JPH11323162A - Insulating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an insulation composition having excellent electrical insulation properties and thermal conductivity, whose composition contains a liquid crystal resin prepared by polymerizing a resin composition containing a monomer having a mesogenic group and has specified or higher thermal conductivities in two rectangular directions. SOLUTION: There is provided an insulation composition containing a liquid crystal resin obtained by thermally reacting a resin composition containing a monomer having a carboxyl-free mesogenic group represented by formula I under a specified voltage applied in the direction of thickness and being in a solid state in which the monomer molecules are partially arranged about the mesogenic groups as centers and having thermal conductivities of 0.4 W/mK in two rectangular directions. If required, this composition contains an inorganic ceramics, such as aluminum oxide, boron nitride, or silicon carbide, having a thermal conductivity of 10 W/mK or above. The resin used is an epoxy resin, a polyurethane resin, an acrylic resin, or the like. In formula I, X is a single bond, -N=N-, -C≡C-, or a bond represented by formula II; n is 0-4; and Y is -R, -OR (wherein R is a 1-8C aliphatic hydrocarbon group), -F, -Cl, -Br, -CN, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating composition having electrical insulation and excellent thermal conductivity.

[0002]

2. Description of the Related Art Most electric devices, from motors and generators to printed wiring boards and IC chips, are composed of a conductor for conducting electricity and an insulating material. In recent years, the miniaturization of these electric devices has been rapidly progressing, and the characteristics required for insulating materials have also become quite high. Above all, the amount of heat generated from high-density conductors has been increasing along with miniaturization, and how to dissipate heat has become an important issue.

Heretofore, organic insulating compositions have been widely used as insulating materials for various electric devices because of their high insulating performance and ease of molding. However, the organic insulating composition generally has a low thermal conductivity, which is one of the factors that hinder the heat dissipation. Therefore, the need for an organic insulating composition having high thermal conductivity is very high.

[0004] As a method of achieving high thermal conductivity, there is a method of using a conductive substance to the extent that electrical insulation is not impaired. For example, Japanese Unexamined Patent Publication No. 67-2716 describes a thermoplastic plastic having good thermal conductivity and electrical insulation properties, in which a resin is filled with a light metal powder represented by aluminum or a non-ferrous metal powder. JP-A-63-175493 describes a printed wiring board using an electron conjugated aromatic polymer such as polythiophene as an insulating material. This utilizes the property that an electron conjugated aromatic polymer becomes conductive when combined with a dopant, but is an insulator when it does not contain a dopant. However, since these methods use a substance that is essentially conductive, the dielectric breakdown voltage of the organic insulating composition has been extremely low.

As another method for achieving high thermal conductivity, there is a method of filling an organic insulating composition with a high thermal conductive inorganic ceramic. As inorganic ceramics, silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride,
Examples of silicon carbide, aluminum fluoride, calcium fluoride and the like are known. By filling an inorganic ceramic having both electric insulation and high thermal conductivity, the dielectric breakdown voltage is improved while achieving high thermal conductivity. However, when the inorganic ceramic is mixed with the monomer of the organic insulating composition, the viscosity of the mixture increases remarkably, so that the workability is extremely poor and it is difficult to produce a fine structure. It is also known that the strength of an organic insulating composition filled with an inorganic ceramic decreases.

Further, in such a composite organic insulating composition in which two or more kinds of materials are mixed as in these cases, separation at the interface between the two or more kinds of materials is liable to occur, and the insulating property becomes long after long-term use. A sharp decrease in breakdown voltage or the like is conceivable.

Japanese Unexamined Patent Publication (Kokai) No. 61-296068 describes a plastic compound having high thermal conductivity filled with ultra-highly oriented polymer fibers. This is POLY
The super-highly oriented polymer fiber described in MER, Vol. 19, P155 (1978) utilizes the property that the thermal conductivity is improved in the fiber axis direction. However, ultra-highly oriented polymer fibers have low thermal conductivity in the direction perpendicular to the fiber axis, so even if polymer fibers are randomly dispersed in the organic insulating composition, the thermal conductivity does not improve much. . By arranging the polymer fibers in one direction in the organic insulating composition, an organic insulating composition having excellent thermal conductivity can be obtained in the arranged direction,
In other directions, the thermal conductivity decreases. Further, also in this case, the composite insulating composition is a mixture of two types of materials, and peeling at the interface between them is likely to occur as described above.

