JPH07331003A - Low dielectric resin composition - Google Patents

Abstract

PURPOSE:To obtain a low dielectric resin composition having low dielectric constant, low dielectric dissipation factor, good heat resistance and good heat conductivity which are highly required for the circuit substrate materials of electric or electronic equipments. CONSTITUTION:The low dielectric resin composition is produced by adding (C) a fibrous material of general formula: aAXOY.bB2O3 (a and b are 1-9; A is monovalent-trivalent metal element; x=2, y=1 or x=y=1 or x=2, y=3) or general formula: pMVOW.qSiO2.rH2O (p, q and r are real numbers defined by 1<=p<=3; 1<=q<=3; 0<=r<=10; and v=2, w=1 or v=w=1 or v=2, w=3; M is the same as the above-mentioned A) to a resin composition comprising (A) a styrenic polymer having mainly a syndiotactic structure and (B) a thermoplastic resin in an amount of 5-60% based on the total amount of the resin components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a low dielectric resin composition.

[0002]

2. Description of the Related Art Conventionally, as a circuit board material, a glass epoxy substrate made by impregnating a glass mat with an epoxy resin which is a thermosetting resin and curing it has been generally used. It can be used only as a substrate, has a high dielectric constant of 4.5 to 5.5, and a high dielectric loss tangent of 0.020 to 0.035. It is used as a substrate material for electric and electronic circuits for the following reasons. It was not sufficiently favorable.

In recent years, with the dramatic increase in the amount of information transmitted by electromagnetic signals, a larger amount of information can be transmitted.
Or to improve the calculation speed of the computer,
The frequency of electric signals used in such devices has begun to shift to a high frequency band of hundreds of megahertz to tens of gigahertz. In such high frequency band applications, it is extremely important to form the circuit board with a material having excellent dielectric properties.

That is, the propagation delay time Td of the electric signal (ns /
m) and the permittivity have a relationship of Td = 3.33 (ε _eff ) ^1/2 (ε _eff : effective permittivity). The lower the permittivity, the shorter the propagation delay time, that is, the faster the propagation speed. It turns out that high-speed calculation is possible. Further, from this equation, it can be seen that if the dielectric constant varies among the substrate materials, the signal propagation speed also varies, which may cause a serious obstacle to information transmission.

The dielectric loss αD (dB / m) is αD =
27.3 × (f / c) × (ε) ^1/2 × tanδ,
Especially in the high frequency band, the transmission energy loss tends to be large, and it is understood that a substrate having a small dielectric constant and a small dielectric loss tangent is required.

In recent years, attempts have been made to integrate a circuit board and structural parts such as a chassis by injection molding into a three-dimensional molded circuit board. However, glass epoxy resin can be used only as a flat printed board. Can not. It has been proposed in JP-A-3-35585 that a thermoplastic resin is used as a matrix resin that enables three-dimensional molding, and glass fibers, milled glass fibers or potassium titanate whiskers are used as reinforcing fibers. , But it has come to be used by mixing only granular inorganic fillers (talc, calcium pyrophosphate, etc.) without using reinforcing fibers, but a substrate reinforced with potassium titanate whiskers has a dielectric loss of potassium titanate,
It is not preferable because of its high dielectric constant. Further, although the compound containing only the granular inorganic filler has a relatively low dielectric constant, it has a problem that the signal transmissivity is lowered due to a large dielectric loss.

Further, when a fiber having a large fiber diameter such as glass fiber is used, there is a problem that the surface smoothness of the resin is deteriorated. The blending of fibers is an effective means for lowering the coefficient of thermal expansion and improving the mechanical properties, but in the case of substrate materials, the deterioration of surface smoothness is a major problem. For example,
The reinforcing fibers disclosed in the above-mentioned JP-A-3-35585 include glass fibers and milled glass fibers, but many of them have a fiber diameter of 5 to 15 μm and a fiber length of 100 μm or more, and have a surface smoothness. Deterioration is inevitable. When the surface smoothness deteriorates, there are problems that an uncovered portion is generated when a fine circuit is formed by plating or the tip of the wire bonder is damaged when connecting a gold wire with the wire bonder. Furthermore, recent studies of electron behavior at high frequencies have revealed that electrons move near the surface in the high frequency region. Therefore, it is not preferable to use a material having a poor surface smoothness for the circuit board, because the electron moving distance becomes long and the signal transmission speed is delayed.

