper foil) so that the second resin layer contacts the object to be adhered, and by heating and pressure bonding, the second resin layer fills the uneven portions of the object to be adhered (such as a copper foil) without gaps. Then, by curing the curable resin laminate, a crosslinking reaction occurs at the interface between the first resin layer, the second resin layer, and the resin layers, and the object to be adhered and the curable resin laminate adhere firmly, thereby obtaining excellent peel strength.

[0178] <<<<<<Manufacturing Method of Curable Resin Laminate>>>>>> <<<<<Raw Materials>>>>> The curable resin laminate can be obtained by diluting the above-described first curable composition and second curable composition with a solvent or the like as necessary to form a solution, and then coating and drying the solution on a base film or a substrate.

[0179] The content of the solvent used for diluting the curable composition is not particularly limited and can be appropriately adjusted according to the use of the curable composition and the desired viscosity.

[0180] <<<<Solvent>>>> As an example of the solvent that can be used in the curable composition of the present invention, in addition to conventionally usable solvents such as chloroform, methylene chloride, and toluene, relatively highly safe solvents such as N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), cyclohexanone, propylene glycol monomethyl ether acetate (PMA), diethylene glycol monoethyl ether acetate (CA), methyl ethyl ketone, and ethyl acetate can be mentioned. Note that the solvent may be N,N-dimethylformamide (DMF). The solvent may be used alone or in combination of two or more.

[0181] <<<<<Manufacturing Process>>>>> Hereinafter, an example of the manufacturing process of the curable resin laminate will be described.

[0182] <<<<Dry Film>>>> The dry film of the present invention is characterized in that at least one side of a curable resin laminate is supported or protected by a film.

[0183] The film serving as the support (base film) is not particularly limited, and examples thereof include metal foils such as copper foil, films such as polyimide film, polyester film, and polyethylene naphthalate (PEN) film. These films can also be used as the support or cover film of the dry film.

[0184] A method for manufacturing a dry film is, for example, by applying a solution of a second curable composition onto a base film using an applicator or the like, drying it to form a second resin layer, and then applying a solution of a first curable composition onto the second resin layer and drying it to form a first resin layer, thereby forming a dry film having a two-layer curable resin laminate in which the second resin layer and the first resin layer are sequentially laminated on the base film. Also, by further forming a second resin layer on the first resin layer of the two-layer curable resin laminate, a dry film having a three-layer curable resin structure having the second resin layer on both sides of the first resin layer can be formed.

[0185] After forming the resin layer, a step of providing other layers (for example, a cover film) may be carried out as necessary.

[0186] Instead of the step of sequentially laminating resin layers on the above-described base film, a dry film having a two-layer curable resin laminate or a three-layer curable resin laminate in which the above two-layer or three-layer curable resin laminate is sandwiched between base films can be produced by preparing in advance a first dry film having a first resin layer and / or a second dry film having a second resin layer, laminating them, and further peeling and laminating the base film.

[0187] The coating and drying of the curable composition can be carried out by known methods and conditions. For example, a curable composition with a uniform thickness can be obtained by known coating methods such as comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, etc.

[0188] Thereafter, the coating film of the curable composition obtained by coating can be heated and dried at a temperature of 60 to 130 °C for 1 to 30 minutes to form a resin layer composed of a dried coating film. The heat drying can be carried out by known heating means such as a hot air circulation drying furnace, IR furnace, hot plate, convection oven, etc.

[0189] The thickness of the resin layer can be adjusted by changing the coating conditions and the viscosity of the curable composition.

[0190] <<<<<<Usage and applications of the curable resin laminate>>>>>> As an example, the curable resin laminate of the present invention is used by laminating a conductor layer (such as copper foil) on the second resin layer after being formed on an appropriate substrate so that the second resin layer is on the surface side. As a method of forming on the substrate, the first curable composition and the second curable composition may be coated and dried on the substrate, or may be formed on the substrate through the above-described dry film form.

