JPH11188814A - Antistatic heat-dissipating film and series production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop excellent thermal conductivity and electrical conductivity by providing an elastic heat-dissipating layer composed of a composition containing a silicone polymer and an electrical conductive layer formed on at least one side thereof. SOLUTION: An antistatic heat-dissipating film 45 has a two-layer structure, where a conductive layer 44 is formed on one side of an elastic heat-dissipating layer 43 composed of a composition containing a silicone polymer. A silicone rubber or the like is used for the silicone polymer, and a conductive coating, a conductive ink, or the like is used for a forming material of the conductive layer 44. First, the composition is made by mixing the silicone polymer and other additive or the like. Next, the composition is dissolved in a solvent, and fed from a feeding pipe 14 to the surface of a release belt 10 for coating. A doctor knife 15 removes the excess compound, and then vulcanized and set through a tunnel oven 16, and the elastic heat-dissipating layer 43 is formed. The conductive coating is applied thereon by a spraying machine 20, and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic heat-dissipating sheet used for manufacturing a liquid crystal display and the like, and a method for continuously producing the same.

[0002]

2. Description of the Related Art A semiconductor mounting system for mounting IC circuits with high density and high precision, especially a TAB (Tape au) is known.
This TAB mounting system can produce a liquid crystal display device in which a plurality of TAB-ICs 2 are joined on a liquid crystal panel 1 at predetermined intervals, as shown in FIG. In this liquid crystal display device, for example, as shown in FIG. 2, a liquid crystal panel 1 is placed on a lower plate 3 and a TAB-IC 2 is placed thereon.
Are placed at predetermined intervals, and the thermocompression bonding plate 4 is pressed in the direction of arrow A under predetermined pressure and temperature conditions, so that the liquid crystal panel 1 and the TA
It is produced by fully joining the B-IC2. In this case, in order to uniformly apply pressure and heat to the TAB-IC 2, a heat radiating sheet (heat conductive sheet) 5 is interposed between the thermocompression bonding plate 4 and the TAB-IC 2.

[0003]

However, since the heat radiating sheet (heat conductive sheet) 5 is an insulator, static electricity is generated when it is repeatedly used, and foreign matter such as dust adheres to the TAB-IC 2, TAB-I by discharge
Problems such as breakage of C2 occur. In addition, there is a possibility that an electric shock may be generated to the operator, or the solvent atmosphere may be ignited during the operation. Therefore, the heat dissipation sheet (heat conductive sheet)
It is conceivable to use a conductive sheet instead of 5. Since this conductive sheet is excellent in electric conductivity, it is excellent in preventing generation of static electricity, but inferior in heat conductivity, it cannot conduct heat sufficiently to the TAB-IC2, Problems such as inhibition of the joining between the TAB-IC 2 and the liquid crystal panel 1 occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antistatic heat radiating sheet having both excellent thermal conductivity and electric conductivity and a continuous production method thereof. .

[0005]

In order to achieve the above object, the present invention provides an elastic heat dissipating layer made of a composition containing a silicone polymer, and a conductive layer formed on at least one surface of the elastic heat dissipating layer. The first gist is an antistatic heat radiating sheet having the following. Also, the present invention provides a step of preparing a composition containing a silicone polymer and a release belt, a step of supplying the composition to the surface thereof while continuously running the release belt, A second aspect of the present invention is to provide a continuous method for producing an antistatic heat radiating sheet including a step of vulcanizing and solidifying an object to form an elastic heat radiation layer and a step of forming a conductive layer on at least one surface of the elastic heat radiation layer.

That is, the inventor of the present invention has intensively studied to obtain an antistatic heat radiation sheet having both excellent thermal conductivity and electric conductivity. Generally, the heat dissipation sheet contains ceramic powder having excellent thermal conductivity, and the conductive sheet contains carbon-based filler having excellent electric conductivity. Therefore, studies were repeated to find a sheet having both characteristics of the ceramic powder having excellent thermal conductivity and the carbon-based filler having excellent electrical conductivity. As a result, the antistatic heat-dissipating sheet including the elastic heat-dissipating layer using the composition containing the silicone polymer and the conductive layer formed on at least one surface of the elastic heat-dissipating layer has excellent heat conductivity and electric conductivity. The present invention has been found to have both the properties of both sexes.

Further, the present inventors have conducted intensive studies to improve the manufacturing efficiency of the antistatic heat dissipation sheet. As a result, after the composition containing the silicone polymer is continuously supplied to the surface of the release belt and vulcanized and solidified to form an elastic heat dissipation layer, a conductive layer is formed on at least one surface of the elastic heat dissipation layer. As a result, it has been found that the antistatic heat radiation sheet can be efficiently manufactured.

