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

Abstract

Provided is a prepreg or the like in which adhesion between prepregs is reduced despite containing a compound having a structural unit derived from a conjugated diene compound. 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 30-90%.

Description

Technical Field

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

[0002] In various electronic devices such as mobile communication devices typified by mobile phones, network infrastructure devices such as their base station devices, servers, and routers, and mainframe computers, the high-speed and large-capacity of signals used have been developing year by year. Along with this, printed circuit boards mounted on these electronic devices need to cope with high frequencies, and a substrate material having excellent dielectric properties (relative dielectric constant and dielectric loss tangent) in a high-frequency band (for example, a high-frequency band of 10 GHz or higher) capable of reducing transmission loss is required. In recent years, in addition to the above-mentioned electronic devices, in the ITS field related to automobiles and transportation systems, and in the indoor short-range communication field, the practical application or practical plan of a new system for processing high-frequency wireless signals is also developing, and a substrate material with low transmission loss is required for printed circuit boards mounted on these devices.

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

[0004] Prior Art Documents

[0005] Patent Documents

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

[0007] Problems to be Solved by the Invention

[0008] However, the inventors further studied and found that if a plurality of prepregs formed using a resin composition containing a compound having a structural unit derived from a conjugated diene compound such as a styrene-based thermoplastic elastomer are overlapped, there is a tendency to adhere to each other and be difficult to peel. Therefore, it was clarified that in the transportation of prepregs and in the manufacture of laminates, the operation of temporarily peeling and then re-overlapping the firmly adhered prepregs so that their lengths and widths are aligned with each other sometimes becomes difficult, which may be a problem in industrial implementation.

[0009] In view of such a situation, an object of the present disclosure is to provide a prepreg in which, although it contains a compound having a structural unit derived from a conjugated diene compound, the adhesion between prepregs is reduced, and to provide a laminate, a printed wiring board, and a semiconductor package obtained by using the prepreg.

[0010] Means for Solving the Problem

[0011] The inventors of the present invention repeatedly conducted in-depth studies and found that the above object can be achieved if it is a prepreg of the present disclosure.

[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 above thermosetting resin composition, the thermosetting resin composition containing: (A) a thermosetting resin and (B) a compound having a structural unit (b1) derived from a conjugated diene compound, the surface of the prepreg having an uneven shape,

[0014] The ratio of the presence of recesses in the above uneven shape is 30 to 90%.

[0015] [2] The prepreg according to [1] above, having a surface roughness (Rz) of 12.0 μm or more.

[0016] [3] The prepreg according to [1] or [2] above, wherein the component (A) includes at least one selected from epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate ester 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 a conjugated diene compound is a 1,2-bonded unit of butadiene, a 1,4-bonded unit of butadiene, a 3,4-bonded unit of isoprene, a 1,4-bonded unit of isoprene, or a bonded unit obtained by hydrogenating at least one selected from these bonded units.

[0018] [5] The prepreg according to any one of [1] to [4] above, wherein in the thermosetting resin composition, the content of the component (B) is 1% by mass or more and less than 14% by mass relative to the total 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] According to the prepreg described in [6] above, wherein, in the above thermosetting resin composition, the content of the above component (C) is 1 to 50% by volume based on the total solid components.

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

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

[0023]

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

[0024]

[11] A printed wiring board having a cured product of the prepreg described in any one of [1] to [9] above.

[0025]

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

[11] above and a semiconductor element.

[0026] Advantages of the Invention

[0027] According to the present disclosure, it is possible to provide a prepreg in which, although it contains a compound having a structural unit derived from a conjugated diene compound, the adhesion between the prepregs is reduced, and a laminate, a printed wiring board, and a semiconductor package obtained by using the prepreg. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a program set by Python during binarization processing.

[0029] Figure 2 It is an SEM image (left figure) of the surface of the prepreg in Example 1 and an image (right figure) obtained by binarizing it.

[0030] Figure 3 It is an SEM image (left figure) of the surface of the prepreg in Example 2 and an image (right figure) obtained by binarizing it.

[0031] Figure 4 It is an SEM image (left figure) of the surface of the prepreg in Comparative Example 1 and an image (right figure) obtained by binarizing it.

[0032] Figure 5 It is an SEM image (left figure) of the surface of the prepreg in Comparative Example 2 and an image (right figure) obtained by binarizing it.

[0033] Figure 6 These are the SEM images of the prepreg surface in Comparative Example 3 (left figure) and the image obtained by binarizing it (right figure).

[0034] Figure 7 These are the SEM images of the prepreg surface in Comparative Example 4 (left figure) and the image obtained by binarizing it (right figure). Detailed implementation mode

[0035] In the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range can be replaced with the values shown in the examples. Additionally, the lower limit value and the upper limit value of the numerical range can be arbitrarily combined with the lower limit value or the upper limit value of other numerical ranges. In the expression of the numerical range "AA to BB", the two end values AA and BB are respectively included in the numerical range as the lower limit value and the upper limit value.

[0036] In the present disclosure, for example, the description "10 or more" means 10 and values exceeding 10, and the same applies in cases where the numerical values are different. Additionally, for example, the description "10 or less" means 10 and values less than 10, and the same applies in cases where the numerical values are different.

[0037] Furthermore, unless otherwise specified, each component and material exemplified in the present disclosure can be used alone in one kind, or two or more kinds can be used in combination. In the present disclosure, regarding the content of each component in the composition, in the case where there are multiple substances corresponding to each component in the composition, unless otherwise specified, it 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 components constituting the resin composition except for inorganic compounds such as the inorganic filler described later.

[0039] In the present disclosure, the "solid component" refers to components other than the solvent, and components that are liquid at 25°C are also regarded as solid components.

[0040] Regarding the expression "containing (including) XX" described in the present disclosure, in the case where XX can react, it can contain XX in a state where XX has reacted, or can directly contain only XX, or can include both of these two methods.

[0041] The ways of arbitrarily combining the matters described in the present disclosure are also included in the present disclosure and this implementation mode.

[0042] [Prepreg]

[0043] The prepreg of this implementation mode is as follows.

[0044] A prepreg comprising a thermosetting resin composition or a semi-cured product of the above thermosetting resin composition, the thermosetting resin composition containing (A) a thermosetting resin and (B) a compound having a structural unit (b1) derived from a conjugated diene compound, and the surface of the prepreg having an uneven shape.

[0045] The presence ratio of the concave portions in the above uneven shape is 30 to 90%.

[0046] Herein, the above "surface" does not include the surfaces in the thickness direction of the prepreg, i.e., the side surfaces of the prepreg.

[0047] By making the presence ratio of the concave portions in the uneven shape on the surface of the prepreg of the present embodiment 30 to 90%, although containing the above component (B) which causes the adhesion between prepregs, the adhesion between prepregs is reduced. Regarding the reason for obtaining this effect, it is speculated as follows. By making the presence ratio of the concave portions in the uneven shape 30 to 90%, the contact area is reduced when the prepregs are overlapped with each other. As a result, it is considered that the adhesion can be reduced to a level that is not problematic in industrial implementation. Whether this speculation is correct has no influence on the scope of the present disclosure.

[0048] In the uneven shape on one or both sides of the prepreg, the presence ratio of the concave portions is preferably 30 to 90%. In addition, based on the above speculation, it is more preferably that the presence ratios of the concave portions on both sides of the prepreg are 30 to 90% respectively.

