Novel crosslinking agent, curable composition, prepreg, laminate, metal-clad laminate, and wiring board

Abstract

The present invention provides: a novel organosilicon compound which is suitable for use as a crosslinking agent or the like; a novel crosslinking agent; a curable composition; a prepreg; a multilayer body; a metal-clad laminate; and a wiring board. An organosilicon compound which is represented by formula (1TQ). (In the formula, M represents a single bond or an optionally substituted alkylene group having 1 to 20 carbon atoms; a benzene ring may have a substituent; the position of substitution of a vinyl group on a benzene ring is arbitrary; n is an integer of 3 or 4; and R represents a hydrogen atom, a hydroxyl group or an organic group; and in cases where R is an organic group, a C atom is bonded to Si.)

Description

[Technical Field]

[0001] The present invention relates to a novel organosilicon compound, a novel crosslinking agent, a curable composition, a prepreg, a laminate, a metal-clad laminate, and a wiring board. [Background technology]

[0002] Wiring boards (also called printed wiring boards) are used for applications such as electrical and electronic devices. Wiring boards can be manufactured, for example, as follows: A fiber substrate is impregnated with a curable composition, and the curable composition is (semi-)cured to produce a prepreg. One or more prepregs are sandwiched between a pair of metal foils, and the resulting first temporary laminate is heated and pressurized to produce a metal-clad laminate. The metal foil on the outermost surface of this metal-clad laminate is used to form a conductor pattern (also called a circuit pattern) such as wiring. The outermost metal foil may be placed on only one side of the first temporary laminate.

[0003] One or more prepregs are then layered on the resulting wiring board, sandwiched between a pair of metal foils, and the resulting second temporary laminate is heated and pressurized to form a conductor pattern such as wiring using the metal foil on the outermost surface, thereby producing a multilayer wiring board (also called a multilayer printed wiring board). The outermost metal foil may be placed on only one side of the second temporary laminate.

[0004] The prepreg heated and pressed product contains a fiber substrate, a resin, an inorganic filler, etc., and is also called a composite substrate. In a wiring board, the composite substrate functions as an insulating layer. The resin contained in the prepreg is a (semi-)cured product of the curable composition, and the resin contained in the composite substrate is a cured product of the curable composition.

[0005] In recent years, in applications such as portable electronic devices, communication speeds and capacity have increased, and signals are becoming increasingly high frequency. Wiring boards used in these applications are required to reduce transmission loss in the high frequency range. Transmission loss mainly consists of conductor loss caused by the surface resistance of metal foil and the dielectric loss tangent (Df ) and dielectric loss due to the dielectric loss. For this reason, the resin contained in the composite base material of the wiring board used for the above purposes is required to reduce the dielectric loss in the high frequency range. Generally, the dielectric loss tangent (D f ) depends on frequency, and for the same material, the higher the frequency, the greater the dielectric loss tangent (D f The resin contained in the composite substrate tends to have a large dielectric loss tangent (D f ) is preferably low.

[0006] If the difference in coefficient of thermal expansion (CTE) between the prepreg or composite substrate and the metal foil is large, there is a risk that the metal foil will shift or peel when a first temporary laminate including the prepreg and the metal foil, or a second temporary laminate including the composite substrate, the prepreg, and the metal foil, is heated and pressurized. It is preferable that the difference in coefficient of thermal expansion (CTE) between the prepreg or composite substrate and the metal foil is small. Generally, resins have a larger coefficient of thermal expansion (CTE) than metal foil, so it is preferable that the coefficient of thermal expansion (CTE) of the prepreg and composite substrate is small. Wiring boards are sometimes used in relatively high-temperature environments, and in order to ensure the reliability of the wiring boards even in such cases, it is preferable that the resins contained in the prepreg and composite base material have a sufficiently high glass transition temperature (Tg).

[0007] In wiring boards, adhesion between a composite substrate and a metal foil is important. Conventionally, a technique for improving adhesion between the composite substrate and the metal foil has been proposed, in which the surface of the metal foil facing the composite substrate is roughened. However, this technique is undesirable because it tends to cause loss of high-frequency current. As a technique for improving adhesion between a composite substrate and a metal foil without roughening the surface of the metal foil on the composite substrate side, Patent Document 1 discloses a resin composition for wiring boards, which contains a polyphenylene oxide resin consisting of polyphenylene oxide and trialkenyl isocyanurate, and a vinyl silane such as trimethoxyvinylsilane (TMVS) and triethoxyvinylsilane (TEVS), and a wiring board obtained using the same (claims 1 to 4). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-259899 [Patent Document 2] Korean Patent No. 10-1481417 [Non-patent literature]

[0009] [Non-Patent Document 1] JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2015, 53, 1707-1718. [Non-patent document 2] J. Org. Chem. 2013, 78, 3329-3335. Summary of the Invention [Problem to be solved by the invention]

[0010] Vinylsilanes such as trimethoxyvinylsilane (TMVS) and triethoxyvinylsilane (TEVS) used in Patent Document 1 are silane coupling agents containing a bond between Si and an oxygen atom (O), which is a polar atom. The inventors have investigated and found that when a silane coupling agent containing a bond between Si and a polar oxygen atom (O) is added to a curable composition, the resulting composite substrate has a dielectric loss tangent (D f ) tended to increase.

[0011] The present inventors have discovered that an organosilicon compound having a specific chemical structure containing two or more reactive vinyl groups and no bond between Si and a polar atom can be used as a crosslinking agent for a curable composition, and that a composite substrate obtained using a curable composition containing this compound has a dielectric loss tangent (D f ) is effectively reduced, the coefficient of thermal expansion (CTE) is sufficiently low, and the glass transition temperature (Tg) is sufficiently high, providing favorable properties for use in wiring boards used in high-frequency regions. In Patent Document 1, the adhesion between the composite substrate and the metal foil is improved by using a silane coupling agent, but there is no mention or suggestion of the use of an organosilicon compound as a crosslinking agent.

[0012] Other related arts of the present invention include Non-Patent Documents 1 and 2 and Patent Document 2. In Non-Patent Document 1, two 4-vinylphenyl groups and two alkyl groups (specifically, -CH 17 ) has been bonded to an organosilicon compound. The reaction scheme is as follows. In Non-Patent Document 1, the synthesized organosilicon compound is polymerized, and the fluorescent properties of the resulting linear polymer are evaluated. In Non-Patent Document 1, the organosilicon compound is used as a monomer, and there is no mention or suggestion of its use as a crosslinking agent, nor is there any mention of its dielectric properties.

[0013] [ka]

[0014] In Non-Patent Document 2, an organosilicon compound is synthesized in which two 2-vinylphenyl groups and two alkyl groups (specifically, -Me, -Et, or -Ph) are bonded to Si. In Non-Patent Document 2, the synthesized organosilicon compound is subjected to ring-closing metathesis to give DibenzoheteropinesThe reaction scheme is as follows: Non-Patent Document 2 does not describe the uses of organosilicon compounds, does not describe or suggest their use as crosslinking agents, and does not describe their dielectric properties.

[0015] [ka]

[0016] In Patent Document 2, several organosilicon compounds are synthesized in which Si is substituted with two 2-, 3-, or 4-vinylphenyl groups and two alkyl groups. The following [Chemical Formula 3] shows an example of the organosilicon compound synthesized in Patent Document 2. In Patent Document 2, the organosilicon compound is used for gas barrier purposes, and there is no mention or suggestion of its use as a crosslinking agent, nor is there any mention of its dielectric properties.

[0017] [ka]

[0018] In addition to the above, several organosilicon compounds have been reported in which all four atoms bonded to Si are nonpolar and have two or more reactive vinyl groups. However, there have been no previous reports of the use of organosilicon compounds in which all four atoms bonded to Si are nonpolar and have two or more reactive vinyl groups as crosslinkers. All organosilicon compounds in which all four atoms bonded to Si are nonpolar and have two or more reactive vinyl groups are novel crosslinkers. Furthermore, among organosilicon compounds in which all four atoms bonded to Si are nonpolar atoms and which have two or more reactive vinyl groups, some organosilicon compounds with specific structures are novel compounds. Specifically, a polyfunctional organosilicon compound in which all four atoms bonded to Si are nonpolar atoms and which contains three or four reactive functional groups including a vinylphenyl group (the benzene ring contained in the organosilicon compound may have a substituent) is a novel compound.

