Composition, sheet, and metal-clad laminate

Abstract

The present disclosure provides a composition for suppressing water absorption and moisture absorption, in particular, a composition for obtaining a sheet in which an increase in dielectric loss tangent due to moisture absorption is suppressed, a sheet using the composition, and a metal-clad laminate. A composition includes a fluororesin, inorganic particles, and an organosiloxane. Also provided are a sheet and a metal-clad laminate using the composition.

Description

Technical Field

[0001] This disclosure relates to compositions, sheets, and metal-coated laminates. Background Technology

[0002] For high-frequency printed circuit boards (PCBs), low transmission loss is required. Fluoropolymer films are known to be used in such PCBs (Patent Document 1, etc.). Furthermore, Patent Documents 2 and 3 describe the use of fluoropolymers mixed with fillers as the PCB substrate material.

[0003] In addition, Patent Document 4 discloses a fluororesin composition in which spherical silica particles are mixed into a fluororesin for use as a circuit substrate.

[0004] Furthermore, Patent Document 5 describes the use of a dispersion containing a tetrafluoroethylene-based polymer and a liquid compound having a specific kinematic viscosity and boiling point to form a polymer layer on a substrate, thereby obtaining a laminate.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-8260

[0008] Patent Document 2: Japanese Patent Application Publication No. 63-259907

[0009] Patent Document 3: Japanese Patent Publication No. 2022-510017

[0010] Patent Document 4: International Publication No. 2020 / 145133

[0011] Patent Document 5: Japanese Patent Application Publication No. 2022-69962 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The purpose of this disclosure is to provide a composition that inhibits water absorption and moisture absorption. Furthermore, the purpose of this disclosure is to provide a composition that not only inhibits appearance defects caused by water absorption but also inhibits the rise in dielectric loss tangent caused by moisture absorption, a sheet using the same, and a metal-coated laminate.

[0014] Methods for solving problems

[0015] This disclosure pertains to compositions comprising fluoropolymers, inorganic particles, and organosiloxanes.

[0016] The inorganic particles are preferably inorganic particles with silicon dioxide as an essential component.

[0017] The fluororesin is preferably a perfluorinated fluororesin.

[0018] The perfluorinated fluoropolymer is preferably polytetrafluoroethylene (PTFE).

[0019] The silica is preferably spherical silica.

[0020] The dielectric loss tangent of the silicon dioxide at 10 GHz is preferably below 0.0025.

[0021] Preferably, the inorganic particles are inorganic particles coated with a silane coupling agent.

[0022] The content of the inorganic particles is preferably 40% or more by mass of the whole composition.

[0023] The average particle size of the inorganic particles is preferably 0.5 μm or greater.

[0024] The viscosity of the organosiloxane is preferably 3 to 18000 mm. 2 / s (25℃).

[0025] The content of the organosiloxane is preferably less than 20% of the total mass of the composition.

[0026] The organosiloxane is preferably a modified organosiloxane.

[0027] The modified organosiloxane is preferably any one of its side chain, single end, and two ends, or all of them having at least one group selected from the group consisting of hydrogen atom, amino, ether group, epoxy group, mercapto group, carboxyl group, acryloyl group, methacryloyl group, carboxylic anhydride group, alkyl group, aralkyl group, fluoroalkyl group, perfluoroalkyl group, ester group, amide group, and phenyl group.

[0028] The modified polyorganosiloxane is preferably composed of any one or both of its side chains, single ends, and double ends, or all of them having at least one group selected from the group consisting of hydrogen atom, amino, carboxyl, acryloyl, carboxylic anhydride, alkyl, fluoroalkyl, perfluoroalkyl, ester, amide, and phenyl.

[0029] The modified polyorganosiloxane preferably has at least one group selected from the group consisting of hydrogen atom, amino group, carboxyl group, acryloyl group, fluoroalkyl group, phenyl group and carboxylic anhydride group in any of its side chain, single end and double end.

[0030] This disclosure also pertains to a sheet composed of the aforementioned moisture-inhibiting composition.

[0031] The moisture content of the tablets disclosed herein is preferably less than 60 ppm when stored at 30°C and 90% RH for 24 hours.

[0032] The dielectric loss tangent of the presently disclosed wafer preferably increases by less than 30% when stored at 30°C and 90%RH for 24 hours.

[0033] The preferred linear expansion coefficient (CTE) of the film disclosed herein is below 200 ppm / K.

[0034] This disclosure also discloses a method for manufacturing a sheet, which is the method for manufacturing the aforementioned sheet, characterized in that a composition containing fluororesin particles, inorganic particles and organosiloxane is molded.

[0035] The preferred method for manufacturing the above-mentioned sheet is to use a composition substantially composed of fluororesin particles, inorganic particles and organosiloxanes for molding.

[0036] This disclosure also describes a metal-clad laminate with a metal layer and the aforementioned sheet as necessary layers.

[0037] The metal-clad laminate may contain at least one sheet selected from the group consisting of formaldehyde, formic acid, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

[0038] The metal layer is preferably copper foil.

[0039] This disclosure is also a circuit board, characterized in that it has a metal-clad laminate in which the metal layer is copper foil.

[0040] Invention Effects

[0041] This disclosure provides a composition for inhibiting water and moisture absorption. In particular, sheets obtained from the water / moisture-inhibiting composition containing fluororesin of this disclosure have the following excellent properties: they can suppress poor appearance and changes in properties caused by water absorption, and suppress the increase in dielectric loss tangent caused by moisture absorption. Detailed Implementation

[0042] The following is a detailed description of this disclosure.

[0043] Extensive research has been conducted on compositions in which inorganic particles and other fillers are mixed into fluoropolymers and other resins.

[0044] However, for example, sheets used as circuit boards and the like, made from compositions that incorporate inorganic particles, sometimes have the following problems: poor appearance and changes in properties due to water absorption and hygroscopicity caused by the incorporation of inorganic particles, especially an increase in the dielectric loss tangent of the sheet.

[0045] In addition, in other applications, sheets, lenses, and sealants made from compositions containing inorganic particles sometimes cause the following problems due to the hygroscopicity of the inorganic particles: in the case of light-diffusing sheets, changes in light diffuseness due to size changes; in the case of lenses, changes in refractive index; and in the case of sealants, peeling due to size changes.

[0046] This disclosure provides a composition for obtaining a sheet that suppresses the rise of dielectric loss tangent under high humidity conditions, a light-diffusing sheet whose light diffuseness does not change, a lens with small refractive index change, and a sealing material with excellent dimensional stability.

[0047] The composition disclosed herein is characterized by the inclusion of inorganic particles and organosiloxanes as essential components in the resin. By adding organosiloxanes, water absorption and moisture absorption can be suppressed, thereby providing a composition capable of reducing changes caused by water absorption and moisture absorption.

[0048] The molded articles formed from the compositions of this disclosure can take the shape of sheets, lenses, sealants, etc. Furthermore, they can be laminates in which the compositions of this disclosure are used as partial layers. Alternatively, these shapes can be formed from a liquid state through a curing reaction.

[0049] Water absorption rate indicates the degree of adsorption of water molecules that form clusters through hydrogen bonds; hygroscopicity depends on the degree of adsorption of water molecules (water vapor). Previously, there were requirements for suppressing water absorption rate, but not specifically for hygroscopicity. Water absorption rate is the effect of water on the liquid; even if water absorption rate can be suppressed, the effect of water vapor cannot be suppressed.

[0050] The film disclosed here is not only low in water absorption but also low in moisture absorption.

[0051] Furthermore, the compositions disclosed herein are characterized in that they comprise a fluoropolymer, inorganic particles, and an organosiloxane. Specifically, the compositions disclosed herein are characterized in that an organosiloxane is mixed with the inorganic particles in the fluoropolymer.

[0052] The mechanisms by which adding organosiloxanes suppresses poor appearance caused by water absorption and the mechanism by which they suppress the increase in dielectric loss tangent caused by moisture absorption have not been specifically elucidated. However, it is believed that in sheets containing fluororesin and inorganic particles, water vapor is adsorbed into the gaps between the inorganic particles and the fluororesin, which serves as the matrix resin, thereby absorbing moisture. It is speculated that by mixing organosiloxanes with low surface tension with fluororesin and inorganic particles to form a composition, the organosiloxanes expand on the surface of the inorganic particles (the surface of the gaps). The sheet formed by this composition prevents water vapor from penetrating into the sheet and also prevents water vapor from being adsorbed on the sheet surface, thereby preventing the adsorption and formation of clusters of water molecules.

[0053] Thus, the sheet made of the composition disclosed herein is not prone to water and moisture absorption, thereby suppressing poor appearance or changes in properties, especially the increase in dielectric loss tangent.

[0054] (organosiloxanes)

[0055] The organosiloxanes used in this disclosure are compounds having Si-O-Si bonds (siloxane bonds) and having organic substituents bonded to silicon.

[0056] The organosiloxanes used in this disclosure can be oligomers or polymers.

[0057] Examples of the aforementioned organosiloxanes include compounds with methyl groups bonded to silicon.

[0058] In this disclosure, dimethyl polysiloxanes with side chains and all terminal methyl groups are preferably used. Among them, linear dimethyl polysiloxanes are preferred.

[0059] It should be noted that volatile organosiloxanes are not suitable in this disclosure. Examples include hexamethyldisiloxane and decamethylcyclopentasiloxane. This is because they will volatilize when heated above 300°C, and the effects of this disclosure cannot be expected.

[0060] Furthermore, in this disclosure, it is preferable to use a modified organosiloxane in which a portion of the methyl group of the aforementioned dimethyl polysiloxane is modified to a hydrogen atom or various organic groups. By using the modified organosiloxane, it is possible to suppress the increase in dielectric loss tangent caused by moisture absorption in the wafer, and it is expected to suppress decomposition during firing and reduce the amount of gas generated.