[0049] The presence ratio of the concave portions in the uneven shape on the surface of the prepreg of the present embodiment is obtained by the following method: performing binarization processing on an image obtained by observing an arbitrary 524.2 μm × 669.2 μm range on the surface of the prepreg using SEM (scanning electron microscope) to obtain a binarized image, and obtaining it from the presence ratios of white and black in the binarized image, and taking the presence ratio of the black as the presence ratio of the concave portions. The observation using SEM can be performed at one place. Wherein, in the case of performing it at multiple places, it is sufficient that the presence ratio of the concave portions is within the above range at one of them. Preferably, the presence ratio of the concave portions is within the above range at more than half of the parts, more preferably at 80% or more of the parts, and further preferably at all of the parts. The SEM image can be set at a magnification of 50 to 500 times, or can also be set at a magnification of 100 times.

[0050] It should be noted that in the above binarization processing, there is no particular limitation, and a binarized image can be obtained by setting the Figure 1 program shown by using the programming language "Python 3.7.9".

[0051] Regarding the setting in Python Figure 1The program shown below will be briefly described.

[0052] import cv2: This is a program to read the OpenCV2 library.

[0053] from matplotlib import pyplot: This is a program to read pyplot in matplotlib for chart drawing.

[0054] import numpy as np: This is a program to read the numpy library and define numpy as np.

[0055] img = cv2.imread: This is a program to read an image. Enter the image file name at the part of "enter the image file name to be read here" above.

[0056] img1 = img[0:600, 0:1280]: This is a program to specify the size of the image to be read.

[0057] cv2.imwrite("out_sample1.jpg", img1): This is a program to save the image specified based on numpy information as sample1.jpg in CV2.

[0058] print("Pixel_original:", img.shape): This is a program to obtain 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.

[0059] img_bw = cv2.imread('out_sample1.jpg', 0): This is a program to detect the image file saved as sample1 in CV2.

[0060] hit, wid = img_bw.shape: This is a program to read the image file saved as sample1 in CV2.

[0061] from numpy import sum: This is a program to read the numpy program.

[0062] img_bw_m = np.where(img_bw < 150, 1, 0)

[0063] pyplot.imshow(img_bw_m)

[0064] print("Rust ratio is :", sum(img_bw_m) / (hit * wid) * 100, '%'): These three lines are the program for cutting out the parts darker than the tone 150.

[0065] More specifically, the existence ratio of the concave portion is calculated by the method described in the examples using the above binarized image.

[0066] From the viewpoint of reducing the adhesion between prepregs, the existence ratio of the concave portion in the above uneven shape is preferably 40 to 90%, more preferably 45 to 90%, further preferably 50 to 90%, may be 50 to 80%, may also be 50 to 70%, and may further be 55 to 65%.

[0067] The above uneven shape is not particularly limited, and examples thereof include needle shape, triangular pyramid shape, quadrangular pyramid shape, cuboid shape, spherical shape, conical shape, cylindrical shape, irregular shape, and combinations thereof.

[0068] The method for forming the uneven shape on the surface of the prepreg is not particularly limited, and the following methods can be listed. First, a thermosetting resin composition is coated on a support having an uneven shape and then dried to produce a resin film with a support. The drying temperature and drying time can be appropriately determined according to the content of the organic solvent in the thermosetting resin composition and the boiling point of the organic solvent, etc. Usually, by drying at preferably 50 to 200 °C (more preferably 80 to 160 °C) for about 1 to 10 minutes, a resin film can be appropriately formed. In the resin film with a support, the thickness of the resin film is not particularly limited, preferably 1 to 100 μm, more preferably 3 to 70 μm, further preferably 5 to 35 μm, and particularly preferably 5 to 25 μm.

[0069] Next, prepare two resin films with supports, impregnate one resin film with a support on each of the front and back surfaces of the sheet-like fiber base material described below, then peel off the support and dry it to obtain a prepreg. If this method is used, an uneven shape caused by the uneven shape of the support is imparted to the resin film. Therefore, by using this resin film to produce a prepreg, a prepreg having an uneven shape on the surface can be obtained. It should be noted that by adjusting the viscosity of the thermosetting resin composition when producing the resin film with a support, or by adjusting the particle size of the inorganic filler in the resin film, etc., the uneven shape of the above prepreg can also be adjusted.

[0070] As the above-mentioned support, plastic films such as polyester films and polyolefin films; metal foils, etc. can be cited. As the above-mentioned polyester film, PET (polyethylene terephthalate) film, polyethylene naphthalate film, etc. can be cited. As the above-mentioned polyolefin film, polyethylene film, polypropylene film, polyvinyl chloride film, etc. can be cited. As the metal foil, copper foil, aluminum foil, etc. can be cited. Among them, as the support, a plastic film is preferred, a polyester film is more preferred, and a PET film is even more preferred.

[0071] It should be noted that the above-mentioned support having a concavo-convex shape can be produced by mixing particles into the support. The concavo-convex shape can be adjusted by the amount of the particles mixed in. The more the amount of the particles used, the greater the tendency for the concavo-convex shape to become larger. The less the amount of the particles used, the smaller the tendency for the concavo-convex shape to become smaller. From the same viewpoint, the amount of the particles mixed into the support is not particularly limited, and it is preferably an amount of 30 to 90% of the surface of the support, more preferably an amount of 60 to 90% of the surface of the support, and further preferably an amount of 80 to 90% of the surface of the support.

[0072] As the above-mentioned particles mixed into the support, particles of the following (C) inorganic filler; particles of organic filler, etc. can be cited. As the particles of the above-mentioned organic filler, crosslinked NBR particles obtained by copolymerizing acrylonitrile and butadiene, copolymers of acrylonitrile and butadiene such as copolymers of acrylonitrile, butadiene and carboxylic acids such as acrylic acid; so-called core-shell rubber particles having a core of polybutadiene, NBR, silicone rubber, etc. and a shell of an acrylic derivative, etc. can be cited.

[0073] In addition, as the support having a concavo-convex shape, commercially available products such as U4000 of the "TOYOBO ESTER (registered trademark) FILM" series manufactured by Toyobo Co., Ltd.; X42 of the "Lumirror (registered trademark)" series manufactured by Toray Industries, Inc. can also be used.

[0074] As described above, the prepreg of the present embodiment contains a thermosetting resin composition or a semi-cured product of the above-mentioned thermosetting resin composition, and the thermosetting resin composition contains (A) a thermosetting resin and (B) a compound having a structural unit (b1) derived from a conjugated diene compound.

[0075] The prepreg of the present embodiment is not particularly limited, and can be produced using a resin film formed from the above thermosetting resin composition and a sheet-like fiber substrate. As described above, the resin film formed from the above thermosetting resin composition uses a resin film with a support. After impregnating the resin film with a support into the sheet-like fiber substrate, it is heated and dried, and semi-cured (B-staged) as needed, whereby the prepreg of the present embodiment can be obtained. More specifically, after impregnating the resin film with a support into the sheet-like fiber substrate, after peeling off the support, it is heated and dried in a drying furnace usually at 80 to 200 °C for 1 to 30 minutes to be semi-cured (B-staged), whereby the prepreg of the present embodiment can be manufactured.

