Prepreg, laminated board, printed wiring board, and semiconductor package

Abstract

Provided is a prepreg which contains a compound having a structural unit derived from a conjugated diene compound and which is not susceptible to winding displacement when wound using a roll or the like. Also provided are a laminate, a printed wiring board, and a semiconductor package, each of which is obtained using the prepreg. Specifically, the prepreg includes a thermosetting resin composition containing (A) a thermosetting resin and (B) a compound having a structural unit (b1) derived from a conjugated diene compound, or a prepreg of the thermosetting resin composition, the prepreg having an uneven shape on the surface, the present ratio of recesses in the uneven shape is less than 30%.

Description

Technical Field

[0001] The present disclosure relates to prepregs, laminates, printed wiring boards, and semiconductor packages. Background Art

[0002] The signals used in various electronic devices, including mobile phones, mobile communication devices, their base stations, network infrastructure equipment such as servers and routers, and mainframe computers, are becoming increasingly faster and larger each year. This trend is accompanied by the need for the printed circuit boards (PCBs) used in these electronic devices to handle higher frequencies, requiring substrate materials with excellent dielectric properties (relative permittivity and dielectric loss tangent) in high-frequency bands (e.g., bands above 10 GHz) to reduce transmission loss. In recent years, in addition to these electronic devices, new systems that handle high-frequency wireless signals have been put into practical use or are being planned for use in the ITS field, such as in automobiles and transportation systems, and in indoor short-range communications. Consequently, printed circuit boards used in these devices are demanding substrate materials with low transmission loss.

[0003] Elastomers, known for their excellent dielectric properties, are one of the materials used in printed wiring boards, which require low transmission loss. For example, it is known that the dielectric properties can be improved by adding a styrene-based thermoplastic elastomer to a resin composition comprising (A) one or more selected from maleimide compounds having two or more N-substituted maleimide groups and derivatives thereof, (B) a polyphenylene ether resin, and (C) an organometallic compound having an alkoxy group bonded to a metal atom (see, for example, Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-138849 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, further research by the present inventors has revealed that when a prepreg formed from a resin composition containing a compound having a structural unit derived from a conjugated diene compound, such as a styrene-based thermoplastic elastomer, is wound onto a roll or the like, tension is applied to the prepreg to prevent wrinkles. This can sometimes result in winding deviation. This deviation can be 5.0 mm or greater for a prepreg with a width of 400 to 500 mm. This deviation can cause the prepreg to be cut at an angle when cut to a specified size, forcing the prepreg to be discarded. This increases manufacturing costs.

[0009] In view of the above situation, the present disclosure aims to provide a prepreg containing a compound having a structural unit derived from a conjugated diene compound and which is less likely to cause winding deviation when wound on a roller, etc., and to provide a laminate, a printed wiring board, and a semiconductor package obtained using the prepreg.

[0010] Means for solving problems

[0011] The present inventors have conducted intensive studies and have found that the above-mentioned objects can be achieved by the prepreg disclosed herein.

[0012] The present disclosure includes the following embodiments [1] to

[12] .

[0013] [1] A prepreg comprising a thermosetting resin composition or a semi-cured product of the thermosetting resin composition, wherein the thermosetting resin composition comprises: (A) a thermosetting resin and (B) a compound having a structural unit (b1) derived from a conjugated diene compound, wherein the prepreg has a concavo-convex shape on its surface.

[0014] The presence ratio of the concave portions in the concavo-convex shape is less than 30%.

[0015] [2] The prepreg according to [1] above, wherein the surface roughness (Rz) is 0.1 to 12.0 μm.

[0016] [3] The prepreg according to [1] or [2], wherein the component (A) comprises at least one selected from the group consisting of epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins.

[0017] [4] The prepreg according to any one of [1] to [3] above, wherein in the component (B), the structural unit (b1) derived from the conjugated diene compound is a 1,2-bonding unit of butadiene, a 1,4-bonding unit of butadiene, a 3,4-bonding unit of isoprene, a 1,4-bonding unit of isoprene, or a hydrogenated bonding unit of at least one of these bonding units.

[0018] [5] The prepreg according to any one of [1] to [4], wherein the content of the component (B) in the thermosetting resin composition is 1% by mass or more and less than 14% by mass relative to the total amount of the resin components.

[0019] [6] The prepreg according to any one of [1] to [5] above, wherein the thermosetting resin composition further contains (C) an inorganic filler.

[0020] [7] The prepreg according to [6], wherein the content of the component (C) in the thermosetting resin composition is 1 to 70% by volume relative to the total solid content.

[0021] [8] The prepreg according to any one of [1] to [7], wherein the thermosetting resin composition further contains (D) a compatibilizer.

[0022] [9] The prepreg according to any one of [1] to [8], wherein the thermosetting resin composition further contains (E) a curing accelerator.

[0023]

[10] A laminate comprising a cured product of the prepreg according to any one of [1] to [9] above and a metal foil.

[0024]

[11] A printed wiring board comprising a cured product of the prepreg according to any one of [1] to [9].

[0025]

[12] A semiconductor package comprising the printed wiring board described in

[11] above and a semiconductor element.

[0026] Effects of the Invention

[0027] The present disclosure provides a prepreg containing a compound having a structural unit derived from a conjugated diene compound and which is less likely to be misaligned when wound on a roller, and provides a laminate, a printed wiring board, and a semiconductor package obtained using the prepreg. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a program set in Python during binarization.

[0029] Figure 2 The SEM image of the prepreg surface in Example 1 (left image) and the image obtained by binarization processing (right image) are shown.

[0030] Figure 3 The SEM image of the prepreg surface in Example 2 (left) and the image obtained by binarization processing (right) are shown.

[0031] Figure 4 The SEM image of the prepreg surface in Example 3 (left) and the image obtained by binarization processing (right) are shown.

[0032] Figure 5The SEM image of the prepreg surface in Example 4 (left) and the image obtained by binarization processing (right) are shown.

[0033] Figure 6 The SEM image of the prepreg surface in Comparative Example 1 (left image) and the image obtained by binarization processing (right image) are shown.

[0034] Figure 7 The SEM image of the prepreg surface in Comparative Example 2 (left image) and the image obtained by binarization processing (right image) are shown. DETAILED DESCRIPTION

[0035] In the numerical ranges described in this disclosure, the upper or lower limit of the numerical range can be replaced with the values ​​shown in the Examples. Furthermore, the lower limit and upper limit of a numerical range can be arbitrarily combined with the lower limit or upper limit of another numerical range, respectively. In the numerical range "AA to BB," the values ​​AA and BB at both ends are included in the numerical range as the lower limit and upper limit, respectively.

[0036] In this disclosure, for example, a description such as "10 or more" refers to 10 and values ​​exceeding 10, and this value applies even if the values ​​differ. In addition, for example, a description such as "10 or less" refers to 10 and values ​​less than 10, and this value applies even if the values ​​differ.

[0037] In addition, unless otherwise specified, each component and material exemplified in this disclosure may be used alone or in combination of two or more. In this disclosure, when the content of each component in a composition is present in a composition with multiple substances corresponding to each component, unless otherwise specified, the content refers to the total amount of the multiple substances present in the composition.

[0038] In the present disclosure, the "resin component" refers to all components in the solid content constituting the resin composition except for inorganic compounds such as an inorganic filler described later.

[0039] In the present disclosure, the term "solid content" refers to components other than the organic solvent described below, and components that are liquid at 25°C are also considered solid content.

[0040] Regarding the expression "containing XX" described in the present disclosure, when XX is capable of reacting, XX may be contained in a reacted state, or XX may be contained directly, and both forms may be included.

[0041] Arbitrary combinations of the matters described in this disclosure are also included in this disclosure and the embodiments.

[0042] [Prepreg]

[0043] The prepreg of this embodiment is as follows.

[0044] A prepreg comprising a thermosetting resin composition or a semi-cured product of the thermosetting resin composition, wherein the thermosetting resin composition comprises (A) a thermosetting resin and (B) a compound having a structural unit (b1) derived from a conjugated diene compound, wherein the prepreg has a concavo-convex shape on its surface.

