JP3249937B2 - Heat dissipation material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipating material which is disposed so as to be in contact with a heat generating element for promoting heat radiation from a heat generating element such as an electronic component.

[0002]

2. Description of the Related Art Conventionally, a CPU built in an electronic device has been known.
2. Description of the Related Art A heat dissipating material made of an elastically deformable elastomer material is known as a heat dissipating material used for a heat dissipating measure of various electronic components (hereinafter, simply referred to as electronic components) serving as a heat source such as an HDD and an HDD.

[0003] This kind of heat dissipating material is used, for example, by being disposed so as to be interposed between a component serving as a heat sink (hereinafter simply referred to as a heat sink) such as a housing panel and an electronic component. Is deformed flexibly and comes into close contact with the electronic component and the heat sink, so even if the shape of the electronic component or the heat sink is somewhat complicated, no gap is formed between the electronic component and the heat sink that hinders heat conduction. Thus, heat from the electronic components could be satisfactorily released to the heat sink.

[0004]

By the way, the heat dissipating material made of the above-mentioned elastomer material is excellent in heat resistance, flexibility, insulation, physical strength and the like. In general, a heat conductive filler was dispersed in the above.

However, since silicone rubber contains some silicone oligomers (low polymers such as dimers and trimers) in addition to the silicone polymer as the main component, the silicone oligomers are volatile. When approaching an electrical contact part such as a relay, the electrical energy from the electrical contact part may be changed to an insulator such as SiO ₂ or SiC, and this kind of insulator may be deposited on the electrical contact part. As a result, there is a fear that an electrical contact failure such as an increase in contact resistance or a contact failure may be caused.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to flexibly deform and adhere to a heating element, and to cause the above-described electric contact failure. It is to provide a heat-dissipating material without heat.

[0007]

Means for Solving the Problems and Effects of the Invention In order to achieve the above-mentioned object, the heat radiating material according to the first aspect of the present invention is made of an elastomer material which can be deformed flexibly and can be in close contact with the heating element. , the elastomeric material is a gel-like base material in which a main component a urethane resin and a plasticizer state, and are obtained by dispersing fine particles of a ceramic material as a thermally conductive filler, wherein the urethane resin, the elastomeric material all
4 to 15% by weight of bifunctional polyoxy by weight relative to the body
Cypropylene glycol, 3 to 13% by weight of trifunctional poly
Oxypropylene glycol, and 0.6 to 12 weight
% Diphenylmethane-4,4'-diisocyanate
It is characterized by being a polymer obtained by the reaction .

In this heat radiating material, the gel-like base material contains a urethane resin and a plasticizer as main components, and the urethane resins cross-link with each other to form a network-like structure. And the like, while losing the fluidity as a whole while containing the fluid components such as. However, as a component other than these main components, various catalysts for adjusting the reaction rate, a coloring agent such as a pigment or a dye, or a colorant within a range not impairing the function required for the heat dissipation material of the present invention, or Other stabilizers and additives may be included. Further, in addition to the above-mentioned plasticizer, fine particles of a ceramic material as a heat conductive filler are contained in the gaps of the network structure.

According to such a heat dissipating material, the heat dissipating material is made of an elastomer material which can be deformed flexibly and can be in close contact with the heating element.
If it is arranged so as to be in close contact with the heating element, heat radiation from the heating element can be promoted, but in particular, since it is mainly composed of urethane resin, it is better than that of silicone rubber like the conventional product. High flexibility can be easily provided. Therefore, the adhesion to the heating element and the like is improved as compared with the conventional product, and a higher heat radiation effect can be obtained.

Also, unlike conventional products, since the base material of the elastomer material is mainly composed of a urethane resin and a plasticizer, the silicone oligomer does not volatilize from the base material, and the electric charge caused by the silicone oligomer does not occur. There is no danger of contact failure. Furthermore, the heat radiating material of the present invention
As compared with the conventional silicone rubber type, a large loss count can be easily secured. Therefore, most of the vibration energy transmitted to the heat radiating material can be internally converted to heat energy and consumed, and can be suitably used as a vibration damping material having an excellent vibration damping / damping function. . In particular, since the present invention can be applied to a place where both a heat radiation function and an anti-vibration / vibration suppression function are required, it is applied to an electronic component serving as a heat source and a vibration source such as an HDD to promote heat radiation. At the same time, the vibration can be suppressed, and the manufacturing cost can be suppressed and the size of the device can be reduced as compared with the case where the heat radiating material and the vibration isolating material are separately applied. In addition, this heat dissipation material
Urethane resin, based on the entire elastomer material
4 to 15% by weight of bifunctional polyoxypropylene
Glycol, 3 to 13% by weight of trifunctional polyoxypro
Pyrene glycol and 0.6 to 12% by weight of diffe
Nylmethane-4,4'-diisocyanate
Since it is a polymer obtained, it is used as a heat dissipation material of this type
It has the desired physical properties suitable for In particular,
At different weight ratios, difunctional and trifunctional polyoxypropyl
Cross-linking density, hardness, rebound when combined with ren glycol
The properties are adjusted very well.