[0076] It should be noted that in the present disclosure, B-staging refers to the state of forming the B-stage defined in JIS K6900 (1994).

[0077] As the above sheet-like fiber substrate, known sheet-like fiber substrates used in various laminated boards for electrical insulating materials can be used. As the material of the sheet-like fiber substrate, inorganic fibers such as E glass, D glass, S glass, and Q glass; organic fibers such as polyimide, polyester, and tetrafluoroethylene; mixtures thereof, etc. can be cited. The sheet-like fiber substrate can be woven fabric, non-woven fabric, roving, chopped strand mat, surface mat, etc. The material of the sheet-like fiber substrate is preferably inorganic fiber, more preferably glass. In addition, the sheet-like fiber substrate is preferably woven fabric.

[0078] The thickness of the sheet-like fiber substrate is not particularly limited, and can be 1 to 100 μm, can also be 3 to 70 μm, and can also be 5 to 35 μm.

[0079] From the viewpoint of reducing the adhesion between prepregs, the surface roughness (Rz) of the prepreg of the present embodiment is preferably 12.0 μm or more, can be 12.0 to 20 μm, can also be 12.5 to 17 μm, and can also be 12.5 to 14.5 μm. Here, the surface roughness (Rz) is a value measured by the method described in the following examples.

[0080] It should be noted that the surface roughness (Rz) of the above prepreg corresponds to the depth of the above concavo-convex shape.

[0081] The thickness of the prepreg of the present embodiment can be 5 to 300 μm, can also be 10 to 250 μm, can also be 15 to 150 μm, can also be 15 to 120 μm, can also be 15 to 100 μm, can also be 20 to 60 μm, and can also be 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 the present disclosure, the thickness of the prepreg is the average value of the values obtained by measuring any 5 places using a digital display micrometer.

[0082] (Thermosetting resin composition)

[0083] Hereinafter, each component contained in the above thermosetting resin composition will be described in detail in turn.

[0084] ((A) Thermosetting resin)

[0085] As the component (A), examples include epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate ester resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, melamine resins, etc. Among them, as the component (A), it is preferably to contain at least 1 kind selected from epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate ester resins and isocyanate resins, more preferably to contain at least 1 kind selected from epoxy resins and maleimide compounds, and further preferably to contain maleimide compounds from the viewpoints of low thermal expansion property, etc.

[0086] As the component (A), 1 kind can be used alone, or 2 or more kinds can be used in combination.

[0087] As the above epoxy resin, an epoxy resin having 2 or more epoxy groups in 1 molecule is preferred. Here, epoxy resins are classified into glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, etc. Among them, glycidyl ether type epoxy resins are preferred.

[0088] Epoxy resins are classified into various epoxy resins according to the main skeleton. Among the above various types of epoxy resins, they are further classified into bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins and other bisphenol type epoxy resins; dicyclopentadiene type epoxy resins and other alicyclic epoxy resins; aliphatic chain epoxy resins; phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, bisphenol F novolac type epoxy resins, phenol aralkylphenol novolac type epoxy resins, biphenyl aralkylphenol novolac type epoxy resins and other novolac type epoxy resins; stilbene type epoxy resins; naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins and other naphthalene skeleton-containing epoxy resins; biphenyl type epoxy resins; xylylene type epoxy resins; dihydroanthracene type epoxy resins, etc.

[0089] As the above-mentioned maleimide compound, it is preferably at least one selected from maleimide compounds having one or more N-substituted maleimide groups and their derivatives. 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 2 N-substituted maleimide groups.

[0090] In addition, as the above-mentioned maleimide compound having two or more N-substituted maleimide groups, a compound in which nitrogen atoms of the maleimide groups are bonded to each other by an organic group is preferred.

[0091] The maleimide compound having one or more N-substituted maleimide groups as described above is not particularly limited, and examples thereof include N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N-benzylmaleimide, etc., which are preferably aromatic maleimide compounds having one N-substituted maleimide group bonded to an aromatic ring; 4,4'-diphenylmethane bismaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, m-phenylene bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, aromatic bismaleimide containing an indane ring, etc., which are preferably aromatic bismaleimide compounds having two N-substituted maleimide groups bonded to an aromatic ring; polyphenylmethane maleimide, biphenyl aralkyl type maleimide, etc., which are preferably aromatic polymaleimide compounds having three or more N-substituted maleimide groups bonded to an aromatic ring; N-dodecyl maleimide, N-isopropyl maleimide, N-cyclohexyl maleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, pyrophosphate binder type long-chain alkyl bismaleimide and other aliphatic maleimide compounds. Among them, from the viewpoints 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, and aromatic bismaleimide containing an indane ring and biphenyl aralkyl type maleimide are further preferred. Here, in the present disclosure, the indane ring refers to a fused bicyclic structure of an aromatic 6-membered ring and a saturated aliphatic 5-membered ring. The aromatic bismaleimide containing an indane ring preferably has a divalent group represented by the following general formula (a1-1).

[0092] [Chemical formula 1]

[0093]

[0094] (In the formula, 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 of 0 to 3. R a2 to Ra4 Each independently represents an alkyl group having 1 to 10 carbon atoms. * indicates the bonding site.)

[0095] As the indane ring-containing aromatic bismaleimide containing the divalent group represented by the above general formula (a1-1), from the viewpoints of relative dielectric constant (Dk), adhesion to a conductor, heat resistance, and ease of manufacture, the substance represented by the following general formula (a1-2) is preferred.

[0096] [Chemical formula 2]

[0097]

[0098] (In the formula, R a1 ~R a4 and n1 are the same as R a1 ~R a4 and n1 in the above general formula (a1-1). R a5 Each independently represents 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 each independently represents an integer of 0 to 4, and n3 represents a number of 0.95 to 10.0.)

[0099] From the viewpoints of relative dielectric constant (Dk), adhesion to a conductor, solubility in an organic solvent, and ease of manufacture, the indane ring-containing aromatic bismaleimide represented by the above general formula (a1-2) is more preferably the substance represented by the following general formula (a1-3) or the substance represented by the following general formula (a1-4).

[0100] [Chemical formula 3]

[0101]

[0102] (In the formula, R a1 ~R a5 and n1 and n3 are the same as R a1 ~R a5 and n1 and n3 in the above general formula (a1-2).)

[0103] [Chemical formula 4]

[0104]

[0105] (In the formula, R a1 ~R a4 and n1 and n3 are the same as R a1 ~R a4 and n1 and n3 in the above general formula (a1-2).)

[0106] The production method of the aromatic bismaleimide containing an indane ring is not particularly limited, and it can be produced while utilizing and applying known production methods.

[0107] As the "derivative" of the above-mentioned maleimide compound, addition reaction products of the above-mentioned maleimide compound having one or more (preferably two or more) N-substituted maleimide groups and amine compounds such as monoamine compounds and diamine compounds can be cited.

[0108] As the above-mentioned monoamine compound, 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, 3,5-dicarboxyaniline can be cited.

[0109] As the above-mentioned diamine compound, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 2,2'-bis(4,4'-diaminophenyl)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, 4,4'-diaminodiphenyl 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 can be cited.

[0110] ((Content of component (A)))

[0111] The content of the thermosetting resin (A) in the thermosetting resin composition in the prepreg of the present embodiment is not particularly limited. From the viewpoints of heat resistance and moldability, 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, based on the total of the resin components in the thermosetting resin composition.