[0019] The present invention has been made in view of the above circumstances, and has as its object to provide a novel organosilicon compound suitable for use as a crosslinking agent or the like. The present invention also provides a curable composition suitable for use in a dielectric loss tangent (D f The present invention aims to provide a novel crosslinking agent that can effectively reduce the thermal expansion coefficient (CTE) and give a (semi-)cured product having a sufficiently low coefficient of thermal expansion (CTE) and a sufficiently high glass transition temperature (Tg), as well as a curable composition using the same. The novel organosilicon compounds and novel crosslinking agents of the present invention are suitable for use in curable compositions used in applications such as prepregs, metal-clad laminates, and wiring boards, but can also be used in any application. [Means for solving the problem]

[0020] The present invention provides the following novel organosilicon compounds, novel crosslinking agents, curable compositions, prepregs, laminates, metal-clad laminates, and wiring boards.

[0021] [1] An organosilicon compound represented by the following formula (1TQ): [2] A crosslinking agent represented by the following formula (1TQ): [ka] (In the above formula, M is a single bond or an alkylene group having 1 to 20 carbon atoms which may have a substituent. The benzene ring may have a substituent. The substitution position of the vinyl group on the benzene ring is optional. n is an integer of 3 or 4. R is a hydrogen atom, a hydroxyl group, or an organic group, and when R is an organic group, the atom bonded to Si is C.)

[0022] [3] A curable composition comprising the crosslinking agent of [2] and a curable compound having two or more crosslinkable functional groups capable of crosslinking with the crosslinking agent. [4] A prepreg comprising a fiber substrate and a semi-cured or cured product of the curable composition of [3]. [5] A laminate comprising a substrate and a curable composition layer made of the curable composition of [3]. [6] A laminate comprising a substrate and a (semi-)cured product-containing layer containing a semi-cured product or a cured product of the curable composition of [3]. [7] The laminate according to [5] or [6], wherein the substrate is a resin film or a metal foil. [8] A metal-clad laminate comprising an insulating layer containing a cured product of the curable composition according to [3] and a metal foil. [9] A wiring board comprising an insulating layer containing a cured product of the curable composition according to [3] and wiring. [Effects of the Invention]

[0023] According to the present invention, a novel organosilicon compound suitable for use as a crosslinking agent or the like can be provided. According to the present invention, a novel organosilicon compound suitable for use in a curable composition and having a dielectric loss tangent (D f The present invention provides a novel crosslinking agent that effectively reduces the thermal expansion coefficient (CTE) and can provide a (semi-)cured product having a sufficiently low coefficient of thermal expansion (CTE) and a sufficiently high glass transition temperature (Tg), as well as a curable composition using the same. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic cross-sectional view of a metal-clad laminate according to a first embodiment of the present invention. [Figure 2] FIG. 3 is a schematic cross-sectional view of a metal-clad laminate according to a second embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view of a wiring board according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0025] In this specification, (semi)curing is a general term for semi-curing and curing. In this specification, unless otherwise specified, the term "wiring board" includes a multilayer wiring board. In this specification, the "high frequency region" is defined as a region with a frequency of 1 GHz or higher. In this specification, unless otherwise specified, the "number average molecular weight (Mn)" is the polystyrene equivalent number average molecular weight determined by gel permeation chromatography (GPC). In this specification, unless otherwise specified, the use of "to" indicating a range of values means that the values before and after it are included as the lower and upper limits. Hereinafter, an embodiment of the present invention will be described.

[0026] [New organosilicon compounds, new crosslinking agents] The organosilicon compound of the present invention is represented by the following formula (1TQ): The organosilicon compound of the present invention is suitable as a crosslinking agent. The crosslinking agent of the present invention is represented by the following formula (1TQ): [ka] (In the above formula, M is a single bond or an alkylene group having 1 to 20 carbon atoms which may have a substituent. The benzene ring may have a substituent. The substitution position of the vinyl group on the benzene ring is optional. n is an integer of 3 or 4. R is a hydrogen atom, a hydroxyl group, or an organic group, and when R is an organic group, the atom bonded to Si is C.)

[0027] The organosilicon compounds and crosslinking agents of the present invention can be used for any purpose, and are suitable for curable compositions, prepregs, laminates, metal-clad laminates, wiring boards, and the like.

[0028] [Curable composition] The curable composition of the present invention comprises the crosslinking agent of the present invention and a curable compound having two or more crosslinkable functional groups capable of crosslinking with the crosslinking agent. The curable composition may be heat-curable or active energy ray-curable. The active energy ray-curable composition is a composition that is cured by irradiation with active energy rays such as ultraviolet rays and electron beams. For applications such as metal-clad laminates and wiring boards, heat-curable compositions are preferred.

[0029] The curable compound includes a monomer, an oligomer, a prepolymer, etc. These may be used alone or in combination. Examples of cured products of the curable compound include polyphenylene ether resin (PPE), bismaleimide resin, epoxy resin, fluororesin, polyimide resin, olefin resin, polyester resin, polystyrene resin, hydrocarbon elastomer, benzoxazine resin, active ester resin, cyanate ester resin, butadiene resin, hydrogenated or non-hydrogenated styrene butadiene resin, vinyl resin, cycloolefin polymer, aromatic polymer, divinyl aromatic polymer, and combinations thereof.

[0030] In applications such as metal-clad laminates and wiring boards, the cured product of the curable compound preferably contains a polyphenylene ether resin (PPE). In this specification, the term "polyphenylene ether resin (PPE)" includes unmodified polyphenylene ether resin and modified polyphenylene ether resin, unless otherwise specified.

[0031] In the above applications, the curable compound is preferably, for example, a polyphenylene ether oligomer represented by the following formula (P). [ka]

[0032] X's at both ends of formula (P) are each independently a group represented by the following formula (x1) or (x2): In these formulas, "*" indicates a bond to the oxygen atom. [ka]

[0033] m is preferably 1-20, and more preferably 3-15. n is preferably 1-20, and more preferably 3-15.

[0034] The (semi-)cured product of the curable composition comprises a reaction product of the curable compound and the crosslinking agent of the present invention.

[0035] The number average molecular weight (Mn) of the oligomer is not particularly limited, but is preferably 1,000 to 5,000, and more preferably 1,000 to 4,000.

[0036] The curable composition preferably contains one or more polymerization initiators, such as organic peroxides, azo compounds, other known polymerization initiators, and combinations thereof. Specific examples include dicumyl peroxide, benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, t-butylcumyl peroxide, α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, trimethylsilyltriphenylsilyl peroxide, and azobisisobutyronitrile.

[0037] The curable composition may optionally contain one or more additives, such as inorganic fillers, compatibilizers, and flame retardants. Examples of inorganic fillers include silica such as spherical silica, metal oxides such as alumina, titanium oxide, and mica; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; talc; aluminum borate; barium sulfate; and calcium carbonate. One or more of these may be used. Among these, silica, mica, and talc are preferred from the viewpoint of low thermal expansion, and spherical silica is more preferred. The inorganic filler may be surface-treated with an epoxy silane type, vinyl silane type, methacryl silane type, or amino silane type silane coupling agent. The timing of the surface treatment with the silane coupling agent is not particularly limited. An inorganic filler surface-treated with a silane coupling agent may be prepared in advance, or the silane coupling agent may be added by integral blending during the preparation of the curable composition.

[0038] Examples of flame retardants include halogen-based flame retardants and phosphorus-based flame retardants. One or more of these may be used. Examples of halogen-based flame retardants include bromine-based flame retardants such as pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, and hexabromocyclododecane; and chlorine-based flame retardants such as chlorinated paraffin. Examples of phosphorus-based flame retardants include phosphate esters such as condensed phosphate esters and cyclic phosphate esters; phosphazene compounds such as cyclic phosphazene compounds; phosphinate-based flame retardants such as aluminum dialkylphosphinate; melamine-based flame retardants such as melamine phosphate and melamine polyphosphate; and phosphine oxide compounds having a diphenylphosphine oxide group.

[0039] The curable composition may contain one or more organic solvents as needed. The organic solvents are not particularly limited, and examples thereof include ketones such as methyl ethyl ketone, ethers such as dibutyl ether, esters such as ethyl acetate, amides such as dimethylformamide, aromatic hydrocarbons such as benzene, toluene, and xylene, and chlorinated hydrocarbons such as trichloroethylene.

[0040] In the curable composition, the solid content concentration and blending composition can be designed depending on the application and the like. For applications such as prepregs, the solid content is preferably 50 to 90 mass %.