As a method for achieving high thermal conductivity with a single organic insulating composition, there is known a method utilizing high thermal conductivity in the direction of oriented molecular chains. JP-A-1-149303
Of Japanese Patent Application Laid-Open Nos. JP-A-2-5307, JP-A-2-28352, and JP-A-2-127438, in which an organic insulating composition such as polyoxymethylene or polyimide is applied while an electrostatic voltage is applied. A method is described. Also, JP-A-63-
Japanese Patent No. 264828 discloses that a sheet in which molecular chains of polypropylene, polyethylene, etc. are arranged is laminated so that the arrangement direction is overlapped and then fixed, and a laminated product is sliced in a direction perpendicular to the orientation direction so that the molecular chains are arranged in the vertical direction. Described organic insulating compositions. This is an organic insulating composition in which the molecular chains are arranged in one direction and the thermal conductivity in the direction of the molecular chains is high, and the thermal conductivity in the other directions is low.

Further, ADVANCED MATERIALS, Vol. 5, P1
07 (1993), and German Patent Application Publication No. 422699.
No. 4 describes a material in which a monomer such as diacrylate having a mesogen group is oriented in one direction and then subjected to a crosslinking reaction. These materials also use the fact that the molecular chains are arranged in one direction and that the thermal conductivity in the direction of the molecular chain is high, so that the thermal conductivity in other directions is a low organic insulating composition. I have.

Japanese Patent Application Laid-Open No. 9-118673 discloses a liquid crystal thermosetting using a liquid crystal twin epoxy monomer having two mesogens which can be cross-linked and are connected by a bent chain portion capable of forming a polymer structure. Describe the polymer.

As a method for achieving high thermal conductivity in any spatial direction with a single organic insulating composition, a method of single-crystallizing the organic insulating composition is considered. However, in practice, it is extremely difficult to single crystallize the organic insulating composition.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an insulating composition which is electrically insulating and has excellent thermal conductivity.

[0013]

Means for Solving the Problems The present inventors have clarified that the cause of the low thermal conductivity of an insulating composition is generally a defect existing in the insulating composition. In addition, since the insulating composition contains, as an essential component, a liquid crystalline resin obtained by polymerizing a resin composition containing a monomer having a mesogen group, defects in the insulating composition are reduced, and a heat conduction of 0.4 W / mK or more. Has been found to be an insulating composition having a high ratio. Then, it has been found that this insulating composition becomes an insulating composition having a thermal conductivity of 0.4 W / mK or more in two or more directions substantially perpendicular to each other.

The features of the present invention are as follows.

An insulating composition containing, as an essential component, a liquid crystalline resin obtained by polymerizing a resin composition containing a monomer having a mesogen group, and having a thermal conductivity of at least 0.4 W / mK in two directions substantially perpendicular to each other. It is characterized by being.

It is preferable that the monomer has an epoxy group.

The monomer preferably has a mesogen group represented by the following formula (1) in the molecule.

[0018]

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The polymerization of the resin composition containing a monomer having a mesogen group may be carried out, if necessary, in (A) an electric field.
(B) can be performed in a magnetic field, (C) can be performed while irradiating an electromagnetic wave, or can be performed in combination of (A) to (C).

After polymerizing the resin composition, stretching, rolling or rubbing may be performed. By the polymerization environment or the post-polymerization treatment, the monomer molecular chains can be preferentially oriented in a certain direction, and a superior thermal conductivity can be achieved in that direction. Moreover, since the liquid crystal resin is contained as an essential component, the thermal conductivity in other directions is excellent.

For stretching, for example, a longitudinal stretching machine having two or more rolls having different rotation speeds can be used. The sheet-like insulating composition is rolled on a low-speed roll of a longitudinal stretching machine,
By passing the rolls in the order of the high-speed roll, a sheet stretched at a ratio of the speed can be manufactured. At this time,
The molecular chains are easily oriented in the stretching direction.

For rolling, for example, a calendar having two or more rolls can be used. The sheet rolled into the gap between the rolls can be manufactured by sandwiching the insulating composition in the form of a powder, a lump, or a sheet between rolls of a calendar and heating and compressing the same. At this time, the molecular chains are easily oriented in the rolling direction.

The insulating composition may include an inorganic ceramic, if necessary.