[0112] ((Compound (B) having a structural unit (b1) derived from a conjugated diene compound))

[0113] From the perspective of the relative dielectric constant (Dk) in the high-frequency band above 10 GHz [hereinafter, simply referred to as "relative dielectric constant (Dk)"], the thermosetting resin composition or its cured product in the prepreg of the present embodiment contains a compound having a structural unit (b1) derived from a conjugated diene compound as the component (B).

[0114] In the above structural unit (b1) derived from a conjugated diene compound, from the perspective of the relative dielectric constant (Dk), the conjugated diene compound is preferably at least one selected from butadiene and isoprene, more preferably contains butadiene, and further preferably is butadiene.

[0115] As the above structural unit (b1) derived from a conjugated diene compound, it can 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 obtained by hydrogenating these bonding units. Here, as the bonding unit obtained by hydrogenating these bonding units, specifically, as shown in the following structural formula, there can be mentioned a "butene unit" which is a bonding unit obtained by hydrogenating a 1,2-bonding unit of butadiene, an "ethylene unit" which is a bonding unit obtained by hydrogenating a 1,4-bonding unit of butadiene (usually expressed like this by focusing on the structural unit surrounded by parentheses in the following structural formula. It should be noted that this parentheses is for explanation and does not intend to divide the structural unit), an "ethylene-butene unit" having both the above butene unit and the above ethylene unit, an "isopentene unit" (a "3-methyl-1-butene unit") which is a bonding unit obtained by hydrogenating a 3,4-bonding unit of isoprene, an "ethylene-propylene unit" which is a bonding unit obtained by hydrogenating a 1,4-bonding unit of isoprene (usually expressed like this by focusing on the structural unit surrounded by parentheses in the following structural formula. It should be noted that this parentheses is for explanation and does not intend to divide the structural unit), etc. (refer to the following structural formula).

[0116] [Chemical formula 5]

[0117]

[0118] As the above structural unit (b1) derived from a conjugated diene compound, from the perspective of the relative dielectric constant (Dk), it is preferably a butene unit, an ethylene unit, or an ethylene-butene unit, and more preferably an ethylene-butene unit.

[0119] In addition, as the above-mentioned conjugated diene compound, specifically, 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene and the like can be cited. Among them, as the above-mentioned conjugated diene compound, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred.

[0120] As the above-mentioned component (B), it is preferably a "compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound". By having the above-mentioned structural unit (b2) in addition to the above-mentioned structural unit (b1), there is a tendency that the non-adhesion between prepregs is further improved.

[0121] 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 viewpoints of relative dielectric constant (Dk) and reduction of adhesion between prepregs, the content ratio [(b1) / (b2)] of each structural unit is preferably 97 / 3 to 50 / 50, more preferably 95 / 5 to 55 / 45, still more preferably 92 / 8 to 60 / 40, particularly preferably 90 / 10 to 65 / 35. In addition, it can be 97 / 3 to 80 / 20, or 85 / 15 to 60 / 40.

[0122] If the content ratio of the structural unit (b1) derived from the conjugated diene compound increases, there is a tendency that the relative dielectric constant (Dk) is excellent. If the content ratio of the structural unit (b2) derived from the aromatic vinyl compound increases, there is a tendency that the adhesion between prepregs decreases.

[0123] In the above-mentioned structural unit (b2), as the above-mentioned aromatic vinyl compound, styrene, α-methylstyrene, 2,4-dimethylstyrene, 1-vinylnaphthalene, 4-methoxystyrene, monochlorostyrene, divinylbenzene and the like can be cited. Among them, styrene is preferred.

[0124] As a compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound, specifically, styrene-butadiene-styrene block copolymer (SBS), a hydrogenated product of styrene-butadiene-styrene block copolymer (e.g., SEBS, SBBS), styrene-isoprene-styrene block copolymer (SIS), a hydrogenated product of styrene-isoprene-styrene block copolymer (SEPS), a hydrogenated product of styrene-(isoprene and butadiene)-styrene block copolymer (SEEPS), etc. can be cited as styrenic thermoplastic elastomers. Among them, from the viewpoints of relative dielectric constant (Dk), non-conformity between prepregs, crack resistance, etc., SEBS and SEPS are preferred, and SEBS is more preferred. Here, the above-mentioned SEBS is obtained by hydrogenating the entire butadiene unit of styrene-butadiene-styrene block copolymer (SBS), and is named by taking the first letters of styrene-ethylene-butene-styrene respectively. The above-mentioned SBBS is obtained by selectively hydrogenating the 1,2-bonded units in the butadiene unit of styrene-butadiene-styrene block copolymer (SBS), and is named by taking the first letters of styrene-(1,4-butadiene)-butene-styrene respectively.

[0125] 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 more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The upper limit of the hydrogenation rate is not particularly limited, and can be 100 mol% or less, or can be 99 mol% or less. That is, the above-mentioned hydrogenation rate can be 70 to 100 mol%.

[0126] It should be noted that the compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound may be a compound modified with an acid anhydride such as maleic anhydride. For example, SEBS modified with an acid anhydride such as maleic anhydride, SEPS modified with an acid anhydride such as maleic anhydride, etc. can be cited. The acid value of the "compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound" modified with an acid is not particularly limited, and is preferably 2 to 20 mgCH 3 ONa / g, more preferably 5 to 15 mgCH 3 ONa / g, still more preferably 7 to 13 mgCH 3 ONa / g. The acid value can be determined by a titration method using sodium methoxide.

[0127] The content of "the compound having a structural unit (b1) derived from a conjugated diene compound and a structural unit (b2) derived from an aromatic vinyl compound" in the above component (B) is not particularly limited, and may be 20% by mass or more, may be 40% by mass or more, may be 50% by mass or more, may be 80% by mass or more, may be 90% by mass or more, may be 95% by mass or more, may be 98% by mass or more, or may be 100% by mass.

[0128] The weight-average molecular weight (Mw) of the above component (B) is not particularly limited, and is preferably 12,000 to 1,000,000, more preferably 30,000 to 500,000, further preferably 50,000 to 250,000, may be 50,000 to 100,000, may be 130,000 to 250,000, or may be 150,000 to 200,000.

[0129] In the present disclosure, the weight-average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) in terms of polystyrene, and specifically, it is a value measured by the method described in the examples.

[0130] ((Content of component (B)))

[0131] When the thermosetting resin composition in the prepreg of the present embodiment contains component (B), its content is not particularly limited. From the viewpoints of relative dielectric constant (Dk), reduction in the adhesion between prepregs, and compatibility, it 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, may be 5 to 12% by mass, may be 6.5 to 11.5% by mass, may be 6.5 to 9.5% by mass, may be 8 to 11.5% by mass, or may be 1 to 8% by mass, may be 3 to 8% by mass, or may be 5 to 8% by mass, relative to the total of the resin components in the thermosetting resin composition.

[0132] If the content of component (B) is above the above lower limit value, there is a tendency to obtain an excellent relative dielectric constant (Dk). If it is below the above upper limit value, there is a tendency to suppress or reduce the increase in the adhesion between prepregs. In addition, there is a tendency to obtain good heat resistance, formability, processability, and flame retardancy.

