Polydopamine-equipped base material and article made using same

Abstract

A polydopamine-equipped base material according to the present disclosure comprises a base material and a polydopamine that is adhered to the base material. The polydopamine-equipped base material satisfies 0<PA / BET≤0.450 or 60≤E*≤80. PA (mass%) represents the adhered / adsorbed amount of the polydopamine. BET (m2 / g) represents the nitrogen adsorption specific surface area of the base material. E* represents the distance from an origin point to the position corresponding to the color of the polydopamine-equipped base material in a color space represented by three-dimensional orthogonal coordinates of L*, a*, and b* in an L*a*b* color system.

Description

Polydopamine-containing substrates and their application products

[0001] The present disclosure relates to a polydopamine-containing substrate and an application product thereof.

[0002] Dopamine-containing proteins secreted from the byssus glands of the blue mussel, a type of bivalve, exhibit stable adhesive strength even in seawater and are known as natural adhesives. According to Non-Patent Document 1, when a substrate is immersed in an aqueous dopamine solution, a thin film of polydopamine is formed on the surface of the substrate through autoxidative polymerization of dopamine, thereby achieving chemical modification of the substrate surface. Such surface chemical modification with polydopamine can be applied to chemical modification of filler surfaces.

[0003] On the other hand, it is essential that the filler used in the insulating layer of a wiring board has insulating properties. However, according to Non-Patent Document 2, polydopamine is known to exhibit semiconducting properties. Therefore, if the amount of polydopamine chemically modified on the filler surface is increased, the insulating properties cannot be ensured.

[0004] Haeshin Lee, Shara M. Dellatore, William M. Miller, Phillip B. Messersmith, Science, 2007, vol. 318, 426-430Marco d'Ischia, Alessandra Napolitano, Vincent Ball, Chun-Teh Chen, Markus J. Buehler, Acc. Chem. Res., 2014, 47, 3541-3550

[0005] The present disclosure provides a polydopamine-containing substrate that has guaranteed insulating properties.

[0006] A polydopamine-attached substrate according to one aspect of the present disclosure includes a substrate and polydopamine attached to the substrate. The polydopamine-attached substrate has a PA / BET ratio of 0<PA / BET≦0.450 or 60≦E ＊ ≦80, where PA (mass%) represents the amount of polydopamine attached and adsorbed, and BET (m 2 / g) represents the nitrogen adsorption specific surface area of ​​the substrate, and E＊ Is, L ＊ a ＊ b ＊ In the color system, L ＊ , a ＊ , and b ＊ The color space is expressed by a three-dimensional orthogonal coordinate system including the above-mentioned three-dimensional coordinates, and represents the distance from the origin to a position corresponding to the color of the polydopamine-attached substrate.

[0007] According to the present disclosure, a polydopamine-attached substrate with guaranteed insulating properties can be provided.

[0008] Fig. 1 is a diagram showing a schematic configuration of one embodiment of a polydopamine-containing substrate of the present disclosure. Fig. 2 is a diagram showing a schematic configuration of one embodiment of a resin composition of the present disclosure. Fig. 3 is a schematic cross-sectional view of one embodiment of a film with a resin layer of the present disclosure. Fig. 4 is a schematic cross-sectional view of one embodiment of a metal foil with a resin layer of the present disclosure. Fig. 5 is a schematic cross-sectional view of one embodiment of a metal-clad laminate of the present disclosure. Fig. 6 is a schematic cross-sectional view of one embodiment of a wiring board of the present disclosure. Fig. 7 is a diagram showing the volume resistivity R of a polydopamine-containing substrate of the present disclosure. v FIG. 1 is a schematic cross-sectional view of a measuring device.

[0009] Representative embodiments of the present disclosure will be described below. The embodiments described below are representative examples of the present disclosure, and the present disclosure is not limited to the embodiments described below.

[0010] <<Knowledge that forms the basis of the present disclosure>> In recent years, in the electronics field, the level of performance required for electronic devices has been increasing in preparation for the expansion of fifth-generation mobile communication systems (5G). For example, 5G uses higher frequency bands to achieve faster communication speeds than previous generations. Therefore, electronic devices require wiring boards that are compatible with high frequencies.

[0011] High-capacity communications such as 5G use high-frequency bands, resulting in short radio wave transmission distances. This necessitates increased output power from electronic devices. Furthermore, the realization of high integration and miniaturization will increase the packaging density of circuits. Meeting these requirements increases the amount of heat generated per unit area of ​​the wiring board. Therefore, wiring boards must have high heat dissipation capabilities.

[0012] One possible technique for improving the heat dissipation of wiring boards is to incorporate a filler with excellent thermal conductivity into the resin composition used as the substrate material for the insulating layer of the wiring board to increase the thermal conductivity of the wiring board. However, increasing the filler content in the resin composition to improve the heat dissipation of the wiring board can impair mechanical properties such as flexibility, resulting in problems such as the insulating layer becoming brittle. This is thought to be due to the aggregation of the filler in the resin composition.