Incidentally, both polyetherimide and polyphenylene sulfide have excellent heat resistance, electrical insulation and mechanical properties, and polyphenylene ether has excellent electrical and mechanical properties. There is.

However, since polyetherimide and polyphenylene sulfide generally have a relatively high dielectric constant, their performance is limited as an insulating material for high density, multi-layer integration or high speed, high frequency circuits. There is.
On the other hand, syndiotactic polystyrene is inferior in heat resistance as compared with the above-mentioned polyetherimide and polyphenylene sulfide, but has a low dielectric constant and excellent electrical characteristics. Moreover, when compared with polyphenylene ether, when a fibrous material is filled, the heat distortion temperature is high and the thermal characteristics are excellent.

Therefore, the resin design of a polymer blend having the characteristics of each polymer by blending two or more polymers having different properties has been actively studied. However, since many polymers are incompatible systems, there are problems that mechanical properties and electrical properties are deteriorated and that they vary from part to part.

Further, as a material having excellent dielectric characteristics in a high frequency band, there are a resin simple substance and a fluorine type material.
Each of these resins alone lacks strength and has a large coefficient of linear expansion, and therefore cannot be said to be sufficiently satisfactory as a substrate material.

Furthermore, since electronic components such as ICs are highly integrated on the circuit board, a material having a large thermal conductivity is preferable in order to dissipate heat generated during use. However, polymers generally have low thermal conductivity, and there is a problem that it is difficult to improve them only by blending the polymers.

A resin composition obtained by adding a fibrous material to an alloy of a styrene-based copolymer having a syndiotactic structure and a thermoplastic resin is disclosed in JP-A-1-18.
2344, JP-A-1-182349, JP-A-1
-182350, Japanese Patent Application Laid-Open No. 1-245052, Japanese Patent Application Laid-Open No. 1-259053, Japanese Patent Application Laid-Open No. 2-641
No. 40, Japanese Patent Application Laid-Open No. 3-126743, etc., all of them have merely been found to be effective in improving mechanical properties, and are low demanded materials for electric and electronic devices. Dielectric properties and low dielectric loss tangent were not satisfied.

Conventionally, a thermoplastic resin composition containing magnesium pyroborate (JP-A-3-203961), a resin composition containing aluminum borate whiskers (JP-A-2-166134), a wax A resin composition containing rustonite (Japanese Patent Publication No. Sho 51-8412) and a resin composition containing zonotolite (Japanese Patent Publication No. Sho 53).
No. 20532, Japanese Patent Publication No. 63-22221, etc.) have been proposed, but all of these are merely used as compositions having excellent mechanical strength.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition having a low dielectric constant, a low dielectric loss tangent, a heat resistance and a thermal conductivity, which are highly required as a circuit board material for electric and electronic devices. To do.

[0016]

That is, the present invention provides (A)
Mainly resin composition comprising a styrene polymer (B) thermoplastic resins having a syndiotactic structure, (C) the general formula _{aA X O Y · bB 2 O} 3 (1~ respectively where a and b are
The number of 9, A is a metal element having a valence of 1 to 3, x and y are x = 2,
y = 1 or x = y = 1 or x = 2, y = 3) or a fibrous substance represented by the general formula pM _v O _w · qSiO ₂ ·
rH ₂ O (where 1 ≦ p ≦ 3, 1 ≦ q ≦ 3, 0 ≦ r ≦ 1
Real numbers of 0 and v and w are v = 2, w = 1 or v = w
= 1 or v = 2, w = 3, M is the same as A above), based on the total weight of the resin components, 5
The present invention relates to a low dielectric resin composition characterized by being mixed in a proportion of 60%.