[0133] ((C) Inorganic filler)

[0134] By making the thermosetting resin composition in the prepreg of the present embodiment contain (C) inorganic filler [hereinafter, sometimes referred to as component (C).], there is a tendency to improve the low thermal expansion coefficient, heat resistance, and flame retardancy.

[0135] The (C) component 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 fired clay), molybdate compounds such as zinc molybdate, talc, aluminum borate, silicon carbide, etc. The (C) component can be used alone or in combination of two or more. Among them, from the viewpoints 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 further preferred. Examples of silica include crushed silica, fumed silica, and fused silica (fused spherical silica).

[0136] The shape and particle size of the (C) component are not particularly limited. The particle size is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, further 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 means the particle size at the point corresponding to 50% of the volume when the total volume of the particles is set to 100% and the cumulative frequency distribution curve based on the particle size is obtained. The particle size of the (C) component can be measured using a particle size distribution measuring device using the laser diffraction scattering method, etc.

[0137] ((Content of the (C) component))

[0138] When the thermosetting resin composition in the prepreg of the present embodiment contains the (C) component, the content of the (C) component in the thermosetting resin composition is not particularly limited. From the viewpoints of reducing the adhesion between prepregs, and thermal expansion coefficient, heat resistance, and flame retardancy, it is preferably 1 to 70% by volume, more preferably 5 to 60% by volume, further preferably 10 to 50% by volume, and can be 10 to 35% by volume, or can be 10 to 25% by volume, or can also be 25 to 50% by volume, can also be 30 to 45% by volume, can also be 1 to 50% by volume, and can also be 1 to 30% by volume, relative to the total of the solid components of the thermosetting resin composition.

[0139] It should be noted that by making the content of the (C) component below the above upper limit value, there is a tendency for the relative dielectric constant (Dk) to decrease, but if the content of the (C) component is suppressed to be small, there is a tendency for the adhesion between prepregs to increase. Therefore, at this time, the effect of the present embodiment brought about by the presence ratio of the concave portions in the uneven shape being 30 to 90%, that is, the effect of reducing the adhesion between prepregs, will have a greater impact. This effect tends to become significant when the upper limit value of the content of the (C) component is 50% by volume or less, and further 30% by volume or less, relative to the total of the solid components.

[0140] In addition, when using the component (C), for the purpose of improving the dispersibility of the component (C) and the adhesion between the component (C) and the organic components in the thermosetting resin composition, a coupling agent can be used in combination as needed. There is no particular limitation on the coupling agent. For example, a silane coupling agent or a titanate coupling agent can be appropriately selected and used. The coupling agent can be used alone as one kind, or two or more kinds can be used in combination. In addition, the amount of the coupling agent used is not particularly limited.

[0141] It should be noted that when using a coupling agent, it can be the so-called overall blending treatment method of adding the coupling agent after blending the component (C) in the thermosetting resin composition. Preferably, an inorganic filler surface-treated with a coupling agent in a dry or wet manner in advance is used. By adopting this method, the advantages of the component (C) can be more effectively exhibited.

[0142] In the present embodiment, when using the component (C), for the purpose of improving the dispersibility of the component (C) in the thermosetting resin composition, it can be used in the form of a slurry in which the component (C) is pre-dispersed in an organic solvent as needed. As the organic solvent, the same organic solvents as those described later can be cited.

[0143] ((D) compatibilizer)

[0144] The thermosetting resin composition in the prepreg of the present embodiment may further contain a (D) compatibilizer [hereinafter, sometimes referred to as the component (D).]. By making the above thermosetting resin composition contain the component (D), there is a tendency that the compatibility between the above component (A) and the above component (B) is improved, and the relative dielectric constant (Dk) is further reduced.

[0145] As the (D) compatibilizer, there is no particular limitation as long as it is a compound that improves the compatibility between the above-mentioned (A) component and the above-mentioned (B) component. For example, when the (A) component contains a maleimide compound and the (B) component 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", as the (D) component, polyphenylene ether, modified polyphenylene ether, conjugated diene polymer, modified conjugated diene polymer, etc. can be used. As the modified polyphenylene ether, a compound in which a functional group is introduced into the polyphenylene ether can be cited. Examples of the above-mentioned functional group include amino group, epoxy group, carboxyl group, styryl group, acryloyl group, methacryloyl group, etc. Among them, from the viewpoints of relative dielectric constant (Dk) and compatibility, acryloyl group and methacryloyl group are preferred, and methacryloyl group is more preferred. That is, as the modified polyphenylene ether, methacryloyl group-modified polyphenylene ether is preferred. The modified polyphenylene ether may have the above-mentioned functional group at the end of the polymer chain or in the interior of the polymer chain. It is preferably at the end of the polymer chain, and more preferably at both ends of the polymer chain.

[0146] Regarding the weight-average molecular weight (Mw) of the above-mentioned polyphenylene ether and modified polyphenylene ether, there is no particular limitation, and it is preferably 1000 to 25000. If the weight-average molecular weight of the above-mentioned polyphenylene ether and modified polyphenylene ether is 1000 or more, the relative dielectric constant (Dk) tends to be better. In addition, if the weight-average molecular weight of the above-mentioned polyphenylene ether and modified polyphenylene ether is 25000 or less, the compatibility of the thermosetting resin composition becomes better, and it is not easily separated even after long-term storage, that is, the storage stability tends to be high. From the same viewpoint, the weight-average molecular weight of the above-mentioned polyphenylene ether and modified polyphenylene ether is more preferably 1000 to 20000, further preferably 1000 to 15000, still further preferably 1200 to 10000, particularly preferably 1200 to 5000, and most preferably 1200 to 3000.

[0147] In addition, as the conjugated diene compound which is the monomer component of the above-mentioned conjugated diene polymer, for example, 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, etc. can be cited.

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

[0150] The number of side-chain vinyl groups in the conjugated diene polymer per molecule is not particularly limited. From the viewpoints of compatibility with other resins and relative dielectric constant (Dk), it is preferably 2 or more, more preferably 5 or more, and still more preferably 10 or more.

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

[0152] Examples of the conjugated diene polymer include polybutadiene having vinyl groups, polyisoprene having vinyl groups, etc. Among them, from the viewpoints of relative dielectric constant (Dk) and heat resistance, polybutadiene having vinyl groups is preferred, and polybutadiene having 1,2-vinyl groups derived from 1,3-butadiene is more preferred. In addition, as the polybutadiene having 1,2-vinyl groups derived from 1,3-butadiene, a homopolymer of polybutadiene having 1,2-vinyl groups derived from 1,3-butadiene is preferred.

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

[0154] [Chemical formula 6]

[0155]

[0156] When the conjugated diene polymer is polybutadiene having 1,2-vinyl groups, the content of the structural unit having 1,2-vinyl groups relative to all the structural units derived from butadiene constituting the polybutadiene [hereinafter, sometimes referred to as "vinyl content"].] is not particularly limited. From the viewpoints 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 still more preferably 85 mol% or more. In addition, the upper limit of the vinyl content is not particularly limited and may be 100 mol% or less, may be 95 mol% or less, or may be 90 mol% or less. As the structural unit having 1,2-vinyl groups, the structural unit represented by the above formula (d1) is preferred.

