JPH0590751U - High temperature heat insulating plate - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a heat dissipation insulating plate for high temperature which can withstand a high temperature of 200 ° C or higher and has good thermal conductivity. In an insulating plate laid between a heating element and a radiator, a high-temperature insulating layer having a heat-resistant insulating material as a core, an inorganic filler having a high thermal conductivity and a silicone resin on the surface of the high-temperature insulating layer. And an adhesion layer having shape conformability.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a heat dissipation insulating plate for high temperature, and more particularly to a heat dissipation insulating plate for high temperature which can withstand a high temperature of 200 ° C. or higher and has good heat dissipation.

[0002]

[Prior Art]

 There are electronic devices that are desired to electrically insulate the heat generated in the heating element and efficiently transfer it to the radiator. For example, for electronic mosquito traps and rice cookers, a heat insulating material is placed between the PTC (Positive Temperature Coefficient) posistor and the heat sink to heat the insecticidal mat and rice cooker placed on the heat sink. It has become.

As described above, the heat dissipation insulating material used in the electronic mosquito catcher and the like has an electrical insulation property, a heat conductivity that transfers the heat generated in the PTC posistor to the heat dissipation plate as quickly as possible, and a high temperature insulating material. Since some PTC posistors reach temperatures of 300 ° C, heat resistance of 300 ° C or higher is required.

Conventionally, as a heat radiation insulating material used for heat radiation and insulation, a silicone rubber sheet or the like is used in a temperature range of 200 ° C. or lower, and a ceramic having good heat conductivity in a temperature range of 200 ° C. or higher. Natural mica was used, which has excellent insulation and mechanical strength even when the plate and thickness are thin.

[0005]

[Problems to be solved by the device]

 However, as described above, in the temperature range of 300 ° C., the silicone rubber sheet or the like is thermally deteriorated at a high temperature of 200 ° C. or higher, and the insulating property is deteriorated, so that it is difficult to use.

Further, ceramic plates and natural mica that can withstand high temperatures of 300 ° C. or higher have problems in heat dissipation. That is, heat dissipation is represented by thermal resistance. In order to reduce the thermal resistance, the thickness of the plate should be as thin as possible, the thermal conductivity of the material should be good, and the surface of the heating element and the radiator should be in close contact with each other, leaving an air layer in the contact area. As shown in FIG. 7 regarding the adhesion, the contact surface of the ceramic plate or the natural mica with the heating element 8 or the heat dissipation plate 9 has fine irregularities unless mirror-finished. Therefore, the contact surface had poor adhesion, and the air layer 11 was formed, and the air layer became a heat insulating layer, and the heat dissipation, that is, the thermal conductivity was poor.

As a means for improving the adhesion, a process of applying grease to each contact surface of the heat generating element 8 and the heat radiating plate 9 is applied to eliminate the formation of the air layer 11 and improve the adhesion. When the temperature exceeds ℃, the silicone oil in the grease becomes vaporized or deteriorates, and there is a problem in heat dissipation when using grease.

The present invention has been made in view of the above points, and an object of the present invention is to provide a high temperature heat insulating plate having heat resistance of 300 ° C. or higher and excellent in adhesion, processability and heat dissipation. ing.

[0009]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the heat dissipation insulating plate for high temperature of the present invention is an insulating plate laid between a heating element and a radiator, wherein a high temperature insulating layer having a heat resistant insulating material as a core and the high temperature insulating layer. It is characterized in that it has an inorganic filler having a high thermal conductivity and an adhesive layer having a shape-following property of a silicone adhesive on the surface thereof, thereby improving the heat dissipation effect.

[0010]

【Example】

 FIG. 1 shows a cross-sectional view of one embodiment of a high temperature heat dissipation insulating plate according to the present invention. The high temperature heat dissipation insulating plate comprises an insulating layer 1 and an adhesion layer 2 on both sides or one side thereof. FIG. 1 shows a diagram of a heat dissipation insulating plate for high temperature in which an adhesive layer 2 is formed on both surfaces of an insulating layer 1.

As the insulating layer 1, a ceramic plate made of a heat-resistant insulating material, a polyimide film, a laminated mica having a binder of a silicone resin or an inorganic adhesive (hereinafter referred to as a heat-resistant mica plate) or natural mica is used.

As is well known, the ceramic plate, the polyimide film, the heat-resistant mica plate or the natural mica forming the insulating layer 1 has excellent heat resistance and insulation properties.

The adhesive layer 2 has an inorganic filler called an inorganic filler 4 and a silicone adhesive 5 provided on both sides or one side of the insulating layer 1. By providing the adhesive layer 2, The heat-resistant mica plate, the polyimide film, the ceramic plate or the natural mica that forms the insulating layer 1 is substantially improved in adhesion, and its thermal conductivity is improved.

