JP2007009172A - Highly dielectric composite-molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly dielectric composite-molded article, excellent in molding property, processability, dimensional stability and heat resistance and also having a high dielectric constant and a low dielectric tangent simultaneously. <P>SOLUTION: This highly dielectric composite-molded article containing a resin and a highly dielectric filler is characterized with that the resin is a benzoxazine resin expressed by formula (1) [wherein, R is a ≥2C divalent substituent; and the hydrogen of the benzene ring may be substituted by an alkyl or alkoxy]. The highly dielectric composite-molded article is the most suitable as a material of an antenna or a capacitor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high dielectric composite molded body. More specifically, the present invention relates to a high dielectric composite molded body that is particularly excellent in moldability, workability, dimensional stability, and heat resistance and has both a high dielectric constant and a low dielectric loss tangent. The high dielectric composite molded body of the present invention is optimal as a material for an antenna or a capacitor.

  In recent years, communication systems such as mobile phone systems, wireless LAN (Local Area Network) systems, GPS (Global Positioning System), ETC (Electronic Toll Collection System), and the like have been increasingly used.

  Such a communication system is desired to be downsized, and electronic circuits and the like are being downsized by various electronic circuit formation techniques.

On the other hand, a rectangular so-called patch antenna in which an electrode is formed on a dielectric is used for the antenna circuit. In this antenna circuit, the resonance frequency f, the relative dielectric constant ε of the substrate material used for the antenna, and the side length d of the electrode have the following relationship.
[Equation 1]
d = c / (2f · ε1 / 2)

  Here, c is the speed of light. That is, the size of the antenna electrode depends on the relative dielectric constant of the substrate in order to design the antenna electrode to have a specific resonance frequency. From this, it is clear that in order to reduce the size of the antenna circuit, it is necessary to increase the relative dielectric constant of the substrate. Furthermore, it is known that if the relative dielectric constant of the substrate is too large, the bandwidth is narrowed. Therefore, the relative dielectric constant of the substrate is preferably 5 to 15, more preferably around 10.

  In addition, the material has an inherent dielectric loss tangent (tan δ). It is known that signal loss occurs in proportion to the product of dielectric loss tangent and relative dielectric constant. Especially in a high dielectric constant material such as an antenna substrate, sufficient loss is obtained unless a material with low dielectric loss tangent is used. There is no gain.

  Also in a capacitor, the dielectric constant is directly proportional to the capacitance, and the dielectric loss tangent leads to signal loss as well.

  Therefore, a material having a high dielectric constant and a low dielectric loss tangent is strongly demanded for a patch antenna or capacitor material.

As a material having such a high dielectric constant and a low dielectric loss tangent, there is a ceramic sintered body. For example, as a typical example, alumina (Al ₂ O ₃ ) has a dielectric constant of about 10 and a dielectric loss tangent of about 0.0002 to 0.0008, and has both a sufficiently high dielectric constant and a low dielectric loss tangent. .

  However, a ceramic sintered body such as alumina is a high-strength material, but on the other hand, it is extremely fragile and, for example, cracking or chipping occurs when drilling holes for placing pins on an antenna substrate. Have a problem.

  Further, ceramics shrink during sintering, and it is difficult to form a substrate with good dimensional accuracy. And when a design dimension and a manufacture dimension differ, there also exists a problem that the shift | offset | difference from a preferable resonance band generate | occur | produces.

In order to overcome these problems, a method of combining a high dielectric material (for example, ceramic powder) with an organic polymer has been studied.
For example, Patent Documents 1 to 4 disclose a composite of a thermoplastic resin such as polyolefin and a highly dielectric inorganic substance. Among thermoplastic resins, polyolefin has a relatively low dielectric loss tangent, and by combination with a high dielectric inorganic substance, molding is relatively easy, dimensional stability is good, and processing is easy.

However, since thermoplastic resins such as polyolefin usually have a melting point of 200 ° C. or lower, there is a possibility that the shape may be deformed when a step such as soldering is required to conduct the electrodes. It is not preferable.
When polyolefin is used, the adhesion between the polyolefin and the inorganic substance is not so good, and thus there is a possibility that pores are generated in the substrate due to the difference in the coefficient of expansion during cooling after molding. When holes are generated, the dielectric constant of the substrate becomes small, so that there is a difference from the design dielectric constant, which may cause a deviation from a preferable resonance band.