Further, in the present invention, (D) a styrene-based copolymer may be blended if necessary.

The present inventor has surprisingly found that a specific fibrous material has an effect of lowering the dielectric loss tangent of a resin, and this effect can be utilized in a substrate for electric / electronic circuits in a high frequency region. As a result of further research, I thought that by blending a specific fibrous substance into a resin alloy made by blending a styrene polymer having a syndiotactic structure, a thermoplastic resin, and if necessary a styrene copolymer. It was found that the resin composition is a highly desirable material that solves the problems of the prior art.

The styrene-based polymer having a predominantly syndiotactic structure, which is the component (A) used in the present invention, usually has a diad of 75% or more, preferably 8%.
Polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (alkoxystyrene), poly having a syndiotacticity of 5% or more, or 30% or more in pentad (racemic pentad), preferably 50% or more (Vinylbenzoic acid ester), a mixture thereof, or a copolymer containing them as a main component can be mentioned.

The thermoplastic resin usable in the present invention includes polyphenylene ether, polyphenylene ether resin, 5-methylpentene resin, and polyphenylene ether resin whose impact resistance and moldability are improved by adding some polystyrene or styrene-butadiene elastomer. Polyamide-4 obtained by condensation polymerization of heat-resistant ABS resin, 1,4-diaminobutane / adipic acid whose heat distortion temperature is increased by copolymerizing a cyclic olefin containing a cyclic olefin such as norbornene resin as a component and maleimide , 6 A polyamide obtained from hexamethylenediamine and terephthalic acid
6T, modified polyamide-6 in which a part of terephthalic acid is replaced with isophthalic acid or adipic acid, heat-resistant polyamide resin such as 6 / 6T, polyphenylene sulfide resin, aromatic polysulfone resin, polyetherimide resin, polyether ketone Examples include resins, polyether nitrile resins, thermotropic liquid crystal polyesters, heat-fusible fluororesins such as ethylene / tetrafluoroethylene copolymers, tetrafluoroethylene / perfluoroalkoxy vinyl ether copolymers, polyethylene naphthalate resins, polybutylene naphthalate resins, etc. be able to.

The styrene-based copolymer that can be used in the present invention is an epoxy-modified styrene-styrene-based copolymer,
Epoxy-modified styrene-methyl methacrylate copolymer, styrene-maleic anhydride copolymer, styrene-phenylmaleimide copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and the like,
Of these, an epoxy-modified styrene-styrene copolymer, an epoxy-modified styrene-methyl methacrylate copolymer, and a styrene-maleic anhydride copolymer are preferable.

The general formula aA which can be used in the present invention
_{X O Y · bB 2 O 3} ( where a and b the number of each of 1 to 9, A is a monovalent to trivalent metal element, x and y are x = 2, y =
1 or x = y = 1 or x = 2, y = 3), A is, for example, Mg, Ca, C
r, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga, Sr,
Examples thereof include Y, Zr, Nb, Mo, Pb, Ba, W and Li. Of these, aluminum borate whiskers in which A is Al, magnesium borate whiskers in which A is Mg, and nickel borate whiskers in which A is Ni are preferable. More preferred aluminum borate whiskers include 9Al ₂ O ₃ .2B ₂ O ₃
Or it can be exemplified those represented by the formula _{2Al 2 O 3 · B 2 O} 3.