[0061] The organopolysiloxane used in this disclosure is preferably a liquid with a viscosity preferably between 3 and 18000 mm. 2 / s (25℃). When the viscosity of organosiloxane is within the above range, it is suitable for easy mixing and high hygroscopic inhibition.

[0062] The lower limit of viscosity for organosiloxanes is more preferably 5 mm. 2 / s (25℃), more preferably 10mm 2 / s (25℃), the optimal value is 20mm 2 / s (25℃). The upper limit of viscosity for organosiloxanes is more preferably 10000 mm² / s. 2 / s (25℃), more preferably 5000mm 2 / s (25℃), the optimal value is 2000mm 2 / s (25℃).

[0063] In this disclosure, the viscosity of the organosiloxane is the value measured at 25°C using an Ubbelohde viscometer.

[0064] In addition, when two or more organosiloxanes are used together, the viscosity at 25°C refers to the viscosity of the mixture.

[0065] As examples of the aforementioned modified organosiloxanes, those in which an organic group other than a hydrogen atom or a methyl group (hereinafter sometimes referred to as an organic group, etc.) is introduced into any one or all of their side chains, single ends, and double ends are considered. For example, substances formed by introducing an organic group, etc., into a portion of the side chain of an organosiloxane, substances formed by introducing an organic group, etc., into any one end of an organosiloxane, substances formed by introducing organic groups, etc., into both ends of an organosiloxane, substances formed by introducing organic groups, etc., into a portion of the side chain and both ends of an organosiloxane, etc., may be selected and used as appropriate.

[0066] From the perspective of suppressing the rate of increase of dielectric loss tangent, it is preferable to introduce organic groups into a portion of the side chain.

[0067] It should be noted that, in this disclosure, "having hydrogen atoms in any one or all of its side chains, single ends, and two ends" does not refer to hydrogen atoms present in organic groups, but rather to the presence of elemental hydrogen atoms in any one or all of its side chains, single ends, and two ends.

[0068] In addition, modified organosiloxanes can be either reactive or non-reactive.

[0069] It should be noted that the organosiloxanes used in this disclosure do not include the silane coupling agents used later in coating inorganic particles. Specifically, the organosiloxanes used in this disclosure do not include organosiloxanes having halogen groups such as alkoxy (-OR (R has 1 to 6 carbon atoms)), hydroxyl, or chlorine groups.

[0070] Specifically, examples of the aforementioned organic groups include carboxyl, amino, ether, epoxy, mercapto, acryloyl, methacryloyl, carbonyl, carboxylic anhydride, alkyl groups other than methyl, aralkyl, fluoroalkyl, perfluoroalkyl, aryl, ester, and amide groups, or substituents containing them.

[0071] Examples of alkyl groups other than methyl include ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, and n-hexyl, which have 1 to 6 carbon atoms, with n-butyl, n-pentyl, and n-hexyl being preferred.

[0072] Examples of aryl groups include phenyl and naphthyl groups with 6 to 10 carbon atoms, with phenyl being the most preferred.

[0073] The aforementioned fluoroalkyl and perfluoroalkyl groups are straight-chain or branched fluoroalkyl or perfluoroalkyl groups with 1 to 50 carbon atoms, and may contain ether bonds.

[0074] Preferably, the fluoroalkyl or perfluoroalkyl group has a straight or branched chain with 1 to 40 carbon atoms and may contain ether bonds. More preferably, the fluoroalkyl or perfluoroalkyl group has a straight or branched chain with 1 to 30 carbon atoms and may contain ether bonds. Particularly preferred are the fluoroalkyl or perfluoroalkyl group with a straight chain with 1 to 20 carbon atoms and may contain ether bonds.

[0075] The modified organosiloxanes used in this disclosure are preferably any one of their side chains, single-terminal and double-terminal groups, or all of them having at least one group selected from the group consisting of hydrogen atom, amino, ether group, epoxy group, mercapto group, carboxyl group, acryloyl group, methacryloyl group, carboxylic anhydride group, alkyl group other than methyl, aralkyl group, fluoroalkyl group, perfluoroalkyl group, aryl group, ester group, amide group and phenyl group.

[0076] The modified organosiloxanes used in this disclosure are more preferably any one of their side chains, single ends, and double ends, or all of them having at least one selected from the group consisting of hydrogen atom, amino, carboxyl, acryloyl, carboxylic anhydride, alkyl, fluoroalkyl, perfluoroalkyl, ester, amide, and phenyl.

[0077] The modified organosiloxanes used in this disclosure are further preferably those having at least one group selected from the group consisting of hydrogen atom, amino group, carboxyl group, acryloyl group, fluoroalkyl group, phenyl group and carboxylic anhydride group in any of their side chains, single ends and double ends.

[0078] Specifically, examples of modified organosiloxanes include methylhydropolysiloxane, methylphenylpolysiloxane as a copolymer of dimethylsiloxane and diphenylsiloxane, carboxyl-modified polysiloxane, amino-modified polysiloxane, acrylic acid-modified polysiloxane, methacrylic acid-modified polysiloxane, fluoroalkyl-modified polysiloxane, carboxylic anhydride-modified polysiloxane, polyether-modified polysiloxane, epoxy-modified polysiloxane, and epoxy-polyether-modified polysiloxane.

[0079] As the polyether in the above-mentioned polyether-modified polysiloxane, polyalkylene glycol is preferred. Examples of such polyalkylene glycols include those derived from polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol, polyhexamethylene glycol, block or random copolymers of ethylene oxide and propylene oxide.

[0080] The organosiloxanes used in this disclosure include polydimethylsiloxane (KF-96, etc.), methylphenyl polysiloxane (KF-50, etc.), methylhydropolysiloxane (KF-99), carboxyl-modified polysiloxane (X-22-3701E, X-22-162C, etc.), amino-modified polysiloxane (KF-868, KF-8012, KF-8008, etc.), anhydride-modified polysiloxane (X-22-168, etc.), acrylic acid-modified polysiloxane (X-22-2445, etc.), fluoroalkyl-modified polysiloxane (X-22-822, etc.), and mercapto-modified polysiloxane (X-22-167B, etc.) (all of which are commercially available products of Shin-Etsu Chemical Co., Ltd.

[0081] In addition, there are WACKER AF98 / 1000, WACKER L655, WACKER FINISH WT1270 manufactured by Asahi Kasei Wacker Silicone, and TSF4704 manufactured by Momentive.

[0082] In this disclosure, dimethyl polysiloxane, methylhydropolysiloxane, methylphenyl polysiloxane, carboxyl-modified polysiloxane, amino-modified polysiloxane, acrylic acid-modified polysiloxane, carboxylic anhydride-modified polysiloxane, fluoroalkyl-modified polysiloxane, etc., are preferably used as organosiloxanes.

[0083] Preferably, the aforementioned organosiloxane comprises less than 20% by mass of the total composition. By setting such a mixing amount, the increase in dielectric loss tangent caused by moisture absorption in the wafer can be effectively suppressed, resulting in a reduction in both the dielectric loss tangent and the linear expansion rate of the wafer, which is preferable in this respect. More preferably, the mixing amount is 10% by mass or less, further preferably 5% by mass or less, and particularly preferably 2% by mass or less. On the other hand, the lower limit of the mixing amount of the organosiloxane is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, further preferably 0.05% by mass or more, and particularly preferably 0.2% by mass or more. By setting such a mixing amount, the increase in dielectric loss tangent caused by moisture absorption in the wafer can be effectively suppressed. It should be noted that if the aforementioned organosiloxane comprises 20% by mass or more of the total composition, there is a tendency for the dielectric loss tangent and linear expansion rate of the wafer to increase.

[0084] (Inorganic particles)

[0085] The inorganic particles used in this disclosure are not particularly limited, and may be selected from one or more of the following: silicon dioxide, ceramics, talc, mica, alumina, zinc oxide, tin oxide, titanium oxide, calcium carbonate, calcium oxide, magnesium oxide, potassium titanate, glass fiber, glass sheet, glass bead, silicon carbide, calcium fluoride, boron nitride, barium sulfate, molybdenum disulfide, and potassium carbonate whiskers. Two or more of these may also be used in combination.

[0086] As one of the objectives of this disclosure, in obtaining a sheet where the rise in dielectric loss tangent caused by moisture absorption is suppressed, it is preferable to use silica as an essential component, which reduces the relative permittivity and dielectric loss tangent, and also reduces the linear expansion rate. Therefore, silica is preferably an essential component of the inorganic particles used in this disclosure.

[0087] When using silica, the surface of silica is Si-O-Si-O, and organosiloxanes also have Si-O-Si-O bonds in the main framework. Therefore, compared with other inorganic particles, they have high compatibility with organosiloxanes. By combining silica and organosiloxanes, the moisture absorption inhibition effect is further improved.

[0088] The silica in the inorganic particles is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more.

[0089] By ensuring the silica content in the inorganic particles falls within the aforementioned range, it is advantageous to reduce the dielectric loss tangent. Furthermore, the inorganic particles may consist solely of silica.

[0090] The shape of the aforementioned inorganic particles is not particularly limited, but spherical shape is particularly preferred. Spherical shape is advantageous because it facilitates uniform processing during hole-opening, has a smaller specific surface area, and exhibits lower transmission loss.

[0091] The silica mentioned above is preferably made of spherical silica particles.

[0092] The aforementioned spherical inorganic particles refer to fillers whose particle shape is close to that of a perfect sphere. Specifically, the sphericity is preferably 0.80 or higher, more preferably 0.85 or higher, further preferably 0.90 or higher, and most preferably 0.95 or higher. Regarding sphericity, the area and perimeter of the observed particles are calculated using SEM photographs, calculated as (sphericity) = {4π × (area) ÷ (perimeter)²}. The closer to 1, the closer to a perfect sphere. Specifically, the average value measured using an image processing device (Spectris Co., Ltd.: FPIA-3000) is used.