[0013] One technique for improving dispersibility while suppressing the aggregation of fillers in a resin composition is to chemically modify the surface of the fillers.

[0014] As described above, increasing the amount of polydopamine chemically modified on the surface of the filler in the resin composition can suppress filler aggregation and improve dispersibility, but it also creates the problem of not being able to ensure insulation.

[0015] Therefore, the present inventors aimed to complete a polydopamine-containing substrate that can suppress aggregation and improve dispersibility in a resin composition while simultaneously suppressing a decrease in insulating properties, and have arrived at the present disclosure.

[0016] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted.

[0017] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0018] 1 is a diagram showing a schematic configuration of one embodiment of a polydopamine-attached substrate of the present disclosure. The polydopamine-attached substrate 10 includes a substrate 1 and polydopamine 2 attached to the substrate 1.

[0019] In one embodiment of the polydopamine-attached substrate of the present disclosure, the adsorption amount (PA) (mass%) of polydopamine and the nitrogen adsorption specific surface area (BET) (m 2 / g) satisfies 0<PA / BET≦0.450. The adsorption amount of polydopamine (PA) (mass%) and the nitrogen adsorption specific surface area (BET) (m 2 / g) satisfying such a relationship makes it possible to ensure that the polydopamine-modified substrate has a volume resistivity equal to or higher than that of an unmodified substrate, and thus makes it possible to suppress a decrease in insulating properties.

[0020] The unit of the above PA / BET value is (mass%) / (m 2 / g), but for the sake of convenience, in this specification (including the results of the Examples and Comparative Examples), the units will be omitted and only the numerical values ​​will be shown.

[0021] In one embodiment of the polydopamine-attached substrate of the present disclosure, from the viewpoint that the polydopamine-modified substrate can more reliably maintain a volume resistivity equivalent to that of an unmodified substrate and can further improve insulating properties, the above PA / BET may be 0.01≦PA / BET≦0.417 or 0.01≦PA / BET≦0.250.

[0022] The amount of polydopamine adsorption (PA) (mass %) can be determined by measuring the change in weight when the temperature is increased from 20°C to 800°C at a rate of 5°C / min in an air atmosphere using a thermogravimetric analyzer (manufactured by Hitachi High-Tech Science Corporation, product name "STA200").

[0023] Nitrogen adsorption specific surface area (BET) of the substrate (m 2 / g) can be determined by filling a measurement cell with a predetermined amount of the substrate and measuring with a gas adsorption measurement device (manufactured by Microtrac-Bel, product name "Belsorp-mini"). The adsorption gas is nitrogen.

[0024] In one embodiment of the polydopamine-containing substrate of the present disclosure, L ＊ a ＊ b ＊ In the color system, L ＊ , a ＊ , and b ＊In the color space represented by three-dimensional orthogonal coordinates, the distance E from the origin to the position corresponding to the color of the polydopamine-attached substrate is ＊ However, 60≦E ＊ ≦80. This E ＊ is 60≦E ＊ ≦75, and 60.5≦E ＊ E may be ≦71.0. ＊ By satisfying this relationship, the polydopamine-modified substrate can ensure a volume resistivity equal to or higher than that of an unmodified substrate, and deterioration in insulating properties can be suppressed.

[0025] When light strikes a solid, light of wavelengths specific to the solid material is absorbed. On the other hand, light of wavelengths that are not absorbed is reflected. Because light of wavelengths that are not absorbed by the material reaches the human eye, the color of the wavelength of the reflected light is perceived as the color of the material. Generally, the greater the number of conjugated carbon atoms in a conjugated molecule, the longer the wavelength of light absorbed by the conjugated molecule shifts to. This shift to longer wavelengths also changes the wavelength of the reflected light, resulting in a change in the apparent color. For example, when comparing two samples of conjugated polymers such as polydopamine that have different degrees of polymerization, i.e., different conjugation lengths, the wavelengths of the reflected light differ because the absorption wavelengths of each sample are different. Therefore, the apparent colors are different. In this way, the color of a solid reflects its molecular structure, so by measuring the color of a solid, information about the molecular structure of that solid can be obtained. L ＊ a ＊ b ＊ A color system is a system for expressing colors numerically. ＊ indicates lightness (brightness), and the larger the value, the brighter the color. ＊ A positive value indicates a reddish hue, and a negative value indicates a greenish hue. ＊ A positive value indicates a yellowish hue, and a negative value indicates a bluish hue. ＊ , a ＊ , and b ＊ The three-dimensional orthogonal coordinate system consisting of these is the color space. In the color space, the distance from the origin to the position corresponding to the color of the solid is called E ＊ It is defined as: ＊ is the L＊ , a ＊ , and b ＊ The value is derived from the following equation (1):

[0026] E of the polydopamine-containing substrate of the present disclosure ＊ By calculating the above, it is possible to estimate the molecular structure of the attached polydopamine, such as the degree of polymerization.