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

[0158] The number-average molecular weight (Mn) of the conjugated diene polymer is not particularly limited, and from the viewpoints of compatibility with other resins, relative dielectric constant (Dk), and heat resistance, it is preferably 400 to 3000, more preferably 600 to 2000, and still more preferably 800 to 1500. In the present disclosure, the number-average molecular weight (Mn) is a value measured by gel permeation chromatography (GPC) in terms of polystyrene, and specifically, it is a value measured by the method described in the examples.

[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, and thus has good heat resistance and low thermal expansion, and has a tendency to easily obtain an excellent relative dielectric constant (Dk).

[0161] As the modified conjugated diene polymer, from the viewpoints of compatibility with other resins, relative dielectric constant (Dk), and conductor adhesiveness, a modified conjugated diene polymer obtained by modifying a conjugated diene polymer having a vinyl group in the side chain with a maleimide compound having two or more N-substituted maleimide groups is preferred.

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

[0163] The conjugated diene polymer having a vinyl group in the side chain can 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 description of the maleimide compound in the component (A) can be used, and the 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'-ethylene bis maleimide, N,N'-hexamethylene bis maleimide, bis(4-maleimidocyclohexyl)methane, 1,4-bis(maleimidomethyl)cyclohexane; maleimides containing an aromatic hydrocarbon group such as N,N'-(1,3-phenylene)bis maleimide, N,N'-[1,3-(2-methylphenylene)]bis maleimide, N,N'-[1,3-(4-methylphenylene)]bis maleimide, N,N'-(1,4-phenylene)bis maleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bis maleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)ketone, 1,3-bis(4-maleimidophenoxy)benzene, bis[4-(3-maleimidophenoxy)phenyl]methane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, polyphenylmethane maleimide. Among them, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bis maleimide is more preferable.

[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, in the side chain: a substituent formed by the reaction of the side chain vinyl of the conjugated diene polymer having a vinyl group in the side chain with the N-substituted maleimide group of the maleimide compound having two or more N-substituted maleimide groups [hereinafter, sometimes referred to as "substituent derived from maleimide compound"].

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

[0169] [Chemical formula 7]

[0170]

[0171] (In the formula, X d1 is a divalent group formed by removing two N-substituted maleimide groups from a maleimide compound having two or more N-substituted maleimide groups, and * d1 is a site bonded to a carbon atom derived from a side-chain vinyl group of a conjugated diene polymer having a vinyl group in the side chain. * d2 is a site bonded to other atoms.)

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

[0173] The vinyl group possessed by 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. From the viewpoints of compatibility with other resins, relative dielectric constant (Dk), low thermal expansibility, and heat resistance, it is preferably 700 to 6000, more preferably 800 to 5000, and further preferably 1000 to 2500.

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

[0176] The method of reacting a conjugated diene polymer having a vinyl group in the 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 the side chain, a maleimide compound having two or more N-substituted maleimide groups, a reaction catalyst, and an organic solvent are put into a reaction vessel, and the reaction is carried out while heating, maintaining the temperature, and stirring as needed, whereby a modified conjugated diene polymer can be obtained.

[0177] When carrying out the above reaction, the number of moles (M m ) of the N-substituted maleimide groups possessed by the maleimide compound having two or more N-substituted maleimide groups relative to the number of moles (M v ) of the side-chain vinyl groups possessed by the conjugated diene polymer having a vinyl group in the side chain, the ratio (M m / M v ) is not particularly limited. From the viewpoints of compatibility of the obtained modified conjugated diene polymer with other resins and suppression of gelation of the product in the reaction, it is preferably 0.001 to 0.5, more preferably 0.005 to 0.1, and further preferably 0.008 to 0.05.

[0178] ((Content of Component (D)))

[0179] When the thermosetting resin composition in the prepreg of the present embodiment contains Component (D), the content of Component (D) in the thermosetting resin composition is not particularly limited. From the viewpoints of relative dielectric constant (Dk) and compatibility, it is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, still 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 of the resin components of the thermosetting resin composition. If the content of Component (D) is at least the above lower limit value, there is a tendency for the relative dielectric constant (Dk) and compatibility to become good. If the content of Component (D) is at most the above upper limit value, there is a tendency for heat resistance, moldability, and processability to become good.

[0180] ((E) Curing Promoter)

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

[0182] Examples of the above Component (E) include amine-based curing promoters, imidazole-based curing promoters, phosphorus-based curing promoters, organic metal salts, acidic catalysts, organic peroxides, etc. It should be noted that in the present disclosure, imidazole-based curing promoters are not classified as amine-based curing promoters. The curing promoter may be used alone as one kind, or two or more kinds may be used in combination. As the curing promoter, it is preferably to contain at least one selected from imidazole-based curing promoters and organic peroxides.

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

[0184] Examples of the above organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hex-3-yne, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylperoxyisopropyl monocarbonate, α,α'-bis(tert-butylperoxy)diisopropylbenzene, etc.

[0185] ((Content of (E) Curing Promoter))

[0186] When the thermosetting resin composition in the prepreg of the present embodiment contains the component (E), the content of the component (E) is not particularly limited, and is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, still more preferably 0.1 to 3.5 parts by mass, and particularly preferably 0.3 to 2.5 parts by mass, based on 100 parts by mass of the component (A) in the thermosetting resin composition. If the content of the (E) curing accelerator is within the above range, there is a tendency to obtain better heat resistance, storage stability, and formability.

[0187] (Other components)

[0188] The thermosetting resin composition in the prepreg of the present embodiment preferably further contains 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 components. In addition, components other than the above may also be contained.

[0189] When the above thermosetting resin composition contains these other components (flame retardants, flame retardant aids, antioxidants, adhesion improvers, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, and components other than these), their respective contents are not particularly limited, and can be, for example, 0.01% by mass or more, and can also be 10% by mass or less, 5% by mass or less, or 1% by mass or less, based on the total amount of the resin components in the thermosetting resin composition. The above thermosetting resin composition may not contain the above other components.

[0190] (Organic solvent)

[0191] From the viewpoints of ease of operation and ease of manufacturing of the resin film, the above thermosetting resin composition can be made into a so-called "varnish" containing an organic solvent and then made into a resin film.

[0192] The organic solvent is not particularly limited, and 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 atom-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur atom-containing solvents such as dimethyl sulfoxide; and ester solvents such as γ-butyrolactone. From the viewpoint of solubility, ketone solvents are preferred, and methyl ethyl ketone is more preferred. The organic solvent can be used alone or in combination of two or more.

[0193] When the above 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 still more preferably 45 to 60% by mass. If the solid content concentration of the thermosetting resin composition is within the above range, the processability of the thermosetting resin composition becomes easy, and in addition, the coatability when forming a resin film also becomes good, and the appearance of the prepreg also tends to become good.

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

[0195] [Laminated board]

[0196] The laminated board of the present embodiment is a laminated board having a cured product of the prepreg of the present embodiment and a metal foil.

[0197] The laminated board of the present embodiment can be produced, for example, by disposing a metal foil on one side or both sides of one sheet of the prepreg of the present embodiment, or by disposing a metal foil on one side or both sides of a laminate obtained by overlapping two or more sheets of the prepreg of the present embodiment, and then performing hot press forming. In the laminated board obtained by this production method, the prepreg of the present embodiment is C-staged. In the present disclosure, C-staging means forming a state of C-stage defined in JIS K6900 (1994). It should be noted that a laminated board having a metal foil is sometimes referred to as a metal-clad laminate.

