WO2024204090A1 - Composite compound for low dielectric loss resin compositions, low dielectric loss resin composition, molded body for high frequency devices, and high frequency device - Google Patents

Abstract

Provided are: a novel composite compound for low dielectric loss resin compositions, the composite compound suppressing the loss coefficient in a high frequency band and having a good dielectric loss; a low dielectric loss resin composition; a molded body for high frequency devices; and a high frequency device. A composite compound for low dielectric loss resin compositions according to the present invention is for use in a low dielectric loss resin composition, and is characterized by containing a base material that is composed of an inorganic fluoride, and fluororesin particles that are held on at least a part of the surface of the base material. This composite compound for low dielectric loss resin compositions is also characterized in that the dielectric loss tangent of the fluororesin particles is 0.002 or less at a frequency of 1 GHz or more and a temperature of 25°C.

Description

Composite compound for low dielectric loss resin composition, low dielectric loss resin composition, molded body for high frequency device, and high frequency device

The present invention relates to a composite compound for a low dielectric loss resin composition that can be used in electronic components such as circuit boards and information and communication devices, a low dielectric loss resin composition, a molded article for high-frequency devices, and high-frequency devices.

In recent years, electronic components such as printed wiring boards, flexible circuit boards, and high-frequency boards, as well as information and communication devices, have been using increasingly higher frequencies for electrical signals in order to achieve high-speed, large-capacity data communication.

In particular, in electronic components for high frequency applications, the attenuation of electrical signals increases due to transmission loss in the transmission path as the frequency increases, and transmission reliability may decrease. Therefore, materials with small loss factors are required for high frequency devices and their components. Here, the loss factor is calculated by multiplying the square root of the relative dielectric constant ( _εr ) and the dielectric loss tangent (tan δ).

For example, Patent Document 1 discloses a thermosetting resin composition containing, as essential components, (A) a polyimide resin having a carboxyl group or an acid anhydride group and a linear hydrocarbon structure with a number average molecular weight of 300 to 6,000, (B) an epoxy resin, (C) an organic solvent with a boiling point of 100°C or higher, and spherical silica, with the aim of achieving a low relative dielectric constant and low dielectric dissipation factor in a multilayer printed circuit board. According to Patent Document 1, it is possible to form an interlayer insulating resin layer that has sufficient adhesion to a conductor and has high heat resistance, flame retardancy, low dielectric constant, low dielectric dissipation factor, and low water absorption.

Patent Document 2 also discloses an inorganic filler whose surface has been modified by sequentially introducing an alkyl group and an amine group, which has excellent compatibility and reactivity with epoxy resins. According to Patent Document 2, by producing an epoxy resin composition using this surface-modified inorganic filler such as silica, it is possible to impart the property of a low dielectric loss factor.

Patent Document 3 also discloses a surface-treated metal oxide particle material having a metal oxide particle material such as silica and a polyorganosiloxane compound that surface-treats the metal oxide particle material. According to Patent Document 3, by incorporating the surface-treated metal oxide particle material into a resin material, it is possible to suppress the viscosity of the resulting resin composition, and also to suppress the relative dielectric constant and dielectric tangent of the resin composition.

However, the resin compositions disclosed in Patent Documents 1 to 3 still have large relative dielectric constants and dielectric loss tangents in the high frequency band, so there is a demand for further reduction in dielectric loss.

Patent No. 5564012 JP 2015-67534 A JP 2020-66678 A

The present invention aims to provide a new composite compound for a low dielectric loss resin composition that reduces the relative dielectric constant and dielectric tangent in the high frequency band and is excellent at reducing dielectric loss, a low dielectric loss resin composition, a molded body for high frequency devices, and high frequency devices.

The composite compound for low dielectric loss resin compositions of the present invention is a composite compound for low dielectric loss resin compositions, which is characterized in that it contains a base material made of an inorganic fluoride and fluororesin particles held on at least a portion of the surface of the base material, and the dielectric tangent of the fluororesin particles is 0.002 or less at a frequency of 1 GHz or more and a temperature of 25°C.

In the above configuration, it is preferable that the fluororesin particles are held on the surface of the inorganic fluoride base material by thermal fusion.

In the above configuration, it is preferable that the fluororesin is polytetrafluoroethylene.

In the above-mentioned structure, the inorganic fluoride is preferably MFn (wherein M is at least one selected from the group consisting of Li, Na, K, Mg, Al, Ca, Sc, Mn, Fe, Ga, Rb, Sr, Y, Zr, Sn, Ba, La, Ce, Yb, Hf and Bi, and n is an integer of 1 to 4) or K ₂ SiF ₆ .

Furthermore, in the above-mentioned structure, it is preferable that the inorganic fluoride is _AlF3 .

In addition, in the above-mentioned configuration, it is preferable that the average particle diameter D50 of the base material made of the inorganic fluoride is 0.05 μm or more and 75 μm or less.

In addition, in the above-mentioned configuration, it is preferable that the content of the fluororesin particles is 0.5% by mass or more and less than 26% by mass with respect to the total mass of the base material made of the inorganic fluoride.

In order to solve the above problems, the low dielectric loss resin composition of the present invention is characterized by containing at least a polymer resin and a composite compound for the low dielectric loss resin composition.

In the above-mentioned composition, it is preferable that the content of the composite compound is 1% by mass or more and 85% by mass or less with respect to the total mass of the low dielectric loss resin composition.

In the above configuration, it is preferable that the polymer resin contains at least one type of thermoplastic resin and/or at least one type of thermosetting resin.

Furthermore, in the above-mentioned configuration, it is preferable that the polymer resin is at least one selected from the group consisting of olefin resins, styrene resins, polyvinyl resins, methacrylic resins, thermoplastic elastomer resins, thermoplastic polyurethane resins, polyacrylonitrile resins, polylactic acid resins, polyamide polyacetal resins, polycarbonate resins, polyphenylene ether resins, polyethylene terephthalate resins, polysulfone resins, polyether sulfone resins, polyphenylene sulfide resins, polyether ether ketone resins, liquid crystal polymer resins, polyimide resins, fluororesins, phenolic resins, amine resins, furan resins, unsaturated polyester resins, epoxy resins, diallyl phthalate resins, guanamine resins, ketone resins, silicone resins, thermosetting elastomer resins, natural rubber, synthetic rubber, and modified versions thereof.

In order to solve the above problems, the molded article for high-frequency devices of the present invention is a molded article for high-frequency devices used in a frequency band of 1 GHz or more, and is characterized in that it is made of a molded article containing the low dielectric loss resin composition.

In order to solve the above problems, the high-frequency device of the present invention is a high-frequency device used in a frequency band of 1 GHz or more, and is characterized by including the low dielectric loss resin composition.

In order to solve the above problems, the high-frequency device of the present invention is a high-frequency device used in a frequency band of 1 GHz or more, and is characterized by including the above-mentioned molded article for high-frequency devices.

According to the present invention, instead of conventional inorganic fillers such as silica, a composite compound in which fluororesin particles are held on at least a portion of the surface of an inorganic fluoride as a base material can be contained in a low dielectric loss resin composition. This allows the present invention to reduce the loss factor in the high frequency band and reduce dielectric loss. Furthermore, by using a low dielectric loss resin composition containing this composite compound in a molded body for high frequency devices or in high frequency devices, attenuation of electrical signals due to transmission loss can be suppressed even when used in the high frequency band of 1 GHz or more, enabling high speed, high frequency transmission.