The inorganic ceramic which may be included in the insulating composition preferably has a thermal conductivity of 1 W / mK or more, and specifically includes silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, It is selected from boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum fluoride, or calcium fluoride. Among these, one kind or a mixture of two or more kinds may be used. More preferably, it is an inorganic ceramic having a thermal conductivity of 10 W / mK or more, and specifically, selected from aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, and aluminum fluoride. Among these, one kind or a mixture of two or more kinds may be used. Among them, aluminum oxide having a volume resistivity of 10 ¹⁶ Ωcm or more is more preferable.

In the production of the insulating composition, the resin composition containing a monomer having a mesogen group is heated under a condition that the resin composition is partially and orderly arranged around the mesogen group at the start of polymerization. Is preferred.

The liquid crystalline resin in the present invention is defined as a mesogenic resin under the condition that a resin composition containing a monomer having a mesogenic group is at least partially arranged in an ordered manner around the mesogenic group during the polymerization reaction. It refers to a polymerized resin composition containing a monomer having a group, which is solidified while being arranged in an order around a mesogen group. A liquid crystalline resin can be obtained by using a polarizing microscope or X-ray.
It can be confirmed by line diffraction.

The insulating composition in the present invention is preferably a polymer or resin which is obtained by polymerizing a monomer having a mesogen group and which can be generally used for insulation. That is, examples thereof include polyamide, polyester, polycarbonate, polysulfone, polyimide, polybenzimidazole, polyurethane resin, epoxy resin, acrylic resin, methacrylic resin, and unsaturated polyester resin. In particular, a high-strength thermosetting resin, that is, a polyurethane resin, an epoxy resin, an acrylic resin, a methacrylic resin, or an unsaturated polyester resin is preferable. Further, an epoxy resin is particularly preferred because of its ease of molding and high insulating properties.

The mesogenic group in the present invention is a functional group that develops a liquid crystal. Specifically, the following (Formula 3)
It is shown in.

[0029]

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Preferably, the one shown in the following (Chemical Formula 1) which is hardly hydrolyzed is preferable.

[0031]

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In these cases, since they are resistant to water and have excellent long-term reliability and can be used outdoors, their applications are widened.

The insulating composition of the present invention does not require that the resin composition containing a monomer having a mesogenic group be partially and orderly arranged around the mesogenic group before the initiation of polymerization. During the polymerization reaction, it is necessary to carry out the polymerization under the condition that the mesogen group is partially and orderly arranged around the mesogen group. A method is preferred in which the resin composition containing a monomer having a mesogen group is heated to produce a state in which the resin composition is arranged with order around the mesogen group at least at the start of polymerization.

Such an insulating composition of the present invention can be formed into an insulating composition containing, as an essential component, a liquid crystal resin obtained by polymerizing a resin composition containing a monomer having a mesogen group, so that two directions substantially perpendicular to each other are formed. In this case, excellent heat conductivity is exhibited, and the heat dissipation of the heat generated from the conductor of the electric device can be improved. In addition, by using the insulating composition according to the present invention, the heat dissipation of the electric device is improved, and the size of the electric device can be reduced.

The reason why the material obtained by aligning the monomer having a mesogen group shown in Chemical Formula 1 in one direction and then performing a cross-linking reaction is susceptible to water and has poor long-term reliability is that the mesogen group contains It was clarified that the contained carboxy group was hydrolyzed, and it was found that long-term reliability could be ensured by using a monomer having a mesogen group having no carboxy group in the molecule.

Another aspect of the present invention is an insulating composition containing, as an essential component, a liquid crystal resin obtained by polymerizing a resin composition containing a monomer having a mesogen group represented by the above formula (1). The thermal conductivity is not less than 0.4 W / mK.

This insulating composition is used for all or a part of an insulating material of an electric device having a conductor for conducting electricity and an insulating material. The conductor used in the electric device generates heat due to the passage of electricity, and the insulating composition used in the present invention is used for such a heat-generating article. Therefore, it is necessary that the thermosetting resin composition be polymerized by heat without being easily deformed by heat.

In this case also, the monomer preferably has an epoxy group. Also in this case, the above-described polymerization environment or post-polymerization treatment may be performed,
The aforementioned inorganic ceramics may be included.

Further, as the insulating composition in this case, those described above can also be used.

In this case, the mesogenic group is a functional group which exhibits a liquid crystal without a carboxyl group. Specifically, it is shown in the above (Chemical Formula 1).