[0198] The metal of the metal foil is not particularly limited. From the viewpoint 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 carrying out the hot press forming is not particularly limited. For example, it can be carried out under the conditions of a temperature of 100 to 300 °C, a pressure of 0.2 to 10 MPa, and a time of 0.1 to 5 hours. In addition, the hot press forming can adopt a method of maintaining a vacuum state for 0.5 to 5 hours using vacuum pressing or the like.

[0200] [Printed wiring board]

[0201] The printed wiring board of the present embodiment has a cured product of the prepreg of the present embodiment. The printed wiring board of the present embodiment may also have one or more selected from the cured product of the prepreg of the present embodiment and the laminated board of the present embodiment.

[0202] The printed circuit board of the present embodiment can be manufactured as follows: using one or more selected from the prepreg of the present embodiment and the laminate of the present embodiment, circuit formation processing such as opening processing, metal plating processing, and etching of metal foil is performed by a known method, thereby manufacturing. In addition, a multilayer printed circuit board can also be manufactured by further performing multilayer bonding processing as needed. In the printed circuit board of the present embodiment, the prepreg of the present embodiment is C-staged.

[0203] [Semiconductor package]

[0204] The semiconductor package of the present embodiment is a semiconductor package having the printed circuit board of the present embodiment and a semiconductor element. The semiconductor package of the present embodiment can be manufactured as follows: after mounting semiconductor elements such as semiconductor chips and memories on a predetermined position of the printed circuit board of the present embodiment by a known method, the semiconductor elements are sealed with a sealing resin or the like, thereby manufacturing.

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

[0206] Examples

[0207] Hereinafter, examples will be listed to specifically illustrate the present embodiment. However, the present embodiment is not limited to the following examples.

[0208] It should be noted that in each example, the number-average molecular weight (Mn) and the weight-average molecular weight (Mw) are measured by the following method.

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

[0210] Using gel permeation chromatography (GPC), conversion is performed from a standard curve using standard polystyrene. The standard curve uses standard polystyrene: TSKstandard POLYSTYRENE (Type: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, trade name], and is approximated by a cubic equation. The measurement conditions of GPC are shown below.

[0211] Apparatus:

[0212] Pump: Model L-6200 [manufactured by Hitachi High-Technologies Corporation]

[0213] Detector: L-3300 type RI [manufactured by Hitachi High-Technologies Corporation]

[0214] Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Corporation]

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

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

[0217] Eluent: Tetrahydrofuran

[0218] Sample concentration: 30 mg / 5 mL

[0219] Injection volume: 20 μL

[0220] Flow rate: 1.00 mL / minute

[0221] Measurement temperature: 40 °C

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

[0223] [Evaluation and measurement method]

[0224] (1. Ratio of the presence of concave parts in the uneven shape on the surface of the prepreg)

[0225] Regarding the ratio of the presence of concave parts in the uneven shape on the surface of the prepreg produced in each example, the central 524.2 μm × 669.2 μm range of the prepreg surface was observed using SEM (scanning electron microscope) to obtain an SEM image (magnification: 100 times). For this SEM image, by using the programming language "Python", the Figure 1 shown program was set to obtain a binary image of the above SEM image. Next, the ratio of the presence of white and black in this binary image was determined, and the ratio of the presence of black was taken as the ratio of the presence of concave parts in the uneven shape on the prepreg surface. It should be noted that the obtained SEM image is shown on the Figures 2 to 7 left side, and the image after binarization processing is shown on the Figures 2 to 7 right side.

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

[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 in the direction of the average line. In this extracted portion, the average value of the absolute values ​​of the peak elevations from the highest peak to the fifth peak and the average value of the absolute values ​​of the valley elevations from the lowest valley to the fifth valley are calculated based on the average line, and this value is calculated as the value Rz expressed in micrometers (μm). It should be noted that Rz was measured using a shape analysis laser microscope "VK-X250" (manufactured by KEYENCE Co., Ltd.).

[0229] (3. Adhesion between prepregs)

[0230] Fifteen prepregs prepared in each example were stacked, placed in an aluminum vapor deposition bag, and left to stand for one week in a state of compression bonding at 1 MPa, and then released. Then, the adhesion was evaluated according to the following evaluation criteria.

[0231] A: The prepreg can be easily peeled off by hand.

[0232] B: When the prepreg was peeled off by hand, cracks occurred in a part of the prepreg.

[0233] C: The overlapped prepregs are integrated and cannot be peeled off by hand.

[0234] (4. Relative dielectric constant (Dk))

[0235] 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.), and then cut into a length of 60 mm and a width of 2 mm, and used as a test piece. Using this test piece, the relative dielectric constant (Dk) was measured by the cavity resonator perturbation method. It should be noted that the measuring instrument uses the vector network analyzer "N5222B" manufactured by Agilent Technologies, the cavity resonator uses the "CP129" (10 GHz band resonator) manufactured by Kanto Electronics Application Development Co., Ltd., and the measurement program uses "CPMA-V2". In addition, the measurement was carried out under the conditions of a frequency of 10 GHz and a measurement temperature of 25°C.

[0236] Production Example 1 [Production of modified conjugated diene polymer (for component (D))]

[0237] Into a 2-L container equipped with a thermometer, a reflux condenser, and a stirring device and capable of heating and cooling, 100 parts by mass of 1,2-polybutadiene homopolymer (number-average molecular weight (Mn) = 1,200, vinyl content = 85% or more), 4.4 parts by mass of an indan-ring-containing aromatic bismaleimide, 0.1 part by mass of α,α'-bis(tert-butylperoxy)diisopropylbenzene, and toluene as an organic solvent were charged. Next, under a nitrogen atmosphere, stirring was carried out at 90 to 100 °C for 5 hours to obtain a solution of a modified conjugated diene polymer having a solid content concentration of 35% by mass.

[0238] [Examples 1 to 2]

[0239] (Preparation of thermosetting resin composition (varnish))

[0240] According to the contents shown in Table 1, each component shown in Table 1 was mixed and stirred with methyl ethyl ketone at room temperature to prepare a thermosetting resin composition (varnish) having a solid content concentration of 55% by mass.

[0241] (Production of resin film with support)

[0242] The varnish obtained above was applied to a PET film (manufactured by Toray Industries, Inc., thickness: 50 μm, surface roughness Rz: 8.5 μm, trade name: Lumirror 50X42, the above "Lumirror" is a registered trademark, the same below) as a support having irregularities using a comma coater, and then heated and dried at 120 °C for 3 minutes to produce a resin film with a support. The thickness of the dried resin film was 10 μm.

[0243] (Production of prepreg)

[0244] Two resin films with supports obtained above were prepared. One resin film with a support was disposed on each of the front and back surfaces of a glass fabric (NE glass, manufactured by Asahi Kasei Corporation) having a thickness of 15 μm in such a manner that the resin film with a support was brought into contact with the glass fabric. Using a vacuum laminating device, the "PET film / resin film / glass fiber cloth / resin film / PET film" laminate thus obtained was vacuum laminated under the conditions of a hot plate temperature of 100 °C, a crimping pressure of 0.3 MPa, a vacuum degree of 100 kPa or less, and a vacuum time of 20 seconds. Then, the PET film of the support was peeled off, and then heated and dried at 130 °C for 3 minutes to produce a prepreg having a thickness of 30 μm. It should be noted that the thickness of the prepreg is the average value of the values measured using a pedestal adjusted to be horizontal at five arbitrary positions and a digital display micrometer (manufactured by Mitutoyo Corporation).