[0027] In one embodiment of the polydopamine-attached substrate of the present disclosure, the PA / BET satisfies 0<PA / BET≦0.450, and the E ＊ is 60≦E ＊ ≦80 may be satisfied.

[0028] In one embodiment of the polydopamine-containing substrate of the present disclosure, its volume resistivity ρ v (Ω cm) is the volume resistivity ρ of the corresponding substrate without polydopamine (non-polydopamine-modified substrate). v0 (Ω cm), for example, ρ v ≧0.8ρ v0 and ρ v ≧0.9ρ v0 and ρ v ≧ρ v0 and ρ v ≧1.1ρ v0 and ρ v ≧1.2ρ v0 In one embodiment of the polydopamine-containing substrate of the present disclosure, ρ v ≧1.5ρ v0 and ρ v ≧1.8ρ v0 may be.

[0029] Polydopamine is a dopamine polymer and may have, for example, a repeating unit represented by general formula (1). In general formula (1), n ​​is 1 or greater and may be an integer of 2 or greater. In general formula (1), the indoline skeleton may be an indole skeleton.

[0030]

[0031] The term "polydopamine" as used herein refers not only to dopamine polymers but also to modified polymers in which some of the functional groups derived from dopamine have been modified by bonding with other substances, etc. For example, polydopamine may include those that are not completely cyclized. That is, polydopamine may contain a mixture of primary amines and secondary amines. Furthermore, in the general formula (1), the indoline skeleton may contain any of the quinone structures represented by the following structural formulas:

[0032]

[0033] The polydopamine 2 may be in the form of a thin film on the surface of the substrate 1. The thickness of the thin film of polydopamine 2 is, for example, 0.1 nm to 300 nm. The thin film of polydopamine 2 covers at least a part of the surface of the substrate 1. The thin film of polydopamine 2 may cover the entire surface of the substrate 1.

[0034] Possible embodiments of the conductive path of polydopamine include electrons moving within the main chain skeleton of polydopamine (within the π-conjugated system), protons moving between hydrogen bonds between polydopamine molecules, electrons moving between π-stacks between polydopamine molecules, etc. It is thought that as the amount of polydopamine attached and adsorbed increases, hydrogen bonds and π-stack formation between polydopamine molecules increases, promoting charge transfer and making it impossible to ensure insulation.

[0035] The substrate 1 may contain at least one selected from the group consisting of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, boehmite, and silica. The polydopamine-containing substrate 10 of the present disclosure may be useful when the substrate 1 contains at least one selected from the above group.

[0036] Substrate 1 may comprise boron nitride. Polydopamine-bearing substrate 10 may be particularly useful when substrate 1 comprises boron nitride. Substrate 1 may be boron nitride.

[0037] Boron nitride has excellent thermal conductivity and can therefore be used particularly as a filler.

[0038] Examples of boron nitride that can be used include hexagonal boron nitride (h-BN) with a graphite-type layered structure, diamond-type cubic boron nitride (c-BN), and amorphous boron nitride (a-BN). Among these, hexagonal boron nitride (h-BN) can be synthesized relatively easily and has excellent thermal conductivity, electrical insulation, chemical stability, and heat resistance.

[0039] As the boron nitride, boron nitride particles can be used. The boron nitride particles are usually white. The shape of the boron nitride particles can be any appropriate shape as long as the effects of the present disclosure are not impaired. The shape of the boron nitride particles can be, for example, scale-like, spherical, oval-spherical, or rod-like.

[0040] The average particle size of the substrate (e.g., boron nitride particles) may be any appropriate average particle size as long as it does not impair the effects of the present disclosure. The average particle size of the substrate (e.g., boron nitride particles) may be, for example, 0.05 μm or more and 100 μm or less, and may be 0.1 μm or more and 50 μm or less. In the present disclosure, the average particle size of the substrate (e.g., boron nitride particles) refers to the median diameter. The median diameter refers to the particle size (d50) when the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is measured, for example, using a laser diffraction measurement device.

[0041] A method for producing the polydopamine-attached substrate 10 of the present disclosure will now be described.

[0042] One embodiment of the method for manufacturing a polydopamine-attached substrate 10 of the present disclosure utilizes autooxidative polymerization of dopamine to form a thin film of polydopamine 2 on the surface of the substrate 1. Specifically, a dopamine solution is brought into contact with the substrate 1, and the dopamine is oxidatively polymerized under predetermined processing conditions, thereby forming a thin film of polydopamine 2 on the surface of the substrate 1.

[0043] The above-mentioned predetermined treatment conditions are the amount of polydopamine adsorption (PA) (mass%) and the nitrogen adsorption specific surface area (BET) (m 2 / g) can be determined so as to satisfy 0<PA / BET≦0.450. Examples of such treatment conditions include the concentration condition of the dopamine solution, the pH condition of the dopamine solution, the temperature condition of the dopamine solution during oxidative polymerization, and the polymerization time of the oxidative polymerization.