[0045] The presence ratio of the concave portions in the concavo-convex shape is less than 30%.

[0046] However, the above-mentioned “surface” does not include the surface in the thickness direction of the prepreg, that is, the side surface of the prepreg.

[0047] By making the ratio of concave portions in the concavo-convex surface of the prepreg of this embodiment less than 30%, winding deviation when the prepreg is wound using a roller or the like is suppressed. The exact reason for this effect is not yet clear, but it is speculated as follows. It is believed that by making the ratio of concave portions in the concavo-convex surface less than 30%, the contact area is increased when the prepregs are overlapped, thereby improving the adhesion to the extent that winding deviation does not occur. However, even if this speculation is incorrect, it will not affect the scope of this disclosure.

[0048] Based on the above assumption, the presence ratio of the recessed portions on both the front and back surfaces of the prepreg is preferably less than 30%.

[0049] The ratio of concave portions in the concave-convex shape of the prepreg surface of this embodiment is determined by binarizing an image obtained by observing an arbitrary 524.2 μm × 669.2 μm range of the prepreg surface using a SEM (scanning electron microscope) to obtain a binary image, and then determining the ratio of white to black in the binary image. It should be noted that the binarization process described above is not particularly limited and is set using the programming language "Python (パイソン) 3.7.9". Figure 1 The procedure shown can thus obtain a binarized image.

[0050] About setting in Python Figure 1 The following is a brief description of the program shown.

[0051] import cv2: is a program that reads the Open CV2 library.

[0052] from matplotlib import pyplot: is a program that reads pyplot in matplotlib for chart drawing.

[0053] import numpy as np: is a program that reads the numpy library and defines numpy as np.

[0054] img = cv2.imread: is the program to read the image. Figure 1 Enter the image file name in the "Here is the image file name to be read" section.

[0055] img1 = img[0:600, 0:1280]: is a program that specifies the size of the image to be read.

[0056] cv2.imwrite("out_sample1.jpg", img1): is the program that saves the image specified based on numpy information as sample1.jpg in CV2.

[0057] print("Pixel_original:",img.shape): is a program that obtains the attribute information of the image (the number of columns and rows, the type of image data, the number of pixels) and the shape of the image.

[0058] img_bw = cv2.imread('out_sample1.jpg', 0): is the program to detect the image file saved as sample1 in CV2.

[0059] hit, wid = img_bw.shape: is a program that reads the image file saved as sample1 in CV2.

[0060] from numpy import sum: is a program that reads the numpy program.

[0061] img_bw_m = np.where(img_bw < 150, 1, 0)

[0062] pyplot.imshow(img_bw_m)

[0063] print("Rust ratio is :", sum(img_bw_m) / (hit wid) 100, '%'): The 1st to 3rd rows from the bottom are the procedures for cutting out the areas that are "darker" than the pixel value 150.

[0064] More specifically, the presence ratio of the concave portions is calculated by the method described in Examples using the above-mentioned binarized image.

[0065] The presence ratio of the concave portion in the concavo-convex shape of the prepreg surface (preferably the surface and back surfaces) is less than 30% as described above. From the viewpoint of suppressing the winding deviation of the prepreg, it is preferably 25% or less, more preferably 20% or less, further preferably 10% or less, particularly preferably 5% or less, and most preferably 1% or less. The lower limit of the presence ratio of the concavo-convex shape can be 0% or more, 0.001% or more, or 0.01% or more. That is, the presence ratio of the concave portion in the concavo-convex shape is 0% or more and less than 30%, and the lower limit and upper limit in this numerical range can be changed to the above values.

[0066] The shape of the concavoconvex shapes is not particularly limited, and examples thereof include needle-like shapes, triangular pyramid-like shapes, quadrangular pyramid-like shapes, rectangular parallelepiped-like shapes, spherical shapes, conical shapes, cylindrical shapes, irregular shapes, and combinations thereof.

[0067] The reason why the uneven shape is formed on the surface of the prepreg is considered to be that the resin film is produced by the following method.

[0068] First, a thermosetting resin composition is applied to a support having an uneven shape and then dried to form a resin film with a support. The drying temperature and drying time are appropriately determined based on factors such as the organic solvent content and boiling point of the thermosetting resin composition. Generally, drying at a temperature of preferably 50-200°C (more preferably 80-160°C) for 1-10 minutes will result in a suitable resin film. The thickness of the resin film with a support is not particularly limited, but is preferably 1-100 μm, more preferably 3-70 μm, even more preferably 5-35 μm, and particularly preferably 5-25 μm.

[0069] Next, two support-attached resin films are prepared, and the front and back surfaces of a sheet-like fiber substrate described below are impregnated with the support-attached resin films, respectively. The support is then peeled off and dried to obtain a prepreg.

[0070] In the case of this method, since the uneven shape caused by the uneven shape of the support is given to the resin film, a prepreg having an uneven shape on the surface can be formed.

[0071] The present embodiment limits the existence ratio of the concave portion in the concavo-convex shape as described above. It should be noted that, in addition to adjusting the concavo-convex shape of the above-mentioned support to be small, by adjusting the viscosity of the thermosetting resin composition when making the resin film with the above-mentioned support, or adjusting the particle size of the inorganic filler in the resin film, the existence ratio of the concavo-convex shape possessed by the above-mentioned prepreg can be adjusted to the above-mentioned range. Specifically, by reducing the viscosity of the thermosetting resin composition when making the resin film with the above-mentioned support, the existence ratio of the concave portion in the concavo-convex shape can be adjusted to be small. In addition, by reducing the particle size of the inorganic filler in the resin film, the existence ratio of the concave portion in the concavo-convex shape can be adjusted to be small.

[0072] Examples of the support include plastic films such as polyester films and polyolefin films, and metal foils. Examples of the polyester films include PET (polyethylene terephthalate) films and polyethylene naphthalate films. Examples of the polyolefin films include polyethylene films, polypropylene films, and polyvinyl chloride films. Examples of the metal foils include copper foil and aluminum foil. Among these, plastic films are preferred, with polyester films and PET films being more preferred.

[0073] It should be noted that, as the above-mentioned support with concavo-convex shape, the support that particle is mixed with in support can be enumerated.Above-mentioned concavo-convex shape can be adjusted by the usage amount of the particle mixed with, and the usage amount of above-mentioned particle is more, then concavo-convex shape has the trend that becomes bigger, and the usage amount of above-mentioned particle is less, then concavo-convex shape has the trend that becomes smaller.From the same viewpoint, as the usage amount of the particle mixed with support, it is not particularly limited, preferably the amount less than 30% on the surface of support, more preferably the amount less than 20% on the surface of support, further preferably the amount less than 10% on the surface of support, particularly preferably the amount less than 5% on the surface of support, most preferably the amount less than 1% on the surface of support.

[0074] Examples of the particles mixed into the support include (C) inorganic filler particles described below and organic filler particles. Examples of the organic filler particles include crosslinked NBR particles formed by copolymerizing acrylonitrile and butadiene, acrylonitrile-butadiene copolymers such as copolymers of acrylonitrile, butadiene, and carboxylic acids such as acrylic acid, and so-called core-shell rubber particles composed of a core of polybutadiene, NBR, silicone rubber, or the like and a shell of an acrylic acid derivative.

[0075] As the support, commercially available products such as A5300 of the "Purex (registered trademark)" series manufactured by Toyobo Co., Ltd. and 50X44 of the "Lumirror (registered trademark)" series manufactured by Toray Industries, Ltd. can be used.

[0076] As described above, the prepreg of this embodiment contains a thermosetting resin composition or a semi-cured product of such a thermosetting resin composition, wherein the thermosetting resin composition contains (A) a thermosetting resin and (B) a compound having a structural unit (b1) derived from a conjugated diene compound. It should be noted that in this disclosure, semi-curing (B-staging) refers to a state in which the B-stage is achieved as defined in JIS K6900 (1994).