In this case, since there is no carboxyl group, hydrolysis hardly occurs, and excellent long-term reliability is obtained.

Such an insulating composition of the present invention has an excellent heat conduction property by comprising, as an essential component, a liquid crystal resin obtained by polymerizing a resin composition containing a monomer having a mesogen group without a carboxyl group. Not only can improve the heat dissipation of the heat generated from the conductors of the electrical equipment, but also have excellent long-term reliability because there is no carboxyl group. By using the insulating composition according to the present invention, heat dissipation can be improved, the size of the electric device can be reduced, and the electric device can be used in a severe environment.

Another aspect of the present invention is to provide, as an essential component, a liquid crystalline resin obtained by polymerizing a resin composition containing a monomer having at least one reactive group represented by the following chemical formula (2) and a mesogen group. Characterized by including an insulating composition. Preferably, the thermal conductivity is 0.4 W / mK or more.

[0044]

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The monomer preferably has a mesogen group represented by the above formula (1) in the molecule.

Also in this case, the above-mentioned polymerization environment and post-polymerization treatment may be performed, and the above-mentioned inorganic ceramic may be included.

In this case, the above-mentioned insulating composition can also be used. Examples include polyamide, polyester, polycarbonate, polysulfone, polyimide, polybenzimidazole, polyurethane resin, epoxy resin, acrylic resin, methacrylic resin, unsaturated polyester resin, and the like. In particular, high-strength thermosetting resins, ie, polyurethane resins, epoxy resins,
Acrylic resins, methacrylic resins, and unsaturated polyester resins are preferred. Further, an epoxy resin is particularly preferred because of its ease of molding and high insulating properties.

The reactive group of the monomer in the present invention includes:

[0049]

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Preferably, the reactive group is

The mesogen group in the present invention is also preferably a functional group which expresses the liquid crystal shown in the above (Chemical Formula 3), and more preferably, the mesogenic group shown in the above (Chemical Formula 1) which hardly causes hydrolysis. Good.

The theory of achieving high thermal conductivity in the present invention is as follows:
It is as follows.

The heat conduction of a substance includes electron conduction and phonon conduction. The heat conduction of an insulator is mainly caused by phonons, and its thermal conductivity is determined by the static scattering of phonons due to defects in the material and the phonon. Scattering by collision of phonons due to anharmonicity of molecular and lattice vibrations (umklapp process)
To be reduced. An ordinary insulating composition (polymer) generally has a low thermal conductivity because it has many defects in the material and a large inharmonicity of molecules and lattice vibration.

As a conventional technique, as a method for increasing the thermal conductivity of the insulating composition (polymer), there is a method using a conductive polymer because the contribution by electron conduction is used. However, as a matter of course, the insulating property is deteriorated, and it is not used as an insulating material.

As another method, there is a method utilizing the fact that the thermal conductivity of the polymer in the main chain direction is large. Since the main chain direction of the polymer is linked by strong conjugate bonds, the anharmonicity of vibration (phonon) in the main chain direction is small,
Defects and the like that cause static scattering of phonons are much smaller than in the intermolecular direction (perpendicular to the main chain). That is, in the main chain direction, both dynamic and static scattering of phonons are smaller than in the intermolecular direction, and therefore, the thermal conductivity is larger. In this method, the main chain is oriented in a desired direction, and the increased thermal conductivity in the orientation direction is used. Examples of a method for orienting the main chain include a stretching method, a method using an electric field, a method using rubbing, and the like. However, in the conventional method, the thermal conductivity in the orientation direction increases, but the thermal conductivity in the direction perpendicular to the orientation decreases. When used as an insulating material, the direction in which the thermal conductivity is desired to be increased is overwhelming in the direction of the thickness of the polymer insulating film. It is extremely difficult to increase the thermal conductivity in the thickness direction of the insulator film.

In the present invention, if the order of a substance increases,
We focused on the fact that the thermal conductivity in the direction between molecular chains can also be increased. That is, due to the increase in the order, the anharmonicity of the vibration is reduced, and the defects causing static scattering of phonons can be reduced. One of the methods for maximizing the order of the material is to use perfect crystals (one example of this is that diamond has a very high thermal conductivity). It is practically impossible to apply as. Therefore,
In the present invention, attention has been paid to a liquid crystal state having a high order following the crystal. Specifically, the insulating composition containing, as an essential component, a liquid crystalline resin obtained by polymerizing the resin composition containing a monomer having a mesogen group of the present invention has defects not only in the molecular chain direction but also in the intermolecular direction. Less and
Vibration anharmonicity is also small, and therefore, compared to conventional organic polymer insulating materials,
Has great thermal conductivity.