By the way, the plasticizer contained in the base material is added during the polymerization reaction of the urethane resin precursor, thereby increasing the fluidity, flexibility, extensibility, etc. of the generated urethane resin. However, in order to finally obtain a gel-like product, it is necessary to adjust the addition amount within an optimum range. The optimum amount of the plasticizer depends on other conditions and cannot be specified unconditionally. However, the results of various studies conducted by the inventors using a phosphate ester plasticizer as the plasticizer are based on the results. For example, as described in claim 2, the gel base material has a weight ratio of 9 to 25% by weight of the urethane resin and 8 to 30% by weight of the phosphate plasticizer based on the entire elastomer material. It has been found that a gel base material having flexibility suitable for use as a heat dissipating material of this type can be obtained when the base material contains. In particular, since phosphate esters are non-halogen flame retardant plasticizers, ignition and combustion caused by heating,
Since it is free of halogen-based gas and has extremely good compatibility with polyurethane, it is most suitable for use as a material of the heat radiation material of the present invention.

When the amount of the plasticizer is larger than the above-mentioned amount,
The crosslinking reaction is hindered during the polymerization of the urethane resin, and as a result, a product having a high fluidity and being close to a liquid is obtained, which makes it difficult to handle as a heat radiating material. On the other hand, if the amount of the plasticizer is less than the above-mentioned amount, the urethane resin crosslinks, and as a result, a product having low flexibility and close to a solid state is obtained.

[0013]

Further, as for the heat conductive filler, a substance having a higher thermal conductivity is more preferable, and an insulating material is preferable in consideration of contact with a conductive portion of an electric component. Further, from the viewpoint of weight reduction, a low-density material is preferable, and in consideration of the manufacturing cost, a cheaper material is more preferable. However, in order to enhance the adhesion to the heating element or the like, the material must not excessively inhibit the flexibility of the substrate. In order to satisfy the above conditions at a relatively high level as a whole, as described in claim 4, the heat conductive filler is made of alumina fine particles having a particle size of 3 to 50 μm, and the elastomer material is used. 60-80 by weight to the whole
% By weight.

With such a heat dissipating material, relatively good thermal conductivity, insulation and flexibility can be ensured, and it is relatively light and the production cost is not excessive. It is extremely useful for industrial production. In particular, the heat dissipating material of the present invention employs a gel base material containing a urethane resin and a plasticizer as main components.
Even if alumina particles are contained in a very high ratio, desired flexibility can be obtained, and a material having sufficiently practical physical properties as a heat radiating material of this kind can be manufactured.

In addition to the above, fine particles of various ceramic materials such as zirconia and titania can be used alone or in combination as the heat conductive filler. By the way, since the heat radiating material described above has a urethane resin and a plasticizer as main components, flexibility can be easily increased more than the conventional heat radiating material made of silicone rubber. As described in 5,
When the Shore hardness (00 scale) is adjusted in the range of 5 to 70, the adhesion to the heating element is higher than that of a general silicone rubber heat radiating material, so that the shape of the heating element is considerably complicated. Also, heat can be radiated from the heating element very well. If the Shore hardness (00 scale) is less than 5, the adhesion is high, but it is difficult to secure the physical strength. On the other hand, those having a Shore hardness (00 scale) of more than 70 are inferior in adhesion due to lack of flexibility, which is a disadvantageous factor for promoting heat radiation.

In addition, the heat dissipating material can be simply brought into contact with a heating element or a heat sink, for example, or can be adhered via an adhesive. If the surface of the material has tackiness, the material can be easily adhered to the contact surface by the tackiness of the elastomer material itself without using an adhesive or the like.

Further, when the surface of the elastomer material has adhesiveness, the protective film is adhered to the surface by the adhesiveness of the surface of the elastomer material as described in claim 7. It may be structured.