[0093] When accumulating the volume of inorganic particles used in this disclosure, starting with the smallest inorganic particles, the D90 / D10 ratio is preferably 2 or more (preferably 2.3 or more, 2.5 or more), and the D50 is 10 μm or less. Furthermore, the D90 / D50 ratio is preferably 1.5 or more (more preferably 1.6 or more). The D50 / D10 ratio is preferably 1.5 or more (more preferably 1.6 or more). Furthermore, the D50 is more preferably 5 μm or less. Since the small-sized inorganic particles can enter the gaps between the large-sized inorganic particles, the filling properties are excellent, and the flowability is improved. In particular, as for the particle size distribution, it is preferable that the frequency of the smaller particle size side is higher compared to the Gaussian curve.

[0094] Particle size can be measured using a particle size distribution measuring device based on laser diffraction scattering. Furthermore, coarse particles make it difficult to produce thin films; therefore, it is preferable to use filters or similar devices to remove coarse particles with a specified particle size.

[0095] The water absorption of the aforementioned inorganic particles is preferably 1.0% or less, more preferably 0.5% or less. If the water absorption of the inorganic particles is within the above range, moisture absorption of the sheet can be suppressed, thereby obtaining a sheet that can suppress the rise of the dielectric loss tangent caused by moisture absorption.

[0096] The water absorption of inorganic particles is based on their mass when dried. In the determination of water absorption, the sample in a dry state is placed at 40°C and 80%RH for 1 hour, and the moisture generated by heating at 200°C is measured and calculated using a Karl Fischer moisture analyzer.

[0097] The average particle size of the aforementioned inorganic particles is preferably 0.5 μm or greater. It should be noted that the average particle size here refers to the D50 value measured using a laser-based particle size analyzer.

[0098] If the average particle size is less than 0.5 μm, inorganic particles will aggregate, which may sometimes prevent the achievement of sufficient results.

[0099] In addition, there is no particular upper limit to the average particle size, but it is preferably 250 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0100] The dielectric loss tangent of the aforementioned silicon dioxide at 10 GHz is preferably 0.0025 or less. Such a value is preferred in terms of low loss in the wafer. The upper limit is more preferably 0.002, further preferably 0.0015, and most preferably 0.0010.

[0101] On the other hand, the lower limit of the dielectric loss tangent is preferably 0.00001.

[0102] In this disclosure, the dielectric loss tangent of silicon dioxide measured at 10 GHz is determined using a cylindrical cavity resonator and a network analyzer. A filler powder sample is filled into a quartz tube and loaded into the resonator for measurement. The characteristics of the resonator (resonant frequency and Q value) before and after sample insertion are obtained, and the dielectric loss tangent is calculated based on the results. This measurement method is based on Japanese Industrial Standard JIS 2565, Test Method for Ferrite Cores for Microwave Use, and is performed at room temperature of 25°C and humidity of 40%.

[0103] Alternatively, the inorganic particles can be removed by heating the sheet at 600°C in an atmospheric atmosphere for 30 minutes to burn off the fluororesin, and then measuring the parameters using the above method.

[0104] The aforementioned inorganic particles are preferably surface-treated inorganic particles. By performing surface treatment beforehand, the aggregation of inorganic particles can be suppressed, and the inorganic particles can be well dispersed in the resin composition.

[0105] In addition, it is preferred in terms of reducing the rate of linear expansion.

[0106] As for the aforementioned surface treatment, there are no particular limitations, and any known surface treatment can be used. Specifically, examples include treatment using silane coupling agents with reactive functional groups such as epoxy silanes, amino silanes, isocyanate silanes, vinyl silanes, acrylate silanes, hydrophobic alkyl silanes, phenyl silanes, and fluorinated alkyl silanes, plasma treatment, and fluorination treatment.

[0107] Preferably, a silane coupling agent is used for surface treatment, and the inorganic particles are coated with the silane coupling agent.

[0108] Coating with a silane coupling agent is advantageous in reducing the dielectric loss tangent.

[0109] Examples of silane coupling agents include epoxy silanes such as γ-epoxypropoxypropyltriethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, amino silanes such as aminopropyltriethoxysilane and N-phenylaminopropyltrimethoxysilane, isocyanate silanes such as 3-isocyanatepropyltrimethoxysilane, vinyl silanes such as vinyltrimethoxysilane, and acrylate silanes such as acryloyloxytrimethoxysilane.

[0110] The inorganic particles disclosed herein are preferably surface-treated with a silane coupling agent at a concentration of 0.05 to 30% by mass relative to the inorganic particles.

[0111] Surface treatment is not particularly limited and can be performed by any known method. Specifically, for example, inorganic particles can be treated with silane coupling agents under conditions such as a solution containing the silane coupling agent in a solvent or a solvent-free state.

[0112] The aforementioned spherical silica particles can be used among commercially available silica particles that satisfy the above properties. Examples of commercially available silica particles include, for instance, Denka fused silica FB grade (manufactured by Denka Corporation), Denka fused silica SFP grade (manufactured by Denka Corporation), EXCELICA (manufactured by Tokuyama Corporation), high-purity synthetic spherical silica ADMAFINE (manufactured by Admatechs Corporation), ADMANANO (manufactured by Admatechs Corporation), and ADMAFUSE (manufactured by Admatechs Corporation).

[0113] The aforementioned inorganic particles preferably contain 40% by mass or more of the total composition. This mixing amount is preferred in terms of maintaining a low dielectric constant and low loss while also exhibiting low thermal expansion. Furthermore, it allows for the production of a composition with excellent formability. The mixing amount is more preferably 50% by mass or more, and even more preferably 55% by mass or more. There is no particular upper limit to the mixing amount of inorganic particles, but it is preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0114] (Fluoropolymer)

[0115] Fluoropolymers have low dielectric properties, and are therefore suitable for obtaining sheets in which the rise of the dielectric loss tangent caused by moisture absorption is suppressed, as is one of the objectives of this disclosure. Therefore, for this purpose, the compositions of this disclosure preferably contain fluoropolymers.

[0116] The fluoropolymers that can be used in this disclosure are not particularly limited, and examples include polytetrafluoroethylene (PTFE), tetrafluoroethylene [TFE] / hexafluoropropylene [HFP] copolymer [FEP], TFE / alkyl vinyl ether copolymer [PFA], TFE / HFP / alkyl vinyl ether copolymer [EPA], TFE / chlorotrifluoroethylene [CTFE] copolymer, TFE / ethylene copolymer [ETFE], polyvinylidene fluoride [PVdF], and tetrafluoroethylene with a molecular weight of less than 300,000 [LMW-PTFE]. One or more of these can be used.

[0117] Perfluorinated fluoropolymers are preferred.

[0118] From the viewpoint of low dielectric properties, polytetrafluoroethylene (PTFE) resin is particularly preferred. PTFE preferably has fibrillatory properties. Fibrillatory PTFE refers to PTFE that can be extruded from unburned polymer powder paste.

[0119] PTFE can be modified polytetrafluoroethylene (hereinafter referred to as modified PTFE), homopolymer polytetrafluoroethylene (hereinafter referred to as homopolymer PTFE), or a mixture of modified PTFE and homopolymer PTFE. It should be noted that, from the viewpoint of maintaining the moldability of polytetrafluoroethylene well, the content of modified PTFE in the polymeric PTFE is preferably 10% by weight or more and 98% by weight or less, more preferably 50% by weight or more and 95% by weight or less. Homopolymer PTFE is not particularly limited, and Japanese Patent Application Publication Nos. 53-60979, 57-135, 61-16907, 62-104816, 62-190206, 63-137906, and 2000-143727 are preferred. Homopolymer PTFE disclosed in Japanese gazettes, Japanese Patent Application Publication Nos. 2002-201217, International Publication Nos. 2007 / 046345, 2007 / 119829, 2009 / 001894, 2010 / 113950, and 2013 / 027850. Among them, homopolymer PTFE disclosed in Japanese Patent Application Publication No. 57-135, Japanese Patent Application Publication No. 63-137906, Japanese Patent Application Publication No. 2000-143727, Japanese Patent Application Publication No. 2002-201217, International Publication No. 2007 / 046345, International Publication No. 2007 / 119829, and International Publication No. 2010 / 113950, which have high tensile properties, is preferred.

[0120] Modified PTFE consists of TFE and monomers other than TFE (hereinafter referred to as modified monomers). Examples of modified PTFE include PTFE uniformly modified using modified monomers, PTFE modified at the initial stage of polymerization, and PTFE modified at the end of polymerization; there is no particular limitation. Preferably, modified PTFE is a TFE copolymer obtained by polymerizing a trace amount of monomers other than TFE together with TFE, within a range that does not significantly impair the properties of the TFE homopolymer. Modified PTFE may preferably be the modified PTFE disclosed in, for example, Japanese Patent Application Publication No. 60-42446, Japanese Patent Application Publication No. 61-16907, Japanese Patent Application Publication No. 62-104816, Japanese Patent Application Publication No. 62-190206, Japanese Patent Application Publication No. 64-1711, Japanese Patent Application Publication No. 2-261810, Japanese Patent Application Publication No. 11-240917, Japanese Patent Application Publication No. 11-240918, International Publication No. 2003 / 033555, International Publication No. 2005 / 061567, International Publication No. 2007 / 005361, International Publication No. 2011 / 055824, and International Publication No. 2013 / 027850. Among them, modified PTFE with high tensile properties is preferred, as disclosed in Japanese Patent Application Publication No. 61-16907, Japanese Patent Application Publication No. 62-104816, Japanese Patent Application Publication No. 64-1711, Japanese Patent Application Publication No. 11-240917, International Publication No. 2003 / 033555, International Publication No. 2005 / 061567, International Publication No. 2007 / 005361, and International Publication No. 2011 / 055824.