  On the other hand, Patent Document 5 refers to a material in which a high dielectric inorganic substance is combined with a thermosetting resin. Unlike a thermoplastic resin, a thermosetting resin does not have a clear melting point, and therefore can be suitably used as a material that requires soldering.

However, for example, the thermosetting resin often has a high dielectric loss tangent such that the dielectric loss tangent of the epoxy resin is 0.01 or more. As a result, there is a drawback that the signal loss increases.
Further, when a large amount of a high dielectric inorganic substance is added to the thermosetting resin in order to sufficiently increase the dielectric constant, there is a problem that the composite becomes brittle and the workability is lowered.

  Patent Document 6 discloses a composite of a liquid crystal polymer and a highly dielectric inorganic substance. However, there is a possibility that the performance of the liquid crystal polymer is lowered by combining the inorganic substances.

Rは任意の置換基を示す。 In contrast, there is a method of using a benzoxazine resin as a thermosetting resin. Benzoxazine is a compound having a structure represented by the following formula (4), for example, and can be easily synthesized from phenols, primary amines, and aldehydes, and can be obtained at low cost and in large quantities.

R represents an arbitrary substituent.

  However, benzoxazine resins are generally brittle and often do not provide sufficient processability.

  On the other hand, Patent Documents 7 and 8 use a method in which a benzoxazine structure is introduced into a polyfunctional phenol in advance. Since this method uses a high molecular weight benzoxazine material as a raw material, the brittleness is improved to some extent. On the other hand, the hydroxyl group tends to be excessive, and as a result, the water absorption becomes high, and the dielectric constant may fluctuate depending on the humidity or lead to an increase in dielectric loss tangent.

As described above, according to the conventional technology, it is not possible to provide a high dielectric molded body having excellent moldability, dimensional stability, workability, and structural stability, and having both a sufficiently high dielectric constant and a low dielectric loss tangent. It was possible. Therefore, a material that is sufficiently suitable for molding a high-frequency communication antenna, a substrate-embedded capacitor, or the like has not been provided.
JP-A-9-139624 JP-A-9-147626 JP 2003-198230 A JP 2003-198231 A JP 2002-344100 A JP 2004-161953 A JP-A-10-130460 JP 2001-214029 A

  The object of the present invention is to solve the above-mentioned problems in conventional high-dielectric molded products, which are excellent in moldability, dimensional stability, workability, and structural stability, and have both a sufficiently high dielectric constant and a low dielectric loss tangent. It is to provide a dielectric molded body.

  In view of the above problems, the present inventors have conducted extensive research on various high dielectric molded products, and as a result, molded products made of a composite material containing a benzoxazine resin having a specific structure and a high dielectric filler are molded. The present invention has been completed by finding that it has a high dielectric property, dimensional stability, workability, and structural stability, and has a sufficiently high dielectric constant and a low dielectric loss tangent.

式中、Ｒは炭素原子数２以上の２価の置換基であり、べンゼン環の水素はアルキル基又はアルコキシ基で置換されていてもよい。 That is, the present invention provides a high dielectric composite comprising a high dielectric composite molded body comprising a resin and a high dielectric filler, wherein the resin is a benzoxazine resin represented by the following formula (1): A molded body is provided.

In the formula, R is a divalent substituent having 2 or more carbon atoms, and hydrogen in the benzene ring may be substituted with an alkyl group or an alkoxy group.

  In the present invention, R in the formula (1) is a linear alkylene group having 2 or more carbon atoms, a branched alkylene group in which hydrogen is alkyl-substituted, or an alkylene group containing an alicyclic structure. It is another object of the present invention to provide the above-mentioned high dielectric composite molded article.

Furthermore, the present invention provides the high dielectric composite molded article, wherein R in the formula (1) is represented by the following formula (2).
[Chemical 6]
_{- (CH 2) n- (2} )
n represents an integer of 2 or more and 30 or less.

  The present invention also provides the high dielectric composite molded article, wherein the alkylene group containing an alicyclic structure is an alkylene group containing a condensed ring type alicyclic structure.