That is, the inorganic filler 4 that forms the adhesion layer 2 is made of, for example, boron nitride, alumina, titanium oxide, magnesium oxide, aluminum nitride, which has good electrical conductivity and thermal conductivity. Is 50 to 90% by weight, the adhesive layer 2 is formed by, for example, 10 to 50% by weight of the silicone adhesive 5 of silicone resin.

This is because when the silicone pressure-sensitive adhesive 5 exceeds 55% by weight, the heat resistance decreases, but the adhesiveness of the adhesive layer 2 increases and workability during processing deteriorates as described later. Is. Further, if the silicone adhesive 5 is 10% by weight or less, there are many gaps in the adhesive layer 2, the thermal resistance of the adhesive layer 2 itself increases, and the adhesive layer 2 becomes brittle.

When the adhesion layer 2 has the above proportion, it has a plastic deformability different from the cushioning property of silicone rubber or the like, and the shape conformability and the adhesiveness of the adhesion layer 2 are in the most preferable state. Next, the reason will be described.

FIG. 2 shows an enlarged explanatory view of a change in the adhesion layer corresponding to tightening. Although the figure illustrates an example of the contact surface between the PTC posistor 7 and the adhesive layer 2, the same applies to the contact surface between the heat sink and the adhesive layer.

When the high temperature heat dissipation insulating plate of the present invention shown in FIG. 1 is laid between the PTC posistor 7 and a heat dissipation plate (not shown), it can be seen from FIG. A) An air layer is generated in the recess 6 as shown.

However, when the PTC posistor 7 and the heat radiating plate are tightened with screws or the like, the adhesive layer 2 has plasticity in the above proportion, so that the plasticity of the inorganic filler 4 and the silicone adhesive around the concave portion 6 is caused by the plasticity. 2 and 5 flow as shown by the arrow in FIG. 2 (B) to start eliminating the air layer in the recess 6.

When the PTC posistor 7 and the heat sink are further tightened, the recess 6 of the PTC posistor 7 is filled with the layer material of the inorganic filler 4 and the silicone adhesive 5 as shown in FIG. 2C. The air layer is expelled and the PTC posistor 7 and the adhesion layer 2 are brought into an adhesion state.

In the case of a cushioning material such as a silicone rubber that returns to its original state, the PTC posistor 7 and the adhesive layer 2 are unlikely to be in an adhered state as described above, and a gap is generated, which is an undesirable state. This is different from that of the present invention in that the thermal conductivity does not improve.

At this time, since the inorganic filler 4 having a high thermal conductivity also enters the concave portion 6, the thermal conductivity is improved. As described above, in order to give the adhesive layer 2 an adhesive property to cause the shape following property and to eliminate the air layer generated by the unevenness of the contact surface, the adhesive property is improved by increasing the silicone adhesive 5. However, if the tackiness is high, for example, during punching, it adheres to the punching machine, resulting in poor workability.

From the balance with this workability and the increase or fragility of the thermal resistance of the adhesive layer 2 itself due to the reduction of the silicone pressure-sensitive adhesive 5, the above-mentioned ratio was obtained by an experiment.

Since the adhesion layer 2 is easily plastically deformed by the tightening pressure, the performance of the adhesion layer 2 is not deteriorated even if the thickness is too thick. However, the PTC posistor 7 and the heat dissipation plate are not necessary. The thickness is sufficient so long as it can follow the roughness of the surface, and 30-100 μm is sufficient.

FIG. 3 shows an experimental result diagram of an example of heat dissipation characteristics comparing rising temperatures with and without an adhesive layer. The heat dissipation insulating plate for high temperature according to the present invention used in the figure uses an alumina ceramic plate as a heat resistant insulating material for the insulating layer 1 and is manufactured as follows.

Shin-Etsu Silicone Co., Ltd. silicone adhesive KR101-10 90 kg, toluene 240 kg and boron nitride 118 kg uniformly stirred suspension in a suspension liquid 1 mm thick, 150 mm wide x 150 mm long alumina ceramic The plate was immersed in water and dried to obtain a 1.1 mm thick heat dissipation insulating plate sample for high temperature as shown in FIG.

As can be seen from FIG. 3, it is understood that the sample of the present invention having the adhesive layer 2 has significantly improved adhesiveness and better heat dissipation than the sample without the adhesive layer. Table 1 shows the decrease in thermal resistance between the alumina ceramic plate having the adhesive layer 2 and the alumina ceramic plate having no adhesive layer.

[0028]

[Table 1]

The thermal resistance decreases from 2.5 ° C./W to 0.75 ° C./W. If the insulating layer 1 is a ceramic plate, other types of ceramics have the same tendency. Table 2 shows the decrease in thermal resistance when the insulating layer 1 is natural mica.