[0044] A dopamine solution can be obtained by adding dopamine hydrochloride to a Tris buffer solution whose pH has been adjusted to between pH 6 and pH 12 and stirring the mixture.

[0045] The pH of the dopamine solution may be in the range of pH 8 to pH 11, or may be in the range of pH 9 to pH 11. The pH of the dopamine solution can be adjusted by mixing with a Tris buffer solution or the like.

[0046] The concentration of the dopamine solution may be any appropriate concentration, for example, in the range of 0.1 mg / mL to 30 mg / mL.

[0047] The temperature of the dopamine solution during oxidative polymerization is, for example, 10°C to 100°C.

[0048] The polymerization time for the oxidative polymerization is, for example, 1 hour to 48 hours. The thickness of the thin film of polydopamine 2 can be controlled by the polymerization time.

[0049] <Filler> The filler of the present disclosure includes the polydopamine-containing substrate of the present disclosure. The filler of the present disclosure may be the polydopamine-containing substrate of the present disclosure itself, or may contain other components.

[0050] <Thermal Dissipation Gap Filler> One embodiment of the filler of the present disclosure is a thermal dissipation gap filler, which includes the polydopamine-containing substrate of the present disclosure.

[0051] In the present disclosure, a thermally dissipating gap filler is a filler that is applied to electronic components such as substrate materials to fill air pockets or gaps, thereby dissipating heat from the electronic components. The thermally dissipating gap filler is a curing-type thermally dissipating paste that hardens from a paste state into a sheet state. The thermally dissipating gap filler of the present disclosure can ensure that a resin composition containing the thermally dissipating gap filler has a volume resistivity equal to or greater than that of a resin composition containing an unmodified base material, thereby suppressing a decrease in insulating properties.

[0052] The heat dissipating gap filler of the present disclosure can be produced, for example, by kneading the polydopamine-containing substrate of the present disclosure with an epoxy resin or a silicone-based resin, or a non-silicone acrylic resin or a ceramic-based resin.

[0053] <Filler for Thermal Grease> Another embodiment of the filler of the present disclosure is a filler for thermal grease, which includes the polydopamine-containing substrate of the present disclosure.

[0054] In this disclosure, a thermal grease filler refers to a filler used in thermal grease. Thermal grease is a thermal paste that is applied to electronic components such as circuit board materials to fill air pockets or gaps, thereby dissipating heat from the electronic components. The thermal grease filler of this disclosure can ensure a volume resistivity equal to or higher than that of a base material containing an unmodified material, thereby suppressing a decrease in insulating properties.

[0055] The filler for thermal grease of the present disclosure can be produced, for example, by kneading the polydopamine-containing substrate of the present disclosure with an epoxy resin or a silicone-based resin, or a non-silicone acrylic resin or a ceramic-based resin.

[0056] Resin composition The resin composition of the present disclosure includes the filler of the present disclosure. Because the resin composition of the present disclosure includes the filler of the present disclosure, it is possible to ensure a volume resistivity equal to or higher than that in the case where an unmodified base material is included, and it is possible to suppress a decrease in insulating properties.

[0057] 2 is a diagram showing a schematic configuration of one embodiment of the resin composition of the present disclosure. The resin composition 20 includes, for example, a filler 22 and a curable resin 24.

[0058] The filler 22 includes the polydopamine-attached substrate 10 of the present disclosure. As the filler 22, only the polydopamine-attached substrate 10 of the present disclosure may be used, or other filler materials such as silica particles may be used in combination with the polydopamine-attached substrate 10 of the present disclosure.

[0059] Examples of the curable resin 24 include epoxy resin, cyanate ester compound, maleimide compound, phenol resin, acrylic resin, polyamide resin, polyamideimide resin, thermosetting polyimide resin, and polyphenylene ether resin. Only one type of curable resin 24 may be used, or two or more types may be used in combination.

[0060] The resin composition 20 may contain other components. Examples of the other components include a curing agent, a flame retardant, an ultraviolet absorber, an antioxidant, a reaction initiator, a silane coupling agent, a fluorescent brightener, a photosensitizer, a dye, a pigment, a thickener, a lubricant, an antifoaming agent, a dispersant, a leveling agent, a gloss agent, an antistatic agent, a polymerization inhibitor, and an organic solvent. Only one of the other components may be used, or two or more may be used in combination.

[0061] <Film with Resin Layer> The film with a resin layer of the present disclosure includes a resin layer containing the resin composition of the present disclosure, or a semi-cured product thereof, or a cured product thereof, and a support film. The film with a resin layer of the present disclosure is suitable for, for example, an insulating layer.

[0062] The semi-cured resin composition of the present disclosure refers to a material in a partially cured state to the extent that the resin composition of the present disclosure can be further cured. That is, the semi-cured resin composition of the present disclosure is a material in a semi-cured state of the resin composition of the present disclosure. In one embodiment of the resin composition of the present disclosure, when heated, its viscosity gradually decreases, and as heating continues, curing then begins and its viscosity gradually increases. In such a case, the semi-cured state of the resin composition of the present disclosure can be the state of the resin composition of the present disclosure from the time when the viscosity starts to increase to the time when it is completely cured.