[0041] [Prepreg] The prepreg of the present invention comprises a fibrous substrate and a (semi-)cured product of the curable composition of the present invention. The (semi-)cured product may contain additives such as inorganic fillers, if necessary. The prepreg can be produced by impregnating a fiber substrate with a curable composition and (semi-)curing it by heat curing or the like.

[0042] The material of the fiber substrate is not particularly limited, and examples thereof include inorganic fibers such as glass fiber, silica fiber, and carbon fiber; organic fibers such as aramid fiber and polyester fiber; and combinations thereof. Glass fiber is preferred for applications such as metal-clad laminates and wiring boards. Examples of the form of the glass fiber substrate include glass cloth, glass paper, and glass mat.

[0043] The curing conditions for the curable composition can be set depending on the composition of the curable composition, and semi-curing conditions (conditions that do not completely cure) are preferred. When a curable composition containing the polyphenylene ether oligomer represented by the above formula (P) is used, it is preferable to carry out heat curing by heating at 80 to 180° C. for 1 to 10 minutes, for example. For applications such as metal-clad laminates and wiring boards, it is preferable to adjust the composition of the curable composition and the curing conditions so that the resin content in the resulting prepreg falls within the range of 40 to 80 mass %.

[0044] [Laminate] The first laminate of the present invention includes a substrate and a curable composition layer made of the above-described curable composition of the present invention. The second laminate of the present invention comprises a substrate and a (semi-)cured product-containing layer containing a (semi-)cured product of the curable composition of the present invention. In the first and second laminates of the present invention, the substrate is not particularly limited, and examples thereof include resin films, metal foils, and combinations thereof. The (semi-)cured product-containing layer may be a layer containing a fibrous substrate and a (semi-)cured product of the curable composition of the present invention. The resin film is not particularly limited, and known resins can be used. Examples of resins that can be used for the resin film include polyimide, polyethylene terephthalate (PET), polyethylene naphthalate, cycloolefin polymer, and polyether sulfide. As the metal foil, copper foil, silver foil, gold foil, aluminum foil, and combinations thereof are preferred because of their low electrical resistance, and copper foil is more preferred.

[0045] [Metal-clad laminate] The metal-clad laminate of the present invention comprises an insulating layer containing a cured product of the curable composition of the present invention and a metal foil. The insulating layer may be a layer containing a fibrous substrate and a cured product of the curable composition of the present invention. As the metal foil, copper foil, silver foil, gold foil, aluminum foil, and combinations thereof are preferred due to their low electrical resistance, with copper foil being more preferred. The metal foil may have a metal plating layer on its surface. The metal foil may be a carrier-attached metal foil comprising an ultrathin metal foil and a carrier metal foil supporting it. The metal foil may have at least one surface subjected to a surface treatment such as anti-rust treatment, silane treatment, surface roughening treatment, or barrier formation treatment. The thickness of the metal foil is not particularly limited, and is preferably 0.1 to 100 μm, more preferably 0.2 to 50 μm, and particularly preferably 1.0 to 40 μm, as this is suitable for forming a conductor pattern (also called a circuit pattern) such as wiring.

[0046] The metal-clad laminate may be a single-sided metal-clad laminate having metal foil on one side, or a double-sided metal-clad laminate having metal foil on both sides, with a double-sided metal-clad laminate being preferred. A single-sided metal-clad laminate can be produced by stacking one or more of the above prepregs and a metal foil, and then heating and pressing the resulting first temporary laminate. The double-sided metal-clad laminate can be produced by sandwiching one or more of the above prepregs between a pair of metal foils and applying heat and pressure to the resulting first temporary laminate. A metal clad laminate using copper foil as the metal foil is called a copper clad laminate (CCL).

[0047] The insulating layer is preferably made of a prepreg that has been heated and pressed. The prepreg contains a fiber substrate and a resin, and may optionally contain one or more additives such as an inorganic filler and a flame retardant. The prepreg is also called a composite substrate. The conditions for heating and pressing the first temporary laminate are not particularly limited, and for example, a temperature of 170 to 250° C., a pressure of 0.3 to 30 MPa, and a time of 3 to 240 minutes are preferred.

[0048] 1 and 2 show schematic cross-sectional views of metal-clad laminates according to first and second embodiments of the present invention. The metal-clad laminate 1 shown in FIG. 1 is a single-sided metal-clad laminate (laminate) made of a heated and pressed prepreg, in which a metal foil (metal layer) 12 is laminated on one side of a composite substrate (cured product-containing layer) 11 containing a cured product of the curable composition of the present invention. The metal-clad laminate 2 shown in FIG. 2 is a double-sided metal-clad laminate made of a heated and pressed prepreg, in which metal foils (metal layers) 12 are laminated on both sides of a composite substrate (cured product-containing layer) 11 containing a cured product of the curable composition of the present invention.

[0049] The metal-clad laminates 1 and 2 may have layers other than those described above. The metal-clad laminates 1 and 2 may have an adhesive layer between the composite substrate (cured product-containing layer) 11 and the metal foil (metal layer) 12 to enhance adhesion therebetween. Known materials for the adhesive layer may be used, including epoxy resins, cyanate ester resins, acrylic resins, polyimide resins, maleimide resins, adhesive fluororesins, and combinations thereof. Commercially available adhesive fluororesins include Fluon LM-ETFE LH-8000, AH-5000, AH-2000, and EA-2000 manufactured by AGC Corporation.

[0050] The thickness of the composite substrate can be appropriately designed depending on the application. From the viewpoint of preventing disconnection of the wiring board, it is preferably 50 μm or more, more preferably 70 μm or more, and particularly preferably 100 μm or more. From the viewpoint of flexibility, miniaturization, and weight reduction of the wiring board, it is preferably 300 μm or less, more preferably 250 μm or less, and particularly preferably 200 μm or less.

[0051] [Wiring board] The wiring board of the present invention comprises an insulating layer containing a cured product of the curable composition of the present invention and wiring. A wiring board can be produced by forming a conductor pattern (circuit pattern) such as wiring using the metal foil on the outermost surface of the metal-clad laminate of the present invention. Methods for forming a conductor pattern such as wiring include the subtractive method, in which wiring is formed by etching a metal foil, and the MSAP (Modified Semi-Additive Process) method, in which wiring is formed on a metal foil by plating.

[0052] A schematic cross-sectional view of a wiring board according to one embodiment of the present invention is shown in Fig. 3. The wiring board 3 shown in Fig. 3 has a conductor pattern (circuit pattern) 22 such as wiring 22W formed using metal foil 12 on at least one outermost surface of the metal-clad laminate 2 of the second embodiment shown in Fig. 2. The wiring board 3 is made of a heated and pressurized prepreg, and has a conductor pattern (circuit pattern) 22 such as wiring 22W formed on at least one surface of a composite substrate (cured product-containing layer, insulating layer) 11 containing a cured product of the curable composition of the present invention.

[0053] One or more prepregs may be further laminated on the obtained wiring board, sandwiched between a pair of metal foils, and the obtained second temporary laminate may be heated and pressed, and a conductor pattern such as wiring may be formed using the metal foil on the outermost surface to produce a multilayer wiring board (also called a multilayer printed wiring board). Second It may be placed on only one side of the temporary laminate. The wiring board of the present invention is 1 It is suitable for use in the frequency range of 100 MHz or higher.

[0054] In recent years, in applications such as portable electronic devices, communication speeds and capacity have increased, and signals are becoming increasingly high frequency. Wiring boards used in these applications are required to have reduced transmission loss in the high frequency range. For this reason, resins contained in the composite base material of wiring boards used in the above applications are required to have reduced dielectric loss in the high frequency range. Generally, the dielectric loss tangent (D f ) depends on frequency, and for the same material, the higher the frequency, the greater the dielectric loss tangent (D f The resin contained in the composite substrate tends to have a large dielectric loss tangent (D f ) is preferably low.

[0055] If the difference in coefficient of thermal expansion (CTE) between the prepreg or composite substrate and the metal foil is large, there is a risk that the metal foil will shift or peel when a first temporary laminate including the prepreg and the metal foil, or a second temporary laminate including the composite substrate, the prepreg, and the metal foil, is heated and pressurized. It is preferable that the difference in coefficient of thermal expansion (CTE) between the prepreg or composite substrate and the metal foil is small. Generally, resins have a larger coefficient of thermal expansion (CTE) than metal foil, so it is preferable that the coefficient of thermal expansion (CTE) of the prepreg and composite substrate is small.