[0191] As the substrate, in addition to a printed wiring board or a flexible printed wiring board on which a circuit is formed in advance, all grades (such as FR-4) of copper-clad laminates using composite materials such as paper-phenol resin, paper-epoxy resin, glass cloth-epoxy resin, glass-polyimide, glass cloth / non-woven cloth-epoxy resin, glass cloth / paper-epoxy resin, synthetic fiber-epoxy resin, fluororesin, polyethylene, PPO, cyanate ester, etc., polyimide film, PET film, glass substrate, ceramic substrate, wafer board, etc. can be used.

[0192] When coating and drying on a substrate to form on the substrate, for example, a solution of a first curable composition is coated and dried on the substrate to form a first resin layer, and then a solution of a second curable composition is coated and dried on the first resin layer to form a second resin layer, whereby a curable resin laminate laminated in the order of the first resin layer and the second resin layer can be formed on the substrate.

[0193] Coating and drying on the substrate can be carried out by known methods and conditions, and a coating and drying method similar to the manufacturing method of the dry film described above can be used.

[0194] When forming on a substrate through the form of a dry film, for example, in the case of a dry film having a two-layer curable resin laminate sandwiched between base films, after peeling off the base film in contact with the first resin layer, it is arranged so that the first resin layer is in contact with the substrate. Then, using a vacuum laminator or the like, heating and pressing are performed from the side of the base film in contact with the second resin layer to laminate the dry film on the substrate, and after cooling to room temperature, the surface base film is peeled off, whereby a curable resin laminate laminated in the order of the first resin layer and the second resin layer can be formed on the substrate.

[0195] Lamination of the dry film onto the substrate can be carried out by known methods and conditions. Among them, it is preferable to use a vacuum laminator because no voids or the like are generated, and lamination can be performed within the range of temperature conditions of 80 to 160 °C and time conditions of 10 to 120 seconds.

[0196] Thereafter, an object to be adhered such as a copper foil is disposed on the second resin layer on the surface layer side of the curable resin laminate, and heating and pressing are performed using a vacuum laminator or a vacuum press to form a conductor layer on the second resin layer. Thereafter, the curable resin laminate is thermally cured by an appropriate method.

[0197] In the thermal curing step, for example, by heating at 100 to 220 °C for 30 to 120 minutes in a hot air circulation drying oven, the curable resin laminate undergoes a thermal curing reaction and a cured product is formed.

[0198] The curable resin laminate and dry film of the present invention are suitably used for forming an insulating film on a circuit board, and are suitable for forming an interlayer adhesive, an electromagnetic wave shielding layer, or an interlayer insulating layer.

Examples

[0199] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0200] <<Synthesis of PPE resin>> <Synthesis of PPE-1 (branched PPE resin)> Into a 3L two-necked eggplant flask, 2.6 g of di-μ-hydroxo-bis[(N,N,N’,N’-tetramethylethylenediamine)copper(II)] chloride (Cu / TMEDA) and 3.18 mL of tetramethylethylenediamine (TMEDA) were added and dissolved thoroughly, and oxygen was supplied at 10 ml / min. A raw material solution was prepared by dissolving 105 g of 2,6-dimethylphenol and 13 g of 2-allylphenol, which are raw material phenols, in 1.5 L of toluene. This raw material solution was dropped into the flask and reacted at 40 °C for 6 hours while stirring at a rotation speed of 600 rpm. After completion of the reaction, it was reprecipitated with a mixed solution of 20 L of methanol and 22 mL of concentrated hydrochloric acid and taken out by filtration, and dried at 80 °C for 24 hours to obtain PPE-1, which is a branched PPE resin.

[0201] The number average molecular weight of PPE-1 was 20,000, and the weight average molecular weight was 60,000.

[0202] The slope of the conformation plot of PPE-1 was 0.31.