Furthermore, the present invention is an alkylene group containing the condensed ring alicyclic structure, 3 (4), 8 (9), - bis (aminomethyl) tricyclo [5,2,1,0 ^2,6] decane The above-mentioned high dielectric composite molded article is characterized in that it is a residue of the amino group.

Furthermore, the present invention provides the high dielectric composite molded article, wherein the high dielectric filler contains an inorganic substance represented by at least the following formula (3).
[Chemical 7]
MO ・ TiO ₂ (3)
M represents one or more metal atoms selected from Ba, Sr, Ca, Mg, Co, Pd, Zn, Be, Cd, and Nd.

  The present invention also provides the above-mentioned high dielectric composite molded article, wherein the high dielectric filler is a particulate material having a particle size of 10 nm to 100 μm.

  Further, according to the present invention, the ratio of the benzoxazine resin and the high dielectric filler contained in the high dielectric composite molded product is from 50 parts by weight to 500 parts by weight of the high dielectric filler with respect to 100 parts by weight of the benzoxazine resin. The present invention provides the above-mentioned highly dielectric composite molded article characterized by being parts by weight.

  The high dielectric molded article of the present invention is excellent in moldability, dimensional stability, workability, and structural stability, and has both a sufficiently high dielectric constant and a low dielectric loss tangent. Due to these excellent characteristics, it is easy to produce a molded body, and furthermore, it is possible to provide a high dielectric molded body exhibiting frequency characteristics as designed with almost no cracks or defects during the production. By using the high dielectric molded body of the present invention, it becomes possible to provide an antenna and a capacitor with low cost and stable performance.

  The present invention is described in detail below using preferred examples. The present invention is not limited to these.

1. Characteristics of benzoxazine The high dielectric shaped product of the present invention uses a specific benzoxazine resin. The benzoxazine resin used in the present invention means a cured product obtained by ring-opening polymerization of a compound having a specific structure represented by the formula (1).

Rは任意の置換基を示す。 As described above, benzoxazine has a basic structure represented by the formula (4), and can be obtained at low cost and in large quantities.

R represents an arbitrary substituent.

式中、Ｒは炭素原子数２以上の２価の置換基であり、べンゼン環の水素はアルキル基又はアルコキシ基で置換されていてもよい。 On the other hand, the benzoxazine used in the present invention is a compound having a specific structure represented by the formula (1).

In the formula, R is a divalent substituent having 2 or more carbon atoms, and hydrogen in the benzene ring may be substituted with an alkyl group or an alkoxy group.

  The benzoxazine of the formula (1) is cured by ring-opening polymerization by heating in the same manner as the benzoxazine of the formula (4) to become a benzoxazine resin. At this time, since the benzoxazine resin becomes a cured product crosslinked with the substituent R, brittleness can be improved.

  In the formula (1), the substituent R is not particularly limited as long as it is a divalent organic group, but preferably has a structure having 2 or more carbon atoms. This is because the brittleness improvement may be insufficient even if the number of carbon atoms is less than 2. The upper limit of the number of carbon atoms is not particularly limited, but is preferably 50 or less, more preferably 30 or less. This is because when the number of carbon atoms is extremely increased, the workability and brittleness become more remarkable, but heat resistance cannot be expected.

  The structure of the substituent R is a hydrocarbon group. The hydrocarbon group may have a substituent such as ketone, ether, sulfone or sulfide. As a specific structure, in the case of a hydrocarbon group, a methylene chain having 2 to 30 carbon atoms and a branched structure thereof, a divalent cyclic cycloalkyl (for example, 1,4-cyclohexyl group, 1,3-adamantyl group, 3,9-dicyclopentadiene group, 3,9-dimethylidene dicyclopentadiene group), divalent aromatic (for example, 1,4-phenyl group, 4,4′-biphenyl group, 3,9-naphthyl group, Bisphenol A type structure, bisphenol F type structure) and the like. When it contains a ketone, 4,4′-benzophenone group, 1,5-pentan-3-one group and the like, and when it contains ether, 4,4′-diphenyl ether group and the like can be mentioned. When a sulfone group is included, a bisphenol S-type structure and the like can be mentioned. In the case of sulfide, 4,4′-diphenylthioether and the like can be mentioned. However, it is not limited to these specific examples, and is not particularly limited as long as a divalent substituent having 2 or more carbon atoms exists between nitrogen atoms. Furthermore, a part of these hydrogens may be substituted with an organic group or halogen, and a structure containing siloxane is also useful.