FIG. 1(a) is an SEM image of Example 1 after mixing α-AlF ₃ and PTFE particles, and FIG. 1(b) is an SEM image of a composite compound in which PTFE particles are heat-fused to the surface of α-AlF ₃ . FIG. 2(a) is an SEM image of Example 2 after mixing α-AlF ₃ and PTFE particles, and FIG. 2(b) is an SEM image of a composite compound in which PTFE particles are thermally fused to the surface of α-AlF ₃ . FIG. 3(a) is an SEM image of Example 5 after mixing α-AlF ₃ and PTFE particles, and FIG. 3(b) is an SEM image of a composite compound in which PTFE particles are heat-fused to the surface of α-AlF ₃ . FIG. 4(a) is an SEM image of Example 6 after mixing _CaF2 and PTFE particles, and FIG. 4(b) is an SEM image of a composite compound in which PTFE particles are heat-fused to the surface of _CaF2 . FIG. 5(a) is an SEM image of Example 8 after mixing α-AlF ₃ and PTFE particles, and FIG. 5(b) is an SEM image of a composite compound in which PTFE particles are thermally fused to the surface of α-AlF ₃ . FIG. 6(a) is an SEM image of Comparative Example 4 after mixing silica and PTFE particles, and FIG. 6(b) is an SEM image of a composite of silica and PTFE particles. FIG. 7(a) is a reference photograph showing how the slurry composition falls smoothly, and FIG. 7(b) is a reference photograph showing how the slurry composition falls in a lump.

(Composite Compound for Low Dielectric Loss Resin Composition)
First, the composite compound for a low dielectric loss resin composition according to the present embodiment (hereinafter referred to as the "composite compound") will be described below.

The composite compound of this embodiment includes a base material (hereinafter sometimes referred to as "base material") made of an inorganic fluoride, and fluororesin particles (hereinafter sometimes referred to as "fluororesin particles") held on at least a part of the surface of the base material. In this specification, the term "held" on at least a part of the surface of the base material means that the fluororesin particles are held (fixed) by chemical bonding to the surface of the base material, as well as the fluororesin particles are thermally melted and physically held (fixed) on the surface of the base material. In this embodiment, the composite compound is preferably in a form in which the fluororesin particles are held on the surface of the base material by thermal fusion. In addition, in this specification, "thermal fusion" means that fluororesin particles, at least the surface of which is thermally melted by heating, come into contact with a base material made of an inorganic fluoride, and the fluororesin particles are fixed to the base material at the contact surface. The melting point of the fluororesin is usually lower than the melting point of the inorganic fluoride.

In the present invention, by holding fluororesin particles on the surface of a base material made of inorganic fluoride, it is possible to reduce the relative dielectric constant and dielectric loss tangent in the high frequency band and reduce the dielectric loss, compared to the case where only inorganic fluoride is contained in the low dielectric loss resin composition. In general, inorganic fluorides have a higher relative dielectric constant and dielectric loss tangent in the high frequency band than silica. Therefore, it is possible to hold fluororesin on the surface of silica as a base material. However, in that case, it was found that even if the relative dielectric constant value can be reduced, the dielectric loss tangent value cannot be reduced. It was also found that it is difficult to obtain a low dielectric loss resin composition that is uniformly dispersed in a polymer resin because of poor affinity with the polymer resin. Furthermore, it was found that when such a low dielectric loss resin composition is used as a material for electronic parts, for example, the silica is eluted when it comes into contact with an alkaline solution during alkaline etching, and the chemical resistance (alkali) is also poor.

In contrast, the present invention employs an inorganic fluoride from among many inorganic fillers as the base material, and further employs a fluororesin from among many polymer resins in combination as the polymer resin to be held on the surface of this base material. As a result, it has been found that the present invention can reduce the relative dielectric constant and dielectric tangent in the high frequency band compared to silica alone or when a fluororesin is held on the surface of the silica. It also has good affinity with polymer resins, making it possible to obtain a resin composition in which the composite compound is uniformly dispersed, and it has also been found to have excellent chemical resistance.

The upper limit of the dielectric constant ε _r0 [-] of the composite compound is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric constant ε _r0 of the composite compound is 6 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the dielectric loss tangent tan δ ₀ [-] of the composite compound is preferably 0.01 or less, more preferably 0.005 or less, further preferably 0.002 or less, and particularly preferably 0.001 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric loss tangent tan δ ₀ of the composite compound is 0.01 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the loss factor of the composite compound is preferably less than 6, more preferably 4 or less, and particularly preferably 3 or less. If the loss factor is less than 6, the loss factor of the composite compound can be reduced, and the dielectric loss can be reduced.

The values of the dielectric constant _εr0 and the dielectric tangent _tanδ0 used to quantify the dielectric properties and the dielectric loss are based on values obtained by measuring the composite compound. The measuring method can be appropriately selected. Specifically, for example, each of them can be measured by the method described in the examples below.

The loss factor can be calculated based on the following formula using the measured values of the relative dielectric constant ε _r0 and the dielectric tangent tan δ ₀ of the composite compound.
(Loss coefficient) = (ε _r0 ) ^1/2 × tan δ ₀ × 10 ³
(In the formula, ε _r0 [-] represents the relative dielectric constant of the composite compound obtained by measurement, and tan δ ₀ [-] represents the dielectric tangent thereof.)

The dielectric constant _εr0 is a parameter that indicates the degree of polarization of the composite compound obtained by measurement, and the higher the dielectric constant, the greater the delay in the propagation of the electric signal. Therefore, in order to increase the propagation speed of the signal, a lower dielectric constant is preferable. The dielectric loss tangent _tanδ0 is a parameter that indicates the amount of the signal that propagates through the inside of the composite compound, which is obtained by measurement, that is lost due to conversion to heat. Therefore, the lower the dielectric loss tangent, the less the signal loss and the improved signal transmission rate.

<Inorganic fluorides>
Next, the base material made of the inorganic fluoride of this embodiment will be described. The base material of this embodiment is preferably a powdered solid particle. The inorganic fluoride is preferably MFn (wherein M is at least one selected from the group consisting of Li, Na, K, Mg, Al, Ca, Sc, Mn, Fe, Ga, Rb, Sr, Y, Zr, Sn, Ba, La, Ce, Yb, Hf, and Bi, and n is an integer of 1 to 4) or K ₂ SiF ₆ (potassium silicofluoride). More specifically, examples of inorganic fluorides include LiF (lithium fluoride), NaF (sodium fluoride), KF (potassium fluoride), _MgF2 (magnesium fluoride), _AlF3 (aluminum fluoride), CaF2 (calcium fluoride), _ScF3 (scandium fluoride), _MnF2 (manganese fluoride), _FeF3 (iron fluoride), _GaF3 (gallium fluoride), _RbF (rubidium fluoride), _SrF2 (strontium fluoride), _YF3 (yttrium fluoride), _ZrF4 (zirconium fluoride), _SnF2 (tin fluoride), _BaF2 (barium fluoride), _LaF3 (lanthanum fluoride), _CeF3 (cerium fluoride), _YbF2 (ytterbium difluoride), YbF ₃ (ytterbium trifluoride), HfF ₄ (hafnium fluoride), and BiF ₃ (bismuth fluoride).

Among the inorganic fluorides given as examples, from the viewpoint of reducing the dielectric loss of the composite compound, aluminum fluoride, calcium fluoride and magnesium fluoride are preferred, with aluminum fluoride being more preferred. Furthermore, for aluminum fluoride, those containing crystalline aluminum fluoride having an α phase as the main component are preferred. Crystalline aluminum fluoride having an α phase exhibits excellent low dielectric loss characteristics in the high frequency band of 1 GHz or more. Therefore, by using a base material containing aluminum fluoride as the main component as a constituent material of a low dielectric loss resin composition, a remarkable effect of reducing the dielectric loss of the low dielectric loss resin composition is achieved.