The protective film may be, for example, a resin film, and covers the adhesive surface of the heat radiating material to protect the heat radiating material from dust and the like until immediately before the heat radiating material is actually used. It also supplements the physical strength of the heat sink,
For example, when the heat radiating material is shipped from a manufacturing plant, the heat radiating material is prevented from being damaged. Further, since the adhesion between the heat radiating materials is prevented, the heat radiating materials can be stacked at the time of shipment. Such a protective film is usually peeled off and removed immediately before actual use, whereby the heat dissipating material can be provided for actual use with good adhesiveness.

Further, such a protective film may be used without peeling off at the time of use. In other words, even when the surface of the elastomer material has adhesiveness, the adhesiveness of the surface on which the protective film is interposed is lost, so by leaving a part or all of the protective film, only one surface, or The tackiness can be partially released. In addition, since a protective film having sufficiently high flexibility and a higher physical strength than that of the elastomer material can be easily selected, the protective film does not impair the flexibility of the entire surface of the elastomer material, and the physical strength of the local surface can be reduced. Can be supplemented. In addition, if the protective film is left unpeeled, the difference in elasticity between the elastomer material and the protective film causes the protective film to hinder free expansion and contraction of the elastomer material, causing twisting and distortion of the heat dissipation material. The effect of attenuating
The anti-vibration / damping function can be further improved.

[0021]

Next, an embodiment of the present invention will be described with reference to an example. First, each substance was mixed at a composition ratio as shown in Table 1 below. In this mixing, two liquids A and B shown in Table 1 were prepared in advance, and the polymerization reaction was started by mixing the two liquids.

[0022]

[Table 1]

Subsequently, a sheet-shaped mold having a thickness of 5 mm and an inner surface of which is subjected to a fluororesin processing is prepared, and the mixed solution is poured into the mold, and the mixture is taken at 100 ° C. for 1 hour. Cured. As a result, a gel-like elastomer material having a sticky surface was obtained. Then, as shown in FIG. 1, both sides of the elastomer material 3 taken out of the mold are filled with PE.
A protective film 5 made of T is attached, and the intended heat dissipation material 1
Was completed. The heat radiating material 1 can be attached to a desired position by peeling off the protective film 5 when actually used.

Next, when the physical properties of the heat radiation material 1 were measured, the measurement results as shown in Table 2 below were obtained.

[0025]

[Table 2]

From the above measurement results, this heat radiating material 1
It was found to be extremely low hardness of 24 Shore hardness (00 scale) and excellent in adhesion to the component surface. Further, the tear strength is about 1.3 times that of the conventional silicone rubber heat radiating material, and it is less likely to be torn than the conventional product. In addition, it has been found that since it has a relatively high thermal conductivity, it can be suitably used as a heat dissipating material. Furthermore, since it contains a large amount of phosphoric acid ester, it is flame-retardant, and there is no problem at all in use under heated conditions.

Next, the loss coefficient d was measured in order to examine the vibration control and vibration control functions. The loss coefficient d is a value representing the degree of absorption of vibration energy, and the larger this value is, the more excellent the vibration damping / damping function is. In measuring the loss coefficient d, first, as shown in FIG. 2, a 10 × 1 is placed on a shaker table 12 arranged on the upper surface side of the shaker 10.
Four heat-dissipating materials 1 having a thickness of 0 mm (thickness: 5 mm) are placed, and an iron plate 14 is placed thereon. In this state, the vibrator table 12 is vibrated up and down at a maximum acceleration of 0.4 G, and takes 2.5 minutes. The resonance curve as shown in FIG. 3 was measured by detecting the vibration at this time by the acceleration pickup 16 while changing the frequency of the vibration from 5 to 500 Hz. Note that the resonance curve shown in FIG. 3 is a measurement result at room temperature (23 ° C.).
(0 ° C.). The resonance curve shown in FIG. 3 is a measurement result when the weight of the iron plate 14 is 100 g.
0g, 300g, 400g, 500g, 1000g 6
Was measured for

From the resonance curve shown in FIG.
The resonance frequency f _{0 at} which the resonance curve has the maximum value Y _m , and the frequencies f ₋₁ and f at which the resonance curve is 3 dB lower than the maximum value.
The width Δf between ₁ was obtained, and the loss coefficient d was obtained from the following equation 1.

[0029]

(Equation 1)

Table 3 shows the measurement results of the loss coefficient d at normal temperature (23 ° C.), and Table 4 shows the measurement results of the loss coefficient d at high temperature (70 ° C.).