All of these whiskers are white needle-like crystals, and for example, at least one aluminum-supplying component selected from aluminum hydroxide and aluminum inorganic salts, boron oxide, oxyacid and alkali metal salt. And at least one boron-supplying component selected from the range of 600 to 1200 ° C., preferably in the presence of at least one melting agent selected from alkali metal sulfates, chlorides and carbonates. It is easily manufactured by reacting and growing by heating to the firing temperature. Aluminum borate whiskers of the formula _{9Al 2 O 3 · 2B 2 O} 3 is a true specific gravity from 2.93 to 2.95, melting point 14
20 to 1460 ° C., firing temperature 900 to 1200 ° C.
Those manufactured by In addition, the formula 2Al ₂ O ₃ ·
Aluminum borate whiskers represented by B ₂ O ₃ have a true specific gravity of 2.92 to 2.94 and a melting point of 1030 to 1070 ° C., and those produced at a firing temperature of 600 to 1000 ° C. are preferable.

The commercially available aluminum borate whiskers are, for example, of the formula 9Al ₂ O ₃ .2B ₂ O ₃
(The product name "Arborex G" manufactured by Shikoku Chemicals Co., Ltd.) is available, and the average fiber diameter of this product is 0.
The average fiber length is 5 to 1 μm and the average fiber length is 10 to 30 μm. By the addition the _{9Al 2 O 3 · 2B 2 O} 3 optionally heating at a temperature of 1200 to 1400 ° C. C. in an oxidizing atmosphere or a reducing atmosphere, also used fibers desorbed a part of the boric acid component be able to.

More specifically, the magnesium borate whiskers which can be used in the present invention are represented by the formula 2 Mg
The whiskers can be exemplified by those represented by O · B ₂ O _3. The whiskers are white needle-shaped crystals, for example, at least one magnesium-supplying component selected from magnesium oxide, hydroxide and inorganic acid salt, At least one boron supplying component selected from oxides of boron, oxyacids and alkali metal salts thereof, preferably in the presence of at least one melting agent selected from sodium halides and potassium halides. 600-1000
It can be easily produced by heating to a firing temperature of ° C to cause reaction and growth. The aluminum borate whisker represented by the formula 2MgO.B ₂ O ₃ has a true specific gravity of 2.9.
It is preferably 0 to 2.92 and a melting point of 1320 to 1360 ° C. These aluminum borate whiskers and magnesium borate whiskers have an average fiber diameter of 0.05 to 5 μm.
m, average fiber length 2-100 μm can be manufactured,
Any of them can be used in the present invention, but for ease of production, the average fiber diameter is 0.1 to 2 μm, the average fiber length is 10 to 50 μm.
Those of m are preferably used.

The general formula used in the present invention pM _v O _w · qS
iO ₂ · rH ₂ O (where 1 ≦ p ≦ 3, 1 ≦ q ≦ 3, 0 ≦
a real number of r ≦ 10, v and w are v = 2, w = 1 or v = w = 1 or v = 2, w = 3, and M is the same as A above). Is, for example, C
aO ・ SiO ₂ (Wollastonite), 6CaO ・ 6SiO ₂・
H ₂ O _{(xonotlite), 3Al 2 O 3 · 2SiO} 2 ( mullite), 2ZnO · SiO ₂ (zinc silicate), 2MgO · 3S
iO ₂ · 3.5H ₂ O (sepiolite), 3MgO · 2SiO
₂ · 2H ₂ O (chrysotile), and the like.
Among these can be exemplified xonotlite like shown particularly preferred as in wollastonite and 6CaO · 6SiO ₂ · H ₂ O represented by CaO · SiO _2. Wollastonite is a naturally occurring white needle crystal, which can be used as it is or after being crushed and classified, regardless of whether it is fibrous or lumpy, and is a synthetic product. May be. The fibrous material has a different aspect ratio depending on the pulverizing method and the place of production, but generally β-type wollastonite having a large aspect ratio is desirable from the viewpoint of reinforcing performance. In order to improve the mechanical properties and thermal properties of the target product, a component having an aspect ratio of 6 or more is contained in an amount of 60% by weight or more, preferably 80% by weight or more, and the fiber diameter is 5 μm.
80% by weight or more, preferably 95% by weight or less of a component of m or less
It is preferable to use fine and long wollastonite containing the above. For example, in the case of thick and long wollastonite that contains 60% by weight or more of components having an aspect ratio of 10 or more and 80% by weight or more of components having a fiber diameter of 6 μm or more, It easily breaks during kneading, and it is difficult to combine mechanical properties and thermal properties.