The half-width of the peak on the (012) plane of the α phase in the X-ray diffraction pattern of aluminum fluoride is 0.3° or less, preferably 0.25° or less, and more preferably 0.2°. In general, as the average particle size of inorganic compound particles decreases, the proportion of the surface layer in the entire particle increases. Since the energy state of the particle surface is higher than that of the interior, the structural order is easily disturbed and the crystallinity decreases. Therefore, the physical and chemical properties derived from the bulk change from the original ones, and the dielectric tangent is likely to increase on the particle surface. Therefore, regardless of the average particle size of the inorganic compound, it is desirable for the crystallinity to be high. Here, the degree of crystallinity can be evaluated by the half-width of the X-ray diffraction peak of the (012) plane derived from aluminum fluoride in this embodiment. In general, the smaller the value of the half-width, the higher the crystallinity and the smaller the fluctuation of the crystal structure, and therefore the smaller the dielectric tangent. Therefore, in the case of aluminum fluoride, the crystallinity can be improved by reducing the half-width of the peak on the (012) plane in the X-ray diffraction pattern. From this perspective, in this embodiment, the upper limit of the half-width is set to 0.3° or less, which prevents the crystallinity of aluminum fluoride from becoming too high while also preventing an increase in the dielectric tangent, thereby reducing the loss factor and enabling a reduction in dielectric loss.

Furthermore, the lower limit of the half-width is preferably 0.12° or more, and more preferably 0.15° or more. By setting the lower limit of the half-width to 0.12° or more, when amorphous aluminum fluoride crystallizes or grows, it is possible to prevent the crystal grains from growing too large and the grain size of the crystal grains from becoming excessively large. This prevents the average particle diameter D50 of aluminum fluoride from becoming large, and suppresses the crystallinity of aluminum fluoride from becoming too high. As a result, when the composite compound of this embodiment is applied to a low dielectric loss resin composition and made into a film-like or sheet-like molded product, even when it is used in electronic components such as thin-layered printed wiring boards, flexible circuit boards, and high-frequency boards, it is possible to reduce or suppress the surface unevenness and prevent the deterioration of electrical properties. In addition, it is possible to manufacture a film-like or sheet-like molded product with a sufficiently suppressed film thickness.

In this specification, "half width" means full width at half maximum. Also, "X-ray diffraction pattern" refers to a plot line of diffraction intensity measured at each incidence angle in a two-dimensional graph with the incidence angle on the horizontal axis and the diffraction intensity on the vertical axis when a sample is measured by (powder) X-ray diffraction. "The (012) plane of the α phase in the X-ray diffraction pattern of aluminum fluoride" is the orientation plane of the aluminum fluoride crystals, and means the (012) plane of the α phase in the X-ray diffraction pattern. The peak of the diffraction intensity due to the (012) plane of the α phase of aluminum fluoride is located at a 2θ of approximately 25.3°.

The upper limit of the dielectric constant ε _r1 [−] of the inorganic fluoride particles is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric constant ε _r1 of the inorganic fluoride particles is 6 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the dielectric loss tangent tan δ ₁ [-] of the inorganic fluoride particles is preferably 0.008 or less, more preferably 0.005 or less, further preferably 0.002 or less, and particularly preferably 0.001 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric loss tangent tan δ ₁ of the inorganic fluoride particles is 0.008 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the loss factor of the inorganic fluoride particles is preferably less than 6, more preferably 4 or less, and even more preferably 3 or less. If the loss factor is less than 6, the loss factor of the low dielectric loss resin composition can be reduced, and the dielectric loss can be reduced.

The values of the relative dielectric constant _εr1 and the dielectric tangent _tanδ1 used to quantify the dielectric properties and the dielectric loss are based on values obtained by measuring inorganic fluoride particles made of powder. The measuring method can be appropriately selected. Specifically, for example, each of them can be measured by the method described in the examples below.

The loss factor can be calculated based on the following formula using the measured values of the relative dielectric constant ε _r1 and the dielectric tangent tan δ ₁ of the inorganic fluoride particles made of powder.
(Loss coefficient) = (ε _r1 ) ^1/2 × tan δ ₁ × 10 ³
(In the formula, ε _r1 [-] represents the relative dielectric constant of the inorganic fluoride particles made of powder obtained by measurement, and tan δ ₁ [-] represents the dielectric tangent thereof.)

The dielectric constant _εr1 is a parameter indicating the degree of polarization of the inorganic fluoride particles obtained by measurement, and the higher the dielectric constant, the greater the delay in the propagation of the electric signal. Therefore, in order to increase the propagation speed of the signal, a lower dielectric constant is preferable. The dielectric loss tangent _tanδ1 is a parameter indicating the amount of the signal propagating inside the inorganic fluoride particles that is lost due to conversion to heat, obtained by measurement. Therefore, the lower the dielectric loss tangent, the less the signal loss and the improved signal transmission rate.

The average particle diameter D50 of the inorganic fluoride particles (particle diameter at 50% of the cumulative particle size in the volume-based cumulative particle size distribution) is not particularly limited, and can be appropriately set according to, for example, the shape of the molded product containing the low dielectric loss resin composition, such as the size and thickness, and the adjustment of the fluidity of the material containing the inorganic fluoride particles in the preparation of the low dielectric loss resin composition. Usually, the upper limit of the average particle diameter D50 of the inorganic fluoride particles is preferably 75 μm or less, more preferably 50 μm or less, even more preferably 10 μm or less, and particularly preferably 1 μm or less. On the other hand, the lower limit of the average particle diameter D50 of the inorganic fluoride particles is preferably 0.05 μm or more, more preferably 0.075 μm or more, and even more preferably 0.1 μm or more. If the average particle diameter D50 of the inorganic fluoride particles is too large, it becomes difficult to make the surface of the molded product flat when applied to a film-like or sheet-like molded product. As a result, for example, when forming a laminate, the electrical properties of the laminate may be impaired due to the unevenness of the molded product surface. On the other hand, if the average particle diameter D50 of the inorganic fluoride particles is too small, it becomes difficult to mix the composite compound uniformly with the polymer resin, and the viscosity of the mixture may increase to such an extent that it becomes difficult to mold the low dielectric loss resin composition.

In addition, when the low dielectric loss resin composition of this embodiment is a film- or sheet-shaped molded product, the average particle diameter D50 of the inorganic fluoride particles is preferably set to 1/5 or less of the thickness of the molded product within the above numerical range, and more preferably set to 1/10 or less. For example, when the molded product of the low dielectric loss resin composition is a film or sheet-shaped product with a thickness of about 20 μm, the average particle diameter D50 of the inorganic fluoride particles is preferably 10 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less. This makes it possible to mold a film- or sheet-shaped molded product with the composite compound containing the inorganic fluoride particles aligned in a single layer. As a result, a molded product with reduced or prevented surface unevenness can be obtained. In addition, in a slurry composition before curing in which a composite compound containing inorganic fluoride particles is dispersed in a solvent, the precipitation of the composite compound can be suppressed, and a film- or sheet-shaped molded product in which the composite compound is uniformly filled can be obtained.

The average particle diameter D50 of inorganic fluoride particles is a value obtained by measurement using a laser diffraction/scattering method, for example, using a Microtrac MT3300EXII (product name: manufactured by Nikkiso Co., Ltd.).

The oxygen content of the inorganic fluoride particles is preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less, based on the total mass of the inorganic fluoride particles. The content of oxygen-atom-containing components (e.g., surface hydroxyl groups, adsorbed moisture, and oxides and oxyfluorides as impurities) contained in the inorganic fluoride particles can be reduced, and the influence on the dielectric properties can be suppressed. More specifically, by reducing the content of oxygen-atom-containing components as impurities, the crystallinity of the inorganic fluoride particles can be improved. In addition, by reducing the content of oxyfluorides as oxygen-atom-containing components, the insulating properties of the inorganic fluoride particles can be improved. Furthermore, by reducing hydroxyl groups and adsorbed moisture, which have high polarizability, as oxygen-atom-containing components, the deterioration of the dielectric properties can be suppressed.

The oxygen content of inorganic fluoride particles can be measured, for example, using an X-ray fluorescence analyzer (X-ray Fluorescence, product name: ZSX Primus II, manufactured by Rigaku Corporation).