[0056] Wiring boards are sometimes used in relatively high-temperature environments, and in order to ensure the reliability of the wiring boards even in such cases, it is preferable that the resins contained in the prepreg and composite base material have a sufficiently high glass transition temperature (Tg).

[0057] The organosilicon compound and crosslinking agent of the present invention differ from the silane coupling agent used in Patent Document 1 listed in the "Background Art" section in that all four atoms bonded to Si are non-polar atoms (specifically, hydrogen atoms or carbon atoms). The inventors have conducted studies and found that when the organosilicon compound of the present invention is added to a curable composition, the organosilicon compound functions as a crosslinking agent that crosslinks a curable compound having two or more crosslinkable functional groups, and also reduces the dielectric loss tangent (D f ) can be effectively reduced. It was also found that the (semi-)cured product of the curable composition containing the organosilicon compound of the present invention has a sufficiently low coefficient of thermal expansion (CTE) and a sufficiently high glass transition temperature (Tg). It was also found that the (semi-)cured product of the curable composition containing the organosilicon compound of the present invention also has practically good adhesion to metals such as copper foil.

[0058] By adding the organosilicon compound of the present invention as a crosslinking agent to the curable composition, the dielectric loss tangent (D f ) is effectively reduced, and a (semi-)cured product can be obtained that has a sufficiently low coefficient of thermal expansion (CTE) and a sufficiently high glass transition temperature (Tg). This (semi-)cured product is suitable for composite substrates and insulating layers suitable for wiring boards used in high-frequency regions.

[0059] The dielectric loss tangent (D f ) is preferably within the following range, for example: Dielectric loss tangent (D f ) is preferably small, preferably 0.01 or less, more preferably 0.005 or less, and particularly preferably 0.003 or less. There is no particular restriction on the lower limit, and it is, for example, 0.0001.

[0060] The coefficient of thermal expansion (CTE) of the (semi-)cured product of the curable composition of the present invention and the composite substrate containing the same is preferably within the following range, for example. The coefficient of thermal expansion (CTE) is preferably small, and is preferably 70 ppm / ° C. or less, and more preferably 60 ppm / ° C. or less. There is no particular lower limit, and it is, for example, 1 ppm / ° C.

[0061] The glass transition temperature (Tg) of the (semi-)cured product of the curable composition of the present invention is preferably 150° C. or higher, more preferably 180° C. or higher, and particularly preferably 200° C. or higher. There is no particular upper limit, and it is, for example, 300° C.

[0062] Dielectric loss tangent (D f ), the coefficient of thermal expansion (CTE) and the glass transition temperature (Tg) can be measured by the method described in the section [Examples] below.

[0063] In the organosilicon compound of the present invention represented by formula (1TQ), the benzene ring may have a substituent. Examples of the substituent that the benzene ring may have include alkyl groups and aryl groups having 1 to 18 carbon atoms, and from the viewpoint of raw material availability, methyl groups, ethyl groups, propyl groups, butyl groups, hexyl groups, octyl groups, phenyl groups, and tolyl groups are preferred. It is preferable that the benzene ring has no substituent.

[0064] In the organosilicon compound of the present invention represented by formula (1TQ), the substitution position of the vinyl group on the benzene ring may be any of the ortho, meta, and para positions. The substitution position may be the ortho or para position. From the viewpoints of small steric hindrance during the crosslinking reaction and ease of raw material availability and synthesis, the substitution position may be the para position.

[0065] In the organosilicon compound of the present invention represented by formula (1TQ), the number of reactive functional groups (also simply referred to as the number of functional groups) n is 3 or 4. It is believed that the greater the number of functional groups n, the higher the crosslink density of the curable composition and the faster the curing rate. According to the investigations of the present inventors, when the number of functional groups n is 3 or 4, the dielectric loss tangent (D f ) can be effectively reduced. If the number of functional groups n is large, the curing rate may be too high, and unreacted reactive functional groups may remain in the curable composition. The crosslinking reaction of the curable composition can be efficiently carried out before curing, and unreacted reactive functional groups may remain after curing of the curable composition, resulting in a low dielectric loss tangent (D f ) can be prevented from increasing, the number of functional groups n is more preferably 3. When the number of functional groups n is 3 or 4, preferably 3, the dielectric loss tangent (D f The reason why the amount of carbon dioxide can be reduced more effectively is not necessarily clear, and the above explanation includes the inventors' speculation.

[0066] The compound of the present invention represented by formula (1TQ) In the organosilicon compound, R is a hydrogen atom, a hydroxyl group, or an organic group, and is preferably an alkyl group having 1 to 18 carbon atoms which may have a substituent. f It is preferable that R does not contain a polar atom such as an oxygen atom (O) because this can more effectively reduce the carbon number 1 to 18. R is preferably an unsubstituted alkyl group having 1 to 18 carbon atoms, and more preferably a linear alkyl group having 1 to 18 carbon atoms. The larger the carbon number of R, the lower the polarity of the crosslinked structure, and the higher the dielectric loss tangent (D f From the viewpoint of ease of synthesis, the upper limit of the number of carbon atoms is 18. The dielectric loss tangent (D f From the viewpoint of the effect of reducing the carbon number 1 and ease of synthesis, the number of carbon atoms in R is more preferably 3 to 18, and particularly preferably 8 to 18.

[0067] In the organosilicon compound of the present invention represented by formula (1TQ), M is a single bond or an alkylene group having 1 to 20 carbon atoms which may have a substituent. From the viewpoint of ease of synthesis, the upper limit of the number of carbon atoms is 20. From the viewpoint of ease of synthesis of the organosilicon compound, M is preferably a single bond or an alkylene group having 1 to 4 carbon atoms, more preferably a single bond or a methylene group.

[0068] The organosilicon compound of the present invention represented by formula (1TQ) can be synthesized by known synthesis methods. For specific synthesis examples, see the section [Examples].

[0069] As described above, the present invention provides a novel organosilicon compound suitable for use as a crosslinking agent, etc. The present invention provides a novel organosilicon compound suitable for use in a curable composition, which has a dielectric loss tangent (D f The present invention provides a novel crosslinking agent that effectively reduces the thermal expansion coefficient (CTE) and can provide a (semi-)cured product having a sufficiently low coefficient of thermal expansion (CTE) and a sufficiently high glass transition temperature (Tg), as well as a curable composition using the same. The novel organosilicon compounds and novel crosslinking agents of the present invention are suitable for use in curable compositions used in applications such as prepregs, metal-clad laminates, and wiring boards, but can also be used in any application.

[0070] [Application] The novel organosilicon compounds of the present invention are suitable as crosslinking agents and the like. The crosslinking agent of the present invention is suitable for use in curable compositions containing curable compounds such as monomers, oligomers and prepolymers. The novel organosilicon compounds and novel crosslinking agents of the present invention are suitable for use in curable compositions used in applications such as prepregs, metal-clad laminates, and wiring boards. The curable composition containing the crosslinking agent of the present invention is suitable for use in applications such as prepregs, metal-clad laminates, and wiring boards. The metal-clad laminate of the present invention is suitable for use as a wiring board or the like in various electric and electronic devices. The wiring board of the present invention is suitable for portable electronic devices such as mobile phones, smartphones, personal digital assistants, and notebook computers; antennas for mobile phone base stations and automobiles; electronic devices such as servers, routers, and backplanes; wireless infrastructure; radar for collision prevention, etc.; and various sensors (for example, automotive sensors such as engine management sensors). The wiring board of the present invention is particularly suitable for applications in which communication is performed using high-frequency signals, and is suitable for a variety of applications in which a reduction in transmission loss in the high-frequency range is required. [Example]

[0071] The present invention will be described in detail below with reference to examples, but is not limited to these. Examples 1 to 6 and 101 are working examples, and Examples 21, 31, and 32 are comparative examples. Unless otherwise specified, room temperature is about 25°C.

[0072] [Commercially available reagents] In the Examples section, unless otherwise specified, commercially available catalysts and reagents were used as they were in the reactions. Dehydrated and deoxygenated commercially available solvents were used.

[0073] [Evaluation items and evaluation methods for organosilicon compounds] (structure) The structure of the synthesized organosilicon compound was analyzed using a nuclear magnetic resonance spectrometer (JEOL Ltd., "JNM-AL300"), 1 It was identified by H-NMR measurement.