  The structure of the substituent R preferable in the present invention is a linear alkylene group having 2 or more carbon atoms, a branched alkylene group in which hydrogen is alkyl-substituted, or an alkylene group containing an alicyclic structure. Linear and branched alkylene groups have moderate flexibility and are effective in improving processability and reducing brittleness. When a branched structure is added, heat resistance and the like are improved. However, if the branched structure is excessively increased, workability improvement and brittleness reduction may be hindered. good. The alicyclic structure is less effective in improving brittleness than straight chain alkylene groups and branched alkylene groups, but it can be expected to improve electrical properties (small dielectric loss tangent) and heat resistance.

From the viewpoint of improving processability and reducing brittleness, the most preferable structure of the substituent R is a methylene chain represented by the formula (2) having moderate flexibility.
[Chemical Formula 10]
_{- (CH 2) n- (2} )
n represents an integer of 2 or more and 30 or less.

  Here, when n is 1, sufficient workability improvement and brittleness reduction effects cannot be obtained, while those with 31 or more are difficult to obtain sufficient heat resistance. A preferable value of the number of carbon atoms n is 2 to 30, more preferably 4 to 12, and further preferably 6 to 10.

On the other hand, although the effect of improving workability is small, R is preferably an alicyclic structure as a substituent capable of achieving both electrical properties (small dielectric loss tangent) and heat resistance. Among them, a cyclic cycloalkane having a condensed ring structure is preferably used because of the good balance of the above characteristics.
Specifically, R is 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, bis (4-aminocyclohexyl). ) methane, bis (4-amino-3-methylcyclohexyl) methane, 3 (4), 8 (9), - bis (aminomethyl) tricyclo [5,2,1,0 ^2,6] decane, 1-amino It is preferably an amino group residue such as -1-methyl-4- (1-amino-1-methylethyl) cyclohexane. Particularly preferably, 3 (4), 8 (9), - bis (aminomethyl) tricyclo [5,2,1,0 ^2,6] residues of the amino groups of decane.

These benzoxazines can be synthesized from the corresponding phenolic raw materials, formaldehyde, and diamine based raw materials. The synthesis method is not particularly limited. For example, it can be synthesized according to the method of US Pat. No. 5,543,516.
In addition, as a resin component, other thermoplastic resins such as styrene may be blended within a range not deteriorating the effect of the present invention, or other thermosetting resins such as epoxy resin may be blended. .
Further, when curing benzoxazine, a catalyst may be used. The catalyst is a Bronsted acid such as carboxylic acid, a Lewis acid such as aluminum chloride, and a phenolic compound, an amine compound, a benzoxazine oligomer, etc. as a co-catalyst. May be added. Furthermore, phenolic compounds, amine compounds, acid anhydrides, and the like can be used as curing agents.

2. Characteristics of High Dielectric Filler The high dielectric filler used in the present invention is not particularly limited, but those having a dielectric constant of 10 or more, particularly 20 or more are preferable. If the dielectric constant is less than 10, sufficient dielectric constant may not be expressed due to mixing with the resin. Although there is no upper limit in particular, a thing of 1000 or less can be preferably used in consideration of securing a certain band. Further, the high dielectric filler is preferably a solid, and more preferably not conductive.

  Specifically, metal oxide ceramics and composites thereof are preferably used. Metal oxides include alumina, titanium oxide, zinc oxide, chromium oxide, zirconium oxide, niobium oxide, tin oxide, antimony oxide, lead oxide, magnesium oxide, cobalt oxide, iron oxide, bismuth oxide, beryllium oxide, copper oxide, Although chromium oxide, manganese oxide, etc. are illustrated, it is not limited to these.