The shape of the inorganic fluoride particles is not particularly limited, and may be appropriately selected, for example, taking into consideration the fluidity of the mixture when mixed with fluororesin particles in producing a composite compound, or the fluidity of the mixture when the composite compound is mixed with a polymer resin. In addition, the shape may be appropriately selected depending on the purpose, such as controlling the mechanical strength, thermal conductivity, and gas diffusivity of a molded product containing a low dielectric loss resin composition.

Specifically, the shape of the inorganic fluoride particles may be any shape, such as spherical, approximately spherical, elliptical, rod-like, needle-like, spindle-like, plate-like, etc. The inorganic fluoride particles may have any of these shapes and may be hollow with an internal space. Furthermore, the inorganic fluoride particles of this embodiment may contain inorganic fluoride particles of the same type of shape, or may contain inorganic fluoride particles of two or more different shapes.

In addition, in the inorganic fluoride particles of this embodiment, for example, the mass reduction after heat treatment at 400°C or more is preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less, based on the mass of the inorganic fluoride particles before heat treatment. By using inorganic fluoride particles with a mass reduction of 2% by mass or less after the heat treatment, it is possible to prevent the low dielectric loss characteristics and mechanical strength of the low dielectric loss resin composition from being reduced due to heat generation during polymerization of the monomers that form the polymer resin, degassing of impurities during heat treatment, and thermal decomposition of the main component of the polymer resin. In the inorganic fluoride particles, the method for reducing the mass reduction after the heat treatment to 2% by mass or less is not particularly limited. For example, a method of removing or reducing materials with high thermal decomposition temperatures contained in the inorganic fluoride particles, materials that do not undergo a phase change when heated, and impurities that cause mass reduction during the synthesis of the inorganic fluoride particles by performing heat treatment or chemical treatment in advance can be mentioned.

<Fluororesin Particles>
The fluororesin particles of this embodiment may be held on at least a part of the base material surface. In the case where the fluororesin particles are held on a part of the base material surface, the Lewis acid sites are exposed on the base material surface where the fluororesin particles are not held. In general, fluororesins do not have good compatibility with polymer resins, but by preventing a part of the base material surface from being covered with fluororesin particles, the affinity of the composite compound to the polymer resin (details will be described later) in the low dielectric loss resin composition is well maintained, and the dispersibility in the polymer resin is prevented from decreasing. On the other hand, in the case where the amount of fluororesin particles held is large, for example, when the fluororesin particles are held on the entire surface of the base material, the dielectric loss can be further reduced.

The fluororesin particles are not particularly limited, and examples include those made of polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluorovinyl ether copolymer (PFA), and tetrafluoroethylene hexafluoropropylene copolymer (FEP). Of these fluororesins, PTFE is preferred from the viewpoint of reducing dielectric loss.

The average particle diameter d50 of the fluororesin particles (particle diameter at 50% of the cumulative particle size in the volume-based cumulative particle size distribution) is preferably in the range of 1/10 to 1/2 of the average particle diameter D50 of the inorganic fluoride particles. By making the average particle diameter d50 of the fluororesin particles 1/10 or more of the average particle diameter D50 of the inorganic fluoride particles, the base material can be entirely covered. On the other hand, by making the average particle diameter d50 of the fluororesin particles 1/2 or less of the average particle diameter D50 of the inorganic fluoride particles, self-fusion can be prevented.

The average particle diameter d50 of the fluororesin particles is a value obtained by measurement using a laser diffraction/scattering method, for example, using a Microtrac MT3300EXII (product name: manufactured by Nikkiso Co., Ltd.).

The shape of the fluororesin particles before they are held in the base material is not particularly limited, and any shape can be used, such as spherical, approximately spherical, elliptical, rod-shaped, needle-shaped, spindle-shaped, plate-shaped, etc. Furthermore, the particles may contain fluororesin particles of the same shape, or may contain fluororesin particles of two or more different shapes.

The content of the fluororesin particles is preferably in the range of 0.5% by mass or more and less than 26% by mass, more preferably in the range of 1% by mass or more and less than 25% by mass, even more preferably in the range of 1% by mass or more and less than 15% by mass, and particularly preferably in the range of 1% by mass or more and less than 10% by mass. By making the content of the fluororesin particles 0.5% by mass or more, it is possible to maintain the good low dielectric loss characteristics of the composite compound. On the other hand, by making the content of the fluororesin particles less than 26% by mass, it is possible to maintain the affinity of the composite compound to the polymer resin well and to suppress a decrease in dispersibility in the polymer resin.

The upper limit of the relative dielectric constant ε _r2 [-] of the fluororesin particles is preferably 3.5 or less, more preferably 3.0 or less, and even more preferably 2.9 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the relative dielectric constant ε _r2 of the fluororesin particles is 3.5 or less, the loss factor of the composite compound and the low dielectric loss resin composition containing the composite compound can be reduced, and the dielectric loss can be reduced.

The fluororesin particles used have a dielectric loss tangent tan δ ₂ [-] of 0.002 or less, preferably 0.001 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric loss tangent tan δ ₂ of the fluororesin particles is 0.002 or less, the dielectric loss tangent of the composite compound and the low dielectric loss resin composition containing the composite compound can be reduced, thereby further reducing the dielectric loss.

The upper limit of the loss factor of the fluororesin particles is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less. If the loss factor is 6 or less, the loss factor of the composite compound and the low dielectric loss resin composition can be reduced, and the dielectric loss can be further reduced.

The values of the relative dielectric constant _εr2 and the dielectric tangent _tanδ2 used to quantify the dielectric properties and dielectric loss are based on values obtained by measuring the fluororesin particles. The measurement method can be appropriately selected. Specifically, for example, each of them can be measured by the method described in the examples below.

The loss factor can be calculated based on the following formula using the measured values of the relative dielectric constant ε _r2 and the dielectric tangent tan δ ₂ of the fluororesin particles.
(Loss coefficient) = (ε _r2 ) ^1/2 × tan δ ₂ × 10 ³
(In the formula, ε _r2 [-] represents the relative dielectric constant of the fluororesin particles obtained by measurement, and tan δ ₂ [-] represents the dielectric tangent.)

The dielectric constant _εr2 is a parameter that indicates the degree of polarization of the fluororesin particles obtained by measurement, and the higher the dielectric constant, the greater the delay in the propagation of the electric signal. Therefore, in order to increase the signal propagation speed, a lower dielectric constant is preferable. The dielectric loss tangent _tanδ2 is a parameter that indicates the amount of a signal that propagates inside the fluororesin particles, obtained by measurement, that is lost due to conversion to heat. Therefore, the lower the dielectric loss tangent, the less the signal loss and the improved signal transmission rate.

<Method of producing a composite compound>
Next, a method for producing the composite compound will be described below.
The method for producing the composite compound of the present embodiment is not particularly limited, and a known method can be adopted. For example, when producing a composite compound in which fluororesin particles are thermally fused to the surface of a base material, the method includes at least a mixing step of mixing fluororesin particles and an inorganic fluoride base material, a heating step of heating the mixture of fluororesin particles and an inorganic fluoride base material, and a cooling step of cooling the mixture after heating (composite treatment).

The heating method in the heating step is not particularly limited, and any known method can be used. The heating temperature is not particularly limited as long as it is equal to or higher than the melting point and lower than the boiling point of the fluororesin particles, and can be set appropriately depending on the type of fluororesin, etc. The heating time is also not particularly limited, and can be set appropriately depending on the heating temperature and the type of material of the fluororesin particles, etc. The cooling method in the cooling step is not particularly limited, and can be performed by, for example, natural cooling or rapid cooling.

＜Other＞
The surface of the inorganic fluoride base material of this embodiment may be chemically modified by introducing functional groups such as hydroxyl groups, epoxy groups, carboxyl groups, carbonyl groups, amino groups, perfluoroalkane groups, ether groups, and ester groups, within the scope of not impairing the effects of the present invention. The surface of the fluororesin particles of this embodiment may also be chemically modified by introducing functional groups such as hydroxyl groups, epoxy groups, carboxyl groups, carbonyl groups, amino groups, perfluoroalkane groups, ether groups, and ester groups, within the scope of not impairing the effects of the present invention.