In the present invention, the mesogen group which is a functional group that expresses a liquid crystal is most preferably the one shown in the following (Formula 4) from the viewpoint of easiness of synthesis, and from the viewpoint that deterioration due to hydrolysis hardly occurs. Those shown in the above (Chemical Formula 1) are preferable. However, in view of the fact that it is a functional group that expresses a liquid crystal, the present invention can be achieved even with the above-mentioned (Formula 3).

[0058]

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Note that the liquid crystal has a property of being arranged with order within a certain temperature range between a solid and a liquid.

[0060]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be shown, and the present invention will be specifically described.

Example 1 An epoxy resin composition obtained by mixing 270 g of 4,4'-biphenol diglycidyl ether and 200 g of 4,4'-diaminodiphenylbenzoate was poured into a mold and cured at 150 ° C. for 10 hours. ,
By heating and curing at 200 ° C. for 5 hours, an epoxy resin plate having a thickness of 1 mm was obtained.

The epoxy resin plate was cut to a thickness of 0.5 mm, polished, and observed with a polarizing microscope. As a result, a schlieren structure was observed, confirming that the epoxy resin plate was a liquid crystalline resin.

The thermal conductivity in the thickness direction and the in-plane direction of the epoxy resin plate was measured. The thermal conductivity was calculated from the thermal diffusivity and specific heat capacity in the thickness direction and the in-plane direction determined by the laser flash method, and the density of the sample, and the measurement was performed at room temperature. The thermal conductivity in the thickness direction is 0.43 W / mK, and the thermal conductivity in the in-plane direction is 0.44 W / mK.
K was high and had excellent thermal conductivity.

The thermal conductivity can be calculated by the following equation.

(Thermal conductivity) = (Thermal diffusivity) × (Volume specific heat) × (Density) The thermal diffusivity is determined by the laser flash method in the in-plane direction,
Can be measured in any thickness direction, (Volume specific heat) x (Density)
Can also be measured by the laser flash method. The laser flash method irradiates the sample surface with a laser pulse,
This is a method of measuring the thermal constant from the temperature history on the back surface. (Volume specific heat) × (density) is determined from the maximum temperature rise width of the sample back surface, and the thermal diffusivity is determined from the time during which the temperature at the sample back surface increases by １ ／ of the maximum temperature rise width. The detection points are the back surface within the laser irradiation range in the thickness direction, and the back surface outside the laser irradiation range in the in-plane direction. The sample shape is, for example, 10φ × 1 mm in the thickness direction and 3 cm × 1 mm in the in-plane direction.

As an evaluation of the hydrolyzability, the epoxy resin plate and the epoxy resin plate were treated in saturated steam at 121 ° C. for one day, and then subjected to a tensile test to calculate the rate of decrease in tensile strength. The tensile test was performed at room temperature, and the tensile strength was an average value of three samples.
In the case of the above resin, the rate of decrease in tensile strength was as small as 10%, and the resin was excellent in long-term reliability.

Here, the change during the polymerization reaction of the monomer having a mesogen group in this example will be described. As shown in FIG. 1, the monomer 2 having a mesogen group in the present invention has a mesogen group 1 in the molecule, but before the start of polymerization, the monomer 2 has an orderly arrangement around the mesogen group at a polymerization temperature of 150 ° C. (A). However, in the course of the polymerization reaction, a partial arrangement is established around the mesogen group 1 with order (b), after which the polymerization reaction proceeds and solidifies (c). In other words, it is only necessary that at least part of the polymerization reaction be ordered with the mesogen group as the center.

(Example 2) An epoxy resin composition obtained by mixing 270 g of 4,4'-biphenol diglycidyl ether and 200 g of 4,4'-diaminophenylbenzoate was poured into a mold, and a voltage of 1 kV was applied in the thickness direction. While being applied, the mixture was cured at 150 ° C. for 10 hours and then heated and cured at 200 ° C. for 5 hours to obtain a 1 mm thick epoxy resin plate.
Observation with a polarizing microscope in the same manner as in Example 1 confirmed that this epoxy resin plate was a liquid crystalline resin.