[0203] <Synthesis of PPE-2 (branched PPE resin)> Into a 3 L two-necked eggplant flask, 2.6 g of di-μ-hydroxo-bis[(N,N,N’,N’-tetramethylethylenediamine)copper(II)] chloride (Cu / TMEDA) and 3.18 mL of tetramethylethylenediamine (TMEDA) were added and dissolved thoroughly, and oxygen was supplied at 10 ml / min. 105 g of 2,6-dimethylphenol and 4.89 g of ortho-cresol, which are starting phenols, were dissolved in 1.5 L of toluene to prepare a starting material solution. This starting material solution was added dropwise to the flask and reacted at 40 °C for 6 hours while stirring at a rotational speed of 600 rpm. After completion of the reaction, it was reprecipitated with a mixed solution of 20 L of methanol: 22 mL of concentrated hydrochloric acid and taken out by filtration, and dried at 80 °C for 24 hours to obtain a branched PPE resin.

[0204] Into a 1 L two-necked eggplant flask equipped with a dropping funnel, 50 g of the branched PPE resin, 4.8 g of allyl bromide as a modifying compound, and 300 mL of NMP were added and stirred at 60 °C. 5 mL of a 5 M aqueous NaOH solution was added dropwise to the solution. Thereafter, it was further stirred at 60 °C for 5 hours. Next, after neutralizing the reaction solution with hydrochloric acid, it was reprecipitated in 5 L of methanol and taken out by filtration, washed 3 times with a mixed solution having a mass ratio of methanol to water of 80:20, and dried at 80 °C for 24 hours to obtain PPE-2, which is a branched PPE resin.

[0205] The number average molecular weight of PPE-2 was 19,000 and the weight average molecular weight was 66,500.

[0206] The slope of the conformation plot of PPE-2 was 0.33.

[0207] The number average molecular weight (Mn) and weight average molecular weight (Mw) of each PPE resin were determined by gel permeation chromatography (GPC). In GPC, Shodex K-805L was used as a column, the column temperature was 40 °C, the flow rate was 1 mL / min, the eluent was chloroform, and the standard substance was polystyrene.

[0208] <Solvent Solubility of PPE Resin> The solvent solubility of each PPE resin was confirmed.

[0209] The branched PPE resins - 1 and 2 were soluble in cyclohexanone. <<<Preparation of the curable composition / Production of the dry film>>> The varnishes and dry films of the curable compositions according to each example and each comparative example were obtained as follows. <<Example 1>> <Preparation of the curable composition for the first resin layer> To 100 parts by mass of PPE - 1 and 49 parts by mass of a styrene elastomer (Asahi Kasei Corporation: trade name "H1051"), 540 parts by mass of cyclohexanone as a solvent was added, and the mixture was mixed and stirred at 40 °C for 30 minutes until completely dissolved. To the obtained PPE resin solution, 60 parts by mass of TAIC (manufactured by Mitsubishi Chemical Corporation) as a cross - linking type curing agent, 534 parts by mass of spherical silica filler (Admatechs Co., Ltd.: trade name "SC2500 - SVJ"), and 16 parts by mass of a maleimide resin (Designer Molecules, Inc.: trade name "BMI - 3000 Mw = 3,000") were added and mixed, and then dispersed with a three - roll mill. Finally, 3 parts by mass of α,α’ - bis(t - butylperoxy - m - isopropyl) benzene (manufactured by NOF Corporation: trade name "Perbutyl P - 40"), which is a peroxide, was blended and stirred with a magnetic stirrer. In this way, the varnish of the curable composition for the first resin layer of Example 1 was obtained.

[0210] <Production of the first resin layer (dry film having the first resin layer)> Next, on a 100 - μm - thick PET film (Toray Industries, Inc.: trade name "TN - 200"), the varnish of the curable composition for the first resin layer of Example 1 was applied with an applicator so that the thickness of the dried resin layer would be 29 μm, and dried at 90 °C for 5 minutes to produce a dry film having the first resin layer of Example 1. Also, for measuring the Young's modulus, a dry film was produced under the same conditions as above so that the thickness of the dried resin layer would be 25 μm.