In the present embodiment, the inorganic fluoride and fluororesin particles can be any combination of the materials exemplified above, but it is preferable to use fluororesin particles that have at least one value smaller than that of the inorganic fluoride, among the relative dielectric constant, dielectric tangent, and loss factor. This makes it possible to further reduce the dielectric loss compared to the case where only inorganic filler consisting of inorganic fluoride particles is used in the low dielectric loss resin composition.

(Slurry Composition for Low Dielectric Loss Resin Composition)
Next, the slurry composition for the low dielectric loss resin composition of this embodiment (hereinafter referred to as "slurry composition") will be described below.

The slurry composition of this embodiment contains at least the above-mentioned complex compound and a solvent. The slurry composition is a dispersion in which the complex compound is dispersed (including floating and suspended) in a solvent. In this specification, the term "dispersion" refers to a state in which the complex compound is dispersed as a dispersoid in a solvent that is a dispersion medium. However, the term "dispersion" does not include a solid colloid (organogel) in which a dispersoid is dispersed in a solid dispersion medium and fluidity is lost.

The lower limit of the content of the complex compound is preferably 1 mass% or more, more preferably 10 mass% or more, and even more preferably 20 mass% or more, based on the total mass of the slurry composition. On the other hand, the upper limit of the content of the complex compound is preferably 85 mass% or less, more preferably 82 mass% or less, and even more preferably 79 mass% or less, based on the total mass of the slurry composition. When the lower limit of the content of the complex compound is 1 mass% or more, the loss coefficient of the slurry composition is reduced, and the dielectric loss is reduced.

Straight-chain alkanes are preferred as the solvent, and straight-chain alkanes having 10 or more carbon atoms and 16 or less carbon atoms are more preferred. More specifically, straight-chain alkanes include n-decane, n-tetradecane, and n-hexadecane. These solvents can be used alone or in combination of two or more. Among these straight-chain alkanes, n-hexadecane is particularly preferred because it can exist as a liquid at room temperature (for example, 5°C to 35°C), has low polarity among straight-chain alkanes, and is difficult to dissolve in water due to its low polarity. In addition, since the boiling point is high, it is possible to suppress the concentration from changing due to volatilization, as in the case of hexane, which has a low boiling point. On the other hand, straight-chain alkanes having 16 or less carbon atoms can suppress the melting point to 20°C or less, and therefore prevent the deterioration of handleability due to their existence as a solid at room temperature. Here, when a range of carbon numbers is expressed in this specification, the range means that all integer carbon numbers included in the range are included. Therefore, for example, a linear alkane having "10 to 16 carbon atoms" means all linear alkanes having 10, 11, 12, 13, 14, 15, and 16 carbon atoms.

The lower limit of the solvent content is preferably 1 mass% or more, more preferably 5 mass% or more, and even more preferably 15 mass% or more, based on the total mass of the slurry composition. On the other hand, the upper limit of the solvent content is preferably 99 mass% or less, more preferably 90 mass% or less, and even more preferably 80 mass% or less, based on the total mass of the slurry composition.

The upper limit of the dielectric constant ε _r3 [-] of the slurry composition is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric constant ε _r3 of the slurry composition is 6 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the dielectric loss tangent tan δ ₃ [-] of the slurry composition is preferably 0.005 or less, more preferably 0.002 or less, and particularly preferably 0.001 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric loss tangent tan δ ₃ of the slurry composition is 0.005 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the loss factor of the slurry composition is preferably less than 6, more preferably 4 or less, and even more preferably 3 or less. If the loss factor is less than 6, the loss factor of the slurry composition can be reduced, and the dielectric loss can be reduced.

The values of the relative dielectric constant _εr3 and the dielectric tangent _tanδ3 used to quantify the dielectric properties and the dielectric loss are based on the values obtained by measuring the slurry composition. The measurement method can be appropriately selected. Specifically, for example, each of them can be measured by the method described in the examples below.

The loss factor can be calculated based on the following formula using the measured values of the relative dielectric constant _εr3 and the dielectric tangent tan _δ3 of the slurry composition.
(Loss coefficient) = (ε _r3 ) ^1/2 × tan δ ₃ × 10 ³
(In the formula, ε _r3 [-] represents the relative dielectric constant of the slurry composition obtained by measurement, and tan δ ₃ [-] represents the dielectric tangent thereof.)

The dielectric constant _εr3 is a parameter indicating the degree of polarization of the slurry composition obtained by measurement, and the higher the dielectric constant, the greater the delay in the propagation of the electric signal. Therefore, in order to increase the signal propagation speed, a lower dielectric constant is preferable. The dielectric loss tangent _tanδ3 is a parameter indicating the amount of the signal propagating inside the slurry composition, which is obtained by measurement, that is lost due to conversion to heat. Therefore, the lower the dielectric loss tangent, the less the signal loss and the improved signal transmission rate.

Furthermore, the slurry composition of this embodiment can contain other additives to the extent that it does not contradict the object of the present invention. The other additives are not particularly limited, and examples thereof include ultraviolet protection agents, colorants, flame retardants, stabilizers, and dispersants. Furthermore, the content of the other additives is not particularly limited, and can be set appropriately depending on the application, purpose, etc.

The method for producing the slurry composition of this embodiment is not particularly limited, and the slurry composition of this embodiment can be produced by adding a predetermined amount of a complex compound to a solvent and stirring for a predetermined period of time.

(Low dielectric loss resin composition)
Next, the low dielectric loss resin composition of the present embodiment will be described below.
The low dielectric loss resin composition of the present embodiment contains at least the above-mentioned composite compound and a polymer resin.

The lower limit of the content of the complex compound is preferably 1 mass% or more, more preferably 10 mass% or more, and even more preferably 20 mass% or more, based on the total mass of the low dielectric loss resin composition. On the other hand, the upper limit of the content of the complex compound is preferably 85 mass% or less, more preferably 82 mass% or less, and even more preferably 79 mass% or less, based on the total mass of the low dielectric loss resin composition. When the lower limit of the content of the complex compound is 1 mass% or more, the loss coefficient of the low dielectric loss resin composition becomes small, and the dielectric loss is reduced. On the other hand, when the upper limit of the content of the complex compound is 85 mass% or less, deterioration of physical strength such as brittleness can be prevented, and it is possible to improve hardness, reduce the thermal expansion coefficient, and improve weather resistance.

The polymer resin preferably contains at least one type of thermoplastic resin and/or at least one type of thermosetting resin.

More specifically, the polymer resins include, for example, olefin-based resins such as polyethylene resin and polypropylene resin; styrene-based resins such as polystyrene resin and acrylonitrile butadiene styrene resin (ABS resin); polyvinyl resins such as polyvinyl acetate resin, polyvinyl chloride resin, polyvinyl alcohol resin and polyvinylidene chloride resin; methacrylic resin; thermoplastic elastomer resin; thermoplastic polyurethane resin; polyacrylonitrile resin; polylactic acid resin; polyamide polyacetal resin; polycarbonate resin; polyphenylene ether resin; polyethylene terephthalate resin; polysulfone resin; polyether sulfone resin; polyphenylene sulfide resin; polyether ether ketone resin; liquid crystal polymer resin; polyimide resin. Examples of the polymer resin include fluororesins such as polytetrafluoroethylene resin (PTFE), copolymers of polytetrafluoroethylene and perfluoroalkoxyethylene (PFA), polychlorotrifluoroethylene resin (PCTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and tetrafluoroethylene-ethylene copolymer (ETFE); phenol resins; amine resins such as urea resins and melamine resins; furan resins; unsaturated polyester resins; epoxy resins; diallyl phthalate resins; guanamine resins; ketone resins; silicone resins; thermosetting elastomer resins; natural rubbers; synthetic rubbers such as neoprene rubber, styrene butadiene rubber, isoprene rubber, butyl rubber and urethane rubber; and modified versions thereof. These polymer resins can be used alone or in combination of two or more types depending on the processability and application of the low dielectric loss resin composition. For example, when using a polymer resin in which an epoxy resin is mixed with a polyphenylene ether resin, the processability can be improved by increasing the fluidity. The degree of polymerization of the polymer resin is not particularly limited and can be selected appropriately depending on the application of the low dielectric loss resin composition.