[0031]

[Table 3]

[0032]

[Table 4]

From the above measurement results, in the normal temperature range,
Very good vibration damping with a loss factor of about 0.9
It turned out that there was a vibration proof function. In addition, even in a high temperature range, the loss coefficient is about 0.4, which is inferior to that in a normal temperature range, but it is found that a sufficiently practical vibration damping and vibration isolation function is secured.

Although the embodiment of the present invention has been described above, various specific embodiments other than the above are conceivable for the embodiment of the present invention. For example, in the above-described embodiment, a heat-radiating material formed into a sheet is exemplified, but the heat-radiating material can be formed into an arbitrary shape by changing a mold for polymerizing the urethane resin. So, for example,
If the heat dissipating material is formed in advance in a shape suitable for a place to be applied, the heat dissipating material can be closely adhered to a more complicated shape.

In the above embodiment, the protective film made of PET is provided on the front and back surfaces of the elastomer material. However, a resin film other than PET may be provided as the protective film. The surface may be protected. However, if the surface of the elastomeric material is sticky, dust or the like may adhere to the surface just before use, and therefore it is better to provide a protective film or a member having a function equivalent to the protective film.

Further, in the above-described embodiment, the elastomer material is molded by the mold, and then the protective film is attached. However, for example, a resin film is disposed in a sheet-like mold. Also, a heat dissipating material having a similar structure can be manufactured by a method of injecting the above-mentioned mixture into the mold and curing the mixture. In this case, unlike a sticky elastomer material, the resin film is easily separated from the mold, so that the inner surface of the mold does not need to be subjected to the fluororesin processing for promoting mold release. Further, since the resin film disposed in the mold can be used as a protective film as it is, it is not necessary to attach the protective film in a later step.

Further, in order to suppress the tackiness of the surface of the elastomer material, a method of coating with a non-tacky resin material may be adopted in addition to attaching a protective film. In this case, even if the elastomer material is formed into a complicated shape, the tackiness can be easily lost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a heat radiating material shown as an embodiment.

FIG. 2 is a configuration diagram of an apparatus for measuring a loss coefficient.

FIG. 3 is a graph of a resonance curve.

[Explanation of symbols]

1 ... heat dissipating material, 3 ... elastomer material, 5 ...
Protective film, 10: shaker, 12: shaker table, 14: iron plate, 16: acceleration pickup.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Kotani 2--24-15 Chiyoda, Naka-ku, Nagoya City, Aichi Prefecture Inside Kitagawa Industry Co., Ltd. No. 15 Kitagawa Kogyo Co., Ltd. (72) Kimito Funado 2--24, Chiyoda, Naka-ku, Nagoya-shi, Aichi Prefecture No. 15 Kitagawa Kogyo Co., Ltd. No.2 Inside Iida Sangyo Co., Ltd. (72) Inventor Takashi Miyagawa 1-27-1 Shinei, Naka-ku, Nagoya City, Aichi Prefecture Inside Iida Sangyo Co., Ltd. (56) References JP-A-60-7155 (JP, A) Kaisho 60-157244 (JP, A)

Claims (6)

(57) [Claims] 1. An elastomer material which can be deformed flexibly and can be brought into close contact with a heating element. The elastomer material is a ceramic material as a heat conductive filler in a gel base material mainly composed of a urethane resin and a plasticizer. der that the fine particles are dispersed is, the urethane resin, against the entire elastomeric material
4 to 15% by weight of bifunctional polyoxypropyl
Len glycol, 3 to 13% by weight of trifunctional polyoxypropylene
Propylene glycol and 0.6 to 12% by weight of diph
Reacting phenylmethane-4,4'-diisocyanate
A heat dissipating material characterized by being a polymer obtained by the above method. 2. The heat-dissipating material according to claim 1, wherein the gel-like base material has a weight ratio of 9 to 25% by weight of the urethane resin to the whole of the elastomer material, and 8
A heat dissipating material characterized by containing a phosphate ester plasticizer in an amount of 30 to 30% by weight. 3. The heat dissipating material according to claim 1, wherein the heat conductive filler is made of alumina having a particle size of 3 to 50 μm.
It is composed of fine particles and has a weight to the entire elastomer material.
A heat dissipating material characterized by being contained in an amount of 60 to 80% by weight . 4. The heat radiating material according to claim 1, wherein a Shore hardness (00 scale) is adjusted in a range of 5 to 70.
A heat dissipating material characterized by being manufactured . 5. The heat radiating material according to claim 1, wherein a surface of said elastomer material has adhesiveness . 6. The heat dissipating material according to claim 5 , wherein the surface of the elastomer material is adhered to the heat dissipating material.
A heat dissipating material, characterized in that a protective film is adhered to the material.