[0121] Modified PTFE comprises TFE-based TFE units and modified monomer units based on modified monomers. The modified monomer units are part of the molecular structure of modified PTFE and are derived from the modified monomers. Modified PTFE preferably comprises 0.001% to 0.500% by weight of all monomer units, more preferably 0.01% to 0.30% by weight. All monomer units are the portions of the molecular structure of modified PTFE derived from all monomers.

[0122] There are no particular limitations on the modified monomers as long as they can copolymerize with TFE. Examples include perfluoroolefins such as hexafluoropropylene (HFP); chlorofluoroolefins such as trifluorochloroethylene (CTFE); hydrofluoroolefins such as trifluoroethylene and vinylidene fluoride (VDF); perfluorovinyl ethers; perfluoroalkyl ethylene (PFAE); and ethylene. One or more modified monomers can be used.

[0123] There are no particular limitations on perfluorovinyl ethers; for example, perfluorounsaturated compounds represented by the following general formula (1) can be cited.

[0124] CF2 = CF - ORf (1)

[0125] (In the formula, Rf represents a perfluorinated organic group.)

[0126] In this specification, a perfluorinated organic group is an organic group in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. The aforementioned perfluorinated organic groups may contain ether oxygen.

[0127] Examples of perfluorovinyl ethers (PAVEs) include perfluoro(alkyl vinyl ethers) in which Rf is a perfluoroalkyl group having 1 to 10 carbon atoms in the general formula (1) above. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 5. Examples of perfluoroalkyl groups in PAVEs include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, and perfluorohexyl. Perfluoropropyl vinyl ether (PPVE) and perfluoromethyl vinyl ether (PMVE) are preferred as PAVEs.

[0128] The term "perfluoroalkyl ethylene (PFAE)" is not specifically limited; examples include perfluorobutylethylene (PFBE) and perfluorohexylethylene (PFHE).

[0129] The modifying monomer used in modified PTFE is preferably selected from at least one of the group consisting of HFP, CTFE, VDF, PAVE, PFAE and ethylene.

[0130] The aforementioned fluoropolymers are preferably non-melt processable. Non-melt processable means that even when heated above its melting point, the resin does not possess sufficient fluidity to be molded using conventional melt molding methods. PTFE meets this requirement.

[0131] In this disclosure, a non-melt-processable fluoropolymer is preferably used, and the resin is formed into sheets by a fibrillation molding method. This molding method is described below.

[0132] The preferred SSG value for the PTFE is 2.0 to 2.3. Using such PTFE readily yields PTFE films with high strength (cohesive strength and puncture strength per unit thickness). High molecular weight PTFE has long molecular chains, making it difficult to form a structure with regularly arranged molecular chains. In this case, the length of the amorphous portion increases, and the degree of molecular entanglement increases. It is believed that with a high degree of molecular entanglement, the PTFE film is less prone to deformation under applied loads, exhibiting excellent mechanical strength. Furthermore, using high molecular weight PTFE readily yields PTFE films with small average pore size.

[0133] The lower limit of the aforementioned SSG is more preferably 2.05, and even more preferably 2.1. The upper limit of the aforementioned SSG is more preferably 2.25, and even more preferably 2.2.

[0134] Standard specific gravity [SSG] is obtained by preparing a sample according to ASTM D-4895-89 and determining the specific gravity of the sample by the water displacement method.

[0135] In this disclosure, the molecular weight (number average molecular weight) of the PTFE constituting the PTFE powder is preferably in the range of 2 million to 12 million. The lower limit of the molecular weight of PTFE can be 3 million or 4 million. The upper limit of the molecular weight of PTFE can be 10 million.

[0136] Methods for determining the number-average molecular weight of PTFE include methods based on standard specific gravity and methods utilizing dynamic viscoelasticity during melting. The method based on standard specific gravity can be performed using samples molded according to ASTM D-4895 98 via the water displacement method according to ASTM D-792. The method utilizing dynamic viscoelasticity is described, for example, by S. Wu in Polymer Engineering & Science, 1988, Vol. 28, 538 and the same paper, 1989, Vol. 29, 273.

[0137] The refractive index of the aforementioned PTFE is preferably in the range of 1.2 to 1.6. This refractive index is preferable from the perspective of low dielectric strength. The refractive index can be adjusted within this range by methods such as adjusting polarizability and the flexibility of the main chain. The lower limit of the aforementioned refractive index is more preferably 1.25, more preferably 1.30, and most preferably 1.32. The upper limit of the aforementioned refractive index is more preferably 1.55, more preferably 1.50, and most preferably 1.45.

[0138] The refractive index mentioned above is a value measured using a refractometer (Abbemat 300).

[0139] In addition, the maximum endothermic peak temperature (crystal melting point) of the above-mentioned PTFE is preferably 340±7℃.

[0140] PTFE can be either low-melting-point PTFE with a maximum peak temperature of less than 338°C on the endothermic curve of the crystal melting curve measured by differential scanning calorimetry, or high-melting-point PTFE with a maximum peak temperature of more than 342°C on the endothermic curve of the crystal melting curve measured by differential scanning calorimetry.

[0141] Low-melting-point PTFE powder is a powder manufactured through emulsion polymerization. It possesses the aforementioned maximum endothermic peak temperature (crystal melting point), a dielectric constant (ε) of 2.08–2.2, and a dielectric loss tangent (tanδ) of 1.9 × 10⁻⁴–4.0 × 10⁻⁴. Commercially available examples include POLYFLON FINE POWDER F201, F203, F205, F301, and F302 manufactured by Daikin Industries, Ltd.; CD090 and CD076 manufactured by Asahi Glass Co., Ltd.; and TF6C, TF62, and TF40 manufactured by DuPont.

[0142] High-melting-point PTFE powder is also a powder manufactured through emulsion polymerization. It possesses the aforementioned maximum endothermic peak temperature (crystal melting point), a dielectric constant (ε) of 2.0–2.1, and a dielectric loss tangent (tanδ) of 1.6 × 10⁻⁶. 4 ~2.2×10- 4 Overall, the price is low. Examples of commercially available products include POLYFLON FINE POWDER F104 and F106 manufactured by Daikin Industries, Ltd.; CD1, CD141, and CD123 manufactured by Asahi Glass Co., Ltd.; and TF6 and TF65 manufactured by DuPont.

[0143] It should be noted that the average particle size of the powder formed by the secondary agglomeration of two PTFE polymer particles is preferably 250 μm to 2000 μm. In particular, from the perspective of improving the flowability during mold filling in preforming, granulated powder obtained by solvent granulation is preferred.

[0144] PTFE powder with the above parameters can be obtained by existing manufacturing methods. For example, it can be manufactured according to the manufacturing methods described in International Publication No. 2015 / 080291, International Publication No. 2012 / 086710, etc.

[0145] (Resins other than fluoropolymers)

[0146] The compositions disclosed herein may use resins other than fluoropolymers as resins.

[0147] Resins other than fluoropolymers include: cellulose triacetate membranes, cyclic olefin polymers, cyclic olefin copolymers, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, transparent polyimide, thermoplastic polyimide, polyacrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, syndiotactic polystyrene, polymethylpentene, epoxy resins, alicyclic epoxy resins, silicone resins (excluding resins contained in the above-mentioned organosiloxanes), polyphenylene ether, modified polyphenylene ether, polyurethane, phenolic resins, bismaleimide resins, cyanate ester resins, urea resins, melamine resins, unsaturated polyester resins, etc.

[0148] (Composition)

[0149] The compositions disclosed herein contain the aforementioned organosiloxanes, inorganic particles, and fluoropolymers or resins other than fluoropolymers.

[0150] The compositions disclosed herein may contain other components besides these as needed, but are preferably substantially composed of organosiloxanes, inorganic particles, and fluoropolymers or resins other than fluoropolymers. Particularly preferred are those composed of organosiloxanes, inorganic particles, and fluoropolymers.

[0151] In this disclosure, "substantially" means that the components other than fluoropolymer particles, resins other than fluoropolymers, inorganic particles, and components other than organosiloxanes in the composition are 10% by mass or less. Furthermore, the compositions of this disclosure preferably consist only of organosiloxanes, inorganic particles, and fluoropolymers or resins other than fluoropolymers. Particularly preferred are those consisting only of organosiloxanes, inorganic particles, and fluoropolymers.

[0152] (Method for manufacturing the composition)

[0153] The composition disclosed herein is obtained, for example, by mixing the resin particles, inorganic particles, and organosiloxane components by stirring or the like.

[0154] No specific mixing conditions are specified; for example, mixing can be carried out by stirring at room temperature using a mixer such as a Wonder crusher. If the stirring time is too short, the mixing may be insufficient; if the stirring time is too long, resin molecules may be broken down or become fibrous. Therefore, stirring for an appropriate time is preferred. Alternatively, stirring at low temperatures in the presence of dry ice can also prevent resin molecules from breaking down or becoming fibrous, thus ensuring proper mixing.

[0155] For example, the composition can be obtained under the following conditions, and tablets can be obtained from the obtained composition by the tablet manufacturing method described later.

[0156] When manufacturing sheets by powder calendering, it is preferable, for example, to measure the resin particles, inorganic particles, and organosiloxane components in the desired proportions and to stir them at room temperature for 10 seconds to 10 minutes using a Wonder crusher. Alternatively, stirring can be performed once or in two or more stages.

[0157] In the case of manufacturing sheets by paste extrusion molding, for example, it is preferable to measure the required amounts of resin particles, inorganic particles, and organosiloxane components and mix them in the presence of dry ice using a mixer. The mixing temperature is preferably below -10°C.

[0158] Alternatively, it is preferable to add 18-23% by mass of an extrusion aid such as oil (IP solvent 2028) to the obtained mixed powder and mix it, then let it mature for about 5 hours.

[0159] (piece)

[0160] The compositions disclosed herein are suitable for use in the formation of tablets.

[0161] This disclosure also pertains to tablets composed of the above-described composition.