[0211] <Measurement of the Young's modulus of the cured film of the first resin layer> A dry film having the first resin layer of Example 1 described above with a thickness of 25 μm was placed on the shiny surface of a low-roughness copper foil (FV-WS (manufactured by Furukawa Electric Co., Ltd.): Rz = 1.2 μm) such that the first resin layer was in contact, and laminated using a vacuum laminator. Then, after peeling off the PET film, nitrogen was completely filled using an inert oven, the temperature was raised to 200 °C, and it was cured for 60 minutes to obtain a cured film composed of the first resin layer. This cured film was cut out to a length of 8 cm and a width of 0.5 cm, and a tensile test was conducted under the following conditions. The Young's modulus was determined from the slope of the strain at a stress of 5 MPa to 10 MPa in the stress-strain diagram. [Measurement Conditions] Testing Machine: Tensile Testing Machine EZ-SX (manufactured by Shimadzu Corporation) Distance between Chucks: 50 mm Testing Speed: 1 mm / min Elongation Calculation: (Tensile Movement Amount / Distance between Chucks) × 100

[0212] <Preparation of Curing Composition for the Second Resin Layer> In the curing composition for the first resin layer described above, a varnish of the curing composition for the second resin layer of Example 1 was obtained in the same manner except that the content of the spherical silica filler was 0 parts by mass.

[0213] <Fabrication of the Second Resin Layer (Dry Film with the Second Resin Layer)> Next, on a PET film with a thickness of 100 μm, the varnish of the curing composition for the second resin layer of Example 1 was applied using an applicator so that the thickness of the dried resin layer would be 2 μm, and dried at 90 °C for 5 minutes to fabricate a dry film having the second resin layer of Example 1. Also, for Young's modulus measurement, a dry film was fabricated under the same conditions as above so that the thickness of the dried resin layer would be 25 μm.

[0214] <Measurement of Young's Modulus of the Cured Film of the Second Resin Layer> Using the dry film having the second resin layer of Example 1 described above with a thickness of 25 μm, the Young's modulus of the cured film of the second resin layer was determined in the same manner as the measurement of the Young's modulus of the first resin layer described above.

[0215] The dry film having the above-described first resin layer and the dry film having the second resin layer of Example 1 were arranged such that the resin layers were in contact with each other, and laminated using a vacuum laminator MVLP-500 manufactured by Meiki Seisakusho Co., Ltd. to obtain the dry film of Example 1.

[0216] <<Examples 2-13, Comparative Examples 1-5>> The curable compositions for the first and second resin layers were adjusted in the same manner as in Example 1, except that the components and the contents were expressed as numerical values in a table. The Young's modulus of each cured film of the first resin layer and the second resin layer according to Examples 2-13 and Comparative Examples 1-5 was measured, and a dry film having the first resin layer and the second resin layer was produced.

[0217] <<Example 14>> After laminating the dry film having the first resin layer and the dry film having the second resin layer, the PET film on the first resin layer side was peeled off, and further the dry film having the second resin layer was laminated to produce the dry film according to Example 14.

[0218] <<Comparative Examples 6-12>> A dry film having the first resin layer was produced, and the Young's modulus of each cured film according to Comparative Examples 6-12 was measured. Further, a PET film was laminated so as to be in contact with such a resin layer to produce the dry film according to Comparative Examples 6-12.

[0219] <<Production of Cured Product>> After peeling off the PET film on the first resin layer side of each dry film of the examples and the comparative examples, the dry film was arranged so that the first resin layer was in contact with the glossy surface of a low-roughness copper foil (FV-WS (manufactured by Furukawa Electric Co., Ltd.): Rz = 1.2 μm) and laminated using a vacuum laminator. Next, after peeling off the remaining PET film, nitrogen was completely filled using an inert oven, the temperature was raised to 200 °C, and then cured for 60 minutes to obtain each cured film of the examples and the comparative examples.

[0220] Note that a cured film could not be produced with the dry film of Comparative Example 3.

[0221] <<<Evaluation>>> The following evaluations were performed on the cured film of the cured product described above.