Some of the wollastonite currently on the market satisfy the above-mentioned standards, and the average fiber diameter of this is 2.0 μm, the average fiber length is 25 μm, and the fiber diameter is 5 μm.
Since the following components are 95% by weight or more and the components having an aspect ratio of 6 or more are 90% by weight or more, the reinforcing performance and the surface smoothness are extremely excellent.

On the other hand, xonotlite has a chemical composition of 6CaO.
It is a fibrous calcium silicate represented by 6SiO · H ₂ O, and has an average fiber diameter of 0.5 to 1 μm and an average fiber length of 2 to 5 μ.
m, aspect ratio 2 to 15 are synthesized. The present inventors have found that xonotlite is different from wollastonite,
It was found that although it contains water of crystallization, it has low dielectric constant and low dielectric loss tangent as dielectric properties of wollastonite. Regarding the reinforcing effect, it was confirmed that the mechanical properties and heat resistance (heat distortion temperature) were improved by using a material having a large aspect ratio (preferably 6 or more).

The fibrous material which can be used in the present invention is effective in improving the wettability and the bondability with the matrix resin, and may be pretreated with a coupling agent within a range not impairing the object of the present invention. . As the coupling agent, for example, a surface treatment with a silane coupling agent such as epoxysilane, aminosilane, acrylsilane or a titanate coupling agent further improves mechanical properties. Of these, epoxysilane and aminosilane coupling agents are highly effective for the fibrous material used in the present invention.
It is preferable to add 0.3 to 5% by weight and to perform surface treatment. Incidentally, it is important that the coupling agent used in the present invention has a low dielectric property.

Next, the compounding ratio of each component in the production of the resin composition of the present invention will be described. Among the resins used in the present invention, the blending ratio of the styrene polymer mainly having a syndiotactic structure as the component (A) and the thermoplastic resin as the component (B) is 2 to 98:98 to 2 (weight ratio). Good to do. Preferably 20-80: 80-2
It is preferable to set it to 0 (weight ratio). One kind or two or more kinds selected from the styrene-based copolymer of the component (D) is, if necessary, 0.1 to 30 parts by weight based on 100 parts by weight of the total of the components (A) and (B), It is preferable to add 0.5 to 20 parts by weight. When the component (B) is polyphenylene ether or polyphenylene sulfide, 0.1 to 30 parts by weight is blended with one or more selected from the styrene copolymers as the component (D). At that time, if the blending amount is too small, the compatibility is insufficient, so that a uniform polymer blend cannot be produced, and the impact resistance and the uniformity of electrical properties are impaired, which is not preferable. Further, if the blending amount exceeds 30 parts by weight, not only the heat resistance lowers but also the mechanical strength may lower, which is not preferable.

100 parts by weight of a thermoplastic resin (polymer blend composition) prepared by blending the above resin components,
5 to 60 parts by weight of the fibrous component (C), preferably 1
The resin composition of the present invention is obtained by intimately mixing 0 to 50 parts by weight. When the compounding amount of the component (C) is less than 5 parts by weight, the mechanical properties are poor and the effect of lowering the dielectric loss tangent cannot be obtained, which is not preferable, and when it exceeds 60 parts by weight, melt-kneading into the thermoplastic resin is difficult. And the viscosity increases during kneading and dispersion operations, making molding extremely difficult, which is not preferable.

In the present invention, in addition to the above essential components, (1) a fine particle filler such as talc for improving the plating property, and (2) an antioxidant for improving the thermal stability, (3) An ultraviolet absorber for improving light resistance, (4) a flame retardant and a flame retardant aid for improving flame retardancy, (5) a lubricant for imparting lubricity, Sliding property improvers (solid lubricants, liquid lubricants), (6) colorants such as dyes and pigments for improving impact resistance, impact resistance imparting agents, and (7) coloring. You may mix | blend each.