[0162] The sheet disclosed herein can suppress water absorption and hygroscopicity. The water absorption rate is preferably 0.1 wt% or less. More preferably, it is 0.08 wt% or less, and most preferably, it is 0.04 wt% or less.

[0163] The water absorption rate was determined based on the value calculated according to IPC TM650 2.6.2.1.

[0164] The moisture content of the disclosed film, when stored at 30°C and 90% RH for one week, preferably increases by 60 ppm or less. If the moisture content increases by 60 ppm or less, moisture absorption can be considered suppressed. More preferably, the moisture content increases by 30 ppm or less, and even more preferably, by 15 ppm or less.

[0165] The aforementioned increase in moisture content was obtained by measuring the moisture generated by heating at 250°C using a Karl Fischer moisture measuring device and calculating the increase in moisture content.

[0166] The disclosed film can also reduce surface hydrophobic tension. Surface hydrophobic tension can be evaluated by the following methods.

[0167] At room temperature, the tablets were immersed in the "wetting tension test solution" manufactured by Wako Pure Chemical Industries, Ltd. for 1 minute, then rinsed with distilled water. The presence or absence of the wetting tension test solution was visually assessed. Wetting tension test solutions No. 22.6 to 70.0 were used. The value of the test solution with the lowest surface tension among the wetting tension test solutions that showed no penetration was taken as the result of the critical hydrophobicity.

[0168] The wetting tension test solution comes in different types with different wetting tensions (23°C). Since each type contains a colorant, it is possible to visually confirm whether it has penetrated into the test subject.

[0169] The critical hydrophobic tension is preferably below 37 mN / M, more preferably 32 mN / M, and most preferably 22.6 mN / M.

[0170] The disclosed sheet, particularly when using a composition containing a fluoropolymer, can suppress variations in the dielectric loss tangent caused by moisture absorption.

[0171] The dielectric constant of the chip disclosed herein is preferably 3.5 or less at 10 GHz. Within this range, it is preferred in terms of low dielectric loss.

[0172] The upper limit of the relative permittivity is more preferably 3.2, and even more preferably 3.1. On the other hand, the lower limit of the relative permittivity is preferably 2.0, and more preferably 2.5.

[0173] The dielectric loss tangent of the chip disclosed herein is preferably 0.0015 or less at 10 GHz. By keeping the dielectric loss tangent within this range, signal loss in the circuit can be suppressed to a lower level, which is preferable. More preferably, the dielectric loss tangent is 0.0012 or less, and even more preferably 0.0011 or less. On the other hand, the lower limit of the dielectric loss tangent is preferably 0.00001.

[0174] The relative permittivity (Dk) and dielectric loss tangent (Df) of the chip in this disclosure at 10 GHz were obtained by measuring Dk and Df at 25 °C and 10 GHz using a split cylindrical dielectric constant / dielectric loss tangent measuring device (manufactured by EM Labs).

[0175] The dielectric loss tangent of the wafer disclosed herein preferably increases by 30% or less when stored at 30°C and 90%RH for 24 hours. More preferably, the increase rate of the dielectric loss tangent is 20% or less, and even more preferably 12% or less.

[0176] The rise rate of the dielectric loss tangent mentioned above was calculated by the following formula after tracking the change of the dielectric loss tangent for 24 hours by configuring each sample in a constant temperature and humidity bath at 30°C and 90%RH.

[0177] Rate of increase (%) = (Dielectric loss tangent after 24 hours - Dielectric loss tangent before constant humidity test) / Dielectric loss tangent before constant humidity test × 100

[0178] The linear expansion coefficient (CTE) of the sheet disclosed herein is preferably 200 ppm / K or less.

[0179] The above-mentioned range is preferred in terms of producing sheets with low shrinkage and excellent dimensional stability. The upper limit is more preferably 150 ppm / K, further preferably 100 ppm / K, and most preferably 70 ppm / K. The lower limit is not particularly limited, but is preferably 10 ppm / K, and more preferably 20 ppm / K.

[0180] The linear expansion rate in this disclosure is as follows: the linear expansion rate is determined by TMA measurement using a TMA-7100 (manufactured by Hitachi High-Tech Science Corporation) in tensile mode. As a sample sheet, a sheet cut into pieces with a length of 20 mm, a width of 5 mm, and a thickness of 150 μm is used. The chuck spacing is set to 10 mm, and the linear expansion rate is determined by the displacement of the sample from 0 °C to 150 °C while applying a load of 49 mN and heating at a rate of 2 °C / min.

[0181] In this disclosure, when a modified organosiloxane is used as the organosiloxane, a sheet with suppressed moisture absorption and suppressed organosiloxane decomposition during firing can be obtained.

[0182] The sheet disclosed herein preferably has a thickness of less than 300 μm. Even when the sheet is relatively thin, its purpose can be fully achieved. From this point of view, a thickness of less than 200 μm is more preferred, and even more preferred is a thickness of less than 150 μm. Furthermore, when it can be processed to a thickness of less than 100 μm as needed, it can be widely used on substrates of various thicknesses, which is preferable.

[0183] (Methods for manufacturing the film)

[0184] The sheet disclosed herein can be obtained by molding a composition containing the aforementioned resin particles, inorganic particles, and organosiloxane. The manufacturing method is not limited; for example, paste extrusion molding, powder calendering, etc., are preferred.

[0185] This disclosure also discloses a method for manufacturing a sheet, which is the method for manufacturing the aforementioned sheet, characterized in that a composition containing fluororesin particles, inorganic particles and organosiloxane is molded.

[0186] The method for manufacturing the film disclosed herein preferably uses a composition substantially composed of fluororesin particles, inorganic particles and organosiloxanes for molding.

[0187] As described above, the fluoropolymer used in the sheets of this disclosure is preferably a non-melt-processable fluoropolymer. When using such a fluoropolymer, it is preferable to mold it into sheets by fibrillating powdered PTFE, which is used as a raw material.

[0188] The powdered PTFE described above preferably uses PTFE with a primary particle size of 0.05–10 μm. Using such a resin offers advantages such as excellent moldability and dispersibility. It should be noted that the primary particle size here is a value determined according to ASTM D 4895.

[0189] The aforementioned powdered PTFE preferably contains 50% by mass or more of polytetrafluoroethylene resin with a secondary particle size of 500 μm or more, and more preferably 80% by mass or more. By ensuring that the PTFE has a secondary particle size of 500 μm or more falls within this range, it is advantageous to be able to produce high-strength compound tablets.

[0190] By using PTFE with a secondary particle size of 500 μm or more, it is possible to obtain compound tablets with lower resistance and greater toughness.

[0191] The lower limit of the aforementioned secondary particle size is more preferably 300 μm, and even more preferably 350 μm. The upper limit of the aforementioned secondary particle size is more preferably 700 μm or less, and even more preferably 600 μm or less. The secondary particle size can be obtained, for example, by sieving.

[0192] From the perspective of obtaining sheets with higher strength and excellent homogeneity, the average primary particle size of the above-mentioned powdered PTFE is preferably 50 nm or more. More preferably, it is 100 nm or more, even more preferably 150 nm or more, and particularly preferably 200 nm or more.

[0193] The larger the average primary particle size of PTFE, the better it can suppress the rise of extrusion pressure and the better the formability when using this powder for paste extrusion molding. There is no particular upper limit, and it can be 500 nm. From the viewpoint of productivity in the polymerization process, 350 nm is preferred.

[0194] Regarding the aforementioned average primary particle size, a calibration curve is prepared using an aqueous dispersion of PTFE obtained through polymerization. This curve compares the transmittance of 550 nm of projected light per unit length relative to the aqueous dispersion with a polymer concentration adjusted to 0.22% by mass with the average primary particle size determined by measuring the directional diameter in a transmission electron microscope image. The transmittance of the aqueous dispersion being measured can be determined based on the calibration curve.

[0195] The PTFE used in this disclosure can have a core-shell structure. Examples of PTFEs with a core-shell structure include, for instance, modified PTFE, which contains a core of high molecular weight polytetrafluoroethylene (PTFE) and a shell of lower molecular weight PTFE or modified PTFE. Examples of such modified PTFEs include, for instance, the PTFE described in Japanese Patent Application Publication No. 2005-527652.

[0196] There are no particular limitations on the specific methods for paste extrusion molding and powder calendering molding; the following describes general methods.

[0197] (Paste extrusion molding)

[0198] The manufacturing method of the above-mentioned sheet may include: step (1a), mixing the above composition comprising fluororesin powder obtained using a hydrocarbon surfactant, inorganic particles and organosiloxane with an extrusion aid; step (1b), extruding the obtained mixture into a paste; step (1c), calendering the extrudate obtained by extrusion; step (1d), drying the calendered sheet; and step (1e), firing the dried sheet to obtain a molded body.

[0199] The above-mentioned paste extrusion molding can also be carried out by adding existing known additives such as pigments to the above composition.

[0200] There are no particular limitations on the extrusion aids mentioned above; commonly known extrusion aids can be used. For example, hydrocarbon oils can be listed.

[0201] (Powder Calendering)

[0202] The aforementioned sheets can also be formed by powder calendering. Powder calendering is a method of forming sheets by applying shear force to resin powder to fibrillate it. Then, a firing process can be included to obtain the molded body.

[0203] More specifically, it can be obtained by the following manufacturing method, which has the following characteristics: In step (1), the above composition, which includes fluororesin powder, inorganic particles and organosiloxane, is mixed while shear force is applied; Step (2) involves shaping the mixture obtained through step (1) into blocks; and Step (3) involves calendering the blocky mixture obtained through step (2) into sheet form.

[0204] It should be noted that when forming sheets by such powder calendering, it is preferable to mix only fluororesin powder, inorganic particles and organosiloxanes for forming.

[0205] It may also include a step of firing the above-obtained sheet at 200-400°C for 1-60 minutes (4).