[0030]

[Table 2]

The thermal resistance decreases from 2.25 ° C./W to 0.45 ° C./W. Tables 3 and 4 show the reductions in thermal resistance when the insulating layer 1 is a heat-resistant mica plate or a polyimide film.

[0032]

[Table 3]

[0033]

[Table 4]

The heat resistance of the heat-resistant mica plate decreases from 2.31 ° C./W to 1.31 ° C./W, and the heat resistance of the polyimide film changes from 1.42 ° C./W to 1.00 ° C./W. Has decreased to.

FIG. 4 is a diagram showing the experimental results of one example of heating time and dielectric breakdown voltage, FIG. 5 is a diagram of the experimental results of one example of heating time and tensile strength, and FIG. The experimental results of one example of the heat dissipation characteristics are shown.

The high temperature heat insulating board according to the present invention used in FIGS. 4 to 6 is manufactured as follows. 220 m of a 140 to 160 g / m ² laminated mica solution of a silicone resin YR3232 manufactured by Toshiba Silicone Co., diluted with toluene to a concentration of 15% was impregnated and dried at 100 ° C. for 3 minutes to prepare a prepreg sheet. Production. Insulating layer 1 is prepared by stacking three pre-freg sheets obtained in this way and heat-pressing at 160 ° C for 1 hour under a pressure of 60 kgf / cm ² to produce a heat-resistant mica plate with a thickness of 0.15 mm. .

Shinetsu Silicone Co., Ltd. silicone adhesive KR101-10 (90 kg), toluene (240 kg) and boron nitride (118 kg) were uniformly stirred into a suspension, which was impregnated with the heat-resistant mica plate of the insulating layer 1 and dried. After that, a sample of 0.3 mm thick high temperature heat insulating board was obtained.

As shown in FIGS. 4 and 5, it is shown that the deterioration of the characteristics is extremely small even by continuous heating at 300 ° C. Further, as shown in FIG. 6, the sample of the present invention having the adhesive layer 2 is about 10 ° C. higher than the sample without the adhesive layer, and its thermal resistance is lowered as described above, and the heat radiation is reduced. The sex is improved.

[0039]

[Effect of the device]

 As described above, according to the present invention, a heat-resistant mica plate, a polyimide film, a ceramic plate or natural mica having high heat resistance is used as an insulating layer, and the surface thereof has a high thermal conductivity and a shape-following adhesion layer. Since the above structure is provided, it is possible to obtain a high-temperature heat radiating insulating plate that has good adhesion to the heating element and the heat sink, has good thermal conductivity, and can withstand high temperatures.

Therefore, it can be used for an electronic mosquito catcher, an electronic rice cooker, or the like which has a high temperature.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a high temperature heat insulating board according to the present invention.

FIG. 2 is an enlarged explanatory view of a change in the adhesion layer corresponding to tightening.

FIG. 3 is an experimental result diagram of an example of heat dissipation characteristics comparing rising temperatures with and without an adhesive layer.

FIG. 4 is a diagram showing experimental results of one example of heating time and dielectric breakdown voltage.

FIG. 5 is a diagram showing experimental results of one example of heating time and tensile strength.

FIG. 6 is an experimental result diagram of an example of heat dissipation characteristics comparing rising temperatures with and without an adhesive layer.

FIG. 7 is an explanatory view of a conventional contact surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation layer 2 Adhesion layer 4 Inorganic filler 5 Silicone adhesive 6 Recesses 7 PTC posistor 8 Heating element 9 Radiating plate 10 Radiating insulating material 11 Air layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Yura 1 Okabe Mica Industrial Co., Ltd. 1 at 6596 Naka, Naka, Osaka, Japan

Claims (4)

[Scope of utility model registration request] 1. An insulating plate laid between a heating element and a radiator, wherein a high-temperature insulating layer having a heat-resistant insulating material as a core, and an inorganic filler and a silicone having high thermal conductivity on the surface of the high-temperature insulating layer. A heat dissipation insulating plate for high temperature, comprising: an adhesion layer having a shape-following property with an adhesive to improve a heat dissipation effect. 2. The high temperature heat dissipation insulating plate according to claim 1, wherein the heat resistant insulating material is composed of any one of an assembled mica plate, a ceramic plate, a natural mica and a polyimide film. 3. The inorganic filler is boron nitride, alumina,
The heat dissipation insulating plate for high temperature according to claim 1, which is made of any one of titanium oxide, magnesium oxide, and aluminum nitride. 4. The composition of the adhesive in the adhesive layer is 10 to 50.
2. The high temperature heat insulating board according to claim 1, wherein the heat radiating insulating board is in weight%.