JP2922811B2 - Extruded sheet and its use - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruded sheet obtained from a resin composition using a polyester resin as a matrix resin. More specifically, high relative permittivity,
Extrusion that combines low dielectric loss tangent, high heat resistance and high mechanical strength, and is extremely suitable as a substrate material for electric circuits used in high-frequency bands such as antenna boards for communication devices and printed wiring boards for electric and electronic devices other than communication devices. The present invention relates to a molded sheet.

[0002]

2. Description of the Related Art To solve the problem of miniaturization of an antenna circuit board, there is an effective solution to increase the relative dielectric constant of the board. In this field, ceramic substrates such as alumina substrates have been mainly used in the field. Was. However, for the production of a thin plate such as a ceramic substrate, a green sheet is produced by extrusion molding or roll rolling molding, punched into a predetermined shape by a punching press or the like, and then these primary molded products are fired and cooled. It is necessary to perform cutting work or the like for finishing later, and the process to obtain the final product is extremely complicated and long, and is not suitable for mass production. On the other hand, a method of mixing a powdery high dielectric filler with a resin is also being studied. However, in order to obtain a desired high dielectric performance, the amount of the powdery high dielectric filler to be added must be increased, so that the extrudability is impaired and the mechanical strength is significantly reduced. In addition, studies are being made to utilize fiber-like dielectric fillers to take advantage of strength and anisotropy. However, none of these conventional materials is sufficiently satisfactory in strength and electrical characteristics.

[0003] Thermoplastic polyester resins represented by PET resins have excellent mechanical properties and electrical properties, and are used in many industrial products. Further, as a polyester having heat resistance, for example, JP-A-54-8
No. 8,954, which has a cyclohexane ring in the molecule. Conventional methods for producing a fibrous metal titanate compound include, for example, Japanese Patent Publication No. 62-71.
As shown in No. 60, a method of reacting potassium titanate fiber, titanium dioxide fiber, etc. with a solution containing divalent metal ions in a closed vessel or under hydrothermal conditions, and Japanese Patent Publication No. 62-55243, A method in which potassium titanate fiber and a barium compound are mixed and fired;
No. 60822 discloses that a titanate fiber and a barium compound are mixed, and NaCl, KC
There is a method of firing after adding l.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an extruded sheet which is a highly dielectric substrate which can be continuously formed by extrusion molding and which is extremely suitable as a practical thermoplastic resin substrate having high heat resistance. The object is to provide a product and its use.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a polyester having a repeating unit of the general formula MO.Ti having at least 85 mol% of 1,4-cyclohexane dimethylene terephthalate repeating units.
O ₂ (M is Ba, Sr, Ca, Mg, Co, Pd, Zn, Be,
One or two or more metal elements selected from the group consisting of Cd) in the form of a fibrous metal titanate and / or an amorphous titanium oxide wrapping the fibrous metal titanate. A composite fiber which is composite-integrated, wherein metal M and T
5 to 80% by weight based on the total weight of the polyester and the fibrous material is blended with a composite fiber having a molar ratio of i: 1.005 to 1.5 in the range of 1.50 to 1.5 and manufactured by extrusion. The present invention relates to an extruded sheet material characterized by the following.

Further, the present invention relates to a rolled board obtained by hot rolling the extruded sheet. In the present invention, a polyester resin having 85% or more of 1,4-cyclohexane dimethylene terephthalate repeating unit (hereinafter, referred to as PCTA) is used as the resin. This resin is a resin having excellent heat resistance, and by blending a specific fibrous material specified in the present invention, a low dielectric loss tangent of the resin is raised to such an extent that use in a high frequency band is hindered. It has an excellent feature that a material having both low strength and low thermal deformation required for a circuit board material having a high dielectric constant can be obtained.