[0063] The resin composition of the present disclosure may be cured by any suitable method as long as the effects of the present disclosure are not impaired. Examples of such a curing method include a thermosetting reaction.

[0064] The curing temperature during the thermosetting reaction may be set to any appropriate temperature depending on the composition or purpose of the resin composition of the present disclosure, and may be, for example, 40°C to 300°C.

[0065] Fig. 3 is a schematic cross-sectional view of one embodiment of a resin layer-included film according to the present disclosure. A resin layer-included film 30 according to the present disclosure includes a resin layer 32 containing the resin composition according to the present disclosure, or a semi-cured product thereof, or a cured product thereof, and a support film 34. In the embodiment shown in Fig. 3, the resin layer 32 is supported by the support film 34. In the embodiment shown in Fig. 3, the support film 34 is disposed on the surface of the resin layer 32. Note that another layer, such as an adhesive layer, may be provided between the resin layer 32 and the support film 34.

[0066] The resin layer 32 may include a fibrous base material. Any appropriate fibrous base material may be used as the fibrous base material as long as the effects of the present disclosure are not impaired. Examples of such fibrous base materials include known materials used in various types of laminates for electrical insulating materials. Examples of such fibrous base materials include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper.

[0067] The resin layer 32 can be an insulating layer either as it is or after curing, such as an insulating layer of a wiring board.

[0068] Any appropriate support film may be used as the support film 34 as long as it does not impair the effects of the present disclosure. Examples of such a support film include a resin film such as a polyethylene terephthalate film.

[0069] The resin layer-attached metal foil of the present disclosure includes a resin layer containing the resin composition of the present disclosure, a semi-cured product thereof, or a cured product thereof, and a metal foil. The resin layer-attached metal foil of the present disclosure can be used as a resin layer-attached metal foil suitable for electronic circuit components such as wiring boards.

[0070] The above-described explanation of the resin layer-attached film may be applied to the semi-cured product of the resin composition of the present disclosure and the cured product of the resin composition of the present disclosure.

[0071] Fig. 4 is a schematic cross-sectional view of one embodiment of the resin layer-provided metal foil of the present disclosure. The resin layer-provided metal foil 40 of the present disclosure includes a resin layer 42 containing the resin composition of the present disclosure, or a semi-cured product thereof, or a cured product thereof, and a metal foil 44. In the embodiment shown in Fig. 4, the resin layer 42 is supported by the metal foil 44. In the embodiment shown in Fig. 4, the metal foil 44 is disposed on the surface of the resin layer 42. Note that another layer, such as an adhesive layer, may be provided between the resin layer 42 and the metal foil 44.

[0072] The resin layer 42 may contain a fibrous base material. The description of the fibrous base material that may be contained in the resin-layered film may be used. The resin layer 42 may become an insulating layer either as is or after curing. An example of such an insulating layer is an insulating layer of a wiring board.

[0073] Any appropriate metal foil may be used as the metal foil 44 as long as it does not impair the effects of the present disclosure. Examples of such metal foils include copper foil and aluminum foil.

[0074] <Prepreg> The prepreg of the present disclosure contains the resin composition of the present disclosure or a semi-cured product thereof.

[0075] For the semi-cured product of the resin composition of the present disclosure, the above description of the film with a resin layer can be applied.

[0076] The prepreg of the present disclosure typically includes a fibrous substrate. The fibrous substrate may be present in a matrix of the resin composition of the present disclosure or a semi-cured product thereof. The prepreg of the present disclosure may be a composite material of the resin composition of the present disclosure or a semi-cured product thereof and the fibrous substrate. The prepreg of the present disclosure having such a configuration may be suitable for high-frequency wiring boards.

[0077] As for the fibrous base material, the description of the fibrous base material that can be contained in the resin layer-attached film can be used.

[0078] In the prepreg of the present disclosure, the resin composition of the present disclosure or a semi-cured product thereof can be impregnated into a fibrous substrate by treatment such as immersion, coating, etc. By heating the fibrous substrate impregnated with the resin composition of the present disclosure or a semi-cured product thereof under predetermined heating conditions, a prepreg of the present disclosure in an uncured or semi-cured state can be obtained.

[0079] <Metal-clad laminate> One embodiment of the metal-clad laminate of the present disclosure includes an insulating layer containing a cured product of the resin composition of the present disclosure and a metal foil. Another embodiment of the metal-clad laminate of the present disclosure includes an insulating layer containing a cured product of the prepreg of the present disclosure and a metal foil. The metal-clad laminate of the present disclosure can be, for example, a metal-clad laminate suitable for wiring boards.

[0080] For the cured product of the resin composition of the present disclosure, the above description of the film with a resin layer may be applied.