The polymer resin content is preferably 15% by mass or more and 99% by mass or less, more preferably 18% by mass or more and 90% by mass or less, and even more preferably 21% by mass or more and 80% by mass or less, based on the total mass of the low dielectric loss resin composition. By making the polymer resin content 15% by mass or more, the properties of the polymer resin, such as adhesion and water resistance, can be fully expressed. On the other hand, by making the polymer resin content 99% by mass or less, the dielectric loss of the resin composition can be reduced by adding a composite compound while maintaining the properties of the polymer resin.

The upper limit of the dielectric constant ε _r4 [-] of the low dielectric loss resin composition is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric constant ε _r4 of the low dielectric loss resin composition is 6 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the dielectric loss tangent tan δ ₄ [-] of the low dielectric loss resin composition is preferably 0.02 or less, more preferably 0.005 or less, even more preferably 0.002 or less, and particularly preferably 0.001 or less, at a frequency of 1 GHz or more and a temperature of 25° C. When the dielectric loss tangent tan δ ₄ of the low dielectric loss resin composition is 0.02 or less, the loss factor can be reduced, and the dielectric loss can be reduced.

The upper limit of the loss factor of the low dielectric loss resin composition is preferably less than 6, more preferably 4 or less, and particularly preferably 3 or less. If the loss factor is less than 6, the loss factor of the low dielectric loss resin composition can be reduced, and the dielectric loss can be reduced.

The values of the relative dielectric constant _εr4 and the dielectric tangent _tanδ4 used to quantify the dielectric properties and dielectric loss are based on the values obtained by measuring the low dielectric loss resin composition. The measurement method can be appropriately selected. Specifically, for example, each of them can be measured by the method described in the examples below.

The loss factor can be calculated based on the following formula using the measured values of the relative dielectric constant _εr4 and the dielectric tangent _tanδ4 of the low dielectric loss resin composition.
(Loss coefficient) = (ε _r4 ) ^1/2 × tan δ ₄ × 10 ³
(In the formula, ε _r4 [-] represents the relative dielectric constant of the low dielectric loss resin composition obtained by measurement, and tan δ ₄ [-] represents the dielectric tangent thereof.)

The relative dielectric constant ε _r4 is a parameter that indicates the degree of polarization of the low dielectric loss resin composition obtained by measurement, and the higher the relative dielectric constant, the greater the propagation delay of the electric signal. Therefore, in order to increase the propagation speed of the signal, a lower relative dielectric constant is preferable. The dielectric loss tangent tanδ ₄ is a parameter that indicates the amount of the signal propagating inside the low dielectric loss resin composition that is lost due to conversion to heat, obtained by measurement. Therefore, the lower the dielectric loss tangent, the less the signal loss and the improved signal transmission rate.

Next, a method for producing the low dielectric loss resin composition according to the present embodiment will be described below.
The low dielectric loss resin composition of the present embodiment can be produced by adding the composite compound and any other additives to a polymer resin and uniformly mixing or kneading them. Alternatively, the low dielectric loss resin composition can be produced by adding and dispersing the composite compound and any other additives to a solution (e.g., varnish or dispersion liquid) in which the polymer resin or a monomer that forms the polymer resin is dissolved or dispersed in an organic solvent.

The low dielectric loss resin composition of this embodiment may contain impurities to the extent that it does not contradict the object of the present invention. Examples of such impurities include metal impurities containing elements other than those constituting the inorganic fluoride, and metal oxides. The content of the impurities is preferably 100 ppm or less, more preferably 10 ppm or less, based on the total mass of the low dielectric loss resin composition.

Furthermore, the low dielectric loss resin composition of this embodiment can contain other additives to the extent that it does not contradict the object of the present invention. The other additives are not particularly limited, and examples thereof include hardeners, lubricants, crystal nucleating agents, ultraviolet protection agents, colorants, flame retardants, stabilizers, plasticizers, reinforcing agents, and dispersants. The content of the other additives is not particularly limited, and can be set appropriately depending on the application, purpose, etc.

The low dielectric loss resin composition of this embodiment can be used as a resin composition for insulating films (solder resist), a resin composition for semiconductor encapsulation, an adhesive, a paint, a coating material for wiring for power supplies and communications, etc.

(Molded body for high-frequency device and its manufacturing method)
The molded article for high-frequency devices (hereinafter referred to as "molded article") of this embodiment is made of a molded article containing a low dielectric loss resin composition.

The molded body can be manufactured, for example, by using a known kneader and extruder. As the kneader, for example, an enclosed pressure kneader or an open roll can be used. After a sheet-shaped low dielectric loss resin composition material is manufactured using these kneaders, the molded body can be manufactured using the low dielectric loss resin composition material. Also, after a pellet-shaped low dielectric loss resin composition material is manufactured using an extruder, a molded body can be manufactured using an injection molding machine. When the polymer resin is mixed with the composite compound and other additives using a molding machine such as an extruder, the number of steps can be reduced, and production efficiency can be improved. Also, the composite compound may be appropriately dried before being mixed with the polymer resin.

In addition, when manufacturing a sheet-shaped molded product, it can be manufactured by a known method. For example, a complex compound and any other additives are added to a varnish tank filled with a solution containing a polymer resin (resin varnish) and uniformly dispersed, and the dispersion is heated under specified temperature conditions. The cured product produced by heating is stretched into a sheet, thereby manufacturing a sheet-shaped molded product.

Also, a sheet-like substrate such as a glass cloth or a bonding sheet is passed through a tank of a dispersion liquid containing a polymer resin, a composite compound, and any other additives while immersed in the dispersion liquid, thereby impregnating the sheet-like substrate with the dispersion liquid. The sheet impregnated with the dispersion liquid is then dried to produce an impregnated sheet impregnated with the low dielectric loss resin composition. It is also possible to produce a laminate in which multiple layers of the low dielectric loss resin composition are laminated by passing the sheet-like substrate through the tank of the dispersion liquid multiple times.

(High frequency equipment)
The high-frequency device according to the present embodiment includes a low dielectric loss resin composition or includes a molded article of a low dielectric loss resin composition.

The high-frequency device of this embodiment is used for information processing and information communication that are performed by electronically exchanging signals. In particular, the high-frequency device of this embodiment is used in high-frequency bands where the frequency band of radio waves and signals used during communication is 1 GHz or higher, and more preferably 10 GHz or higher. The high-frequency device of this embodiment also includes high-frequency electronic components used in such high-frequency bands.

Examples of high-frequency devices include housings for information processing and information communication devices, circuit boards, printed wiring boards, transmission lines, high-frequency electronic components such as capacitors and inductors, and ceiling and wall materials for rooms in which high-frequency devices are installed. In addition, high-frequency devices equipped with insulating films and semiconductor sealing resins formed from a low dielectric loss resin composition, and wiring coated with a low dielectric loss resin composition as a coating material, are also included in the high-frequency devices of this embodiment.

Below, preferred embodiments of the present invention are described in detail as examples. However, the materials and compounding amounts described in these embodiments are not intended to limit the scope of the present invention unless otherwise specified.