In the same manner as in Example 1, the thermal conductivity in the thickness direction and the in-plane direction of the epoxy resin plate was measured. The thermal conductivity in the in-plane direction was 0.43 W / mK, which was almost the same value as in Example 1 manufactured without applying a voltage, and was high.
Further, the thermal conductivity in the thickness direction was even higher at 2.2 W / mK. Each direction had excellent thermal conductivity.

Further, by treating the epoxy resin in saturated steam at 121 ° C. for 1 day in the same manner as in Example 1, the rate of decrease in tensile strength was as small as 13%, and the long-term reliability was excellent.

Example 3 4,4'-Bis (3,4-epoxybutene-1-yloxy) phenylbenzoate 3
70 g and 4,4'-diaminodiphenylmethane 200
g of the epoxy resin composition mixed in a mold.
After curing at 50 ° C. for 10 hours, it was cured by heating at 200 ° C. for 5 hours to obtain an epoxy resin plate having a thickness of 1 mm. Observation with a polarizing microscope in the same manner as in Example 1 confirmed that this epoxy resin plate was a liquid crystalline resin.

In the same manner as in Example 1, the thermal conductivity in the thickness direction and in-plane direction of the epoxy resin plate was measured. The heat conductivity in the thickness direction was as high as 0.44 W / mK, and the heat conductivity in the in-plane direction was as high as 0.46 W / mK, indicating excellent heat conductivity.

Further, the rate of decrease in tensile strength by treating the epoxy resin in saturated steam at 121 ° C. for 1 day in the same manner as in Example 1 was 45%.

Comparative Example 1 An epoxy resin plate was prepared in the same manner as in Example 1 except that bisphenol A-diglycidyl ether was used.

This epoxy resin plate was cut to a thickness of 0.5 mm, polished and observed with a polarizing microscope. As a result, no structure derived from the liquid crystalline resin was observed.

In the same manner as in Example 1, the thermal conductivity in the thickness direction and the in-plane direction of the epoxy resin plate was measured. The thermal conductivity in the thickness direction was 0.18 W / mK, and the thermal conductivity in the in-plane direction was 0.20 W / mK, which was low.

Further, the rate of decrease in tensile strength by treating the epoxy resin in saturated steam at 121 ° C. for 1 day in the same manner as in Example 1 was 11%.

Example 4 100 g of 4,4'-diamino-α-methylstilbene and pyrometic dianhydride 120
g and N, N'-dimethylacetamide in 20 ml at room temperature for 5 hours to synthesize polyamic acid. The polyamic acid solution was applied on glass and dried at 120 ° C. for 2 hours to obtain a polyamic acid film having a thickness of 80 μm. The film was heat-treated at 300 ° C. for 1 hour to obtain a polyimide film.

When this polyimide film was observed with a polarizing microscope, a schlieren structure was observed, and it was confirmed that the film was a liquid crystalline resin.

The thermal conductivity in two directions in the plane of the polyimide film was measured. The thermal conductivity was calculated from the thermal diffusivity and specific heat capacity in two perpendicular directions in the plane determined by the photo-current method, and the density of the sample, and the measurement was performed at room temperature. Thermal conductivity is 0.44 W / mK, 0.4
It had an excellent thermal conductivity of 5 W / mK.

The photo-current method is a method capable of measuring the thermal conductivity in the in-plane direction of a thin film. In the optical AC method, a part of the surface of a sample is irradiated with intermittent light, and the thermal diffusivity is determined from the AC temperature amplitude of a region on the back surface of the sample where light is not irradiated and the distance from the irradiated region. The sample shape is, for example, 10 mm x
5 mm.

Further, by treating the epoxy resin in saturated steam at 121 ° C. for 1 day in the same manner as in Example 1, the rate of decrease in tensile strength was as small as 5%, and the long-term reliability was excellent.

Example 5 100 g of 4,4'-diaminophenylbenzoate and 120 g of pyromethic dianhydride
And a polyimide film was obtained in the same manner as in Example 4. Observation by a polarizing microscope in the same manner as in Example 4 confirmed that this polyimide film was a liquid crystalline resin.

In the same manner as in Example 4, the in-plane thermal conductivity of the polyimide film was measured in two directions. The thermal conductivity was as high as 0.44 W / mK and 0.46 W / mK, and had excellent thermal conductivity.