[0222] <<CTE: Coefficient of Thermal Expansion>> The cured film was cut into a length of 3 cm and a width of 0.3 cm, and using a TMA (Thermomechanical Analysis) Q400 manufactured by TA Instruments, in tensile mode, with a distance between chucks of 16 mm, a load of 30 mN, under a nitrogen atmosphere, the temperature was raised from 20 to 250 °C at a rate of 5 °C / min, and then cooled from 250 to 20 °C at a rate of 5 °C / min for measurement. The average coefficient of thermal expansion from 100 °C to 50 °C during cooling was determined.

[0223] <<Young's Modulus and Elongation at Break>> The cured film was cut into a length of 8 cm and a width of 0.5 cm, and the Young's modulus and elongation at break were measured under the following conditions. The Young's modulus was determined from the slope of the strain in the obtained stress-strain diagram where the stress was from 5 MPa to 10 MPa. [Measurement Conditions] Testing machine: Tensile testing machine EZ-SX (manufactured by Shimadzu Corporation) Distance between chucks: 50 mm Test speed: 1 mm / min Elongation calculation: (Tensile movement amount / Distance between chucks) × 100

[0224] <<Dielectric Constant>> The relative dielectric constant Dk and the dielectric loss tangent Df were measured according to the following method. A cured film cut into a length of 80 mm and a width of 45 mm was used as a test piece and measured by the SPDR (Split Post Dielectric Resonator) resonator method. As the measuring instrument, a vector network analyzer E5071C manufactured by Keysight Technologies Co., Ltd., an SPDR resonator, and a calculation program manufactured by QWED were used. The conditions were a frequency of 10 GHz and a measurement temperature of 25 °C.

[0225] <<Peel Strength>> The surface of the copper-clad laminate with a solid copper (full copper foil) was pretreated with CZ-8100 manufactured by Meck. Next, the PET films on the first resin layer side of the dry films of Examples 1-13 and Comparative Examples 1-3, and the single-sided PET films of Example 14 and Comparative Examples 4-10 were peeled off, and they were laminated by a vacuum laminator so that the exposed resin layer was in contact with the treated surface. Then, the remaining PET films were peeled off, and after laminating by a vacuum laminator so that the rough surface of the low roughness copper foil (FV-WS (manufactured by Furukawa Electric Co., Ltd.): Rz = 1.2 μm) was in contact with the exposed resin layer, nitrogen was completely filled using an inert oven, heated to 200 °C, and cured for 60 minutes to produce a substrate for peel strength evaluation. A cut with a width of 10 mm and a length of 100 mm was made in the low roughness copper foil part of the substrate for peel strength evaluation described above. One end of this was peeled off and grasped with a gripping tool, and a 90° peel strength measurement was performed under the following conditions. [Measurement Conditions] Testing machine: Tensile testing machine EZ-SX (manufactured by Shimadzu Corporation) Testing speed: 1 mm / min

[0226] [Table 1]

[0227] [Table 2]

Claims

1. A curable resin laminate having a first resin layer and a second resin layer laminated on at least one main surface of the first resin layer, wherein the second resin layer has a thickness of 5 to 35% with respect to the total thickness of the first resin layer and the second resin layer, the first resin layer contains (A1) polyphenylene ether and (B1) filler, The second resin layer contains (A2) polyphenylene ether and has a Young's modulus (YM ２ ) of 3.0 GPa or less as a cured product, The Young's modulus (YM １ ) of the cured product of the first resin layer and the Young's modulus (YM ２ ) of the cured product of the second resin layer satisfy the relationship YM １ > YM ２ and the (A1) polyphenylene ether and (A2) polyphenylene ether are obtained from raw material phenols containing phenols satisfying at least condition 1, and are polyphenylene ethers having a slope calculated by a conformation plot of less than 0.6 A curable resin laminate characterized by this. (Condition 1) Having hydrogen atoms at the ortho and para positions

2. A dry film having the curable resin laminate according to Claim 1.

3. A cured product obtained by curing the curable resin laminate according to Claim 1 or the curable resin laminate included in the dry film according to Claim 2.

4. An electronic component having the cured product of Claim 3.

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