[0081] Figure 5 is a schematic cross-sectional view of one embodiment of a metal-clad laminate of the present disclosure. The metal-clad laminate 50 of the present disclosure includes an insulating layer 52 and at least one metal foil 54. The insulating layer 52 includes a cured product of the resin composition of the present disclosure or a cured product of the prepreg of the present disclosure. In the embodiment shown in Figure 5, the metal foil 54 is disposed on the front surface of the insulating layer 52. In the embodiment shown in Figure 5, a metal foil 54 is disposed on each of the front and back surfaces of the insulating layer 52.

[0082] A typical embodiment of the metal-clad laminate of the present disclosure is manufactured using the prepreg of the present disclosure. The metal-clad laminate of the present disclosure is manufactured, for example, by stacking 1 to 20 prepregs to form a laminate, placing metal foil on one or both sides of the resulting prepreg laminate, and applying heat and pressure to produce the metal-clad laminate of the present disclosure.

[0083] As the metal foil, any appropriate metal foil can be used as long as the effects of the present disclosure are not impaired. Examples of such metal foils include copper foil and aluminum foil.

[0084] As the molding conditions for producing the metal-clad laminate of the present disclosure, any appropriate molding conditions can be adopted as long as the effects of the present disclosure are not impaired. For example, molding conditions generally adopted for producing laminates for electrical insulating materials and multilayer boards can be applied.

[0085] <<Wiring Board>> One embodiment of the wiring board of the present disclosure includes an insulating layer containing a cured product of the resin composition of the present disclosure, and wiring. Another embodiment of the wiring board of the present disclosure includes an insulating layer containing a cured product of the prepreg of the present disclosure, and wiring. The wiring board of the present disclosure can be, for example, a wiring board suitable for high frequencies.

[0086] For the cured product of the resin composition of the present disclosure, the above description of the film with a resin layer may be applied.

[0087] FIG. 6 is a schematic cross-sectional view of one embodiment of a wiring board according to the present disclosure. The wiring board 60 according to the present disclosure includes an insulating layer 62 and wiring 64. The insulating layer 62 includes a cured product of the resin composition according to the present disclosure or a cured product of the prepreg according to the present disclosure. In the embodiment shown in FIG. 6, the wiring 64 is supported by the insulating layer 62. The wiring 64 is typically disposed on the insulating layer 62. The wiring 64 can be formed, for example, by partially removing the metal foil. For example, by patterning the metal foil on the surface of the metal-clad laminate according to the present disclosure by a method such as etching, a wiring board 60 having wiring 64 forming a circuit on the surface of the insulating layer 62 can be obtained.

[0088] A new laminate may be formed by laminating the prepreg of the present disclosure on at least one surface of the wiring board of the present disclosure, and then applying heat and pressure. A multilayer wiring board can be obtained by patterning the metal foil on the surface of the resulting laminate to form wiring.

[0089] <<Additional Notes>> Based on the above description, the following techniques are disclosed.

[0090] (Technology 1) A polydopamine-attached substrate comprising a substrate and polydopamine attached to the substrate, wherein 0<PA / BET≦0.450 or 60≦E ＊ ≦80, where PA (mass%) represents the amount of polydopamine attached and adsorbed, and BET (m 2 / g) represents the nitrogen adsorption specific surface area of ​​the substrate, and E ＊ Is, L ＊ a ＊ b ＊ In the color system, L ＊ , a ＊ , and b ＊ The polydopamine-containing substrate is a substrate having a polydopamine-containing color, and the distance from the origin to a position corresponding to the color of the polydopamine-containing substrate in a color space represented by a three-dimensional orthogonal coordinate system including the above coordinates.

[0091] (Technology 2) The polydopamine-containing substrate according to Technology 1, wherein the substrate contains at least one selected from the group consisting of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, boehmite, and silica.

[0092] (Technology 3) The polydopamine-containing substrate according to Technology 2, wherein the substrate contains boron nitride.

[0093] (Technology 4) A filler comprising the polydopamine-containing substrate according to any one of Technology 1 to Technology 3.

[0094] (Technology 5) A resin composition comprising the filler according to Technology 4.

[0095] (Technology 6) A film with a resin layer, comprising: a resin layer containing the resin composition according to Technology 5, a semi-cured product of the resin composition, or a cured product of the resin composition; and a support film.

[0096] (Technology 7) A metal foil with a resin layer, comprising: a resin layer containing the resin composition according to Technology 5, a semi-cured product of the resin composition, or a cured product of the resin composition; and a metal foil.

[0097] (Technology 8) A prepreg comprising the resin composition according to Technology 5 or a semi-cured product of the resin composition.

[0098] (Technology 9) A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to Technology 5 and a metal foil.

[0099] (Technology 10) A metal-clad laminate comprising an insulating layer containing a cured product of the prepreg according to Technology 8, and a metal foil.

[0100] (Technology 11) A wiring board comprising an insulating layer containing a cured product of the resin composition according to Technology 5 and wiring.