As the composite ceramic, a titanium oxide composite ceramic represented by barium titanate can be preferably used. The titanium oxide composite ceramic is a compound represented by the formula (3).
[Chemical 11]
MO ・ TiO ₂ (3)
M represents one or more metal atoms selected from Ba, Sr, Ca, Mg, Co, Pd, Zn, Be, Cd, and Nd.
Incidentally, in equation (3), and when M is 2 or more metal atoms, specifically, titanium oxide-based composite ceramics such as _{BaO · SrO · TiO 2, BaO} · Nd 2 O 3 TiO 2 I mean.
Among these compounds, barium titanate (BaTiO ₃ ) can be particularly preferably used in the present invention as a material that stably exhibits a high dielectric constant.

  These high dielectric fillers may be used in combination. Moreover, you may use an inorganic or organic filler for the purpose of improvement of a mechanical physical property etc. as needed.

The high dielectric filler used in the present invention is preferably in the form of particles. The form of the particles is not particularly limited. The shape may be not only spherical, square, etc., but also irregular. The particle size is not particularly limited. If the particle size is small, uniform dispersion is easily performed in benzoxazine. On the other hand, it is generally known that the smaller the particle size, the smaller the dielectric constant tends to be, and there is a possibility that a sufficient dielectric constant cannot be obtained. On the other hand, if the particle size is too large, it may cause uneven performance in the molded body. Therefore, the preferred particle size for the present invention is 10 nm to 100 μm, more preferably 30 nm to 1 μm. Moreover, you may use it, mixing the material of 2 or more types of particle shape and a particle size.
These high dielectric fillers may be surface-treated with a silane coupling agent or the like in advance.

3. Production of High Dielectric Composite Molded Body The high dielectric composite molded body is obtained by blending a benzoxazine represented by the formula (1) and a high dielectric filler and then curing them.
The ratio of the benzoxazine and the high dielectric filler is not particularly limited, but the high dielectric filler is preferably in the range of 50 to 500 parts by weight with respect to 100 parts by weight of the benzoxazine. When the high dielectric filler is less than 50 parts by weight, a sufficient dielectric constant may not be obtained. On the other hand, when the amount exceeds 500 parts by weight, the high dielectric filler becomes excessive, and it becomes difficult to obtain sufficient processability. The actual blending amount of the high dielectric filler is determined in view of the dielectric constant and workability of the finally obtained high dielectric composite molded body.
When other resin components other than benzoxazine are included, the high dielectric filler is preferably in the range of 50 to 500 parts by weight with respect to 100 parts by weight of the total of benzoxazine and other resin components. .

  The method of blending is not particularly limited, but a known method such as powder kneading, melt kneading, dissolution and dispersion using a solvent or the like can be used. In particular, the benzoxazine resin used in the present invention is a solid at room temperature (15 ° C.) and becomes a melt having a low viscosity when heated. Therefore, after melting, a high dielectric filler is introduced, and a homogenizer or ball mill is introduced. Etc., and can be dispersed by a known method. When the solvent is used, it is not particularly limited as long as the benzoxazine compound can be dissolved, but an aromatic solvent such as toluene and xylene, a halogen solvent such as chloroform, and an alcohol solvent such as methanol, ethanol, propanol and butanol. General solvents such as ketone solvents such as acetone and 2-butanone, ester solvents such as ethyl acetate and ethyl lactate, carbonate solvents such as ethylene carbonate and propylene carbonate, and hydrocarbon solvents such as hexane and cyclohexane Can be used.

A composition containing benzoxazine in which a high dielectric filler is dispersed can be produced by heating and curing to produce a high dielectric composite molded body. The method for forming the desired shape is not particularly limited. For example, casting into a mold may be performed, or molding may be performed by pressing, injection, or the like. Moreover, after making it into a semi-hardened state, a shape may be shape | molded and it may be made to harden completely after that.
Since the curing conditions vary depending on the structure of the raw material and the blending amount of the high dielectric filler, it cannot be said unconditionally. Typical curing conditions are 30 minutes to 5 hours at a temperature in the range of 120 to 220 ° C. At the time of curing, two-stage curing may be performed in which the resin is semi-cured at 100 to 160 ° C. and then cured at 160 to 220 ° C. for complete curing.

  The high dielectric composite molded body of the present invention is a molded body in which a benzoxazine resin represented by the formula (1) and a high dielectric filler are combined. In addition, an antioxidant, a heat stabilizer, a light stabilizer, a UV absorber, a weathering agent, a lubricant, a compatibilizer, a colorant, and the like may be added as necessary without departing from the effects of the present invention. Good.