[0074] (molecular weight) The molecular weight of the synthesized organosilicon compounds was measured using a gas chromatograph mass spectrometer (GC-HRMS) (Agilent 7890A 」 / JEOL Made The results were obtained by electron impact (EI) using a JMS-T200 AccuTOF GCx-plus.

[0075] [Method for preparing evaluation samples (cured film)] As the curable compound, the following two types of polyphenylene ether oligomers were prepared. (SA9000) Bifunctional methacrylic modified PPE (SABIC "SA9000"), (OPE-2st) Bifunctional chloromethylstyrene-modified PPE ("OPE-2st" manufactured by Mitsubishi Gas Chemical Company, Inc.).

[0076] SA9000 and OPE-2st are expressed by the following formula. [ka]

[0077] The above bifunctional methacrylic modified PPE (SA9000) or bifunctional chloromethylstyrene modified PPE (OPE-2st) and the synthesized or prepared PPEs in each example were used. did An organosilicon compound, dicumyl peroxide as a radical polymerization initiator, and toluene were mixed in a mass ratio of 7:3:0.1:7 and stirred at room temperature to prepare a toluene solution (curable composition). Next, the toluene solution was applied onto a polyimide film having a thickness of 125 μm using an applicator (manufactured by Yoshimitsu Seiki Co., Ltd.) to form a coating film having a thickness of 250 μm. The coating was dried by heating in an oven under air at 80°C for 30 minutes, and then heated under nitrogen at 200°C for 2 hours to thermally cure (thermal crosslinking reaction) the coating, yielding an evaluation sample (film-like cured product) with a thickness of approximately 100µm. The evaluation sample thus obtained was evaluated as follows.

[0078] [Evaluation items and evaluation methods for film-like cured products] (Relative permittivity (D k ) and dielectric loss tangent (D f )) The relative dielectric constant (D k ) and dielectric loss tangent (D f ) was measured at room temperature by the SPDR method using a vector network analyzer ("E8361C" manufactured by Agilent Technologies).

[0079] (glass transition temperature Tg) The evaluation sample (film-like cured product) was subjected to dynamic viscoelasticity measurement (DMA) using a dynamic viscoelasticity measuring device ("DVA-200" manufactured by IT Measurement & Control Co., Ltd.) to measure the glass transition temperature (Tg) (°C). The measurement was performed under conditions of a frequency of 10 Hz, a heating rate of 2°C / min, and a temperature range of 25 to 300°C.

[0080] (Coefficient of Thermal Expansion (CTE)) The coefficient of thermal expansion (CTE) of the evaluation sample (cured film) below the glass transition temperature (Tg) was measured using a thermomechanical analyzer (TMA / SS7100 manufactured by SII NanoTechnology Inc.) at a temperature rise rate of 5°C / min over a temperature range of -50 to 340°C.

[0081] [Example 1] Synthesis of methyltris(4-vinylphenyl)silane (C1-Tp-St-Si) <Synthesis of tris(4-formylphenyl)methylsilane> Under a nitrogen atmosphere, a 500 mL four-neck flask was charged with 4-bromobenzaldehyde dimethyl acetal (24.0 g, 102 mmol) and tetrahydrofuran (300 mL). The solution was cooled to below -70 °C, and n-BuLi / n-hexane solution (2.6 mol / L, 39 mL, 100 mmol) was added dropwise over 1 hour. The reaction solution was stirred at below -70 °C for 2 hours. Trichloro(methyl)silane (3.17 mL, 27.1 mmol) was added dropwise over 40 minutes to the resulting suspension, and the mixture was stirred at the same temperature for 2 hours. The flask was warmed to room temperature and stirred for 12 hours or more. The reaction mixture was quenched with hydrochloric acid (2 mol / L, 120 mL), and diethyl ether (100 mL) was added to separate the organic phase. Furthermore, diethyl ether (100 mL) was added to the aqueous phase, and the organic phase was separated and extracted. The organic phases obtained from these extractions were combined. The combined organic phases were washed with saturated brine (100 mL), dried over magnesium sulfate, filtered, and the filtrate was concentrated under vacuum to obtain a crude mixture of acetal and aldehyde. Tetrahydrofuran (100 mL) and hydrochloric acid (2 mol / L, 100 mL) were added to the crude mixture, and the mixture was heated to reflux for 2 hours. After cooling to room temperature, saturated aqueous sodium bicarbonate solution (400 mL) was added dropwise to the reaction mixture. Diethyl ether (100 mL) was added to the reaction mixture, and extraction to separate the organic phase was performed three times. The organic phases obtained from these extractions were combined. The combined organic phases were washed with saturated brine (100 mL), dried over magnesium sulfate, filtered, and the filtrate was concentrated under vacuum to obtain a crude product (yellow oil). The crude product was purified using silica gel column chromatography (mobile phase: ethyl acetate / n-hexane=1:4 (volume ratio)) to obtain 9.95 g of colorless liquid tris(4-formylphenyl)methylsilane (yield: 98%, purity: 96%).

[0082] The reaction scheme and NMR analysis results are as follows: [ka]

[0083] 1H-NMR (CDCl3): δ(ppm)10.06(s,3H,CHO),7.89(d,6H,J=7.68Hz,Ar-H),7.67(d,6H,J=7.68Hz,Ar-H),0.97(s,3H,Si-CH3).

[0084] <Synthesis of methyltris(4-vinylphenyl)silane> A 500 mL four-neck flask was charged with methyltriphenylphosphonium bromide (27.5 g, 77.0 mmol) and tetrahydrofuran (128 mL) under a nitrogen atmosphere. The flask was cooled to 0 °C, and potassium tert-butoxide (9.74 g, 86.8 mmol) was added to the suspension. The reaction mixture was stirred at the same temperature for 5 minutes or more. A solution of tris(4-formylphenyl)methylsilane (8.00 g, 21.4 mmol) in tetrahydrofuran (128 mL) was added dropwise to the reaction mixture over 20 minutes. The flask was warmed to room temperature and stirred for 2 hours. 4-tert-butylpyrocatechol (0.60 mg) was added to the reaction mixture, which was then concentrated under reduced pressure at 30 °C. Water (200 mL) and diethyl ether (200 mL) were added to the resulting mixture, and the organic phase was separated and extracted. Further, diethyl ether (200 mL) was added to the aqueous phase, and extraction was performed to separate the organic phase. The organic phases obtained from these extractions were combined. The combined organic phases were dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude mixture. n-Hexane (160 mL) and diethyl ether (40 mL) were added to the crude mixture and stirred for 30 minutes. The mixture was filtered through filter paper, and the filtrate was concentrated under reduced pressure to obtain a crude product (yellow oil). The crude product was purified using silica gel column chromatography (mobile phase: n-hexane) to obtain 6.41 g of colorless liquid methyltris(4-vinylphenyl)silane (C1-Tp-St-Si) (yield: 85%).

[0085] The reaction scheme, NMR analysis results and HRMS analysis results are as follows: [ka]

[0086] 1 H-NMR(CDCl3):δ(ppm)7.47(d,6H,J=7.68Hz,Ar-H),7.39(d,6H,J=7.68 Hz,Ar-H),6.72(dd,3H,J=11.1,17.9Hz,-CH=CH2),5.78(d,3H,J=17.9Hz,-CH=CH2),5.27(d,3H,J=11.1Hz,-CH=CH2),0.81(s,3H,Si-CH3). HRMS(EI):m / z Calcd for C 25 H 24 Si:(M + )352.165,found 352.162.

[0087] [Example 2] Synthesis of dodecyltris(4-vinylphenyl)silane (C12-Tp-St-Si) <Synthesis of dodecyltris(4-formylphenyl)silane> A 500 mL four-neck flask was charged with 4-bromobenzaldehyde dimethyl acetal (24.0 g, 102 mmol) and tetrahydrofuran (300 mL) under a nitrogen atmosphere. The solution was cooled to below -66 °C, and n-BuLi / n-hexane solution (2.6 mol / L, 39 mL, 100 mmol) was added dropwise over 1 hour. The reaction solution was stirred at below -70 °C for 2 hours. Dodecyltrichlorosilane (8.08 mL, 27.2 mmol) was added dropwise over 40 minutes and stirred at the same temperature for 2 hours. The flask was warmed to room temperature and stirred for 12 hours or more. The reaction mixture was quenched with hydrochloric acid (2 mol / L, 120 mL), and diethyl ether (100 mL) was added to separate the organic phase. Furthermore, diethyl ether (100 mL) was added to the aqueous phase, and the organic phase was separated and extracted. The organic phases obtained from these extractions were combined. The combined organic phase was washed with saturated brine (100 mL), dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude product. The crude product was purified using silica gel column chromatography (mobile phase: chloroform / n-hexane = 1:1 (volume ratio)) to obtain 9.53 g of colorless liquid dodecyltris(4-formylphenyl)silane (yield: 68%).