[0077] The prepreg of the present embodiment is not particularly limited and can be made using a resin film formed by the above-mentioned thermosetting resin composition and a sheet-like fiber substrate. As mentioned above, the resin film formed by the above-mentioned thermosetting resin composition uses a resin film with a support. The prepreg of the present embodiment can be obtained by impregnating the resin film with a support into the sheet-like fiber substrate. More specifically, the resin film can be impregnated into the sheet-like fiber substrate as follows. The resin film with a support is arranged on at least one side of the sheet-like fiber substrate in such a manner that the resin film abuts against the above-mentioned sheet-like fiber substrate. Then, the arranged resin film with a support and the above-mentioned sheet-like fiber substrate are heated and pressurized, so that the above-mentioned resin film is impregnated into the above-mentioned sheet-like fiber substrate. The operation of heating and pressurizing the resin film with a support and the sheet-like fiber substrate can be performed on each side of the sheet-like fiber substrate or on both sides simultaneously. Heating and pressurizing are preferably performed using a laminating device, and more preferably performed using a vacuum laminating device. The heating temperature is preferably 50 to 170° C., more preferably 80 to 160° C., the pressing time is preferably 5 to 120 seconds, more preferably 10 to 80 seconds, and the pressing pressure is preferably 0.05 to 1.0 MPa, more preferably 0.1 to 0.6 MPa.

[0078] The sheet-like fiber substrate can be any known sheet-like fiber substrate used in various laminates for electrical insulating materials. Examples of materials for the sheet-like fiber substrate include inorganic fibers such as glass (E-glass, D-glass, S-glass, Q-glass), organic fibers such as polyimide, polyester, and tetrafluoroethylene, and mixtures thereof. The sheet-like fiber substrate may be a woven fabric, non-woven fabric, roving, chopped strand mat, or surface mat. The sheet-like fiber substrate is preferably made of inorganic fibers, more preferably glass. Furthermore, the sheet-like fiber substrate is preferably a woven fabric.

[0079] The thickness of the sheet-like fiber base material is not particularly limited and may be 1 to 100 μm, 3 to 70 μm, or 5 to 35 μm.

[0080] From the perspective of suppressing prepreg winding deviation, the surface roughness (Rz) of the prepreg of this embodiment is preferably 0.1 to 12.0 μm, and may be 0.1 to 10.0 μm, 0.1 to 5.0 μm, or even 0.5 to 3.0 μm. The surface roughness (Rz) is a value measured by the method described in the Examples below.

[0081] In addition, the surface roughness (Rz) of the prepreg mentioned above corresponds to the depth of the above-mentioned concavo-convex shape.

[0082] The thickness of the prepreg of this embodiment can be 5 to 300 μm, 10 to 250 μm, 15 to 150 μm, 15 to 120 μm, 15 to 100 μm, 20 to 60 μm, or 20 to 45 μm. Here, the thickness of the prepreg refers to the thickness of one sheet of prepreg. It should be noted that in this disclosure, the thickness of the prepreg is the average value of the values ​​obtained by measuring any five locations using a digital micrometer.

[0083] (Thermosetting resin composition)

[0084] Hereinafter, each component contained in the above-mentioned thermosetting resin composition will be described in detail.

[0085] ((A) Thermosetting resin)

[0086] Examples of the component (A) include epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins. Among these, the component (A) preferably contains at least one selected from epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate resins, and isocyanate resins, more preferably contains at least one selected from epoxy resins and maleimide compounds, and even more preferably contains a maleimide compound from the viewpoint of low thermal expansion properties.

[0087] As the component (A), one type may be used alone, or two or more types may be used in combination.

[0088] The epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule. Epoxy resins are classified into glycidyl ether epoxy resins, glycidyl amine epoxy resins, glycidyl ester epoxy resins, and the like. Among these, glycidyl ether epoxy resins are preferred.

[0089] Epoxy resins are classified into various types of epoxy resins according to the differences in their main skeletons. Among the above-mentioned various types of epoxy resins, they are further classified into: bisphenol-type epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin; alicyclic epoxy resins such as dicyclopentadiene epoxy resin; aliphatic chain epoxy resins; phenolic epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, phenol aralkyl novolac type epoxy resin, and biphenyl aralkyl novolac type epoxy resin; stilbene type epoxy resin; naphthalene skeleton-containing epoxy resins such as naphthol novolac type epoxy resin and naphthol aralkyl type epoxy resin; biphenyl type epoxy resin; xylylene type epoxy resin; dihydroanthracene type epoxy resin, etc.

[0090] The maleimide compound preferably comprises at least one selected from maleimide compounds having one or more N-substituted maleimide groups and derivatives thereof. The maleimide compound having one or more N-substituted maleimide groups is preferably a maleimide compound having two or more N-substituted maleimide groups, more preferably a maleimide compound having 2 to 10 N-substituted maleimide groups, further preferably a maleimide compound having 2 to 5 N-substituted maleimide groups, and particularly preferably a maleimide compound having two N-substituted maleimide groups.

[0091] The maleimide compound having two or more N-substituted maleimide groups is preferably a compound in which nitrogen atoms of the maleimide groups are bonded to each other via an organic group.

[0092] The maleimide compound having one or more N-substituted maleimide groups is not particularly limited, and examples thereof include aromatic maleimide compounds preferably having one N-substituted maleimide group bonded to an aromatic ring, such as N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, and N-benzylmaleimide; 4,4'-diphenylmethanebismaleimide, bis(4-maleimidephenyl)ether, bis(4-maleimidephenyl)sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide; Aromatic bismaleimide compounds preferably having two N-substituted maleimide groups bonded to an aromatic ring, such as amine, 4-methyl-1,3-phenylenebismaleimide, m-phenylenebismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, and indane ring-containing aromatic bismaleimide; aromatic polymaleimide compounds preferably having three or more N-substituted maleimide groups bonded to an aromatic ring, such as polyphenylmethanemaleimide and biphenylaralkyl maleimide; and aliphatic maleimide compounds such as N-dodecylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, and pyrophosphate binder-type long-chain alkyl bismaleimide. Among these, from the perspectives of compatibility with other resins, adhesion to conductors, heat resistance, low thermal expansion, mechanical properties, and relative dielectric constant (Dk), aromatic bismaleimide compounds having two N-substituted maleimide groups bonded to an aromatic ring are preferred. Aromatic polymaleimide compounds having three or more N-substituted maleimide groups bonded to an aromatic ring are more preferred. Indane ring-containing aromatic bismaleimides and biphenylaralkyl-type maleimides are even more preferred. In this disclosure, an indane ring refers to a fused bicyclic structure consisting of an aromatic six-membered ring and a saturated aliphatic five-membered ring. Indane ring-containing aromatic bismaleimides preferably have a divalent group represented by the following general formula (a1-1).

[0093] [Chemical Formula 1]

[0094]

[0095] (Where R a1 is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group or a mercapto group, and n1 is an integer from 0 to 3. a2~R a4 Each independently represents an alkyl group having 1 to 10 carbon atoms. Indicates the bonding area.)

[0096] As the indane ring-containing aromatic bismaleimide containing a divalent group represented by the general formula (a1-1), preferably one represented by the following general formula (a1-2) is used from the viewpoints of relative dielectric constant (Dk), adhesion to a conductor, heat resistance, and ease of production.

[0097] [Chemical Formula 2]

[0098]

[0099] (Where R a1 ~R a4 and n1 and R in the above general formula (a1-1) a1 ~R a4 Same as n1. a5 Each of them is independently an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group or a mercapto group, n2 is independently an integer of 0 to 4, and n3 is a number of 0.95 to 10.0.

[0100] From the viewpoints of relative dielectric constant (Dk), adhesion to conductors, solubility in organic solvents, and ease of production, the indane ring-containing aromatic bismaleimide represented by the general formula (a1-2) is more preferably a substance represented by the following general formula (a1-3) or a substance represented by the following general formula (a1-4).

[0101] [Chemical Formula 3]

[0102]

[0103] (Where R a1 ~R a5 and n1 and n3 are the same as R in the above general formula (a1-2) a1 ~R a5 Same as n1 and n3.)

[0104] [Chemical Formula 4]

[0105]

[0106] (Where R a1 ~R a4 and n1 and n3 are the same as R in the above general formula (a1-2) a1 ~R a4Same as n1 and n3.)