[0007] The PCTA resin used in the present invention can be prepared by a conventional method using a low polymer obtained by a normal esterification reaction or a transesterification reaction of a lower alkyl ester of terephthalic acid with 1,4-cyclohexanedimethanol. It can be obtained by melt polymerization or solid state polymerization. PCTA resin of the present invention, in addition to 1,4-cyclohexane dimethylene terephthalate-based repeating unit,
It may contain various acid components, glycol components and the like as a copolymer component. Among the components that may be included as such a copolymerization component, examples of the acid component include isophthalic acid, naphthalenedicarboxylic acid, diphenylmethanedicarboxylic acid, diphenylsulfonedicarboxylic acid, p- (2-
(Hydroxyethoxy) benzoic acid, 5-sodium sulfoisophthalic acid, tetradecane-1,14-dicarboxylic acid, octadecane-1,18-dicarboxylic acid, 6-ethyl-hexadecane-1,16-dicarboxylic acid and the like.

The glycol component includes propylene glycol, diethylene glycol, butylene glycol, pentyl glycol, neopentyl glycol,
Examples thereof include polyalkylene glycols such as polytetramethylene glycol. In the PCTA resin of the present invention, it is necessary to contain 85 mol% or more of 1,4-cyclohexane dimethylene terephthalate-based repeating units, and it is preferable to use a resin containing 88 mol% or more. When the amount of the 1,4-cyclohexane dimethylene terephthalate repeating unit falls below 85 mol%,
This is because the melting point becomes as low as 250 ° C. or less, and it becomes impossible to have solder heat resistance.

The dielectric fibrous material that can be used in the present invention includes a general formula MO.TiO ₂ (M is Ba, Sr, C
a, Mg, Co, Pd, Zn, Be, and Cd, which represent one or more metal elements selected from the group consisting of fibrous metal titanates (hereinafter referred to as fibers A; A single metal is referred to as fiber A-1, and a metal in which M is two or more metals is referred to as fiber A-2) and a general formula MO.
TiO ₂ (M is Ba, Sr, Ca, Mg, Co, Pd, Zn, B
e, one or two or more metal elements selected from the group consisting of Cd.) A fibrous metal titanate having a composition represented by) is compositely integrated in a form in which amorphous titanium oxide is wrapped. A composite fiber, wherein the molar ratio of metal M to Ti is 1:
Those in the range of 1.005 to 1.5 (hereinafter referred to as fiber B, those in which M is a single metal are referred to as fiber B-1, and those in which M is two or more metals are referred to as fiber B-2. ) Is preferably used. The metal element M in the fibers A and B is preferably at least two or more divalent metals. This is because it has a preferable feature that the dielectric loss tangent in a high frequency band is lower than when M is a single metal.

[0010] Further, since fiber B has the advantage of generally higher strength than fiber A due to amorphous titanium oxide, fiber B has a high shape retention during blending and can be more preferably used. It is to be noted that the fiber B in which the molar ratio of the metal M to Ti exceeds 1.5 is not preferable because the relative dielectric constant is inferior. The fibers A-1 and A-2 which can be used in the present invention have a general formula of TiO ₂ · mH ₂ O (where m is 0 ≦ m <
8) One or two or more kinds of substances that can become an oxide of metal M by heating and a titanium source compound such as titania compound or rutile sand are mixed in the presence of a flux such as an alkali metal halide. It can be obtained by performing a heating reaction at a temperature of about 900 ° C. As an example of a preferred method for producing the fiber, a carbonate of one or more metal elements is deposited on the surface of the fibrous titania compound at a predetermined ratio such that the titanium component is excessive relative to the metal component. And then heat-treated. This is a composite fiber in which granular metal titanate (in the case of two or more metals, a solid solution of metal titanate) is wrapped in a matrix of amorphous titanium oxide. is there.

The preferred method for producing the fibers will be described in more detail. As the fibrous titania compound as a raw material, the ratio of the fiber length to the fiber diameter is 3 or more, preferably 3 or more and less than 10, and the general formula TiO having a fiber shape is used. Preferably, the component represented by ₂ · nH ₂ O (where n is 0 ≦ n ≦ 10) is 90% or more. Such a fibrous titania compound can be easily obtained by, for example, treating a fibrous alkali metal titanate in an acidic solution and performing a dealkalization reaction. As the titania compound, needle-like or fibrous titanium oxide with n = 0 may be used. First, after the fibrous titania compound is dispersed in a dispersion medium such as water or various organic solvents to form a slurry, a compound solution of one or more metal elements is added to the slurry. As such a compound of a metal element,
Metal halides, nitrates, sulfates, phosphates, formates, oxalates, hydroxides, hypochlorites, perchlorates, and the like can be exemplified. Two or more kinds may be used in combination. If the compounds of these metal elements are not liquid, they can be dissolved to form a solution. Water or various organic solvents can be used as the solvent that can be used at that time. When the addition amount is such that the total number of moles of one or more metals M is 1.005 to 1.5 per mole of the fibrous titania compound, fiber B can be obtained. Done, 1
In the case of adding so as to obtain, the fiber A can be obtained.