[0206] Alternatively, step (2) can be omitted.

[0207] In addition, the film disclosed herein can be formed by casting, etc., after preparing a solution or dispersion containing fluororesin, inorganic particles and organosiloxane, coating and drying it on a substrate.

[0208] It should be noted that when the above-mentioned sheet is manufactured, if the firing process is set at a temperature of 300°C or above, for example, if the firing time is set to about 30 minutes or less, the decomposition of organosiloxanes can be limited to a portion, and a sheet with the effects of the present disclosure can be obtained.

[0209] (Layered structure)

[0210] The sheet disclosed herein can be used, for example, as a sheet for a circuit board and laminated with a metal layer. For example, a metal-clad laminate in which a metal layer is bonded to one or both sides of the sheet can be described.

[0211] This disclosure also describes a metal-clad laminate with a metal layer and the aforementioned sheet as necessary layers.

[0212] As described above, sheets containing the fluororesin of this disclosure are particularly suitable for use in circuit board applications and are therefore suitable for use as such metal-clad laminates.

[0213] Examples of suitable metal layers include copper foil, gold foil, silver foil, platinum foil, and ruthenium foil. Among these, copper foil is preferred due to its low conductor loss.

[0214] The copper foil described above preferably has an Rz of 1.6 μm or less. The sheet disclosed herein also exhibits excellent adhesion to copper foil with high smoothness and an Rz of 1.6 μm or less. Furthermore, the copper foil only needs to have an Rz of 1.6 μm or less on at least the side that is bonded to the sheet; the Rz value of the other side is not particularly limited.

[0215] The Rz mentioned above is the sum of the highest part (maximum peak height: Rp) and the deepest part (maximum valley depth: Rv). The surface roughness mentioned above is the ten-point average roughness specified in JIS-B0601. In this specification, the Rz mentioned above is the value measured using a surface roughness meter (trade name: SURFCOM 470A, manufactured by Tokyo Seiki Co., Ltd.) with the measurement length set to 4 mm.

[0216] The thickness of the copper foil is not particularly limited, but is preferably in the range of 1 to 100 μm, more preferably in the range of 5 to 50 μm, and even more preferably in the range of 9 to 35 μm.

[0217] The copper foil mentioned above is not specifically limited; for example, rolled copper foil and electrolytic copper foil can be cited.

[0218] There are no particular limitations on the copper foil with a thickness Rz of 1.6μm or less, and commercially available copper foil can be used. Examples of commercially available copper foil with a thickness Rz of 1.6μm or less include electrolytic copper foil CF-T9DA-SV-18 (thickness 18μm / Rz 0.85μm) (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd.).

[0219] To improve the adhesion strength with the sheet disclosed herein, the copper foil may be surface treated.

[0220] The surface treatments described above are not particularly limited and can include silane coupling treatment, plasma treatment, corona treatment, UV treatment, electron beam treatment, etc. The reactive functional groups used as silane coupling agents are not particularly limited, but from the perspective of adhesion to the resin substrate, it is preferable to have at least one terminal group selected from amino, (meth)acryloyl, mercapto, and epoxy groups. Furthermore, the hydrolyzable groups are not particularly limited, and examples include alkoxy groups such as methoxy and ethoxy. The copper foil used in this disclosure can be formed with an anti-rust layer (such as an oxide film like chromate) and a heat-resistant layer.

[0221] Surface-treated copper foil having a surface treatment layer formed from the aforementioned silane compound on its surface can be manufactured as follows: after preparing a solution containing the silane compound, the copper foil is surface-treated using the solution, thereby manufacturing the copper foil.

[0222] To improve adhesion to the sheet, the copper foil can have a roughening treatment layer on its surface.

[0223] It should be noted that if the roughening treatment may reduce the performance required by this disclosure, the roughening particles electrodeposited on the copper foil surface may be reduced as needed, or the roughening treatment may be omitted.

[0224] To enhance various properties, one or more layers selected from the group consisting of heat-resistant treatment layers, rust-proof treatment layers, and chromate treatment layers can be placed between the copper foil and the surface treatment layer. These layers can be single layers or multiple layers.

[0225] The metal-clad laminate of this disclosure may also have a metal layer and layers other than the sheet of this disclosure.

[0226] The metal layer and the layers other than the sheet are preferably composed of at least one layer selected from the group consisting of polyimide, modified polyimide, liquid crystal polymer, polyphenylene sulfide, cyclic olefin polymer, polystyrene, epoxy resin, bismaleimide, polyphenylene oxide, modified polyphenylene ether, polyphenylene ether and polybutadiene.

[0227] There are no particular limitations on the composition of these layers other than the metal layer and the sheet, as long as they are made of the aforementioned resin. Furthermore, the thickness of these layers other than the metal layer and the sheet is preferably in the range of 12.5 to 260 μm.

[0228] In the metal-clad laminate disclosed herein, the metal layer can be formed on one side or both sides of the sheet. Methods for forming the metal layer include laminating (adhering) the metal layer to the surface of the rolled sheet, vapor deposition, and plating. Hot pressing is another method for laminating the metal layer. The hot pressing temperature can be, for example, from the melting point of the sheet to -150°C to +40°C. The hot pressing time is, for example, 1 to 30 minutes. It can be manufactured by using a hot pressing pressure of 0.1 to 10 MPa.

[0229] The metal-clad laminate disclosed herein may contain formaldehyde, formic acid, and at least one selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. During the manufacture of the metal-clad laminate, the processing temperature is above 300°C, resulting in the decomposition of the organosiloxanes contained in the laminate. If the organosiloxanes decompose, formaldehyde, formic acid, and hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane derived from the organic groups of the organosiloxanes are produced. Therefore, the metal-clad laminate contains formaldehyde, formic acid, and at least one selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

[0230] In this disclosure, the presence of formaldehyde, formic acid, and hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane in the sheet contained in the metal-coated laminate can be confirmed by heating the sheet at 360°C and capturing the generated gas, and then analyzing the gas using thermal desorption GCMS.

[0231] When the sheet contained in the metal-clad laminate contains, for example, more than 50 ppm of formaldehyde, formic acid, and at least one of the following: hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane, it can be said that the sheet used in manufacturing the metal-clad laminate contains an organosiloxane.

[0232] The use of the metal-clad laminate disclosed herein is not particularly limited, and it can be suitably used as a circuit board.

[0233] This disclosure also relates to a circuit board having the aforementioned metal-clad laminate.

[0234] A circuit board is a plate-shaped component used to electrically connect and fix electronic components such as semiconductors and capacitor chips within a limited space. There are no particular limitations on the configuration of the circuit board formed from the metal-clad laminate of this disclosure. The circuit board can be any of a rigid substrate, a flexible substrate, or a rigid-flexible substrate. The circuit board can be any of a single-sided substrate, a double-sided substrate, or a multilayer substrate (such as a build-up substrate). It is particularly suitable for use with flexible and rigid substrates. It is particularly suitable for use as a printed circuit board for high-frequency applications above 10 GHz.

[0235] In this disclosure, the high-frequency circuit is not only composed of circuits that transmit only high-frequency signals, but also includes circuits that transmit signals other than high-frequency signals, such as a transmission path that converts high-frequency signals into low-frequency signals and outputs the generated low-frequency signals to the outside, and a transmission path that supplies power for driving high-frequency corresponding components. Furthermore, it can also be used as a circuit board for antennas, filters, etc.

[0236] This disclosure also describes an antenna formed from the aforementioned circuit board. A millimeter-wave antenna for mobile vehicles such as automobiles and aircraft is particularly preferred.

[0237] As a circuit substrate, there are no particular limitations; the aforementioned metal-clad laminate can be used and manufactured using conventional methods.

[0238] The sheets and metal-clad laminates disclosed herein are used as electrical and electronic components. Examples include antennas used in electronic devices such as ETC, GPS, wireless LAN and mobile phones, connectors for high-speed transmission, CPU sockets, millimeter-wave and quasi-millimeter-wave radars such as anti-collision radars, RFID tags, capacitors, inverter parts, cable sheathing materials, insulating materials for secondary batteries such as lithium-ion batteries, speaker diaphragms, etc.

[0239] Examples of substrates suitable for high-speed communication include base station antenna substrates, antenna distribution substrates, RRH (Remote Radio Head) substrates for the wireless portion of a wireless base station, substrates for the control section or baseband unit (BBU) of a wireless base station, transceiver substrates for high-speed communication, RNC (Radio Network Controller) substrates, high-speed transmitter substrates, high-speed receiver substrates, high-speed signal multiple loop substrates, WiFi substrates for use in the 60GHz band, and data transmission substrates used in servers for data centers. Furthermore, examples of substrates suitable for high-speed communication include antenna substrates, such as substrates for Massive MIMO antennas for high-capacity communication required for standards beyond 5G. Moreover, examples include microwave-based space transmission wireless power supply antennas. The sheet disclosed herein exhibits good adhesion to a low-loss, smooth copper foil; therefore, when an antenna is obtained by processing a copper-clad laminate containing the sheet of this disclosure and the smooth copper foil, the gain is improved, making it particularly suitable for antennas.

[0240] The sheet disclosed herein can be used not only as an insulator for substrates, but also as an insulator for signal line sheathing materials. For example, it can be used as an insulating sheathing material (e.g., an insulating tube) for waveguides transmitting high-speed signals, QSFP cables for high-speed LANs, coaxial cables (e.g., SFP+ cables, QSFP+ cables, etc.) for high-speed communication applications, and coaxial cables for low-loss applications.

[0241] In the context of using the aforementioned high frequencies, materials used in communication equipment, such as connectors and housings, require stable electrical characteristics such as a low relative permittivity (εr) and a low dielectric loss tangent (tanδ). The sheet disclosed herein can also be used as an insulating material for such applications.