[0107] The method for producing the indane ring-containing aromatic bismaleimide is not particularly limited, and the indane ring-containing aromatic bismaleimide can be produced by utilizing and applying a known production method.

[0108] Examples of the “derivatives” of the maleimide compounds include addition reaction products of the maleimide compounds having one or more (preferably two or more) N-substituted maleimide groups and amine compounds such as monoamine compounds and diamine compounds.

[0109] Examples of the monoamine compound include monoamine compounds having an acidic substituent such as o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline.

[0110] Examples of the diamine compound include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 2,2'-bis(4,4'-diaminodiphenyl)propane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylethane, 3,3'-diethyl-4,4'-diaminodiphenylethane, and 4,4'-diaminodiphenylethane. ether, 4,4'-diaminodiphenyl sulfide, 3,3'-dihydroxy-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dibromo-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrachloro-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrabromo-4,4'-diaminodiphenylmethane, siloxane diamine and other aromatic diamine compounds, etc.

[0111] (Content of ingredient (A))

[0112] The content of the thermosetting resin (A) in the thermosetting resin composition in the prepreg of the present embodiment is not particularly limited. However, from the viewpoint of heat resistance and formability, it is preferably 5 to 95% by mass, more preferably 30 to 95% by mass, further preferably 50 to 95% by mass, particularly preferably 60 to 95% by mass, and most preferably 70 to 90% by mass, relative to the total mass of the resin components in the thermosetting resin composition.

[0113] ((B) Compound Having Structural Unit (b1) Derived from a Conjugated Diene Compound)

[0114] From the perspective of relative dielectric constant (Dk) in high frequency bands above 10 GHz [hereinafter referred to simply as "relative dielectric constant (Dk)"]., the thermosetting resin composition or cured product thereof in the prepreg of this embodiment contains, as component (B), a compound having a structural unit (b1) derived from a conjugated diene compound.

[0115] In the structural unit (b1) derived from a conjugated diene compound, from the viewpoint of relative dielectric constant (Dk), the conjugated diene compound is preferably at least one selected from butadiene and isoprene, more preferably butadiene, and even more preferably butadiene.

[0116] The structural unit (b1) derived from the conjugated diene compound may be a 1,2-bonding unit of butadiene, a 1,4-bonding unit of butadiene, a 3,4-bonding unit of isoprene, a 1,4-bonding unit of isoprene, or a bonding unit formed by hydrogenating these bonding units. Specifically, as shown in the following structural formula, the bonding units formed by hydrogenating these bonding units include: a "butene unit" as a bonding unit formed by hydrogenating a 1,2-bonding unit of butadiene, an "ethylene unit" as a bonding unit formed by hydrogenating a 1,4-bonding unit of butadiene (usually expressed as such with an eye on the structural units enclosed in parentheses in the following structural formula. It should be noted that the parentheses are for illustrative purposes only and are not intended to divide the structural units.), a structural unit having the above-mentioned butene unit and the above-mentioned ethylene unit. The two ethylene units are “ethylene-butene units”, “isopentene units” (“3-methyl-1-butene units”) which are bonding units formed by hydrogenating the 3,4-bonding units of isoprene, and “ethylene-propylene units” which are bonding units formed by hydrogenating the 1,4-bonding units of isoprene (usually expressed as such with attention paid to the structural units enclosed in parentheses in the following structural formula. It should be noted that the parentheses are for explanation and are not intended to divide the structural units.) etc. (refer to the following structural formula).

[0117] [Chemical Formula 5]

[0118]

[0119] The structural unit (b1) derived from a conjugated diene compound is preferably a butene unit, an ethylene unit, or an ethylene-butene unit, and more preferably an ethylene-butene unit, from the viewpoint of relative dielectric constant (Dk).

[0120] Specific examples of the conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene. Among these, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred.

[0121] The component (B) preferably contains a compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound.

[0122] In the compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound, from the viewpoint of relative dielectric constant (Dk), the content ratio of the structural units [(b1) / (b2)] is preferably 97 / 3 to 50 / 50, more preferably 95 / 5 to 55 / 45, further preferably 92 / 8 to 60 / 40, particularly preferably 90 / 10 to 65 / 35, and may be 97 / 3 to 80 / 20, or may be 85 / 15 to 60 / 40.

[0123] When the content ratio of the structural unit (b1) derived from the conjugated diene compound is increased, the relative dielectric constant (Dk) tends to be excellent and winding deviation of the prepreg tends to be easily suppressed.

[0124] In the structural unit (b2), examples of the aromatic vinyl compound include styrene, α-methylstyrene, 2,4-dimethylstyrene, 1-vinylnaphthalene, 4-methoxystyrene, monochlorostyrene, and divinylbenzene. Among them, styrene is preferred.

[0125] Specific examples of compounds having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound include styrene-based thermoplastic elastomers such as styrene-butadiene-styrene block copolymers (SBS), hydrogenated styrene-butadiene-styrene block copolymers (e.g., SEBS and SBBS), styrene-isoprene-styrene block copolymers (SIS), hydrogenated styrene-isoprene-styrene block copolymers (SEPS), and hydrogenated styrene-(isoprene and butadiene)-styrene block copolymers (SEEPS). Among these, SEBS and SEPS are preferred, with SEBS being more preferred, from the perspectives of relative dielectric constant (Dk) and crack resistance. Here, the above-mentioned SEBS is obtained by hydrogenating the entire butadiene unit of a styrene-butadiene-styrene block copolymer (SBS) and is named after the initials of styrene-ethylene-butylene-styrene. The above-mentioned SBBS is obtained by selectively hydrogenating the 1,2-bonded units in the butadiene unit of a styrene-butadiene-styrene block copolymer (SBS) and is named after the initials of styrene-(1,4-butadiene)-butylene-styrene.

[0126] In a compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound, the hydrogenation rate is preferably 70 mol% or higher, more preferably 80 mol% or higher, even more preferably 90 mol% or higher, and particularly preferably 95 mol% or higher. The upper limit of the hydrogenation rate is not particularly limited and may be 100 mol% or lower or 99 mol% or lower. In other words, the hydrogenation rate may be 70 to 100 mol%.

[0127] The compound having structural units (b1) derived from a conjugated diene compound and structural units (b2) derived from an aromatic vinyl compound may be modified with an acid anhydride such as maleic anhydride. Examples include SEBS modified with an acid anhydride such as maleic anhydride and SEPS modified with an acid anhydride such as maleic anhydride. The acid value of the acid-modified "compound having structural units (b1) derived from a conjugated diene compound and structural units (b2) derived from an aromatic vinyl compound" is not particularly limited, but is preferably 2 to 20 mgCH3ONa / g, more preferably 5 to 15 mgCH3ONa / g, and even more preferably 7 to 13 mgCH3ONa / g.

[0128] The content of the "compound having structural units (b1) derived from a conjugated diene compound and structural units (b2) derived from an aromatic vinyl compound" in the component (B) is not particularly limited and may be 20% by mass or more, 40% by mass or more, 50% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, or 100% by mass.

[0129] The weight average molecular weight (Mw) of the component (B) is not particularly limited, but is preferably 12,000 to 1,000,000, more preferably 30,000 to 500,000, further preferably 50,000 to 250,000, and may be 50,000 to 100,000.

[0130] In the present disclosure, the weight average molecular weight (Mw) is a value measured in terms of polystyrene by gel permeation chromatography (GPC), and more specifically, a value measured by the method described in Examples.

[0131] (Content of component (B))

[0132] When the thermosetting resin composition in the prepreg of the present embodiment contains component (B), the content thereof is not particularly limited. However, from the viewpoint of relative dielectric constant (Dk) and compatibility, the content thereof is preferably 1% by mass or more and less than 14% by mass, more preferably 1 to 13% by mass, further preferably 3 to 12% by mass, 5 to 12% by mass, 6.5 to 11.5% by mass, 6.5 to 9.5% by mass, 8 to 11.5% by mass, 1 to 8% by mass, 3 to 8% by mass, or 5 to 8% by mass, relative to the total amount of the resin components in the thermosetting resin composition.