[0088] The reaction scheme and NMR analysis results are as follows: [ka]

[0089] 1 H-NMR(CDCl3):δ(ppm)10.06(s,3H,CHO),7.89(d,6H,J=8.54Hz,Ar-H),7.67(d,6H,J=8.54Hz,Ar-H), 1.47~1.39(m,6H,-CH2-),1.23(brs,16H,-CH2-),0.87(t,3H,J=6.83 Hz,Si-CH3).

[0090] <Synthesis of dodecyltris(4-vinylphenyl)silane> A 500 mL four-neck flask was charged with methyltriphenylphosphonium bromide (21.3 g, 59.6 mmol) and tetrahydrofuran (136 mL) under a nitrogen atmosphere. The flask was cooled to 0 °C, and potassium tert-butoxide (7.53 g, 67.1 mmol) was added to the suspension. The reaction mixture was stirred at the same temperature for 5 minutes or more. A solution of dodecyltris(4-formylphenyl)silane (8.50 g, 16.6 mmol) in tetrahydrofuran (136 mL) was added dropwise to the reaction mixture over 20 minutes. The flask was warmed to room temperature and stirred for 1 hour. 4-tert-butylpyrocatechol (2.55 mg) was added to the reaction mixture, which was then concentrated under reduced pressure at 30 °C. Water (200 mL) and diethyl ether (200 mL) were added to the resulting mixture, and the organic phase was separated and extracted. Further, diethyl ether (200 mL) was added to the aqueous phase, and extraction was performed to separate the organic phase. The organic phases obtained from these extractions were combined. The combined organic phases were dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude mixture. n-Hexane (160 mL) and diethyl ether (40 mL) were added to the crude mixture and stirred for 30 minutes. The mixture was filtered through filter paper, and the filtrate was concentrated under reduced pressure to obtain a crude product (yellow oil). The crude product was purified using silica gel column chromatography (mobile phase: n-hexane) to obtain 4.73 g of dodecyltris(4-vinylphenyl)silane (C12-Tp-St-Si) as a pale yellow liquid (yield: 56%).

[0091] The reaction scheme, NMR analysis results and HRMS analysis results are as follows: [ka]

[0092] 1H-NMR(CDCl3):δ(ppm)7.47(d,6H,J=7.68Hz,Ar-H),7.39(d,6H,J=8.54Hz,Ar-H),6.72(dd,3H,J=10.7,17.5Hz,-CH=CH2), 5.79(d,3H,J=17.9Hz,-CH=CH2),5.27(d,3H,J=11.1Hz,-CH=CH2),1.49~1.22(m,22H,-CH2-),0.86(t,3H,J=6.40Hz,CH3). HRMS(EI):m / z Calcd for C 36 H 46 Si:(M + )506.337,found 506.331.

[0093] [Example 3] Synthesis of dodecyltris(3-vinylphenyl)silane (C12-Tm-St-Si) <Synthesis of dodecyltris(3-formylphenyl)silane> A 500 mL four-neck flask was charged with 3-bromobenzaldehyde diethyl acetal (24.0 g, 90.8 mmol) and tetrahydrofuran (300 mL) under a nitrogen atmosphere. The solution was cooled to below -65°C, and n-BuLi / n-hexane solution (2.6 mol / L, 35 mL, 91 mmol) was added dropwise over 1 hour. The reaction solution was stirred at below -70°C for 2 hours. Dodecyltrichlorosilane (7.20 mL, 24.2 mmol) was added dropwise over 40 minutes and stirred at the same temperature for 2 hours. The flask was warmed to room temperature and stirred for 12 hours or more. The reaction mixture was quenched with hydrochloric acid (2 mol / L, 120 mL), stirred at room temperature for 1 hour, and the organic phase was separated. Ethyl acetate (100 mL) was added to the aqueous phase, and two extractions were performed to separate the organic phase. The organic phases obtained from these extractions were combined. The combined organic phase was washed with saturated brine (100 mL), dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude product, which was purified using silica gel column chromatography (mobile phase: chloroform / n-hexane = 1:1 (volume ratio)) to obtain 10.5 g of colorless liquid dodecyltris(3-formylphenyl)silane (yield: 85%).

[0094] The reaction scheme and NMR analysis results are as follows: [ka]

[0095] 1 H-NMR(CDCl3):δ(ppm)10.01(s,3H,CHO),8.00(brs,3H,s,Ar-H), 7.97(td,3H,J=7.68,1.71 Hz,Ar-H),7.76(d,3H,J=7.68Hz,Ar-H),7.58(t,3H,J=7.68Hz,Ar-H),1.56~1.33(m,6H,-CH2-),1.22(brs,16H,-CH2-),0.87(t,3H,J=6.83 Hz,CH3).

[0096] <Synthesis of dodecyltris(3-vinylphenyl)silane> A 500 mL four-neck flask was charged with methyltriphenylphosphonium bromide (22.6 g, 63.3 mmol) and tetrahydrofuran (144 mL) under a nitrogen atmosphere. The flask was cooled to 0 °C, and potassium tert-butoxide (7.98 g, 71.1 mmol) was added to the suspension. The reaction mixture was stirred at the same temperature for 5 minutes or more. A solution of dodecyltris(3-formylphenyl)silane (9.00 g, 17.6 mmol) in tetrahydrofuran (144 mL) was added dropwise to the reaction mixture over 20 minutes. The flask was warmed to room temperature and stirred for 1 hour. 4-tert-butylpyrocatechol (2.55 mg) was added to the reaction mixture, which was then concentrated under reduced pressure at 30 °C. Water (200 mL) and diethyl ether (200 mL) were added to the resulting mixture, and the organic phase was separated and extracted. Further, diethyl ether (200 mL) was added to the aqueous phase, and extraction was performed to separate the organic phase. The organic phases obtained from these extractions were combined. The combined organic phases were dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude mixture. n-Hexane (160 mL) and diethyl ether (40 mL) were added to the crude mixture and stirred for 30 minutes. The mixture was filtered through filter paper, and the filtrate was concentrated under reduced pressure to obtain a crude product (red oil). The crude product was purified using silica gel column chromatography (mobile phase: n-hexane) to obtain 6.32 g of dodecyltris(3-vinylphenyl)silane (C12-Tm-St-Si) as a pale yellow liquid (yield: 71%).

[0097] The reaction scheme, NMR analysis results and HRMS analysis results are as follows: [ka]

[0098] 1H-NMR(CDCl3):δ(ppm)7.54(brs,3H,Ar-H),7.48(d,3H,J=6.83Hz,Ar-H),7.40(d,3H,J= 6.83Hz,Ar-H),7.32(t,3H,J=6.83Hz,Ar-H),6.69(dd,3H,J=11.10,17.93Hz,-CH=CH2), 5.69(d,3H,J=17.93Hz,-CH=CH2),5.21(d,3H,J=11.10Hz,-CH=CH2),1.52-1.42(m,2H,- CH2-),1.42-1.32(m,4H,-CH2-),1.32-1.11(m,16H,-CH2-),0.87(t,3H,J=6.83Hz,CH3). HRMS(EI):m / z Calcd for C 36 H 46 Si:(M + )506.337,found 506.329.

[0099] [Example 4] Synthesis of dodecyltris(4-vinylbenzyl)silane (C12-Tp-Bn-Si) A 50 mL four-neck flask was charged with magnesium turnings (0.898 g, 36.9 mmol) and diethyl ether (21.1 mL) under a nitrogen atmosphere and cooled in an ice bath. A solution of 4-(chloromethyl)styrene (5.12 g, 33.5 mmol) in diethyl ether (10.5 mL) was added dropwise to the suspension over 1 hour. After stirring at the same temperature for 1 hour, dodecyltrichlorosilane (3.33 mL, 11.2 mmol) was added dropwise over 20 minutes. The flask was warmed to room temperature and stirred for 12 hours or more. Water (15 mL) was added to the reaction mixture and stirred for 10 minutes or more to separate the organic phase. Further extractions were performed twice, with diethyl ether (30 mL) added to the aqueous phase to separate the organic phase. The organic phases obtained from these extractions were combined. The combined organic phase was dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain the crude product. The crude product was purified using silica gel column chromatography (mobile phase: n-hexane) to obtain 1.09 g of pale yellow liquid dodecyltris(4-vinylbenzyl)silane (C12-Tp-Bn-Si) (yield: 18%).