Next, a carbonate containing a metal compound is deposited on the surface of the fibrous titania compound as a raw material by adding a solution containing carbonate ions with stirring or by blowing carbon dioxide gas into the solution with stirring. I can do it. At this time, the pH of the solution during the reaction can be adjusted to a weak alkalinity of 8 to 10 using an alkaline solution such as ammonia. You can get things. Next, the fibrous titania compound on which the carbonate was deposited was appropriately filtered,
After washing with water and drying, 500-1300 ° C, preferably 7
The desired fiber can be obtained by performing a heat treatment at a temperature of about 00 to 1100 ° C. for about 3 minutes to 24 hours.
The fibrous material used in the present invention may be used alone or in combination of two or more. Further, a powdery high dielectric substance such as barium titanate, strontium titanate, barium strontium titanate, or lead zirconate titanate may be used in combination within a range not to impair the effects of the present invention.

The aspect ratio (fiber length / fiber diameter) of the fibrous material used in the present invention is preferably 3 or more, more preferably about 6 to 100. or,
The fiber diameter is preferably from 0.01 to 10 μm, more preferably from 0.1 to 5 μm. When a thick fibrous material having a fiber diameter of more than 10 μm is used, the smoothness of the surface of the molded product is inferior, and the signal transmission speed may be delayed particularly in a high frequency range. It is not preferable because the variation such as tangent increases. PC in the present invention
The mixing ratio of the inorganic fibrous material to the TA resin can be selected from a wide range depending on the purpose of use.
It is usually preferable to set the range of 5 to 80% by weight based on the total amount of the PCTA resin and the fibrous material. If the amount is less than 5% by weight, the effect of improving the dielectric constant of the sheet is poor, which is not preferable. If the amount is more than 80% by weight, molding becomes difficult and the strength is remarkably reduced. The present invention has an excellent effect that the relative permittivity of the target product can be freely set in a wide range by adjusting the mixing ratio.

In the present invention, in addition to the above essential components, (1) the affinity and bonding at the interface between the polymer and the fibrous material are improved and the mechanical strength is improved as long as the effects of the present invention are not impaired. Therefore, a coupling agent such as a silane coupling agent, a titanate coupling agent, or a zircoaluminate coupling agent, and (2) a fine particle filler such as talc or calcium pyrophosphate in order to improve plating properties. (3) an antioxidant to further improve thermal stability, (4) a light stabilizer such as an ultraviolet absorber to improve light resistance, and (5) a further improvement in flame retardancy. Therefore, a flame retardant such as a halogen-based or phosphorus-based compound and an antimony-based compound, a flame-retardant assistant such as zinc borate, barium metaborate, and zirconium oxide are added to (6) impact resistance in order to improve impact resistance. Agent To improve 7) lubrication, lubricant, sliding property improving agent (solid lubricant, liquid lubricant),
(8) For coloring, a coloring agent such as a dye or a pigment is used.
(9) In order to adjust physical properties, additives such as a plasticizer and a crosslinking agent can be blended. In producing the resin composition of the present invention, conventionally known methods can be widely employed. For example, if necessary, the resin is mixed with a tumbler or a ribbon mixer or the like, and then melt-kneaded using a twin-screw extruder. It is good to pelletize.