[0133] When the content of the component (B) is at least the above lower limit, an excellent relative dielectric constant (Dk) tends to be obtained, while when it is at most the above upper limit, good heat resistance, moldability, processability, and flame retardancy tend to be obtained.

[0134] ((C) Inorganic filler)

[0135] When the thermosetting resin composition in the prepreg of this embodiment contains the (C) inorganic filler [hereinafter sometimes referred to as the (C) component], the thermal expansion coefficient tends to be low, and the heat resistance and flame retardancy tend to be improved.

[0136] Component (C) is not particularly limited, and examples thereof include silica, alumina, titanium oxide, mica, beryllium oxide, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay (such as calcined clay), molybdate compounds such as zinc molybdate, talc, aluminum borate, and silicon carbide. Component (C) may be used alone or in combination of two or more. From the perspective of thermal expansion coefficient, heat resistance, and flame retardancy, silica, alumina, mica, and talc are preferred, silica and alumina are more preferred, and silica is even more preferred. Examples of silica include crushed silica, fumed silica, and fused silica (fused spherical silica).

[0137] The shape and particle size of component (C) are not particularly limited. The particle size is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, even more preferably 0.2 to 1 μm, and particularly preferably 0.3 to 0.8 μm. Here, the particle size refers to the average particle size, which is the particle size at the point corresponding to 50% volume when the cumulative frequency distribution curve based on the particle size is calculated, with the total volume of the particles being 100%. The particle size of component (C) can be measured using a particle size distribution analyzer using a laser diffraction scattering method, for example.

[0138] (Content of component (C))

[0139] When the thermosetting resin composition in the prepreg of the present embodiment contains the component (C), the content of the component (C) in the thermosetting resin composition is not particularly limited. From the viewpoint of thermal expansion coefficient, heat resistance, and flame retardancy, the content is preferably 1 to 70 volume %, more preferably 5 to 60 volume %, further preferably 10 to 50 volume %, 10 to 35 volume %, 10 to 25 volume %, 25 to 50 volume %, 30 to 45 volume %, 1 to 50 volume %, or 1 to 30 volume % relative to the total solid content of the thermosetting resin composition.

[0140] When using component (C), a coupling agent may be used as needed to improve the dispersibility of component (C) and the adhesion between component (C) and the organic component in the thermosetting resin composition. The coupling agent is not particularly limited; for example, a silane coupling agent or a titanate coupling agent may be appropriately selected and used. One coupling agent may be used alone or in combination of two or more. The amount of coupling agent used is also not particularly limited.

[0141] When a coupling agent is used, a so-called bulk blending method can be employed, in which component (C) is added to the thermosetting resin composition after the coupling agent is blended. However, it is preferred to use an inorganic filler that has been surface-treated with the coupling agent in a dry or wet process. This method allows the advantages of component (C) to be more effectively demonstrated.

[0142] In this embodiment, when component (C) is used, it can be used in the form of a slurry prepared by pre-dispersing component (C) in an organic solvent, if necessary, to improve its dispersibility in the thermosetting resin composition. Examples of the organic solvent include the same organic solvents described below.

[0143] ((D) Compatibilizer)

[0144] The thermosetting resin composition in the prepreg of this embodiment may further contain a compatibilizer (D) [hereinafter sometimes referred to as component (D)]. Inclusion of component (D) in the thermosetting resin composition tends to improve the compatibility between component (A) and component (B), and further reduce the relative dielectric constant (Dk).

[0145] The compatibilizer (D) is not particularly limited as long as it is a compound that improves the compatibility between the components (A) and (B). For example, if component (A) comprises a maleimide compound and component (B) comprises a compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound, component (D) may include polyphenylene ether, modified polyphenylene ether, conjugated diene polymer, or modified conjugated diene polymer. Modified polyphenylene ethers include compounds in which functional groups have been introduced into polyphenylene ether. Examples of these functional groups include amino, epoxy, carboxyl, styryl, acryloyl, and methacryloyl groups. From the perspective of relative dielectric constant (Dk) and compatibility, acryloyl and methacryloyl groups are preferred, with methacryloyl being more preferred. In other words, methacryloyl-modified polyphenylene ether is preferred as the modified polyphenylene ether. The modified polyphenylene ether may have the above functional groups at the terminal of the polymer chain or inside the polymer chain. It preferably has the above functional groups at the terminal of the polymer chain, and more preferably has the above functional groups at both terminals of the polymer chain.

[0146] The weight-average molecular weight (Mw) of the polyphenylene ether and modified polyphenylene ether is not particularly limited, but is preferably 1,000 to 25,000. When the weight-average molecular weight of the polyphenylene ether and modified polyphenylene ether is 1,000 or greater, the relative dielectric constant (Dk) tends to be improved. Furthermore, when the weight-average molecular weight of the polyphenylene ether and modified polyphenylene ether is 25,000 or less, the compatibility of the thermosetting resin composition is improved, and separation is less likely to occur even after prolonged storage, which tends to improve storage stability. From the same perspective, the weight-average molecular weight of the polyphenylene ether and modified polyphenylene ether is more preferably 1,000 to 20,000, further preferably 1,000 to 15,000, even more preferably 1,200 to 10,000, particularly preferably 1,200 to 5,000, and most preferably 1,200 to 3,000.

[0147] Examples of the conjugated diene compound as a monomer component of the conjugated diene polymer include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene.

[0148] The conjugated diene polymer may be a polymer of one conjugated diene compound, or a copolymer of two or more conjugated diene compounds.

[0149] As the conjugated diene polymer, a conjugated diene polymer having a vinyl group in a side chain is preferred from the viewpoint of compatibility with other resins and relative dielectric constant (Dk).

[0150] The number of side chain vinyl groups in one molecule of the conjugated diene polymer is not particularly limited, but is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more, from the viewpoint of compatibility with other resins and relative dielectric constant (Dk).

[0151] The upper limit of the number of side-chain vinyl groups in one molecule of the conjugated diene polymer is not particularly limited, and may be, for example, 100 or less, 80 or less, or 60 or less.

[0152] Examples of conjugated diene polymers include polybutadiene containing a vinyl group and polyisoprene containing a vinyl group. Among these, polybutadiene containing a vinyl group is preferred from the perspectives of relative dielectric constant (Dk) and heat resistance, and polybutadiene containing a 1,2-vinyl group derived from 1,3-butadiene is more preferred. Furthermore, polybutadiene containing a 1,2-vinyl group derived from 1,3-butadiene is preferably a polybutadiene homopolymer containing a 1,2-vinyl group derived from 1,3-butadiene.

[0153] The 1,2-vinyl group derived from 1,3-butadiene in the conjugated diene polymer refers to a vinyl group contained in the structural unit represented by the following formula (d1).

[0154] [Chemical Formula 6]

[0155]

[0156] When the conjugated diene polymer is polybutadiene containing a 1,2-vinyl group, the content of the structural units containing a 1,2-vinyl group relative to the total structural units derived from butadiene constituting the polybutadiene (hereinafter sometimes referred to as the "vinyl content") is not particularly limited. However, from the perspectives of compatibility with other resins, relative dielectric constant (Dk), and heat resistance, it is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more. The upper limit of the vinyl content is not particularly limited and may be 100 mol% or less, 95 mol% or less, or even 90 mol% or less. The structural units containing a 1,2-vinyl group are preferably those represented by formula (d1) above.

[0157] From the same viewpoint, the polybutadiene having a 1,2-vinyl group is preferably a 1,2-polybutadiene homopolymer.

[0158] The number average molecular weight (Mn) of the conjugated diene polymer is not particularly limited, but is preferably 400 to 3000, more preferably 600 to 2000, and even more preferably 800 to 1500 from the viewpoint of compatibility with other resins, relative dielectric constant (Dk), and heat resistance.

[0159] The modified conjugated diene polymer is a polymer obtained by modifying the above-mentioned conjugated diene polymer.

[0160] The resin composition of the present embodiment contains a modified conjugated diene polymer, thereby having good heat resistance and low thermal expansion, and tends to easily obtain an excellent relative dielectric constant (Dk).