Further, the rate of decrease in tensile strength by treating the epoxy resin in saturated steam at 121 ° C. for 1 day in the same manner as in Example 1 was 33%.

Comparative Example 2 A polyimide film was obtained in the same manner as in Example 4 using 100 g of 4,4'-diaminodiphenyl ether and 120 g of pyromethic dianhydride.

When this polyimide film was observed with a polarizing microscope, no structure derived from the liquid crystalline resin was observed.

In the same manner as in Example 4, the in-plane thermal conductivity of the polyimide film was measured in two directions. The thermal conductivity was 0.15 W / mK, 0.17 W / mK, which was low.

Further, by treating the epoxy resin in saturated steam at 121 ° C. for 1 day in the same manner as in Example 1, the rate of decrease in tensile strength was 5%.

Example 6 FIG. 2 shows an example of a generator coil using the insulating composition of the present invention. This generator coil uses an insulating composition as the ground insulating layer 11 of the conductor 10. By using the insulating composition of the present invention for the ground insulating layer 11, heat generated from the conductor can be efficiently radiated, and the capacity can be increased.

Example 7 FIG. 3 shows an example of a semiconductor package using the insulating composition of the present invention. In this semiconductor package, a die pad 44 is formed on a printed circuit board 43 through which a thermal via 45 penetrates. The solder bump electrodes 41 are formed on the printed board 43. Further, a wiring pattern 42 is formed on the surface of the printed circuit board 43 on which the die pad 44 is formed.
Are formed, and are connected to the bare chip 31 formed on the die pad 44 by the Au wire 34. The sealing material 32 for sealing the wiring pattern 42, the bare chip 31, the Au wire 34, and the die pad 44 thus formed is formed, and a semiconductor package is formed. By using the insulating composition of the present invention for the thermal via 45 of such a semiconductor package, the weight can be reduced and the heat generated from the bare chip can be effectively released. Note that it is also effective to use the insulating composition of the present invention for a sealing material.

[0092]

According to the present invention, it is possible to obtain an insulating composition which is electrically insulating and has excellent thermal conductivity in two or more directions perpendicular to each other.

Further, according to the present invention, it is possible to obtain an insulating composition having electrical insulation and excellent thermal conductivity, and having long-term reliability.

Further, according to the present invention, it is possible to obtain an insulating composition which is electrically insulating and has excellent thermal conductivity.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a change during a polymerization reaction of a monomer having a mesogenic group in one example of the insulating composition of the present invention.

FIG. 2 is a schematic perspective view of one embodiment of a generator coil using the insulating composition of the present invention.

FIG. 3 is a schematic cross-sectional view of one embodiment of a semiconductor package using the insulating composition of the present invention.

[Explanation of symbols]

1 ... mesogen group, 2 ... monomer having mesogen group, 1
0: conductor, 11: ground insulating layer, 31: bare chip, 32
... Sealant, 34 ... Au wire, 41 ... Solder bump electrode,
42: wiring pattern, 43: printed circuit board, 44: die pad, 45: thermal via.

Claims (6)

[Claims] An insulating composition containing a liquid crystalline resin obtained by polymerizing a resin composition containing a monomer having a mesogen group as an essential component, and having a thermal conductivity of 0.4 W / in two directions substantially perpendicular to each other. An insulating composition having a mK or more. 2. The insulating composition according to claim 1, wherein said monomer has an epoxy group. 3. The monomer according to claim 1, wherein the monomer has a mesogen group represented by the following formula (1) in the molecule.
Insulating composition. Embedded image 4. An insulating composition used for an article that generates heat, wherein the composition is a heat-polymerized resin composition containing a monomer having a mesogen group and having a thermal conductivity of 0.4 W / mK or more. An insulating composition comprising a curable liquid crystalline resin as an essential component. 5. An insulating composition used for an article generating heat, which has a mesogen group shown in the following chemical formula (1) in a molecule and has a thermal conductivity of 0.4 W / mK or more. A characteristic insulating composition. Embedded image 6. An insulating composition used for an article generating heat, wherein said composition comprises a monomer having at least one reactive group of a reactive group and a mesogen group represented by the following chemical formula (2). An insulating composition comprising, as an essential component, a liquid crystalline resin obtained by polymerizing a polymer. Embedded image