The sheet material of the present invention is preferably subjected to hot rolling in order to improve dimensional stability, low warpage, heat resistance and the like. As such hot rolling conditions, usually, a heating temperature of 110 to 250 ° C. and a heating rate of 3 to 15 ° C./min are preferable, and preferably 150 to 220 ° C. and a heating rate of 5 ° C.
The temperature is preferably set to -10 ° C / min. Further, the pressure condition is 15 to 90 kg / cm ² , preferably 30 to 70 kg / cm ² . The sheet material of the present invention is particularly excellent as a prepreg for lamination of a circuit board or the like. In manufacturing such a laminated substrate, other materials are laminated as necessary,
Alternatively, plating, bonding, or the like is performed, and the resultant can be used as a circuit board. Hereinafter, a preferred configuration of the circuit board will be exemplified. (1) A sheet-like material of the present invention in which a conductive metal thin film is adhered or plated on at least one surface. (2) A reinforcing sheet such as a glass cloth, a low-dielectric glass cloth, a ceramic fiber papermaking sheet, or an aramid fiber sheet is sandwiched between at least two sheets of the present invention, and at least one surface of the sheet is electrically conductive metal. Adhered or plated thin film of Such a circuit board can be manufactured by an ordinary lamination method.

The sheet-like material of the present invention can be used very suitably as an electric circuit board used in a high-frequency band such as an antenna substrate of a communication device and a printed wiring board of an electric / electronic device other than the communication device. Here, as the electric and electronic equipment other than the communication device, for example, computers and their terminals, office equipment, measurement and control equipment, video equipment, automobiles, transportation equipment such as airplanes,
Examples include audio, television, and camera.

[0017]

The present invention will be described in more detail with reference to the following examples. Production methods 1 to 4 show the methods of synthesizing various dielectric fibrous materials specifically shown in Examples.

Production Example 1 20 g of fibrous titania hydrate (TiO ₂ .1 / 2H ₂ O, average fiber length 12 μm, average fiber diameter 0.3 μm) was dispersed in 1 liter of deionized water, and ammonia was stirred while stirring. The pH was adjusted to 9 by dropping 15 ml of water [25% manufactured by Wako Pure Chemical Industries, Ltd., reagent grade]. Thereafter, 260 g of a 20% by weight aqueous barium acetate solution and 170 g of a 15% by weight aqueous ammonium carbonate solution were simultaneously added dropwise without mixing. The dropping was performed at room temperature with stirring for 60 minutes. At that time, 10
The pH was checked every minute and adjusted with aqueous ammonia so that the pH was in the range of 8-10. According to the results of X-ray diffraction, infrared absorption spectrum analysis, and scanning electron microscope observation, this fibrous material retains the shape of titania hydrate, which is a fiber raw material, has an average aspect ratio of about 20, and its surface has It was found that the composition was covered with barium carbonate and had a composition of Ba / Ti = 0.9 / 1 (molar ratio). 20g of this fibrous material
Was transferred to an alumina crucible, and was heated at 950 ° C.
After heating for 1 hour, 16.3 g of a white fibrous substance was obtained. When this was chemically analyzed, Ba / Ti =
It was found to be 0.9 / 1 (molar ratio). Further, X-ray diffraction and transmission electron microscopy of this product results are crystalline BaTiO ₃ 90 mol% consists of amorphous TiO ₂ 10 mol%, such as crystalline BaTiO ₃ is amorphous TiO ₂ enveloping It was found to be a fibrous material that was compositely integrated in the shape. This is called FB-1.

Production Example 2 20 g of fibrous titania hydrate (TiO ₂ ８H ₂ O, average fiber length 15 μm, average fiber diameter 0.3 μm) was dispersed in 1 liter of deionized water, and ammonia was stirred. The pH was adjusted to 9 by dropping 10 ml of water [25% manufactured by Wako Pure Chemical Industries, Ltd., reagent grade]. Thereafter, 153 g of a 20% by weight aqueous barium acetate solution and 127 g of a 20% by weight aqueous strontium acetate solution were simultaneously added dropwise. Dropping was performed over 30 minutes while stirring at room temperature. Thereafter, 200 g of a 15% by weight aqueous solution of ammonium carbonate was added dropwise with stirring over 60 minutes. After completion of the dropwise addition, the mixture was further stirred for 30 minutes, then filtered, washed with water, and dried to obtain 61 g of a white fibrous material.
I got From the results of X-ray diffraction, infrared absorption spectrum analysis and scanning electron microscope observation, this fibrous material retains the shape of titania hydrate, which is the fiber raw material, and has barium carbonate and strontium carbonate deposited on its surface. It turned out to be. In addition, from the result of the fluorescent X-ray analysis, Ba /
It was found that Sr / Ti = 0.490 / 0.504 / 1.000 (molar ratio). 30 g of the fibrous material was transferred to an alumina crucible and heat-treated at 970 ° C. for 3 hours in an air atmosphere to obtain 24.5 g of a white fibrous material. When this was chemically analyzed, Ba / Sr / Ti
= 0.490 / 0.504 / 1.000 (molar ratio). From the results of X-ray diffraction and transmission electron microscopy, it was found to be crystalline (Ba, Sr) TiO ₃ 9
It is a fibrous material composed of 9.4 mol% and 0.6 mol% of amorphous TiO ₂ , in which crystalline (Ba, Sr) TiO ₃ is combined and integrated in such a manner that amorphous TiO ₂ wraps around it. Was confirmed. This is called FB-2.