[0161] From the viewpoints of compatibility with other resins, relative dielectric constant (Dk), and adhesion to conductors, the modified conjugated diene polymer is preferably a modified conjugated diene polymer obtained by modifying a conjugated diene polymer having a vinyl group in its side chain with a maleimide compound having two or more N-substituted maleimide groups.

[0162] As the conjugated diene polymer having a vinyl group in a side chain, for example, the conjugated diene polymers described above for the conjugated diene polymer can be used, and preferred embodiments are also the same.

[0163] The conjugated diene polymer having a vinyl group in a side chain may be used alone or in combination of two or more.

[0164] As the maleimide compound having two or more N-substituted maleimide groups, for example, the maleimide compound having two or more N-substituted maleimide groups described in the above-mentioned maleimide compound in the component (A) can be used, and preferred embodiments are the same.

[0165] Examples of the maleimide compound having two or more N-substituted maleimide groups include maleimides containing an aliphatic hydrocarbon group, such as N,N'-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, bis(4-maleimidocyclohexyl)methane, and 1,4-bis(maleimidomethyl)cyclohexane; and N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N,N'-[1,3-(4-methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, 3,3'-dimethyl-5,5'-diethyl-4,4 Maleimides containing aromatic hydrocarbon groups, such as '-diphenylmethane bismaleimide, bis(4-maleimidephenyl) ether, bis(4-maleimidephenyl) sulfone, bis(4-maleimidephenyl) sulfide, bis(4-maleimidephenyl) ketone, 1,3-bis(4-maleimidephenoxy)benzene, bis[4-(3-maleimidephenoxy)phenyl]methane, 2,2-bis[4-(3-maleimidephenoxy)phenyl]propane, 2,2-bis[4-(4-maleimidephenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidephenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,4-bis[4-(4-maleimidephenoxy)-α,α-dimethylbenzyl]benzene, and polyphenylmethane maleimide. Among them, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide is more preferred.

[0166] The maleimide compound having two or more N-substituted maleimide groups may be used alone or in combination of two or more.

[0167] The modified conjugated diene polymer preferably has a substituent in its side chain formed by reacting a side chain vinyl group of a conjugated diene polymer having a side chain vinyl group with an N-substituted maleimide group of a maleimide compound having two or more N-substituted maleimide groups (hereinafter sometimes referred to as "substituent derived from the maleimide compound").

[0168] Regarding the substituent derived from the maleimide compound, from the viewpoints of compatibility with other resins, relative dielectric constant (Dk), low thermal expansion and heat resistance, the structure derived from the maleimide compound having two or more N-substituted maleimide groups is preferably a group containing a structure represented by the following general formula (d2) or (d3).

[0169] [Chemical Formula 7]

[0170]

[0171] (Where X d1 A divalent group formed by removing two N-substituted maleimide groups from a maleimide compound having two or more N-substituted maleimide groups. d1 This is a site bonded to a carbon atom derived from a vinyl group in a side chain of a conjugated diene polymer having a vinyl group in a side chain. d2 The site where atoms bond to other atoms.)

[0172] The modified conjugated diene polymer preferably has a substituent derived from a maleimide compound and a vinyl group in a side chain.

[0173] The vinyl group of the modified conjugated diene polymer is preferably a 1,2-vinyl group derived from 1,3-butadiene.

[0174] The number average molecular weight (Mn) of the modified conjugated diene polymer is not particularly limited, but is preferably 700 to 6000, more preferably 800 to 5000, and even more preferably 1000 to 2500 from the viewpoints of compatibility with other resins, relative dielectric constant (Dk), low thermal expansion, and heat resistance.

[0175] The modified conjugated diene polymer can be produced by reacting a conjugated diene polymer having a vinyl group in its side chain with a maleimide compound having two or more N-substituted maleimide groups.

[0176] The method for reacting a conjugated diene polymer having a vinyl group in its side chain with a maleimide compound having two or more N-substituted maleimide groups is not particularly limited. For example, a conjugated diene polymer having a vinyl group in its side chain, a maleimide compound having two or more N-substituted maleimide groups, a reaction catalyst, and an organic solvent are placed in a reaction vessel and reacted while heating, maintaining the temperature, and stirring as necessary to obtain a modified conjugated diene polymer.

[0177] When the above reaction is carried out, the molar number of N-substituted maleimide groups (Mm ) relative to the molar number of the side chain vinyl groups of the conjugated diene polymer having vinyl groups in the side chain (M v ) ratio (M m / M v ) is not particularly limited, but is preferably 0.001 to 0.5, more preferably 0.005 to 0.1, and even more preferably 0.008 to 0.05, from the viewpoint of compatibility of the obtained modified conjugated diene polymer with other resins and suppression of gelation of the product during the reaction.

[0178] (Content of component (D))

[0179] When the thermosetting resin composition in the prepreg of this embodiment contains component (D), the content of component (D) in the thermosetting resin composition is not particularly limited. However, from the perspective of relative dielectric constant (Dk) and compatibility, it is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, even more preferably 5 to 25% by mass, particularly preferably 5 to 20% by mass, and most preferably 5 to 15% by mass relative to the total resin components of the thermosetting resin composition. When the content of component (D) is at least the lower limit, relative dielectric constant (Dk) and compatibility tend to be improved. When the content of component (D) is at most the upper limit, heat resistance, formability, and processability tend to be improved.

[0180] ((E) Curing accelerator)

[0181] The thermosetting resin composition in the prepreg of the present embodiment may further contain (E) a curing accelerator [hereinafter, sometimes referred to as component (E)].

[0182] Examples of the component (E) include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, organic metal salts, acidic catalysts, and organic peroxides. It should be noted that, in this disclosure, imidazole-based curing accelerators are not classified as amine-based curing accelerators. A single curing accelerator may be used alone, or two or more may be used in combination. The curing accelerator preferably includes at least one selected from the group consisting of imidazole-based curing accelerators and organic peroxides.

[0183] Examples of the imidazole-based curing accelerator include imidazole compounds such as methylimidazole, phenylimidazole, and 2-undecylimidazole; and isocyanate-masked imidazoles such as addition reaction products of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole.

[0184] Examples of the organic peroxide include dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3-ol, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylperoxyisopropyl monocarbonate, and α,α′-bis(tert-butylperoxy)diisopropylbenzene.

[0185] ((E) Content of curing accelerator)

[0186] When the thermosetting resin composition in the prepreg of this embodiment contains component (E), the content of component (E) is not particularly limited, but is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, even more preferably 0.1 to 3.5 parts by mass, and particularly preferably 0.3 to 2.5 parts by mass, relative to 100 parts by mass of component (A) in the thermosetting resin composition. When the content of the curing accelerator (E) is within this range, better heat resistance, storage stability, and moldability tend to be achieved.

[0187] (Other ingredients)

[0188] The thermosetting resin composition in the prepreg of this embodiment preferably further comprises one or more selected from flame retardants, flame retardant aids, antioxidants, adhesion improvers, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, and lubricants as other ingredients. In addition, it may also contain ingredients other than those mentioned above.

[0189] When the thermosetting resin composition contains other components (flame retardants, flame retardant aids, antioxidants, adhesion enhancers, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, and other components), the content of each component is not particularly limited. For example, the content may be 0.01% by mass or greater, 10% by mass or less, 5% by mass or less, or even 1% by mass or less, relative to the total amount of the resin components in the thermosetting resin composition. The thermosetting resin composition may not contain these other components.

[0190] (Organic solvent)

[0191] From the viewpoint of ease of handling and ease of producing a resin film, the thermosetting resin composition may be prepared as a so-called "varnish" containing an organic solvent before producing a resin film.

[0192] The organic solvent is not particularly limited, but examples thereof include: alcohol solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester solvents such as γ-butyrolactone. Ketone solvents are preferred from the perspective of solubility, with methyl ethyl ketone being more preferred. The organic solvent may be used alone or in combination of two or more.

[0193] When the thermosetting resin composition is used as a varnish, the solid content concentration is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 60% by mass. When the solid content concentration of the thermosetting resin composition is within this range, the thermosetting resin composition is easy to handle, the coating properties when formed into a resin film are improved, and the appearance of the prepreg tends to be improved.