[0242] The sheet disclosed herein can also be used as an insulating material for printed wiring boards of connectors that require soldering. The sheet disclosed herein has excellent heat resistance, therefore it is less prone to problems even at the high temperatures during soldering.

[0243] In dielectric waveguide circuits, materials with low dielectric loss are required for low-loss transmission of high-frequency millimeter or submillimeter waves. The sheet disclosed herein can also be used as an insulating material for dielectric waveguide circuits transmitting millimeter waves, submillimeter waves, etc. Examples of dielectric waveguide circuits include cylindrical dielectric lines, square dielectric lines, elliptical dielectric lines, tubular dielectric lines, image lines, island image lines, trapped image lines, ridge waveguides, strip dielectric lines, reverse striplines, H-shaped waveguides, non-radioactive dielectric lines (NRD waveguides), and so on.

[0244] In this disclosure, "mobile body" refers to all means and methods related to movement and transportation, including automobiles such as private cars, buses, taxis, and trucks, as well as motorcycles, bicycles, two-wheeled vehicles such as bicycles with prime movers, railways, bicycles for the elderly, and compact personal mobile bodies for one person. Furthermore, it is not necessarily limited to movement on land; it can also move in the air or water.

[0245] The laminate used for circuit board substrates can be a laminate having a copper foil layer, the aforementioned sheet, and a substrate layer. The substrate layer is not particularly limited, but preferably has a fabric layer made of glass fiber and a resin film layer.

[0246] The fabric layer composed of the aforementioned glass fibers is a layer made of glass cloth, glass nonwoven fabric, etc. Commercially available glass cloth can be used as the glass cloth; to improve its affinity with fluoropolymer, treatment with a silane coupling agent is preferred. Examples of glass cloth materials include E-glass, C-glass, A-glass, S-glass, D-glass, NE-glass, and low-dielectric-constant glass; E-glass, S-glass, and NE-glass are preferred for ease of acquisition. The fiber weave can be plain weave or twill weave. The thickness of the glass cloth is typically 5μm to 90μm, preferably 10μm to 75μm; a glass cloth thinner than the fluoropolymer film used is preferred.

[0247] The aforementioned laminate can use glass nonwoven fabric as the fabric layer composed of glass fibers. Glass nonwoven fabric is a substance formed by bonding short glass fibers together with a small amount of binder compound (resin or inorganic material), or a substance that maintains its shape by winding the short glass fibers without using a binder compound; commercially available products can be used. The diameter of the glass short fibers is preferably 0.5 μm to 30 μm, and the fiber length is preferably 5 mm to 30 mm. Specific examples of binder compounds include epoxy resin, acrylic resin, cellulose, polyvinyl alcohol, fluoropolymers, and inorganic materials such as silica compounds. The amount of binder compound used is typically 3% to 15% by mass relative to the glass short fibers. Examples of glass short fiber materials include E-glass, C-glass, A-glass, S-glass, D-glass, NE-glass, and low-dielectric-constant glass. The thickness of the glass nonwoven fabric is typically 50 μm to 1000 μm, preferably 100 μm to 900 μm. It should be noted that the thickness of the glass nonwoven fabric in this application refers to the value measured according to JIS P8118:1998 using a digital gauge DG-925 (110 g load, 10 mm surface diameter) manufactured by Ono Instrument Co., Ltd. To improve the affinity with fluoropolymers, the glass nonwoven fabric can be treated with a silane coupling agent.

[0248] Most glass nonwoven fabrics have a porosity of over 80%, which is very high. Therefore, it is preferable to use glass nonwoven fabrics that are thicker than those made of fluororesin and to compress them under pressure. The aforementioned fabric layer made of glass fibers can be in the form of a resin-impregnated prepreg.

[0249] The aforementioned fabric layer composed of glass fibers can be a layer formed by laminating glass cloth and glass nonwoven fabric. This allows for the combination of their respective properties, resulting in suitable properties.

[0250] In the above-mentioned laminate, the fabric layer and sheet made of glass fiber can be bonded at the interface, and the sheet can also be partially or completely impregnated into the fabric layer made of glass fiber.

[0251] Alternatively, the fluoropolymer composition can be impregnated into a fabric made of glass fiber to produce a prepreg. The resulting prepreg can then be further laminated with the fluoropolymer sheets disclosed herein. In this case, the fluoropolymer composition used in making the prepreg is not particularly limited, and the sheets disclosed herein can also be used.

[0252] As the resin film used as the substrate layer, a heat-resistant resin film or a thermosetting resin film is preferred. Examples of heat-resistant resin films include polyimide, modified polyimide, liquid crystal polymer, and polyphenylene sulfide. Examples of thermosetting resins include epoxy resin, bismaleimide, polyphenylene oxide, modified polyphenylene ether, polyphenylene ether, and polybutadiene.

[0253] Heat-resistant resin films and thermosetting resin films may contain reinforcing fibers. There are no particular limitations on the reinforcing fibers, but glass cloth, especially low dielectric constant type reinforcing fibers, is preferred.

[0254] The dielectric properties, coefficient of linear expansion, and water absorption rate of the heat-resistant resin film and thermosetting resin film are not particularly limited. For example, the dielectric constant at 20 GHz is preferably 3.8 or less, more preferably 3.4 or less, and even more preferably 3.0 or less. The dielectric loss tangent at 20 GHz is preferably 0.0030 or less, more preferably 0.0025 or less, and even more preferably 0.0020 or less. The coefficient of linear expansion is preferably 100 ppm / ℃ or less, more preferably 70 ppm / ℃ or less, even more preferably 40 ppm / ℃ or less, and most preferably 20 ppm / ℃ or less. The water absorption rate is preferably 1.0% or less, more preferably 0.5% or less, and even more preferably 0.1% or less.

[0255] When laminating a metal-clad laminate consisting of the aforementioned sheet and copper foil with a substrate layer such as a resin film, lamination can be achieved by bonding the sheet side of the metal-clad laminate to the substrate layer. In this case, a metal-clad laminate whose adhesive properties are improved by performing a surface treatment on the sheet side of the metal-clad laminate before lamination can also be used. No particular limitation is made to the surface treatment here; examples include the plasma treatment described above.

[0256] In the above-mentioned laminate, there is no particular limitation on the stacking order or manufacturing method of the copper foil layer, the substrate and the above-mentioned sheet, and it can be set as a layer configuration according to the purpose.

[0257] Specifically, examples of the aforementioned stacking order include a stacking order consisting of a substrate layer / sheet / copper foil layer, a stacking order consisting of a copper foil layer / sheet / substrate layer / sheet / copper foil layer, and a stacking order consisting of a copper foil layer / substrate layer / sheet / substrate layer / copper foil layer.

[0258] Additionally, other layers may be included as needed.

[0259] Example

[0260] The present disclosure will now be described in detail based on embodiments. In the following embodiments, unless otherwise stated, “parts” and “%” represent “parts by mass” and “% by mass”, respectively.

[0261] The spherical silica used in each embodiment and comparative example is described below.

[0262] Admatechs SC6500-SQ (Silica A: average particle size 2.1μm, dielectric loss tangent 0.00051)

[0263] The material obtained by treating Admatechs SC6500-SQ (average particle size 2.1 μm) with 3-aminopropyltriethoxysilane at a rate of 0.2% by weight relative to the silica particles (dielectric loss tangent 0.00058).

[0264] The material obtained by treating Admatechs SC6500-SQ (average particle size 2.1 μm) with 3-aminopropyltriethoxysilane at a rate of 1% by mass relative to the silica particles (dielectric loss tangent 0.00044).

[0265] Admatechs SC6500-SQ (average particle size 2.1 μm) was treated with 3-isocyanate propyltriethoxysilane at an amount of 0.2% by mass relative to the silica particles (dielectric loss tangent 0.00052).

[0266] The pulverized silica used in each embodiment and comparative example is described below.

[0267] Longsen Corporation's ZA-30 (Silica B: average particle size 5.6μm, dielectric loss tangent 0.00838)

[0268] The organosiloxanes used in each embodiment and comparative example are described below.

[0269] Shin-Etsu Chemical Co., Ltd. manufactures KF-96-50CS (polydimethyl silicone oil: abbreviated as PDMS).

[0270] Shin-Etsu Chemical Co., Ltd. manufactures X-22-162C (a substance of polydimethyl silicone oil with RCOOH groups at both ends).

[0271] Shin-Etsu Chemical Co., Ltd. manufactures KF-8012 (a substance whose ends of polydimethyl silicone oil are modified with RNH2 groups).

[0272] Shin-Etsu Chemical Co., Ltd. manufactures X-22-168B (a substance whose two ends of polydimethyl silicone oil are modified with carboxylic anhydride groups).

[0273] Shin-Etsu Chemical Co., Ltd. manufactures X-22-2445 (a substance whose ends of polydimethyl silicone oil are modified with acryloyl groups).

[0274] KF-868 (a substance in which the side chain of polydimethyl silicone oil is modified with RNH2 groups) manufactured by Shin-Etsu Chemical Co., Ltd.

[0275] KF-99 (a substance whose side chain of polydimethyl silicone oil is modified with hydrogen atoms) manufactured by Shin-Etsu Chemical Co., Ltd.

[0276] Shin-Etsu Chemical Co., Ltd. manufactures KF-50-100CS (a substance whose side chain of polydimethyl silicone oil is modified with phenyl groups).

[0277] Shin-Etsu Chemical Co., Ltd. manufactures X-22-822 (a substance in which the side chain of polydimethyl silicone oil is modified with C2H4CF3 groups).

[0278] The fluoropolymer particles (PTFE) used in each embodiment have the following properties.

[0279] Average particle size: 500 μm

[0280] Apparent density: 460g / L

[0281] Standard specific gravity: 2.17

[0282] (Powder Calendering)

[0283] Fluoropolymer granules (PTFE), silica, and organosiloxane were measured according to the proportions shown in Tables 1 and 2, and stirred twice for 30 seconds each time at room temperature using a Wonder crusher with memory 6. The resulting mixture was calendered using a twin-roll calender (roller gap: set to 100 μm, roll temperature: 100 °C) to obtain a sample with a film thickness of 125 μm, which was then calcined at 360 °C for 15 minutes to obtain a sheet.