  As described above, the high dielectric composite molded body of the present invention can be manufactured. The high dielectric composite molded article of the present invention is excellent in moldability, dimensional stability, workability, and structural stability, and is a material having both a sufficiently high dielectric constant and a low dielectric loss tangent. Therefore, it is particularly suitable as a material for patch antennas or capacitors.

  Hereinafter, the present invention will be described based on examples and comparative examples. The present invention is not limited thereby. In addition, all the compounds and solvents used in Examples and Comparative Examples were commercially available products.

[Evaluation method]
(1) Dielectric constant and dielectric loss tangent A high dielectric composite molded body was formed into a sheet having a thickness of 500 μm, and the obtained sheet-shaped molded body was cut into 15 mm × 15 mm, and a dielectric constant measuring apparatus (manufactured by HEWLETT PAKARD, product number “HP4291B”) and measured at 23 ° C., and the dielectric constant and dielectric loss tangent at 100 MHz were read.
(2) Workability A high dielectric composite molded body was formed into a sheet having a thickness of 500 μm, and the obtained sheet-shaped molded body was observed for cracking and chipping of the punched portion when drilled 3 mm with a drilling machine. It was evaluated by.
○: There is no crack or chipping.
X: There is a crack or chip.

"Synthesis of benzoxazine"
(1)
1 mol of 1,2-diaminoethane, 2 mol of phenol and 4 mol of formaldehyde were mixed and heated to 100 ° C. After the mixture becomes a uniform transparent liquid, the temperature is raised to 120 ° C. with stirring, the reaction is performed for 30 minutes, and a bifunctional benzoxazine in which R in the general formula (1) is an ethylene group (hereinafter referred to as “benzoxazine compound”). (C2) ”).
(2)
1 mol of 1,6-diaminohexane, 2 mol of phenol and 4 mol of formaldehyde were mixed and heated to 100 ° C. After the mixture becomes a uniform transparent liquid, the temperature is raised to 120 ° C. with stirring, the reaction is performed for 30 minutes, and R in the general formula (1) is a bifunctional benzoxazine (hereinafter referred to as “benzoxazine compound”). (C6) ”).
(3)
3 (4), 8 (9), - bis (aminomethyl) tricyclo [5,2,1,0 ^2,6] decane 1 mole, mixture of 2 moles of phenol and paraformaldehyde 4 mol and chloroform 1500 g, stirring The reaction was performed at 60 ° C. for 2 hours. After completion of the reaction, the reaction mixture was washed with 1N aqueous sodium hydroxide solution and then with ion exchange water. Next, after the chloroform phase was dried with anhydrous sodium sulfate, chloroform was distilled off by a rotary evaporator, and R in the formula (1) was 3 (4), 8 (9),-bis (aminomethyl) tricyclo [5,2 , 1,0 ^2,6 ] decane amino group residue, bifunctional dihydrobenzoxazine (hereinafter referred to as “benzoxazine (TCD)”) was obtained.

"High dielectric filler"
Barium titanate (manufactured by Wako Pure Chemical Industries, Ltd., average particle size 100 nm) was used.

[Example 1]
20 g of barium titanate is added to 10 g of the benzoxazine compound (C2), and after mixing well in a mortar with powder, heated at 120 ° C. under a reduced pressure of 133.3 Pa, stirred for 1 hour, A composition was obtained. The obtained composition was supplied to a mold having a length of 100 mm, a width of 20 mm, and a depth of 500 μm, and cured by heating at 140 ° C. for 1 hour, then at 160 ° C. for 1 hour, and finally at 180 ° C. for 2 hours. A sheet-like molded body having a size of 100 mm, a width of 20 mm, and a thickness of 500 μm was obtained.
The obtained sheet-like molded body was measured for dielectric constant and dielectric loss tangent, and was evaluated for workability.