[0194] The thermosetting resin composition can be produced by mixing component (A) and component (B), and optionally the aforementioned components, using a known method. In this case, the components can be dissolved or dispersed in the aforementioned organic solvent while stirring. Conditions such as the mixing order, temperature, and time are not particularly limited and can be set arbitrarily.

[0195] [Laminated board]

[0196] The laminated plate of the present embodiment includes a cured product of the prepreg of the present embodiment and a metal foil.

[0197] The laminated plate of this embodiment can be manufactured, for example, by placing metal foil on one or both sides of a single prepreg of this embodiment, or placing metal foil on one or both sides of a laminated product obtained by stacking two or more prepregs of this embodiment, and then performing heat and pressure molding. In the laminated plate obtained by this manufacturing method, the prepreg of this embodiment is C-staged. In this disclosure, C-stage refers to the state of forming a C-stage as defined in JIS K6900 (1994). It should be noted that a laminated plate having a metal foil is sometimes also referred to as a metal-clad laminated plate.

[0198] The metal of the metal foil is not particularly limited. From the perspective of conductivity, it can be copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing one or more of these metal elements. Copper and aluminum are preferred, and copper is more preferred.

[0199] The method for performing heat and pressure molding is not particularly limited, and can be performed, for example, at a temperature of 100 to 300°C, a pressure of 0.2 to 10 MPa, and a time of 0.1 to 5 hours. Alternatively, heat and pressure molding can be performed by maintaining a vacuum state for 0.5 to 5 hours using a vacuum press or the like.

[0200] [Printed circuit board]

[0201] The printed wiring board of this embodiment includes a cured product of the prepreg of this embodiment. The printed wiring board of this embodiment may include one or more selected from the group consisting of a cured product of the prepreg of this embodiment and a laminate of this embodiment.

[0202] The printed wiring board of this embodiment can be manufactured by using one or more of the prepregs and laminates of this embodiment and performing circuit forming processing such as hole drilling, metal plating, and metal foil etching using known methods. Furthermore, by further performing multilayer bonding processing as needed, a multilayer printed wiring board can also be manufactured. In the printed wiring board of this embodiment, the prepreg of this embodiment is C-staged.

[0203] [Semiconductor Package]

[0204] The semiconductor package of this embodiment is a semiconductor package comprising a printed wiring board of this embodiment and a semiconductor element. The semiconductor package of this embodiment can be manufactured by mounting a semiconductor element such as a semiconductor chip or memory on a predetermined position of the printed wiring board of this embodiment using a known method, and then sealing the semiconductor element with a sealing resin or the like.

[0205] The prepreg, laminate, printed wiring board, and semiconductor package of this embodiment can be suitably used in electronic devices that process high-frequency signals of 10 GHz or higher. In particular, the printed wiring board is useful as a printed wiring board for millimeter-wave radar.

[0206] Example

[0207] Hereinafter, the present embodiment will be described in detail with reference to examples, but the present embodiment is not limited to the following examples.

[0208] In addition, in each example, the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by the following method.

[0209] (Method for measuring weight average molecular weight (Mw) and number average molecular weight (Mn))

[0210] Gel permeation chromatography (GPC) was used to convert the concentration using a calibration curve using standard polystyrene. The calibration curve used standard polystyrene: TSK standard POLYSTYRENE (Types: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, trade name], and a cubic equation was used for approximation. The GPC measurement conditions are shown below.

[0211] Device:

[0212] Pump: L-6200 [Hitachi High-Technologies Co., Ltd.]

[0213] Detector: L-3300 RI [manufactured by Hitachi High-Technologies Co., Ltd.]

[0214] Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Co., Ltd.]

[0215] Column: Guard column; TSK Guardcolumn HHR-L + column; TSKgel G4000HHR + TSKgel G2000HHR (both manufactured by Tosoh Corporation, trade names)

[0216] Column size: 6.0×40mm (guard column), 7.8×300mm (column)

[0217] Eluent: tetrahydrofuran

[0218] Sample concentration: 30mg / 5mL

[0219] Injection volume: 20 μL

[0220] Flow rate: 1.00mL / min

[0221] Measurement temperature: 40°C

[0222] In addition, each evaluation and each measurement method in each example are shown below.

[0223] [Evaluation and measurement methods]

[0224] (1. Existence ratio of concave portions in the concavo-convex shape of the prepreg surface)

[0225] The ratio of concave portions in the concave-convex shape of the prepreg surface produced in each example was observed using a SEM (scanning electron microscope) over a 524.2 μm × 669.2 μm area in the center of the prepreg surface, and an SEM image was obtained. This SEM image was set using the programming language "Python (パイソン)" Figure 1 The procedure shown in FIG. 4 is followed to obtain a binary image of the above-mentioned SEM image. Next, the ratio of white to black in the binary image is determined and used as the ratio of concave portions in the concave-convex shape of the prepreg surface. Figures 2 to 7 On the left side, the binarized image is shown in Figures 2 to 7 on the right side.

[0226] (2. Surface roughness of prepreg (Rz))

[0227] The surface roughness (Rz) of the prepreg produced in each example was measured. The details are as follows.

[0228] First, a reference length is extracted from the roughness curve along its mean line. Within this extracted portion, the sum of the absolute values ​​of the peak elevations from the highest peak to the fifth peak and the absolute values ​​of the valley elevations from the lowest valley to the fifth valley is calculated, using the mean line as a reference. This sum is then calculated as the value Rz expressed in micrometers (μm). Rz is measured using a VK-X250 shape analysis laser microscope (manufactured by KEYENCE Co., Ltd.).

[0229] (3. Prepreg winding deviation)

[0230] The prepreg (100 m long, 400 mm wide) produced in each example was wound onto a core with a diameter of 9.2 cm. The length of the prepreg protruding from the end of the core after winding 100 m from the end of the first turn was measured, and winding deviation was evaluated according to the following evaluation criteria.

[0231] A: The length of the protruding prepreg is less than 1.0 mm.

[0232] B: The length of the protruding prepreg is 1.0 mm or more and less than 5.0 mm.

[0233] C: The length of the protruding prepreg is 5.0 mm or more and less than 10.0 mm.

[0234] D: The length of the protruding prepreg is 10.0 mm or more.

[0235] (4. Relative dielectric constant (Dk))

[0236] The outer copper foil of the double-sided copper-clad laminate obtained in each example was removed by immersing it in a copper etching solution (a 10% by mass solution of ammonium persulfate, manufactured by Mitsubishi Gas Chemical Co., Ltd.). The resulting pieces were then cut into 60 mm long and 2 mm wide sections to serve as test pieces. The relative dielectric constant (Dk) was measured using the cavity resonator perturbation method using the Agilent Technologies vector network analyzer "N5222B," the cavity resonator used was the "CP129" (10 GHz band resonator) manufactured by Kanto Electronics Application Development Co., Ltd., and the measurement program used was "CPMA-V2." Measurements were performed at a frequency of 10 GHz and a temperature of 25°C.

[0237] Production Example 1 [Production of Modified Conjugated Diene Polymer (for Component (D))]

[0238] Into a 2-L container equipped with a thermometer, reflux condenser, and stirring device capable of heating and cooling, 100 parts by mass of a 1,2-polybutadiene homopolymer (number average molecular weight (Mn) = 1200, vinyl content = 85% or greater), 4.4 parts by mass of an indane ring-containing aromatic bismaleimide, 0.1 parts by mass of α,α'-bis(tert-butylperoxy)diisopropylbenzene, and toluene as an organic solvent were placed. The mixture was then stirred at 90-100°C for 5 hours under a nitrogen atmosphere to obtain a solution of a modified conjugated diene polymer with a solids concentration of 35% by mass.

[0239] [Examples 1 and 2]

[0240] (Preparation of Thermosetting Resin Composition (Varnish))

[0241] The components described in Table 1 were mixed and stirred at room temperature together with methyl ethyl ketone according to the contents described in Table 1 to prepare a thermosetting resin composition (varnish) having a solid content concentration of 55% by mass.