The flame retardant must be selected according to the thermoplastic resin or thermosetting resin used, but in general, decabromobiphenyl ether, hexabromobiphenyl, brominated polystyrene, an oligomer of tetrabromobisphenol A, Halogenated polycarbonate oligomers such as brominated polycarbonate oligomers, halogen-based flame retardants such as halogenated epoxy compounds, and phosphorus-based flame retardants such as ammonium phosphate, tricresyl phosphate, and triphenylphosphine oxide can be used. Further, when an antimony-based compound typified by antimony trioxide and zinc borate, barium metaborate, or zirconium oxide are used together as a flame retardant aid, the flame retardant effect is improved.

There are no particular restrictions on the production of the resin composition of the present invention, and conventionally known methods can be widely adopted. However, a mixing mixer having a heating function and a mixing function, or a single or twin screw extruder is used. A manufacturing apparatus such as can be preferably used.

Above all, it is preferable to use a twin-screw extruder to mix and supply the resin components in a predetermined composition from the main hopper, add the fibrous components to the melt-kneaded mixture, and further knead the mixture. The resin composition of the present invention may be molded into any molded product immediately after production, or may be once formed into pellets.

[0036]

EXAMPLES The effects of the present invention will now be specifically described with reference to Examples of the present invention and Comparative Examples, but the present invention is not limited thereto.

Examples 1 to 15 and Comparative Examples 1 to 5 Styrene-based polymers (SPS) mainly having a syndiotactic structure; prepared according to the formulation described in JP-A-63-191811. The linear expansion coefficient of SPS alone is 6.5 × 10 ⁻⁵ cm / cm / ° C. (flow direction), 6.3 × 1
0 is ^-5 cm / cm / ℃ (perpendicular direction). Atactic polystyrene; "Idemitsu Styrol US-305" manufactured by Idemitsu Petrochemical Co., Ltd. Polyetherimide (PEI); "Ultem 1000" manufactured by General Electric, USA Polyphenylene ether (PPE); "P1" manufactured by Asahi Kasei Corporation
01M "Polyphenylene sulfide;" Toprene T-4P "manufactured by Topren Co., Ltd. Styrene-based copolymer;" Dailark D-332 "manufactured by MTC-ARCO Co., Ltd .; fibrous material; aluminum borate whiskers;" Arborex "manufactured by Shikoku Chemicals Co., Ltd. G "Magnesium borate whiskers;" Suwanite "manufactured by Otsuka Chemical Co., Ltd. was used to measure the physical properties of the resin composition blended at a predetermined ratio shown in Tables 1 to 3.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

Examples 16 to 30 and Comparative Examples 6 to 9 Fibrous materials were made of wollastonite; CaO.SiO ₂ ; Partek.
Minerals Co. "WICROLL-10" and xonotlite; except for using 6CaO · 6SiO ₂ · H ₂ O was performed in the same manner as in Examples 1 to 15, measurement results are shown in Table 4-6.

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

[0045]

As described in detail above, the resin composition of the present invention improves the heat resistance and dielectric properties of the thermoplastic resin mainly by improving the compatibility with the styrene copolymer having a syndiotactic structure. With excellent characteristics, mechanical strength of polyphenylene ether or polyether imide,
Combined with the excellent heat resistance, the general formula aA _x O _y ·
fibrous material represented by bB ₂ O ₃ or the general formula pM _v O _w · q
By blending the fibrous material represented by SiO ₂ · rH ₂ O, not only the mechanical strength and heat distortion temperature (solder heat resistance) are further increased, but also the dielectric loss tangent is maintained while keeping the dielectric constant low. It is possible to provide a low dielectric resin composition which can be greatly reduced in size, has a high thermal conductivity, and is extremely desirable as a circuit board having improved heat dissipation.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C08L 25:08) (72) Inventor Ayumi Kusumoto 463 Kagasuno, Kawauchi-cho, Tokushima-shi, Tokushima Otsuka Chemical Co., Ltd. Company Tokushima Research Institute (72) Inventor Shogo Kawakami 3-2 27 Otedori, Chuo-ku, Osaka City, Osaka Otsuka Chemical Co., Ltd.