[0245] For the obtained prepreg, each evaluation and measurement were carried out by the above method. The results are shown in Table 1.

[0246] (Manufacture of Double-sided Copper-clad Laminates)

[0247] On the top and bottom of the obtained prepreg, a low-profile copper foil with a thickness of 12 μm (3M-VLP12, manufactured by Mitsui Mining & Smelting Co., Ltd., where the above "VLP" is a registered trademark) was arranged in such a way that the M surface (matte surface) was in contact with the prepreg, and then heat and pressure forming was carried out under the conditions of a temperature of 230 °C, a pressure of 3.0 MPa, and a time of 90 minutes, thereby manufacturing a double-sided copper-clad laminate (thickness: 0.30 mm).

[0248] For the obtained double-sided copper-clad laminate, the relative dielectric constant (Dk) was measured by the above method. The results are shown in Table 1.

[0249] [Comparative Example 1]

[0250] In Example 1, a PET film (manufactured by Toray Industries, Inc., thickness: 50 μm, surface roughness Rz: 6.5 μm, trade name: Lumirror 50X44) was used to replace the PET film (manufactured by Toray Industries, Inc., thickness: 50 μm, surface roughness Rz: 8.5 μm, trade name: Lumirror 50X42), and other than that, the same operations as in Example 1 were carried out, thereby manufacturing a prepreg and a double-sided copper-clad laminate. The results of each evaluation and measurement are shown in Table 1.

[0251] [Comparative Example 2]

[0252] In Example 2, a PET film (manufactured by Toray Industries, Inc., thickness: 50 μm, surface roughness Rz: 6.5 μm, trade name: Lumirror 50X44) was used to replace the PET film (manufactured by Toray Industries, Inc., thickness: 50 μm, surface roughness Rz: 8.5 μm, trade name: Lumirror 50X42), and other than that, the same operations as in Example 2 were carried out, thereby manufacturing a prepreg and a double-sided copper-clad laminate. The results of each evaluation and measurement are shown in Table 1.

[0253] [Comparative Example 3]

[0254] In Example 1, a PET film (manufactured by Toyobo Co., Ltd., thickness: 50 μm, surface roughness Rz: 0.1 μm, trade name: Purex A5300, where the above "Purex" is a registered trademark, the same below) was used to replace the PET film (manufactured by Toray Industries, Inc., thickness: 50 μm, surface roughness Rz: 8.5 μm, trade name: Lumirror 50X42), and other than that, the same operations as in Example 1 were carried out, thereby manufacturing a prepreg and a double-sided copper-clad laminate. The results of each evaluation and measurement are shown in Table 1.

[0255] [Comparative Example 4]

[0256] In Example 2, 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 the PET film (manufactured by Toray Industries, Inc., thickness: 50 μm, surface roughness Rz: 8.5 μm, trade name: Lumirror 50X42). Except for this, the same operations as in Example 2 were carried out, and thus prepregs and double-sided copper-clad laminates were produced. The results of each evaluation and measurement are shown in Table 1.

[0257] [Table 1]

[0258]

[0259] *1: Volume % relative to the total amount of solid components

[0260] *2: Refers to the content (parts by mass) relative to 100 parts by mass of component (A).

[0261] · In the case of using a solution or dispersion, the compounding amount of each component is the amount in terms of solid components.

[0262] The details of each component described in Table 1 are as follows.

[0263] [(A) Thermosetting resin]

[0264] ・ Maleimide compound A-1: Aromatic bismaleimide containing an indane ring

[0265] ・ Maleimide compound A-2: Biphenyl aralkyl type maleimide

[0266] [(B) Compound having a structural unit (b1) derived from a conjugated diene compound]

[0267] ・ Styrenic thermoplastic elastomer B-1: Hydride of styrene-butadiene-styrene block copolymer (SEBS), hydrogenation rate of 95 mol% or more, styrene content of 30 mass%, weight average molecular weight (Mw) = 70000

[0268] [(C) Inorganic filler]

[0269] ・ Inorganic filler C-1: Spherical fused silica, average particle diameter = 0.5 μm

[0270] [(D) Compatibilizer]

[0271] ・ Modified polyphenylene ether D-1: A dimethylacryloyl-modified polyphenylene ether derivative represented by the following formula, weight average molecular weight = 1700

[0272] [Chemical Formula 8]

[0273]

[0274] (In the above formula, x1 and x2 are each independently 0 to 20.)

[0275] ・Modified conjugated diene polymer D-2: The modified conjugated diene polymer produced in Production Example 1

[0276] [(E) Curing accelerator]

[0277] ・Curing accelerator E-1: α,α'-bis(tert-butylperoxy)diisopropylbenzene

[0278] ・Curing accelerator E-2: Isocyanate-masked imidazole "G8009L" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name)

[0279] From the results in Table 1, it can be seen that in Examples 1 to 2, although a compound having a structural unit derived from a conjugated diene compound was contained to reduce the relative dielectric constant (Dk), the presence ratio of the concave portions in the uneven shape was 59%, so the adhesiveness between the prepregs was reduced.

[0280] On the other hand, in Comparative Examples 1 to 4 which also contained a compound having a structural unit derived from a conjugated diene compound to reduce the relative dielectric constant (Dk), when the presence ratio of the concave portions in the uneven shape was 26% or 0.1%, a result of higher adhesiveness between the prepregs was obtained.

Claims

1. A prepreg comprising a thermosetting resin composition or a semi-cured product of the thermosetting resin composition, the thermosetting resin composition containing: Component A, namely a thermosetting resin; and Component B, namely a compound having a structural unit b1 derived from a conjugated diene compound, The surface of the prepreg has an uneven shape, The ratio of the presence of concave portions in the uneven shape is 30% to 90%.

2. The prepreg according to claim 1, wherein the surface roughness Rz is 12.0 μm or more.

3. The prepreg according to claim 1, wherein, Component A includes at least 1 selected from the group consisting of epoxy resins, maleimide compounds, phenolic resins, polyimide resins, cyanate ester 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 Component B, the structural unit b1 derived from the conjugated diene compound is a 1,2-bonded unit of butadiene, a 1,4-bonded unit of butadiene, a 3,4-bonded unit of isoprene, a 1,4-bonded unit of isoprene, or a bonded unit obtained by hydrogenating at least 1 selected from these bonded units.

5. The prepreg according to claim 1, wherein, In the thermosetting resin composition, the content of Component B is 1% by mass or more and less than 14% by mass relative to the total amount of the resin components.

6. The prepreg according to claim 1, wherein, The thermosetting resin composition further contains Component C, namely an inorganic filler.

7. The prepreg according to claim 6, wherein, In the thermosetting resin composition, the content of Component C is 1% to 50% by volume relative to the total amount of the solid components.

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

9. The prepreg according to claim 1, wherein, The thermosetting resin composition further contains Component E, namely a curing accelerator.

10. A laminate having a cured product of the prepreg according to any one of claims 1 to 9 and a metal foil.

11. A printed circuit board having a cured product of the prepreg according to any one of claims 1 to 9.

12. A semiconductor package having the printed circuit board according to claim 11 and a semiconductor element.

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