[0100] The reaction scheme, NMR analysis results and HRMS analysis results are as follows: [ka]

[0101] 1 H-NMR(CDCl3):δ(ppm)7.26(d,6H,J=7.68Hz,Ar-H),6.91(d,6H,J=8.54Hz,Ar-H),6.68(dd,3H,J=11.1,17.9Hz,-CH=CH2),5.68(d,3H,J=17.9Hz,-C H=CH2),5.17(d,3H,J=10.2Hz,-CH=CH2),2.09(s,6H,Si-CH2-Ar),1.38-1.08(m,20H,-CH2-),0.88(t,3H,J=6.40Hz,CH3),0.53-0.38(m,2H,-CH2-). HRMS(EI):m / z Calcd for C 39 H 52 Si:(M + )548.384,found 548.374.

[0102] [Example 5] Synthesis of dodecyltris(vinylbenzyl)silane isomer mixture (C12-T-mp-Bn-Si) A 50 mL four-neck flask was charged with magnesium turnings (0.898 g, 36.9 mmol) and diethyl ether (21.1 mL) under a nitrogen atmosphere and cooled in an ice bath. A solution of 4-(chloromethyl)styrene / 3-(chloromethyl)styrene (1:1 molar ratio, 5.12 g, 33.5 mmol) in diethyl ether (10.5 mL) was added dropwise to the suspension over 1 hour. After stirring at the same temperature for 1 hour, dodecyltrichlorosilane (3.33 mL, 11.2 mmol) was added dropwise over 20 minutes. The flask was warmed to room temperature and stirred for 12 hours or more. Water (15 mL) was added to the reaction mixture, and the mixture was stirred for 10 minutes or more to separate the organic phase. Furthermore, diethyl ether (30 mL) was added to the aqueous phase, and extraction to separate the organic phase was performed twice. The organic phases obtained from these extractions were combined. The combined organic phase was dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude product. The crude product was purified using silica gel column chromatography (mobile phase: n-hexane) to obtain 0.319 g of a colorless liquid dodecyltris(vinylbenzyl)silane isomer mixture (C12-T-mp-Bn-Si) (yield: 5.2%). From the NMR analysis results, the molar ratio of 3-vinylbenzyl groups to 4-vinylbenzyl groups in the isomer mixture was estimated to be 1.4:1.6.

[0103] The reaction scheme, NMR analysis results and HRMS analysis results are as follows: [ka]

[0104] 1 H-NMR(CDCl3):δ(ppm)7.35~6.81(m,12H,Ar-H),6.74~6.55(m,3H,H-5,-CH=CH2),5.68(d,3H,J=17.1Hz,-CH=CH2),5.20(d,1.36H,J=10.2Hz,-CH=CH 2, m-body),5.17(d,1.64H,J=11.1Hz,-CH=CH 2,o-body), 2.10(s,6H,Si-CH2-Ar),1.38-1.06(m,20H,-CH2-),0.88(t,3H,J=6.83Hz,CH3),0.56-0.39(m,2H,-CH2-). HRMS(EI):m / z Calcd for C 39 H 52 Si:(M + )548.384,found 548.376.

[0105] [Example 6] Synthesis of tetrakis(4-vinylphenyl)silane (C1-Qp-St-Si) <Synthesis of tetrakis(4-formylphenyl)silane> A 300 mL four-neck flask was charged with 4-bromobenzaldehyde dimethyl acetal (12.0 g, 50.9 mmol) and tetrahydrofuran (150 mL) under a nitrogen atmosphere. The solution was cooled to below -65°C, and n-BuLi / n-hexane solution (2.6 mol / L, 20 mL, 52 mmol) was added dropwise over 1 hour. The reaction solution was stirred at below -68°C for 2 hours. Tetrachlorosilane (1.14 mL, 9.81 mmol) was added dropwise over 30 minutes to the resulting suspension, and the mixture was stirred at the same temperature for 2 hours. The flask was warmed to room temperature and stirred for 12 hours or more. The reaction mixture was quenched with hydrochloric acid (2 mol / L, 60 mL), and diethyl ether (50 mL) was added. The organic phase was separated and extracted. moreover,Diethyl ether (50 mL) was added to the aqueous phase, and extraction to separate the organic phase was performed twice. The organic phases obtained from these extractions were combined. The combined organic phases were washed with saturated brine (50 mL), dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude mixture of acetal and aldehyde. Tetrahydrofuran (50 mL) and hydrochloric acid (2 mol / L, 50 mL) were added to the crude mixture, and the mixture was heated to reflux for 2 hours. After cooling to room temperature, saturated aqueous sodium bicarbonate solution (100 mL) was added dropwise to the reaction mixture. Diethyl ether (50 mL) was added to the reaction mixture, and extraction to separate the organic phase was performed three times. The organic phases obtained from these extractions were combined. The combined organic phases were washed with saturated brine (50 mL), dried over magnesium sulfate, filtered, and the filtrate was concentrated under vacuum to obtain the crude product (pale yellow oil). An ethyl acetate / n-hexane mixed solution (1:3 (volume ratio), 40 mL) was added to the crude product, and the mixture was heated to reflux and then slowly cooled to 0° C. The suspension was filtered, and the resulting solid was dried under reduced pressure to obtain 2.25 g of tetrakis(4-formylphenyl)silane (yield: 51%).

[0106] The reaction scheme and NMR analysis results are as follows: [ka]

[0107] 1 H-NMR (CDCl3): δ(ppm)10.09(s,4H,CHO),7.94(d,8H,J=7.68Hz,Ar-H),7.73(d,8H,J=8.54Hz,Ar-H).

[0108] <Synthesis of tetrakis(4-vinylphenyl)silane> A 100 mL four-neck flask was charged with methyltriphenylphosphonium bromide (8.03 g, 22.5 mmol), potassium tert-butoxide (3.03 g, 27.0 mmol), and tetrahydrofuran (34 mL) under a nitrogen atmosphere. The flask was cooled to 0 °C, and the reaction mixture was stirred for at least 5 minutes. A solution of tetrakis(4-formylphenyl)silane (2.10 g, 4.68 mmol) in tetrahydrofuran (34 mL) was added dropwise to the reaction mixture over 10 minutes. The flask was warmed to room temperature and stirred for 2 hours. The reaction mixture was concentrated under reduced pressure at 30 °C, and the resulting mixture was extracted with water (50 mL) and diethyl ether (50 mL) to separate the organic phase. The aqueous phase was further extracted with diethyl ether (50 mL) to separate the organic phase. The organic phases obtained from these extractions were combined. The combined organic phase was dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude mixture. To the crude mixture, n-hexane (40 mL) and diethyl ether (10 mL) were added and stirred for 30 minutes. The mixture was filtered through filter paper, and the filtrate was concentrated under reduced pressure to obtain a crude product. To the crude product, methanol (10 mL) and 4-tert-butylpyrocatechol (0.6 mg) were added and stirred at room temperature for 30 minutes. The suspension was filtered, and the resulting solid was dried under reduced pressure to obtain 0.747 g of tetrakis(4-vinylphenyl)silane (C1-Qp-St-Si) (yield: 36%).

[0109] The reaction scheme and NMR analysis results are as follows: [ka]

[0110] 1 H-NMR (CDCl3): δ(ppm)7.53(d,8H,J=7.68Hz,Ar-H),7.41(d,8H,J=8.54Hz,Ar-H),6.73(dd,4H ,J=10.7,17.5Hz,-CH=CH2),5.80(d,4H,J=17.9Hz,-CH=CH2),5.29(d,4H,J=11.1Hz,-CH=CH2).