[0242] (Production of a Supported Resin Film)

[0243] The varnish obtained above was applied to a PET film (manufactured by Toray Industries, Ltd., thickness: 50 μm, surface roughness Rz: 6.5 μm, trade name: Lumirror 50X44) as a support with irregularities using a comma coater. The film was then heated and dried at 120°C for 3 minutes to produce a support-attached resin film. The dried film had a thickness of 10 μm.

[0244] (Prepreg production)

[0245] Two sheets of the support-attached resin film obtained above were placed, one on each side, on the front and back sides of a 15μm-thick glass woven fabric (NE glass, manufactured by Asahi Kasei Corporation), with the support-attached resin film contacting the glass woven fabric. The resulting "PET film / resin film / glass cloth / resin film / PET film" laminate was vacuum laminated using a vacuum laminator at a hot plate temperature of 100°C, a pressing pressure of 0.3 MPa, a vacuum level of 100 kPa or less, and a vacuum time of 20 seconds. The PET support film was then removed to produce a 30μm-thick prepreg (length: 100 m, width: 400 mm). The prepreg thickness is the average of values ​​measured using a digital micrometer (manufactured by Mitutoyo Co., Ltd.) and a horizontal stand at five arbitrary locations.

[0246] The obtained prepreg was subjected to various evaluations and measurements by the above-mentioned methods. The results are shown in Table 1.

[0247] (Production of double-sided copper-clad laminates)

[0248] The resulting prepreg was cut into a size of 400 mm x 500 mm, and a low-profile copper foil (3M-VLP12, manufactured by Mitsui Mining & Smelting Co., Ltd., "VLP" is a registered trademark) with a thickness of 12 μm was arranged on the upper and lower sides thereof with the M side (matt side) in contact with the prepreg. After that, heat and press molding was performed at a temperature of 230°C, a pressure of 3.0 MPa, and a time of 90 minutes to produce a double-sided copper-clad laminate (thickness: 0.30 mm).

[0249] The relative dielectric constant (Dk) of the obtained double-sided copper-clad laminate was measured by the above-mentioned method. The results are shown in Table 1.

[0250] [Example 3]

[0251] In Example 1, a prepreg and a double-sided copper-clad laminate were produced by the same procedures as in Example 1, except that a PET film (manufactured by Toyobo Co., Ltd., thickness: 50 μm, surface roughness Rz: 0.1 μm, trade name: Purex A5300; "Purex" is a registered trademark, the same shall apply hereinafter) was used instead of a PET film (manufactured by Toray Industries, Ltd., thickness: 50 μm, surface roughness Rz: 6.5 μm, trade name: Lumirror 50X44). The evaluation and measurement results are shown in Table 1.

[0252] [Example 4]

[0253] In Example 2, a prepreg and a double-sided copper-clad laminate were produced by the same procedures as in Example 2, except that a PET film (manufactured by Toyobo Co., Ltd., thickness: 50 μm, surface roughness Rz: 0.1 μm, trade name: Purex A5300) was used instead of a PET film (manufactured by Toray Industries, Ltd., thickness: 50 μm, surface roughness Rz: 6.5 μm, trade name: Lumirror 50X44). The evaluation and measurement results are shown in Table 1.

[0254] [Comparative Example 1]

[0255] In Example 1, a prepreg and a double-sided copper-clad laminate were produced by the same procedures as in Example 1, except that a PET film (manufactured by Toray Industries, Ltd., thickness: 50 μm, surface roughness Rz: 8.5 μm, trade name: Lumirror 50X42) was used instead of a PET film (manufactured by Toray Industries, Ltd., thickness: 50 μm, surface roughness Rz: 6.5 μm, trade name: Lumirror 50X44). The results of the evaluations and measurements are shown in Table 1.

[0256] [Comparative Example 2]

[0257] In Example 2, a prepreg and a double-sided copper-clad laminate were produced by the same procedures as in Example 2, except that a PET film (manufactured by Toray Industries, Ltd., thickness: 50 μm, surface roughness Rz: 8.5 μm, trade name: Lumirror 50X42) was used instead of a PET film (manufactured by Toray Industries, Ltd., thickness: 50 μm, surface roughness Rz: 6.5 μm, trade name: Lumirror 50X44). The evaluation and measurement results are shown in Table 1.

[0258] [Table 1]

[0259]

[0260] The details of the components described in Table 1 are as follows.

[0261] [(A) Thermosetting resin]

[0262] Maleimide compound A-1: ​​an aromatic bismaleimide containing an indane ring represented by the general formula (a1-2)

[0263] Maleimide compound A-2: biphenyl aralkyl type maleimide

[0264] [(B) Compound Having Structural Unit (b1) Derived from a Conjugated Diene Compound]

[0265] Styrene-based thermoplastic elastomer B-1: hydrogenated styrene-butadiene-styrene block copolymer (SEBS), hydrogenation rate 95 mol% or more, styrene content 30% by mass, weight average molecular weight (Mw) = 70,000

[0266] [(C) Inorganic filler]

[0267] Inorganic filler C-1: spherical fused silica, average particle size = 0.5 μm

[0268] [(D) Compatibilizer]

[0269] Modified polyphenylene ether D-1: a polyphenylene ether derivative having methacryloyl groups at both ends, represented by the following formula, with a weight average molecular weight of 1700

[0270] [Chemical Formula 8]

[0271]

[0272] (In the above formula, x1 and x2 are each independently 0 to 20.)

[0273] Modified conjugated diene polymer D-2: the modified conjugated diene polymer prepared in Preparation Example 1

[0274] [(E) Curing accelerator]

[0275] Curing accelerator E-1: α,α'-bis(tert-butylperoxy)diisopropylbenzene

[0276] Curing accelerator E-2: Isocyanate-masked imidazole "G8009L" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name)

[0277] The results in Table 1 show that in Examples 1 to 4, in the prepregs containing a compound having a structural unit derived from a conjugated diene compound and having a low relative dielectric constant (Dk), the presence ratio of the concave portions in the concavo-convex shape is less than 30%, thereby suppressing winding deviation of the prepreg.

[0278] On the other hand, in Comparative Examples 1 and 2, which similarly contained a compound having a structural unit derived from a conjugated diene compound and obtained a prepreg having a low relative dielectric constant (Dk), the presence ratio of concave portions in the uneven shape of the prepreg surface was 59%, resulting in increased winding deviation of the prepreg.

Claims

1. A prepreg comprising a thermosetting resin composition or a semi-cured product of the thermosetting resin composition, wherein the thermosetting resin composition comprises: (A) thermosetting resins; and (B) a compound having a structural unit (b1) derived from a conjugated diene compound, The prepreg has a concavo-convex shape on the surface, The presence ratio of the concave portions in the concavo-convex shape is less than 30%. 2 . The prepreg according to claim 1 , wherein the surface roughness Rz is 0.1 μm to 12.0 μm.

3. The prepreg according to claim 1, wherein The component (A) comprises at least one selected from epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins.

4. The prepreg according to claim 1, wherein In the component (B), the structural unit (b1) derived from the conjugated diene compound is a 1,2-bonding unit of butadiene, a 1,4-bonding unit of butadiene, a 3,4-bonding unit of isoprene, a 1,4-bonding unit of isoprene, or a hydrogenated bonding unit of at least one selected from these bonding units.

5. The prepreg according to claim 1, wherein In the thermosetting resin composition, the content of the component (B) is 1% by mass or more and less than 14% by mass based on the total amount of the resin components. The prepreg according to claim 1 , wherein: The thermosetting resin composition further contains (C) an inorganic filler.

7. The prepreg according to claim 6, wherein In the thermosetting resin composition, the content of the component (C) is 1% by volume to 70% by volume based on the total solid content.

8. The prepreg according to claim 1, wherein The thermosetting resin composition further contains (D) a compatibilizer.

9. The prepreg according to claim 1, wherein The thermosetting resin composition further contains (E) a curing accelerator. 10 . A laminate comprising a cured product of the prepreg according to claim 1 and a metal foil.

11. A printed wiring board comprising a cured product of the prepreg according to any one of claims 1 to 9. 12 . A semiconductor package comprising the printed wiring board according to claim 11 and a semiconductor element.

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