Production Example 3 Potassium titanate hydrate fiber (2K ₂ O.11TiO _2.
3H ₂ O, the ratio of fiber length to fiber diameter is at least 10) 2.0 g was placed in a Moray type autoclave having a capacity of 23 ml together with 4.4 g of barium hydroxide and 12.0 ml of water.
It was kept at 0 ° C. for 24 hours. After the reaction, the quenched sample was taken out, filtered, washed with water, and dried at 80 ° C. overnight. Chemical analysis of the product showed that Ba / Ti = 1/1 (molar ratio). X-ray diffraction and transmission electron microscopy revealed that this was crystalline BaTiO ₃ . This is called FA-1.

Production Example 4 20 g of fibrous titania hydrate (TiO ₂ ８H ₂ O, average fiber length 15 μm, average fiber diameter 0.3 μm) was dispersed in 1 liter of deionized water, and ammonia was stirred. The pH was adjusted to 9 by dropping 10 ml of water [25% manufactured by Wako Pure Chemical Industries, Ltd., reagent grade]. Thereafter, 156 g of a 20% by weight aqueous solution of barium acetate and 126 g of a 20% by weight aqueous solution of strontium acetate were simultaneously dropped. Dropping was performed over 30 minutes while stirring at room temperature. Thereafter, 200 g of a 15% by weight aqueous solution of ammonium carbonate was added dropwise with stirring over 60 minutes. After completion of the dropping, the mixture was further stirred for 30 minutes, and then filtered, washed with water and dried to obtain a white fibrous material 61.
g was obtained. From the results of X-ray diffraction, infrared absorption spectrum analysis and scanning electron microscope observation, this fibrous material retains the shape of titania hydrate, which is the fiber raw material, and has barium carbonate and strontium carbonate deposited on its surface. It turned out to be. Also, from the result of the fluorescent X-ray analysis, B
It was found that a / Sr / Ti = 0.500 / 0.500 / 1.000 (molar ratio). 3.0 g of the fibrous material was transferred to an alumina crucible and heat-treated at 1000 ° C. for 5 hours in an air atmosphere to obtain 24.3 g of a white fibrous material. When this was chemically analyzed, Ba / Sr / Ti
= 0.500 / 0.500 / 1.000 (molar ratio). X-ray diffraction and transmission electron microscopy confirmed that this was crystalline (Ba, Sr) TiO ₃ . This is called FA-2.

Examples 1 to 7 Polycyclohexane dimethylene terephthalate / isophthalate having an intrinsic viscosity of 1.00 (95 mol% of terephthalate, 5 mol% of isophthalate) (hereinafter abbreviated as PCTA)
The dielectric fibrous materials obtained in the above Production Examples 1 to 4 were blended and prepared at the blending ratios shown in the columns of Examples 1 to 7 in Table 1, respectively.
The mixture was melt-kneaded at 285 ° C. using a twin-screw extruder to obtain pellets. Each of these was formed into a sheet having a thickness of 1.0 mm by an extrusion sheet forming apparatus using a T die. In each case, an extruded sheet having a smooth surface and good appearance was obtained. These extruded sheets were heated to 180 ° C. at an extrusion pressure of 40 kg / cm ² at a rate of 5 ° C./min, held for 15 minutes, and immediately cooled to obtain a board. When the bending strength, solder resistance and dielectric properties of these boards were measured, good results were obtained.
In addition, the measuring method and evaluation were performed as follows. Surface smoothness: Surface roughness meter Surfcom 300B [Co., Ltd.]
5μm or less at maximum height Rmax using Tokyo Seimitsu] ○ good, 5μm or more and 10μm or less △ slightly good, 10μ
m or more are indicated in three stages of x failure. Flexural strength: measured according to ASTM D790. Deformation rate: Measured according to ASTM D790. Flexural modulus: measured according to ASTM D790. Solder resistance: A test piece of 2cm wide x 5cm long is 260 ° C x 6
The change when immersed in a solder bath for 0 sec was indicated in three stages: 良好 good, △ good, and × bad. Dielectric constant and dielectric tangent: The dielectric constant and dielectric tangent at 1 MHz were measured by a capacitance method using an impedance analyzer (4192A manufactured by Yokogawa Hewlett-Packard Company).
The dielectric constant and the dielectric loss tangent at GHz were measured by a cavity resonance method using a network analyzer (8510C, manufactured by Hewlett-Packard Company). The evaluation results of these boards are also shown in Examples 1 to 7 of Table 2.