[Example 2]
20 g of barium titanate was added to 10 g of the benzoxazine compound (C6), and after mixing well in a mortar with powder, heated at 100 ° C. under a reduced pressure of 133.3 Pa, stirred for 1 hour, A composition was obtained. The obtained composition was supplied to a mold having a length of 100 mm, a width of 20 mm, and a depth of 500 μm, and cured by heating at 140 ° C. for 1 hour, then at 160 ° C. for 1 hour, and finally at 180 ° C. for 2 hours. A sheet-like molded body having a size of 100 mm, a width of 20 mm, and a thickness of 500 μm was obtained.
The obtained sheet-like molded body was measured for dielectric constant and dielectric loss tangent, and was evaluated for workability.
[Example 3]
20 g of barium titanate is added to 10 g of the benzoxazine compound (TCD), and after mixing well in a mortar with powder, heated at 100 ° C. under a reduced pressure of 133.3 Pa, stirred for 1 hour, A composition was obtained. The obtained composition was supplied to a mold having a length of 100 mm, a width of 20 mm, and a depth of 500 μm, and cured by heating at 140 ° C. for 1 hour, then at 160 ° C. for 1 hour, and finally at 180 ° C. for 2 hours. A sheet-like molded body having a size of 100 mm, a width of 20 mm, and a thickness of 500 μm was obtained.
The obtained sheet-like molded body was measured for dielectric constant and dielectric loss tangent, and was evaluated for workability.

[Comparative Example 1]
Except that benzoxazine Pa (manufactured by Shikoku Kasei Kogyo Co., Ltd.) was used as the benzoxazine compound, a molded product was obtained in the same manner as in Example 1, and the same evaluation was performed. The benzoxazine Pa is a compound in which R is a phenyl group in the formula (4).

"Evaluation results"

As is clear from Example 1, Example 2, and Example 3, the high dielectric composite molded article of the present invention is excellent in workability and has both a sufficiently high dielectric constant and a low dielectric loss tangent.
In terms of dielectric constant, a dielectric constant of 10 is preferred for antenna applications. On the other hand, Example 1, Example 2, and Example 3 have a dielectric constant comparable to it. On the other hand, the dielectric loss tangent of Examples 1-3 has a sufficiently low value. In particular, Example 3 is excellent in dielectric loss tangent.
Furthermore, the processability is clearly superior to that of the benzoxazine of Comparative Example 1. Therefore, the high dielectric composite molded body of the present invention can be easily produced, and a high dielectric molded body that exhibits frequency characteristics as designed can be provided without cracking or chipping during the production.
By using the high dielectric composite molded body of the present invention, an antenna (particularly a patch antenna) and a capacitor can be provided at low cost and with stable performance.

  Next, as a specific example of using the high dielectric composite molded body of the present invention for an antenna, an embodiment of the antenna will be shown. When the high dielectric composite molded body of the present invention having a high dielectric constant is used as a substrate, the following antenna has a smaller effective wavelength and can be made compact. Therefore, it is preferable to use it by incorporating it in a mobile phone.

"Example 1"
FIG. 1 and FIG. 3 show an example in which the high dielectric composite molded body of the present invention is used for a planar antenna (patch antenna). The high dielectric composite molding of the present invention is used as the high dielectric constant substrate for the dielectric 112 of the planar antenna.
An electric conductor called a ground conductor 113 is provided on one surface of the high dielectric constant substrate. The electrical conductor is a continuum that conducts electrons, but a metal having a high conductivity, particularly copper, is desirable in order to reduce electrical loss.
A radiation conductor 111 that radiates electromagnetic waves is formed on the opposite surface of the ground conductor 113 via a high dielectric substrate 112. The power feeding pin 124 is connected to the radiation conductor 111 at the electrical connection point 121. The power feeding pin 124 is provided through the high dielectric substrate 112 toward the installation conductor 113 side. Electric power for radiating is supplied between 124 and the ground conductor 113. The electrical conductor is a continuum that conducts electrons, but a metal having a high conductivity, particularly copper, is desirable in order to reduce electrical loss.
The length of one side of the radiation conductor is an integral multiple of 1/2 of the effective wavelength of the electromagnetic wave at the frequency used. At this time, the radiation efficiency at the operating frequency increases. The effective wavelength is a value obtained by dividing the wavelength in vacuum at the frequency to be used by the square root of the dielectric constant.