[0101] (Technology 12) A wiring board comprising an insulating layer containing a cured product of the prepreg according to Technology 8, and wiring.

[0102] The present disclosure will be specifically described below with reference to examples. The examples are intended to illustrate the present disclosure and are not intended to limit the scope of the present disclosure.

[0103] <Measurement of Adsorbed Amount of Polydopamine (PA)> The powder of the polydopamine-attached substrate obtained in the Examples and Comparative Examples was measured for weight change when the temperature was increased from 20°C to 800°C at a rate of 5°C / min in an air atmosphere. The weight change at this time was taken as the adsorbed amount of polydopamine (PA). A thermogravimetric analyzer (manufactured by Hitachi High-Tech Science Corporation, product name "STA200") was used as the measuring device.

[0104] <Measurement of Nitrogen Adsorption Specific Surface Area (BET) of Substrate> A gas adsorption measuring device (manufactured by Microtrac-Bel, product name "Belsorp-mini") was used to measure the nitrogen adsorption specific surface area of ​​the substrate. The nitrogen gas adsorption isotherm at 77 K was measured and analyzed by the BET method to determine the BET specific surface area. Pretreatment was performed under reduced pressure (10 Pa or less) at 200°C for 1 hour.

[0105] <E of polydopamine-containing substrate ＊The powder of the polydopamine-containing substrate obtained in the Examples and Comparative Examples was placed in a container and molded into pellets using a hand press. ＊ , a ＊ , and b ＊ The light source was set to D50, and the SCE (specularly reflected light excluded) method was used. ＊ , a ＊ , and b ＊ Using Equation (1), ＊ was calculated.

[0106] <Volume resistance R v Measurement of volume resistivity ρ v The volume resistivity of the polydopamine-containing substrate obtained in the examples and comparative examples was calculated by measuring the volume resistivity R using a measuring device 70 in which a cylindrical electrode was placed between two insulating plates 73 as shown in FIG. 7 under an environment of 23° C., 50% RH (relative humidity), and normal pressure (105 Pa). v 7 shows the volume resistance R of the polydopamine-attached substrate of the present disclosure. v 1 is a schematic cross-sectional view of the measurement device 70. Specifically, first, about 2 g of polydopamine-attached substrate 75, which is the measurement target, is placed on the lower electrode 71 so as not to be biased, and then the upper electrode 72 is placed on top to sandwich the substrate. Then, with a load 77 of 20 kN applied to the measurement device 70, a voltage of 100 V is applied to the electrodes using a microcurrent meter (manufactured by ADC Corporation, product name "ULTRA HIGH RESISTANCE (R8340A)"), and the current after 1 minute is measured to determine the volume resistance R v (Ω) was measured. Then, the volume resistivity ρ was calculated based on the following formula: v was calculated. v = (πd 2 / 4t) x R v π: Circular constant d: Electrode diameter (cm) t: Electrode surface spacing (cm) R v : Volume resistance (Ω)

[0107] Example 1 Trishydroxymethylaminomethane (Tris) was added to distilled water and stirred to obtain a Tris buffer solution with a pH of 10.8. 340 mL of the obtained Tris buffer solution was used, and 15.75 g of boron nitride was added to the mixture while stirring with a magnetic stirrer to obtain a mixed solution. The temperature of the obtained mixed solution was set to 72°C, and 10 mL of 3-hydroxytyramine hydrochloride solution (3-hydroxytyramine hydrochloride concentration: 150 mg / mL) was added all at once while stirring with a magnetic stirrer. The mixture was stirred at 72°C for 60 minutes with a magnetic stirrer. The solution was then cooled, and a solid was obtained by filtration. The obtained solid was washed with water and then dried. This resulted in a polydopamine-attached substrate (1) in which polydopamine was attached to the surface of boron nitride. The attachment of polydopamine to the boron nitride surface was confirmed by the black-brown coloration of the boron nitride surface. The PA / BET of the polydopamine-attached substrate (1) was 0.099, and E ＊ is 68.62, and the volume resistivity ρ v is 4.7 x 10 12 The results are shown in Tables 1 and 2.

[0108] Example 2 A polydopamine-attached substrate (2) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 90 minutes. The results are shown in Tables 1 and 2.

[0109] Example 3 A polydopamine-attached substrate (3) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 120 minutes. The results are shown in Tables 1 and 2.

[0110] Example 4 A polydopamine-attached substrate (4) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 180 minutes. The results are shown in Tables 1 and 2.

[0111] Example 5 A polydopamine-attached substrate (5) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 210 minutes. The results are shown in Tables 1 and 2.

[0112] Example 6 A polydopamine-attached substrate (6) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 240 minutes. The results are shown in Tables 1 and 2.

[0113] Example 7 A polydopamine-attached substrate (7) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 300 minutes. The results are shown in Tables 1 and 2.