Comparative Examples 1 to 3 In the same manner as in the examples, the compounds were blended at the compounding ratios shown in the columns of Comparative Examples 1 to 3 in Table 1. These were made into pellets in the same manner as in the example,
A sheet was formed and pressed to obtain a test piece. Evaluation was performed in the same manner as in the examples, and the results are shown in Comparative Examples 1 to 3 in Table 2. Barium titanate powder as the dielectric powder used in the comparative example: trade name H manufactured by Fuji Titanium Industry
PBT average particle size 0.5 μm, length 1.5 mm Glass fiber: E glass short fiber manufactured by Nippon Electric Glass Fiber Co., Ltd. Diameter 13 μm, length 3.0 mm. Comparative Examples 1 and 2 are excellent in the surface smoothness of the board, but are inferior in mechanical properties, and also inferior in dielectric properties as compared with Examples 2 and 3. In Comparative Example 3, although the mechanical properties are improved, the surface smoothness of the board is inferior.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

As is clear from the above description, according to the present invention, excellent surface smoothness, high relative permittivity, low dielectric loss tangent,
Extruded sheet material that has both high heat resistance and high mechanical strength and is extremely suitable as a substrate material for electric circuits used in high-frequency bands such as antenna boards for communication devices and printed wiring boards for electric and electronic devices other than communication devices. Can be obtained.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H05K 1/03 610 H05K 1/03 610M // B29K 67:00 B29L 7:00 (72) Inventor Shogo Kawakami Ote-dori, Chuo-ku, Osaka-shi, Osaka 3-2-27 Otsuka Chemical Co., Ltd. (72) Inventor Fumio Ohama 31-3 Uji Hinojiri, Uji City, Kyoto Prefecture Unitika Corporation Uji Plastic Factory (72) Inventor Atsunori Okada Chuo-ku, Osaka City, Osaka Prefecture 4-3-1 Kutarocho 3 Unitika Co., Ltd. (72) The inventor Yasuki Nakayama 31-3 Uji Hinojiri, Uji City, Kyoto Prefecture Unitika Co., Ltd. Uji Plastic Factory (56) References JP-A-4-285657 ( JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 67/02 C08K 3 / 22,7 / 08 B29C 47/00 C08J 5/18 CFD H05K 1/03

Claims (4)

(57) [Claims] 1. A polyester having 85 mol% or more of 1,4-cyclohexane dimethylene terephthalate-based repeating units is represented by a general formula MO.TiO ₂ (M is Ba, Sr, C
a, Mg, Co, Pd, Zn, Be, Cd, which represents one or more metal elements) and / or the fibrous metal titanate. Is a composite fiber in which amorphous titanium oxide is wrapped, and the molar ratio of metal M to Ti is 1: 1.00.
An extruded sheet obtained by blending 5 to 80% by weight of a composite fiber in the range of 5 to 1.5 with respect to the total weight of the polyester and the fibrous material and extruding the mixture. . 2. A board obtained by hot rolling the extruded sheet material of claim 1. 3. The method according to claim 1, wherein M is at least two metal elements.
Extruded sheet material. 4. A high-frequency electric circuit board for handling an electric signal having a frequency of 100 MHz or more, comprising the material according to claim 1, 2 or 3.