Example 1
<Inorganic fluorides>
First, α-AlF ₃ (manufactured by Stella Chemifa Co., Ltd.) was prepared as an inorganic fluoride, and the half-width of the peak on the (012) plane in the X-ray diffraction pattern of this powdered α-AlF ₃ was measured. For the measurement, an X-ray diffractometer (product name: RINT-ULTIMA, manufactured by Rigaku Co., Ltd.) was used. The measurement conditions were as follows:
・X-ray tube: Cu
Tube voltage: 40 kV
Tube current: 40mA
・Step size (width): 0.02°
Measurement range (scanning range of diffraction angle): 2θ = 10° to 70°

The half-width was calculated from the diffraction intensity peak corresponding to the (012) plane of α-AlF ₃ appearing near 2θ=25.3°, and the half-width of α-AlF ₃ was found to be 0.17°.

Next, the average particle diameter D50 of α-AlF ₃ was measured. First, 0.1 to 0.3 g of powdered α-AlF ₃ was added to 200 mL of circulating solvent (water) flowing in a particle size distribution measuring device (product name: Microtrac MT3300EXII, manufactured by Nikkiso Co., Ltd.). This produced an aqueous dispersion in which the concentration of α-AlF ₃ was in the range of 0.05 to 0.15 mass% relative to the total mass, and this aqueous dispersion was measured by a laser diffraction/scattering method. In the obtained particle size distribution, the average particle diameter at which the cumulative volume was 50% was calculated as D50. As a result, the average particle diameter D50 of α-AlF ₃ was 2 μm.

Next, the powder of α-AlF ₃ was filled into a quartz tube, and the relative dielectric constant and dielectric loss tangent were measured by a cavity resonator method in the 10 GHz frequency range under an environmental atmosphere with a temperature of 25°C and a relative humidity of 40%. A vector network analyzer (manufactured by Anritsu Co., Ltd., product name: MS46122B) was used for the measurement. Then, the measured values of the relative dielectric constant and dielectric loss tangent of the quartz tube filled with α-AlF ₃ were corrected for voids using the bulk density and true density of α-AlF ₃ and the amount of α-AlF ₃ filled relative to the filling volume, and the relative dielectric constant ε _r1 [-] and dielectric loss tangent tanδ ₁ [-] of α-AlF ₃ were calculated. As a result, the relative dielectric constant ε _r1 was 3.2 [-] and the dielectric loss tangent tanδ ₁ was 0.0027 [-].

<Fluororesin Particles>
As the fluororesin particles, PTFE particles having an average particle diameter d50 in the range of 200 nm to 500 nm, a relative dielectric constant ε _r2 of 3.0 [-] or less, and a dielectric loss tangent tan δ ₂ of 0.002 [-] or less were used.

<Preparation of Complex Compounds>
After mixing 99 parts by mass of α-AlF ₃ and 1 part by mass of PTFE particles, the mixture was heated at a temperature equal to or higher than the melting point of the PTFE particles so that the PTFE particles were thermally fused to the surface of the α-AlF _3. After that, the mixture was cooled to room temperature to prepare the composite compound according to this embodiment.

Example 2
In this embodiment, the content of α- _AlF3 was changed to 90 parts by mass, and the content of PTFE particles was changed to 10 parts by mass.Other than that, the composite compound according to this embodiment was prepared in the same manner as in embodiment 1.

(Comparative Example 1)
In this comparative example, 100 parts by mass of an inorganic filler made of α- _AlF3 was used in place of the composite compound.

Example 3
In this example, α-AlF ₃ having an average particle diameter D50 of 2 μm was changed to α-AlF ₃ having an average particle diameter D50 of 10 μm. Otherwise, the composite compound according to this example was produced in the same manner as in Example 1.

Example 4
In this example, the α-AlF ₃ having an average particle diameter D50 of 2 μm was changed to α-AlF ₃ having an average particle diameter D50 of 10 μm. Otherwise, the composite compound according to this example was produced in the same manner as in Example 2.

Example 5
In this embodiment, the content of α- _AlF3 is changed to 80 parts by mass, and the content of PTFE particles is changed to 20 parts by mass.Other than that, the composite compound according to this embodiment is prepared in the same manner as in embodiment 3.

Example 6
In this embodiment, 95 parts by mass of CaF ₂ (manufactured by Stella Chemifa Co., Ltd.) with an average particle diameter D50 of 40 μm was used instead of α-AlF _3. Also, the content of PTFE particles was changed to 5 parts by mass. Other than that, the composite compound according to this embodiment was produced in the same manner as in Example 1.

(Example 7)
In this example, 95 parts by mass of K ₂ SiF ₆ (manufactured by Stella Chemifa Co., Ltd.) having an average particle diameter D50 of 3 μm was used instead of α-AlF _3. The content of the PTFE particles was changed to 5 parts by mass. Other than these, the composite compound according to this example was produced in the same manner as in Example 1.

(Comparative Example 2)
In this comparative example, 100 parts by mass of an inorganic filler made of α-AlF ₃ having an average particle size D50 of 10 μm was used in place of the composite compound.

(Comparative Example 3)
In this comparative example, 100 parts by mass of an inorganic filler made of silica having an average particle size D50 of 1 μm was used in place of the composite compound.

(Comparative Example 4)
In this comparative example, 95 parts by mass of silica having an average particle size D50 of 1 μm was used instead of α-AlF _3. Also, the content of PTFE particles was changed to 5 parts by mass. Other than that, the composite according to this comparative example was produced in the same manner as in Example 1.

(Comparative Example 5)
In this comparative example, 100 parts by mass of an inorganic filler made of _CaF2 having an average particle diameter D50 of 40 μm was used in place of the composite compound.

(Comparative Example 6)
In this comparative example, 100 parts by mass of an inorganic filler made of K ₂ SiF ₆ having an average particle size D50 of 3 μm was used in place of the composite compound.

(Example 8)
In this embodiment, the content of α- _AlF3 was changed to 95 parts by mass, and the content of PTFE particles was changed to 5 parts by mass.Other than that, the composite compound according to this embodiment was prepared in the same manner as in Example 1.

(SEM image)
SEM images were taken using an electron microscope (product name: SU1510, manufactured by Hitachi High-Technologies Corporation) for the composite compounds according to Examples 1, 2, 5, 6, and 8, and the composite according to Comparative Example 4. The respective SEM images are shown in Figs.

As can be seen from Figures 1 to 3 and Figure 5, in Examples 1, 2, 5 and 8, it was confirmed that a composite compound in which PTFE particles are heat-fused to a part of the surface of α-AlF ₃ was obtained by performing a composite treatment on a mixture of α-AlF ₃ and PTFE particles. Also, as can be seen from Figure 4, it was confirmed that a composite compound in which PTFE particles are heat-fused to a part of the surface of CaF ₂ was obtained by performing a composite treatment on a mixture of CaF ₂ and PTFE particles in Example 6. On the other hand, in Comparative Example 4, as can be seen from Figure 6, it was confirmed that a composite compound like that in Example 1 was not obtained even when a composite treatment was performed on a mixture of silica and PTFE particles.

(Measurement of dielectric constant and dielectric tangent)
The dielectric constant and dielectric loss tangent of each sample of the composite compounds according to Examples 1 to 7, the inorganic fillers according to Comparative Examples 1 to 3, 5 and 6, and the composite according to Comparative Example 4 were measured. That is, each sample was filled into a quartz tube, and the dielectric constant and dielectric loss tangent were measured by a cavity resonator method in the 10 GHz frequency range under an environmental atmosphere of a temperature of 25°C and a relative humidity of 40%. For the measurement, a vector network analyzer (manufactured by Anritsu Corporation, product name: MS46122B) was used. Furthermore, the measured values of the dielectric constant and dielectric loss tangent of the quartz tube filled with each sample were corrected for voids using the bulk density and true density of each sample and the filling amount of each sample relative to the filling volume, and the dielectric constant ε _r0 [-] and dielectric loss tangent tan δ ₀ [-] of each sample were calculated. The results are shown in Table 1.