[0284] (Paste extrusion molding)

[0285] The specified amounts of fluoropolymer granules (PTFE), silica, and organosiloxane were measured according to the proportions shown in Table 1 and mixed using a mixer in the presence of dry ice. The mixing temperature was below -10°C.

[0286] Add 18-23% oil (IP Solvent 2028) to the obtained mixed powder, mix, and mature for about 5 hours.

[0287] The cured composition was pre-formed under a pressure of 3 MPa. The pre-formed body was then extruded at 40°C and 50 mm / min to obtain an extruded sample. The extruded sample was calendered using two rollers to obtain a sample with a film thickness of 125 μm. The sample was dried at 200°C for 2 hours and then fired at 360°C for 15 minutes to obtain a sheet.

[0288] The samples obtained were evaluated based on the following criteria.

[0289] [Slice thickness]

[0290] The measurement was performed using a micrometer.

[0291] [Dielectric constant (Dk) and dielectric loss tangent (Df) of the wafer]

[0292] The relative permittivity and dielectric loss tangent were measured at 25°C and 10 GHz using a split cylindrical dielectric constant / dielectric loss tangent measuring device (manufactured by EM Labs).

[0293] [Constant Humidity Test]

[0294] Each sample was prepared in a constant temperature and humidity bath at 30°C and 90%RH, and the change in dielectric loss tangent was tracked after 24 hours.

[0295] The rate of increase is calculated using the following formula.

[0296] Rate of increase (%) = (Dielectric loss tangent after 24 hours - Dielectric loss tangent before constant humidity test) / Dielectric loss tangent before constant humidity test × 100

[0297] [Cyclic Elongation at Scale (CTE)]

[0298] TMA measurements were performed in tensile mode using a TMA-7100 (manufactured by Hitachi High-Tech Science). As a sample, a 20 mm long, 5 mm wide, and 150 μm thick sample was used. The chuck spacing was set to 10 mm. While applying a load of 49 mN, the coefficient of linear expansion was determined from the displacement of the sample at a heating rate of 2 °C / min from 0 to 150 °C.

[0299] The results are shown in Tables 1 and 2.

[0300] [The increase in the moisture content of the slices]

[0301] Each sample was prepared in a constant temperature and humidity bath maintained at 30°C and 90%RH and stored for one week. The samples before and after the above constant humidity test were chopped and put into the vaporization chamber of a moisture measuring device (Mitsubishi Chemical CA-200, VA-200) to analyze the moisture generated at 250°C.

[0302] The concentration of the tablet in Comparative Example 1 was 190 ppm before the constant humidity test and 280 ppm after the constant humidity test.

[0303] The pH of the sample in Example 1 was 240 ppm before the constant humidity test and 220 ppm after the constant humidity test.

[0304] In addition, there are 2 significant digits.

[0305] [The content of formaldehyde and other substances in the sheets contained in the metal-coated laminate]

[0306] The sample was cut into approximately 10 mm squares and sealed in a heating container. It was heated at 360°C in the presence of N2 gas for 30 minutes, and the generated gas was collected in an adsorption tube for thermal desorption GC / MS determination (Markes TD-100 and Agilent GC7890A+5875C). A standard curve was constructed using the absolute amounts of the standards and the obtained peak area values ​​for quantification.

[0307] The gas produced by the sheet in Example 5 was 220 μg / g, and contained cyclic siloxanes.

[0308] The gas produced by the sheet in Example 9 was 110 μg / g, and contained cyclic siloxanes.

[0309] [Water Absorption Test]

[0310] Perform the test according to IPC-TM-650 test method 2.6.2.1. Calculate the water absorption rate using the following formula.

[0311] [Formula 1]

[0312] The water absorption rate of the sheet in Example 1 was 0.021 wt%.

[0313] The water absorption rate of the tablet in Comparative Example 1 was 0.195 wt%.

[0314] The water absorption rate of the sheet in Example 5 was 0.022 wt%.

[0315] The water absorption rate of the sheet in Example 6 was 0.018 wt%.

[0316] [Surface hydrophobic tension test]

[0317] At room temperature, the tablets were immersed in the "wetting tension test solution" manufactured by Wako Pure Chemical Industries, Ltd. for 1 minute, then rinsed with distilled water. The presence or absence of the wetting tension test solution was visually assessed. Wetting tension test solutions No. 22.6 to 70.0 were used. The value of the test solution with the lowest surface tension among the wetting tension test solutions that showed no penetration was taken as the result of the critical hydrophobicity.

[0318] The critical hydrophobic tension of the sheet in Example 1 is 22.6 mN / M.

[0319] The critical hydrophobic tension of the sheet in Comparative Example 1 is 22.6 mN / M.

[0320] The sheets of Comparative Example 1 and Example 1 have the same surface hydrophobic tension, but the sheet of Comparative Example 1 is less absorbent. The compositions of this disclosure can also reduce the absorbency.

[0321] [Table 1]

[0322] [Table 2]

[0323] Based on the above results, the wafer disclosed herein exhibits superior performance in these respects, as water and moisture absorption are suppressed under high humidity, and the rise of the dielectric loss tangent is suppressed.

[0324] Industrial applicability

[0325] The wafer disclosed herein is particularly suitable for use as a circuit board, especially a high-frequency printed circuit board.

Claims

1. A composition comprising a fluoropolymer, inorganic particles, and an organosiloxane.

2. The composition according to claim 1, wherein, The inorganic particles are inorganic particles with silicon dioxide as an essential component.

3. The composition according to claim 1 or 2, wherein, The fluororesin is a perfluorinated fluororesin.

4. The composition according to claim 3, wherein, The perfluorinated fluoropolymer is polytetrafluoroethylene.

5. The composition according to any one of claims 2 to 4, wherein, The silicon dioxide is spherical silicon dioxide.

6. The composition according to any one of claims 2 to 4, wherein, The dielectric loss tangent of the silicon dioxide at 10 GHz is below 0.0025.

7. The composition according to any one of claims 1 to 4, wherein, The inorganic particles are inorganic particles coated with a silane coupling agent.

8. The composition according to any one of claims 1 to 4, wherein, The content of the inorganic particles is more than 40% by mass of the whole composition.

9. The composition according to any one of claims 1 to 4, wherein, The inorganic particles have an average particle size of 0.5 μm or more.

10. The composition according to any one of claims 1 to 9, wherein, The viscosity of the organosiloxane at 25°C is 3 mm. 2 / s~18000mm 2 / s.

11. The composition according to any one of claims 1 to 10, wherein, The content of the organosiloxane is less than 20% of the total mass of the composition.

12. The composition according to any one of claims 1 to 11, wherein, The organosiloxane is a modified organosiloxane.

13. The composition according to claim 12, wherein, The modified organosiloxane has at least one of the following in any one or all of its side chain, single end, and double end: hydrogen atom, amino group, ether group, epoxy group, mercapto group, carboxyl group, acryloyl group, methacryloyl group, carboxylic anhydride group, alkyl group, aralkyl group, fluoroalkyl group, perfluoroalkyl group, ester group, amide group, and phenyl group.

14. The composition according to claim 12, wherein, The modified organosiloxane has at least one of the following in any one or all of its side chain, single end, and double end: hydrogen atom, amino group, carboxyl group, acryloyl group, carboxylic anhydride group, alkyl group, fluoroalkyl group, perfluoroalkyl group, ester group, amide group, and phenyl group.

15. The composition according to claim 12, wherein, The modified organosiloxane has at least one of the following in any of its side chain, single end, and double end: selected from the group consisting of hydrogen atom, amino group, carboxyl group, acryloyl group, fluoroalkyl group, phenyl group, and carboxylic anhydride group.

16. The composition according to claim 1, wherein, The fluororesin is polytetrafluoroethylene. The inorganic particles are silicon dioxide. The content of the inorganic particles is 50% by mass or more and 70% by mass or less. The organosiloxane is at least one selected from the group consisting of dimethyl polysiloxane, methylhydropolysiloxane, methylphenyl polysiloxane, carboxyl-modified polysiloxane, amino-modified polysiloxane, acrylic acid-modified polysiloxane, carboxylic anhydride-modified polysiloxane, and fluoroalkyl-modified polysiloxane. The content of the organosiloxane is 0.05% by mass or more and 2% by mass or less.

17. A tablet comprising the composition of any one of claims 1 to 16.

18. The sheet according to claim 17, wherein, The moisture content increases by less than 60 ppm when stored for one week at 30°C and 90% RH.

19. The sheet according to claim 17 or 18, wherein, The rate of increase of dielectric loss tangent when stored at 30℃ and 90%RH for 24 hours is less than 30%.

20. The sheet according to any one of claims 17 to 19, wherein, The linear expansion rate, or CTE, is below 200 ppm / K.

21. A method for manufacturing a sheet, comprising the method for manufacturing a sheet according to any one of claims 17 to 20, characterized in that, A composition containing fluororesin particles, inorganic particles, and organosiloxanes is molded.

22. The method for manufacturing a sheet according to claim 21, wherein, Molding is performed using a composition substantially consisting of fluoropolymer particles, inorganic particles, and organosiloxanes.

23. A metal-clad laminate, wherein a metal layer and the sheet according to any one of claims 17 to 20 are necessary layers.

24. The metal-clad laminate according to claim 23, wherein, The sheet included in the metal-clad laminate contains at least one selected from the group consisting of formaldehyde, formic acid, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

25. The metal-clad laminate according to claim 23 or 24, wherein, The metal layer is copper foil.

26. A circuit board, characterized in that, The metal-coated laminate having any one of claims 23 to 25.

Images