[0114] Example 8 A polydopamine-attached substrate (8) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 360 minutes. The results are shown in Tables 1 and 2.

[0115] Example 9 A polydopamine-attached substrate (9) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 420 minutes. The results are shown in Tables 1 and 2.

[0116] Comparative Example 1 A polydopamine-attached substrate (C1) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 450 minutes. The results are shown in Tables 1 and 2.

[0117] Comparative Example 2 A polydopamine-attached substrate (C2) was obtained in the same manner as in Example 1, except that the stirring time after the 3-hydroxytyramine hydrochloride solution was added all at once was changed to 480 minutes. The results are shown in Tables 1 and 2.

[0118] Reference Example 1 Volume resistivity ρ of polydopamine-unmodified boron nitride v is 2.1 x 10 12 (Ω·cm).

[0119]

[0120]

[0121] <<Discussion>> As shown in Table 1, in Examples 1 to 9 in which the PA / BET of the polydopamine-attached substrate was 0.450 or less, the volume resistivity of the polydopamine-attached substrate was equal to or higher than that of boron nitride unmodified with polydopamine (Reference Example 1). On the other hand, in Comparative Example 1 in which the PA / BET of the polydopamine-attached substrate was 0.521 and Comparative Example 2 in which the PA / BET was 0.576, the volume resistivity of the polydopamine-attached substrate was significantly lower than that of boron nitride unmodified with polydopamine.

[0122] As shown in Table 2, the E of the polydopamine-attached substrate ＊ is 60≦E ＊ In Examples 1 to 9, which satisfy the condition of ≦80, it can be seen that the volume resistivity of the polydopamine-attached substrate is equal to or higher than that of boron nitride not modified with polydopamine (Reference Example 1). ＊ In Comparative Example 1 where the volume resistivity is 58.24 and Comparative Example 2 where the volume resistivity is 58.74, it can be seen that the volume resistivity of the substrate with polydopamine is significantly lower than that of boron nitride not modified with polydopamine.

[0123] As explained in the section "Knowledge that Forms the Basis of the Present Disclosure," the present inventors conducted research aimed at completing a polydopamine-containing substrate that can simultaneously suppress aggregation and improve dispersibility in a resin composition while suppressing a decrease in insulating properties. As a result, the amount of polydopamine attached and adsorbed (PA) (mass%) and the nitrogen adsorption specific surface area (BET) (m 2 / g) satisfies the relationship 0<PA / BET≦0.450, or L ＊ a ＊ b ＊ In the color system, L ＊ , a ＊ , and b ＊ In the color space represented by three-dimensional orthogonal coordinates, the distance E from the origin to the position corresponding to the color of the polydopamine-attached substrate is ＊ However, 60≦E ＊ It was found that if the condition of ≦80 is satisfied, a polydopamine-attached substrate with guaranteed insulating properties can be provided.

[0124] As described above, in order to express the present disclosure, the present disclosure has been appropriately and sufficiently described through the embodiments, but it should be recognized that those skilled in the art can easily change and / or improve the above-described embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that deviates from the scope of the claims described in the claims, the changes or improvements are interpreted as being encompassed within the scope of the claims.

[0125] The polydopamine-containing substrate of the present disclosure can simultaneously suppress aggregation and improve dispersibility in a resin composition while suppressing deterioration in insulating properties, and is therefore suitable for applications such as wiring boards for electronic devices used in high-capacity communications.

[0126] REFERENCE SIGNS LIST 1 Substrate 2 Polydopamine 10 Substrate with polydopamine 20 Resin composition 22 Filler 24 Curable resin 30 Film with resin layer 32 Resin layer 34 Support film 40 Metal foil with resin layer 42 Resin layer 44 Metal foil 50 Metal-clad laminate 52 Insulating layer 54 Metal foil 60 Wiring board 62 Insulating layer 64 Wiring 70 Measuring device 71 Lower electrode 72 Upper electrode 73 Insulating plate 75 Substrate with polydopamine 77 Load

Claims

1. A polydopamine-attached substrate comprising a substrate and polydopamine attached to the substrate, wherein 0<PA / BET≦0.450, or 60≦E ＊ ≦80, where PA (mass%) represents the amount of polydopamine attached and adsorbed, and BET (m 2 / g) represents the nitrogen adsorption specific surface area of ​​the substrate, and E ＊ Is, L ＊ a ＊ b ＊ In the color system, L ＊ , a ＊ , and b ＊ a distance from the origin to a position corresponding to the color of the polydopamine-containing substrate in a color space represented by three-dimensional orthogonal coordinates including the above-mentioned color space and the above-mentioned color space.

2. The polydopamine-containing substrate according to claim 1, wherein the substrate contains at least one selected from the group consisting of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, boehmite, and silica.

3. The polydopamine-containing substrate according to claim 2, wherein the substrate comprises boron nitride.

4. A filler comprising a polydopamine-containing substrate according to any one of claims 1 to 3.

5. A resin composition comprising the filler according to claim 4.

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