As can be seen from Table 1, the composite compounds according to Examples 1 and 2 have a lower dielectric tangent value compared to the inorganic filler made of α-AlF ₃ according to Comparative Example 1, and it was confirmed that the dielectric loss was reduced. In addition, in the composite compounds according to Examples 3 to 5, the dielectric tangent value was lower compared to the inorganic filler made of α-AlF ₃ according to Comparative Example 2, and it was confirmed that the dielectric loss was reduced. Furthermore, in the composite compound according to Example 6, the dielectric tangent value was lower compared to the inorganic filler made of CaF ₂ according to Comparative Example 5, and in the composite compound according to Example 7, the dielectric tangent value was lower compared to the inorganic filler made of K ₂ SiF ₆ according to Comparative Example 6, and it was confirmed that the dielectric loss was reduced in both cases. This is thought to be due to the fact that the PTFE particles are thermally fused to the surface of the base material made of each inorganic fluoride and composited, and the dielectric loss of the PTFE particles is expressed as a synergistic effect.

In the case of the inorganic filler made of silica in Comparative Example 3, the relative dielectric constant was 2.8 and the dielectric loss tangent was 0.0016. In Comparative Example 4, in which a composite treatment was performed on a mixture of silica and PTFE particles, the relative dielectric constant value decreased compared to the silica in Comparative Example 3, but the dielectric loss tangent value increased (worsened), and no synergistic effect was confirmed by using PTFE particles in combination. The decrease in the relative dielectric constant value in the composite in Comparative Example 4 is presumed to be due to the formation of air layers in the silica during the composite treatment with PTFE particles.

(Evaluation of dispersibility and fluidity)
Next, the dispersibility in polymer resin was evaluated for each sample of the composite compounds according to Examples 1 to 7, the inorganic fillers according to Comparative Examples 1 to 3, 5 and 6, and the composite according to Comparative Example 4. That is, each sample and an epoxy resin (product names: jER (registered trademark) 828, jER (registered trademark) Cure, manufactured by Mitsubishi Chemical Corporation) were placed in a container cup so that the concentration of each sample was 50 mass% relative to the total mass of the obtained composition, and the compositions were prepared by kneading with a defoaming mixer.

The dispersibility and flowability of each of the resulting compositions were evaluated based on the following criteria. The results are shown in Table 1.
◯: As shown in FIG. 7( a ), the slurry composition falls smoothly.
Δ: The slurry composition falls but lacks smoothness.
×: No slurry composition was obtained, or as shown in FIG. 7( b ), the slurry composition fell in clumps.

As can be seen from Table 1, in all of Examples 1 to 7, slurry compositions were obtained in which the composite compound was well dispersed (suspended) in the epoxy resin. In particular, the composite compounds of Examples 1 to 4, 6, and 7 had excellent dispersibility in the epoxy resin, and all of them obtained slurry compositions with good fluidity. Generally, PTFE does not have good compatibility with polymer resins, but in the composite compounds of Examples 1 to 4, 6, and 7, the surface of the base material made of each inorganic fluoride is not completely covered with PTFE particles, and it is considered that the Lewis acid sites on the surface of the base material are exposed. Therefore, it is considered that these composite compounds maintained their affinity with the epoxy resin, and as a result, they were uniformly dispersed in the epoxy resin. On the other hand, since the composite compound of Example 5 contains a large amount of PTFE particles, more PTFE particles were heat-fused to the surface of the base material compared to the composite compounds of Examples 1 to 4, 6, and 7, and as a result, it is considered that the affinity with the epoxy resin was reduced and the fluidity was slightly reduced.

In addition, in Comparative Examples 3 and 4, silica does not inherently have good affinity with epoxy resins, so phase separation occurred with the epoxy resin and a slurry composition could not be obtained.

(Evaluation of chemical resistance)
Either the composite compound according to Example 8, the silica according to Comparative Example 3, or the composite according to Comparative Example 4 was added to a 1N NaOH aqueous solution so that the concentration was 10 mass%. After addition, the solution was stored in a stationary state for 3 days in an environment at a temperature of 80°C. After the storage was completed, the amount of eluted Al element or Si element was measured using an ICP-AES analyzer (product name: ULTIMA 2, manufactured by Horiba, Ltd.) (Al detection wavelengths: 396 nm and 152 nm, Si detection wavelengths: 611 nm and 251 nm). The results are shown in Table 2.

As can be seen from Table 2, the composite compound of Example 8 was able to suppress aluminum elution to 100 ppm or less even when immersed in an aqueous sodium hydroxide solution at 80°C for three days, confirming that it has excellent chemical resistance. On the other hand, in both the silica of Comparative Example 3 and the composite of Comparative Example 4, silicon eluted at 3 mass% or more relative to the total mass of each, confirming that they have poor chemical resistance.

Claims (14)

1. A composite compound for a low dielectric loss resin composition, comprising:
   A base material made of an inorganic fluoride;
   Fluorine resin particles held on at least a portion of the surface of the base material;
   Including,
   The composite compound for a low dielectric loss resin composition, wherein the dielectric tangent of the fluororesin particles is 0.002 or less at a frequency of 1 GHz or more and a temperature of 25°C.
2. The composite compound for low dielectric loss resin composition according to claim 1, in which the fluororesin particles are held by thermal fusion to the surface of the base material made of the inorganic fluoride.
3. The composite compound for low dielectric loss resin composition according to claim 1, wherein the fluororesin is polytetrafluoroethylene.
4. The composite compound for low dielectric loss resin composition according to claim 1, wherein the inorganic fluoride is MFn (wherein M is at least one selected from the group consisting of Li, Na, K, Mg, Al, Ca, Sc, Mn, Fe, Ga, Rb, Sr, Y, Zr, Sn, Ba, La, Ce, Yb, Hf and Bi, and n is an integer of 1 to ₄ ) or _K2SiF6 .
5. The composite compound for low dielectric loss resin composition according to claim 4, wherein said inorganic fluoride is _AlF3 .
6. The composite compound for low dielectric loss resin composition according to claim 1, wherein the average particle diameter D50 of the base material made of the inorganic fluoride is 0.05 μm or more and 75 μm or less.
7. The composite compound for low dielectric loss resin composition according to claim 1, wherein the content of the fluororesin particles is 0.5% by mass or more and less than 26% by mass with respect to the total mass of the base material made of the inorganic fluoride.
8. A low dielectric loss resin composition comprising at least a polymer resin and a composite compound for a low dielectric loss resin composition according to any one of claims 1 to 7.
9. The low dielectric loss resin composition according to claim 8, wherein the content of the composite compound is 1 mass% or more and 85 mass% or less with respect to the total mass of the low dielectric loss resin composition.
10. The low dielectric loss resin composition according to claim 8, wherein the polymer resin comprises at least one thermoplastic resin and/or at least one thermosetting resin.
11. The low dielectric loss resin composition according to claim 10, wherein the polymer resin is at least one selected from the group consisting of olefin resins, styrene resins, polyvinyl resins, methacrylic resins, thermoplastic elastomer resins, thermoplastic polyurethane resins, polyacrylonitrile resins, polylactic acid resins, polyamide polyacetal resins, polycarbonate resins, polyphenylene ether resins, polyethylene terephthalate resins, polysulfone resins, polyether sulfone resins, polyphenylene sulfide resins, polyether ether ketone resins, liquid crystal polymer resins, polyimide resins, fluororesins, phenolic resins, amine resins, furan resins, unsaturated polyester resins, epoxy resins, diallyl phthalate resins, guanamine resins, ketone resins, silicone resins, thermosetting elastomer resins, natural rubber, synthetic rubber, and modified versions thereof.
12. A molded article for high-frequency devices used in a frequency band of 1 GHz or more,
    A molded article for use in high-frequency devices, comprising a molded article comprising the low dielectric loss resin composition according to claim 8.
13. A high-frequency device used in a frequency band of 1 GHz or more,
    A high-frequency device comprising the low dielectric loss resin composition according to claim 8.
14. A high-frequency device used in a frequency band of 1 GHz or more,
    A high-frequency device comprising the molded article for high-frequency devices according to claim 12.