[0111] [Example 21] Synthesis of dimethylbis(4-vinylphenyl)silane (C1-Dp-St-Si) <Synthesis of bis(4-formylphenyl)dimethylsilane> A 500 mL four-neck flask was charged with 4-bromobenzaldehyde dimethyl acetal (24.0 g, 102 mmol) and tetrahydrofuran (300 mL) under a nitrogen atmosphere. The solution was cooled to below -65°C, and n-BuLi / n-hexane solution (2.6 mol / L, 39 mL, 100 mmol) was added dropwise over 1 hour. The reaction solution was stirred at below -70°C for 2 hours. Dichlorodimethylsilane (4.93 mL, 40.7 mmol) was added dropwise over 40 minutes and the mixture was stirred at the same temperature for 2 hours. The flask was warmed to room temperature and stirred for 12 hours or more. The reaction mixture was quenched with hydrochloric acid (2 mol / L, 120 mL), and diethyl ether (100 mL) was added to separate the organic phase. Furthermore, diethyl ether (100 mL) was added to the aqueous phase, and extraction to separate the organic phase was performed twice. The organic phases obtained from these extractions were combined, washed with saturated saline (100 mL), and sulfuric acid The mixture was dried over magnesium sulphate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude acetal / aldehyde mixture. Tetrahydrofuran (100 mL) and hydrochloric acid (2 mol / L, 100 mL) were added to the crude mixture and heated to reflux for 2 hours. After cooling to room temperature, saturated aqueous sodium bicarbonate (240 mL) was added dropwise to the reaction mixture. Diethyl ether (100 mL) was added to the reaction mixture, and extraction to separate the organic phase was performed three times. The organic phases obtained from these extractions were combined. The combined organic phases were washed with saturated brine (100 mL), dried over magnesium sulphate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude product (pale yellow oil). A mixed solution of ethyl acetate / n-hexane (1:7 (volume ratio), 120 mL) was added to the crude product, heated to reflux, and then slowly cooled to 0 °C. The suspension was filtered, and the resulting solid was dried under reduced pressure to obtain 8.40 g of bis(4-formylphenyl)dimethylsilane (yield: 77%).

[0112] The reaction scheme and NMR analysis results are as follows: [ka]

[0113] 1 H-NMR (CDCl3): δ(ppm)10.03(s,2H,CHO),7.86(d,4H,J=7.68Hz,Ar-H),7.68(d,4H,J=8.54Hz,Ar-H),0.64(s,6H,Si-CH3).

[0114] <Synthesis of dimethylbis(4-vinylphenyl)silane> A 500 mL four-neck flask was charged with methyltriphenylphosphonium bromide (25.6 g, 71.7 mmol) and tetrahydrofuran (128 mL) under a nitrogen atmosphere. The flask was cooled to 0 °C, and potassium tert-butoxide (9.03 g, 80.5 mmol) was added to the suspension. The reaction mixture was stirred at the same temperature for 5 minutes or more. A solution of bis(4-formylphenyl)dimethylsilane (8.00 g, 29.8 mmol) in tetrahydrofuran (128 mL) was added dropwise to the reaction mixture over 20 minutes. The flask was warmed to room temperature and stirred for 2 hours. 4-tert-butylpyrocatechol (0.60 mg) was added to the reaction mixture, which was then concentrated under reduced pressure at 30 °C. Water (200 mL) and diethyl ether (200 mL) were added to the resulting mixture, and the organic phase was separated and extracted. Further, diethyl ether (200 mL) was added to the aqueous phase, and extraction was performed to separate the organic phase. The organic phases obtained from these extractions were combined. The combined organic phases were dried over magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude mixture. n-Hexane (160 mL) and diethyl ether (40 mL) were added to the crude mixture and stirred for 30 minutes. The mixture was filtered through filter paper, and the filtrate was concentrated under reduced pressure to obtain a crude product. The crude product was purified using silica gel column chromatography (mobile phase: n-hexane) to obtain 7.27 g of colorless liquid dimethylbis(4-vinylphenyl)silane (C1-Dp-St-Si) (yield: 92%).

[0115] The reaction scheme, NMR analysis results and HRMS analysis results are as follows: [ka]

[0116] 1 H-NMR(CDCl3):δ(ppm)7.48(d,4H,J=8.54Hz,Ar-H),7.38(d,4H,J=7.68Hz,Ar-H),6.71(dd,2H,J=11.1,1 7.9Hz,-CH=CH2),5.77(d,2H,J=17.1Hz,-CH=CH2),5.25(d,2H,J=10.2Hz,-CH=CH2),0.54(s,6H,Si-CH3). HRMS(EI):m / z Calcd for C 18 H 20 Si:(M + )264.133,found 264.131.

[0117] [Example 31] As an organosilicon compound for comparison, a commercially available silane coupling agent, trimethoxyvinylsilane (TMVS, a product of TCI), was prepared.

[0118] [Example 32] As an organosilicon compound for comparison, a commercially available silane coupling agent, triethoxyvinylsilane (TEVS, a product of TCI), was prepared.

[0119] [Evaluation and Results] In Examples 1 to 3, 21, 31, and 32, evaluation samples were produced and evaluated using the obtained or prepared organosilicon compounds according to the above-mentioned "Method for producing evaluation samples (film-like cured products)." The evaluation results are shown in Tables 1 to 3.

[0120] [Table 1]

[0121] [Table 2]

[0122] [Table 3]

[0123] [Summary of results] In Examples 1 to 3, a film-like cured product was obtained using a tri- or higher functional organosilicon compound (an organosilicon compound represented by formula (1TQ)). In Example 21, a bifunctional organosilicon compound for comparison was used to obtain a film-like cured product. In Examples 31 and 32, a silane coupling agent, which is an organosilicon compound for comparison, was used to obtain a film-like cured product. In Examples 1 to 3 and 21, the dielectric loss tangent (D f ) was effectively reduced. Comparing Example 1 and Example 21, it is clear that by using an organosilicon compound with three or more functional groups as a crosslinking agent, the dielectric loss tangent (D f ) can be reduced more effectively. In Examples 1 to 3, the dielectric loss tangent (D f ) was effectively reduced, and a film-like cured product was obtained with a sufficiently low coefficient of thermal expansion (CTE) and a sufficiently high glass transition temperature (Tg).

[0124] [Example 101] Bifunctional methacrylic-modified PPE (SA9000), the organosilicon compound synthesized in Example 1, dicumyl peroxide as a radical polymerization initiator, spherical silica as an inorganic filler, and toluene were mixed in a mass ratio of 7:3:0.1:10:10 and stirred at room temperature to prepare a curable composition (varnish). The obtained curable composition (varnish) was impregnated into a glass cloth (E glass, #2116) as a fiber substrate, and then heated at 130°C for 5 minutes to semi-cure the curable composition, thereby obtaining a prepreg. Two sheets of the obtained prepreg were stacked and sandwiched between a pair of copper foils, and the obtained temporary laminate was heated and pressed at 200°C for 1.5 hours at 3 MPa to produce a metal-clad laminate.

[0125] The present invention is not limited to the above-described embodiments and examples, and various modifications can be made to the design as appropriate without departing from the spirit of the present invention.

[0126] This application claims priority based on Japanese Patent Application No. 2021-094354, filed on June 4, 2021, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0127] 1, 2: metal-clad laminate, 3: wiring board, 11: composite substrate, 12: metal foil, 22: conductor pattern (circuit pattern), 22W: wiring.

Claims

1. A crosslinking agent represented by the following formula (1TQ): 【Chemical 1】 (In the above formula, M is a single bond or an alkylene group having 1 carbon atom which may have a substituent. The benzene ring may have a substituent. The substitution position of the vinyl group on the benzene ring is optional. n is 3. R is an alkyl group having 1 to 18 carbon atoms.)

2. The crosslinker of claim 1 , wherein M is a single bond.

3. 3. The crosslinking agent according to claim 1, wherein R is a linear alkyl group having 1 to 18 carbon atoms.

4. The crosslinking agent described in claim 3, wherein R is a linear alkyl group having 1 to 12 carbon atoms.

5. The crosslinking agent according to any one of claims 1 to 4, which is for use in a curable composition used in the production of a prepreg, a metal-clad laminate, or a wiring board.

6. A curable composition comprising the crosslinking agent according to any one of claims 1 to 5 and a curable compound having two or more crosslinkable functional groups capable of crosslinking with the crosslinking agent.

7. A prepreg comprising a fibrous substrate and a semi-cured or cured product of the curable composition according to claim 6.

8. A laminate comprising a substrate and a curable composition layer comprising the curable composition according to claim 6.

9. A laminate comprising a substrate and a (semi-)cured product-containing layer containing a semi-cured product or a cured product of the curable composition according to claim 6.

10. The laminate according to claim 8 or 9, wherein the substrate is a resin film or a metal foil.

11. A metal-clad laminate comprising an insulating layer containing a cured product of the curable composition described in claim 6 and a metal foil.

12. A wiring board comprising an insulating layer containing a cured product of the curable composition described in claim 6 and wiring.

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