Claims (7)

[Claims] 1. A resin composition comprising (A) a styrene polymer mainly having a syndiotactic structure (B) a thermoplastic resin, and (C) a general formula aA _X O _Y .bB ₂ O ₃ (where a is a). And b are 1 to
The number of 9, A is a metal element having a valence of 1 to 3, x and y are x = 2,
y = 1 or x = y = 1 or x = 2, y = 3) or a fibrous substance represented by the general formula pM _v O _w · qSiO ₂ ·
rH ₂ O (where 1 ≦ p ≦ 3, 1 ≦ q ≦ 3, 0 ≦ r ≦ 1
Real numbers of 0 and v and w are v = 2, w = 1 or v = w
= 1 or v = 2, w = 3, M is the same as A above), based on the total weight of the resin components, 5
A low dielectric resin composition characterized by being mixed in a proportion of from 60% to 60%. 2. (A) A styrene polymer mainly having a syndiotactic structure (B) A thermoplastic resin (D) An epoxy-modified styrene-styrene copolymer, an epoxy-modified styrene-methyl methacrylate copolymer,
Styrene-maleic anhydride copolymer, styrene-phenylmaleimide copolymer, styrene-acrylic acid copolymer, a resin composition comprising a styrene-based copolymer selected from the group of styrene-methacrylic acid copolymer, ( C) formula _{aA X O Y · bB 2 O} 3 (1~ respectively where a and b are
The number of 9, A is a metal element having a valence of 1 to 3, x and y are x = 2,
y = 1 or x = y = 1 or x = 2, y = 3) or a fibrous substance represented by the general formula pM _v O _w · qSiO ₂ ·
rH ₂ O (where 1 ≦ p ≦ 3, 1 ≦ q ≦ 3, 0 ≦ r ≦ 1
Real numbers of 0 and v and w are v = 2, w = 1 or v = w
= 1 or v = 2, w = 3, M is the same as A above), based on the total weight of A + B + D,
A low dielectric resin composition characterized by being mixed in a proportion of 5 to 60%. 3. The low dielectric resin composition according to claim 1, wherein the thermoplastic resin (B) is one kind or two or more kinds selected from polyphenylene ether, polyetherimide and polyphenylene sulfide. 4. The (C) fibrous material is 9Al ₂ O ₃ .2B ₂ O.
_{3, 2Al 2 O 3 · B} 2 O 3 at is at least one selected from the group consisting of magnesium borate represented by aluminum borate and 2MgO · B ₂ O ₃ is shown, and fiber form the average fiber diameter 0. The low dielectric resin composition according to claim 1 or 2, which has an average fiber length of 05 to 5 µm and an average fiber length of 2 to 100 µm. 5. The general formula of (C) aM _X O _Y .bSiO ₂ .c
The fibrous material represented by H ₂ O contains 60% by weight or more of a component having an aspect ratio of 6 or more, and 80% by weight or more of a component having a fiber diameter of less than 5 μm. Dielectric resin composition. 6. The general formula of (C) pM _v O _w · qSiO ₂ · r.
H fibrous material represented by ₂ O is _{pCa v O w · qSiO 2 ·} rH
₂ O (where p, q, r, v, w and M are the same as above)
The low dielectric resin composition according to claim 1, which is represented by 7. The general formula of (C) pM _v O _w .qSiO ₂ .r
The fibrous material represented by H ₂ O is wollastonite containing CaO.SiO ₂ as a main component and / or 6CaO.6SiO ₂ .H ₂ O
The low dielectric resin composition according to claim 6, which is xonotlite represented by