"Example 2"
2 and 4 show other embodiments in which the high dielectric composite molded body of the present invention is used for a planar antenna (patch antenna).
The high dielectric composite molding of the present invention is used as the high dielectric constant substrate for the dielectric 212 of the planar antenna.
An electric conductor called a ground conductor 213 is provided on one surface of the high dielectric constant substrate. The electrical conductor is a continuum that conducts electrons, but a metal having a high conductivity, particularly copper, is desirable in order to reduce electrical loss.
A radiation conductor 211 that radiates electromagnetic waves is formed on the opposite surface of the ground conductor 213 through a high dielectric substrate 212. The power supply pin 224 is connected to the radiation conductor 211 at the electrical connection point 221. The power feeding pin 224 is provided through the high dielectric substrate 212 toward the installation conductor 213 side. Electric power for radiation is supplied between 224 and the ground conductor 213. The electrical conductor is a continuum that conducts electrons, but a metal having a high conductivity, particularly copper, is desirable in order to reduce electrical loss.
By providing the short-circuit conductor 214 between the radiating electrode and the ground conductor, an inverted F antenna is formed, and the length of one side is set to 1/2 the vertical and horizontal length of the radiating conductor of the first form, and the area is set to 1/4. Can do.
The length of one side of the radiation conductor is an integral multiple of 1/4 of the effective wavelength of the electromagnetic wave at the frequency used. At this time, the radiation efficiency at the operating frequency increases. The effective wavelength is a value obtained by dividing the wavelength in vacuum at the frequency to be used by the square root of the dielectric constant.

  The high dielectric composite molded body of the present invention is a molded body having excellent workability and having both a sufficiently high dielectric constant and a low dielectric loss tangent. Therefore, it can be preferably used for forming an antenna (particularly a patch antenna) or a capacitor.

It is a perspective view which shows the planar antenna using the high dielectric composite molded object of this invention. It is a perspective view which shows the planar antenna using the high dielectric composite molded object of this invention. It is sectional drawing of the planar antenna which uses the high dielectric composite molded object of this invention. It is sectional drawing of the planar antenna which uses the high dielectric composite molded object of this invention.

Explanation of symbols

111, 211: Radiation conductor 112, 212: High dielectric substrate 113, 213: Ground conductor 214: Short-circuit conductor 121, 221: Electrical connection point 124, 224: Feeding pin between radiation electrode and ground conductor

Claims (8)

A high dielectric composite molded body comprising a resin and a high dielectric filler, wherein the resin is a benzoxazine resin represented by the following formula (1).

In the formula, R is a divalent substituent having 2 or more carbon atoms, and hydrogen in the benzene ring may be substituted with an alkyl group or an alkoxy group.   R in the formula (1) is a linear alkylene group having 2 or more carbon atoms, a branched alkylene group in which hydrogen is alkyl-substituted, or an alkylene group containing an alicyclic structure. The high dielectric composite molded article according to claim 1. R in said Formula (1) is represented by following formula (2), The high dielectric composite molded object of Claim 1 characterized by the above-mentioned.
[Chemical 2]
_{- (CH 2) n- (2} )
n represents an integer of 2 or more and 30 or less.   3. The high dielectric composite molded article according to claim 2, wherein the alkylene group containing an alicyclic structure is an alkylene group containing a condensed ring type alicyclic structure. Alkylene groups containing the condensed ring alicyclic structure, 3 (4), 8 (9), - bis residues (aminomethyl) tricyclo [5,2,1,0 ^2,6] amino group decane The high dielectric composite molded article according to claim 4, wherein: The high dielectric composite molded article according to claim 1, 2, 3, 4, or 5, wherein the high dielectric filler contains at least an inorganic substance represented by the following formula (3).
[Chemical formula 3]
MO ・ TiO ₂ (3)
M represents one or more metal atoms selected from Ba, Sr, Ca, Mg, Co, Pd, Zn, Be, Cd, and Nd.   The high dielectric composite molded article according to claim 1, 2, 3, 4, 5 or 6, wherein the high dielectric filler is a particulate filler having a particle size of 10 nm or more and 100 µm or less. The ratio of the benzoxazine resin and the high dielectric filler contained in the high dielectric composite molding is 50 parts by weight to 500 parts by weight of the high dielectric filler with respect to 100 parts by weight of the benzoxazine resin. The high dielectric composite molded article according to claim 1, 2, 3, 4, 5, 6 or 7.

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