The properties of the "composition containing a silicone polymer" in the present invention are not particularly limited. In addition to those obtained by dissolving a silicone polymer or the like in a solvent and liquefied, the composition may be in the form of rubber, powder, or solid. , Liquid and the like.

[0009]

Next, an embodiment of the present invention will be described.

FIG. 3 shows an example of the antistatic heat radiation sheet of the present invention.
Shown in The antistatic heat radiating sheet 45 is a sheet having a two-layer structure in which a conductive layer 44 is formed on one surface of an elastic heat radiating layer 43 made of a composition containing a silicone polymer.

The elastic heat dissipation layer 43 is a layer having both excellent elasticity and thermal conductivity. Examples of the silicone polymer that is a material for forming the elastic heat dissipation layer 43 include:
There is no particular limitation as long as it can impart elasticity to the sheet, and examples thereof include silicone rubber and silicone resin, which can be used alone or in combination of two or more. Among them, silicone rubber is preferred because it can impart excellent elasticity to the sheet.

The composition for forming the elastic heat radiation layer 43 includes a curing agent, in addition to the silicone polymer,
Thermal conductive fillers, pigments, reaction modifiers, softeners, filler surface treatment agents, and the like can be appropriately included.

The curing agent is not particularly limited, and is appropriately selected depending on the type of the silicone polymer to be used, the method of vulcanization and solidification, and the like. For example, an acyl peroxide is used in hot air vulcanization, and an alkyl peroxide is used in other vulcanization. The content ratio of the curing agent is 0.1 to 100 parts of the silicone polymer.
It is preferable to set in the range of 5 to 3 parts.

The thermal conductive filler is not particularly limited as long as it can impart thermal conductivity to the elastic heat dissipation layer 43. For example, aluminum oxide (alumina), boron nitride, aluminum nitride, zinc oxide, magnesium oxide ,
Examples thereof include silicon carbide, quartz, and aluminum hydroxide, which may be used alone or in combination of two or more. Among them, aluminum oxide is preferable in terms of dispersibility in the elastic heat dissipation layer 43.

The material for forming the conductive layer 44 formed on at least one surface of the elastic heat dissipation layer 43 is not particularly limited as long as it can impart conductivity to the sheet. Ink and the like are used, and they are used alone or in combination of two or more. The conductive paint is a paint using a conductive material,
It is excellent in adhesion and adhesion for the purpose of protecting the adherend. Examples of the conductive paint include a conductive material (silver powder, silver oxide, silver nitrate, an organic compound of silver, copper powder,
Nickel powder, carbon black, etc.) and binder (synthetic resin such as ethyl cellulose, phenolic resin, acrylic resin, low melting glass powder, lead borate, lead silicate, vegetable oil, etc.)
And a solvent (acetone, cellosolve derivative, ethyl acetate,
Ketones, benzene, toluene, ethylene chloride, etc.). Further, the above-mentioned conductive ink refers to one having excellent printability for the purpose of printing.

The antistatic heat dissipation sheet of the present invention can be manufactured, for example, by the method shown in FIG. That is,
First, a silicone polymer and other additives and the like are blended at a predetermined ratio and mixed using a roll, a kneader, a Banbury mixer or the like to prepare a composition. On the other hand, FIG.
As shown in (1), a releasable belt (hereinafter simply referred to as "belt") 10 is fed out from a belt supply roll 11, stretched between a forming drum 12 and a winding drum 13, and continuously fed out in that state. . Next, after dissolving the composition in a solvent, the composition is supplied to the surface of the belt 10 from a supply pipe 14 provided above the forming drum 12 for coating. Then, after the excess composition is removed by the doctor knife 15 in which the gap with the belt 10 is adjusted, the composition is vulcanized and solidified by passing through the tunnel furnace 16 to form the elastic heat radiation layer 43. Next, the conductive paint is spray-coated on the surface of the elastic heat dissipation layer 43 using a spray coater 20, and then dried using a drying device (not shown) such as a hot-air circulation oven. Thus, the antistatic heat dissipation sheet 45 in which the conductive layer 44 is formed on one surface of the elastic heat dissipation layer 43 can be continuously manufactured. The antistatic heat-dissipating sheet 45 is wound around the winding drum 13 together with the belt 10 in a state where the separator 19 supplied from the separator supply roll 18 is sandwiched therebetween, thereby forming a wound body. Then, the antistatic heat radiating sheet 45 is fed out of the wound body and separated from the belt 10, and then cut into a desired shape for use. According to such a continuous production method, the production efficiency of the antistatic heat radiation sheet 45 is improved, and mass production is possible.

The belt 10 between the forming drum 12 and the take-up drum 13 is preferably stretched horizontally without bending in order to obtain a sheet having higher thickness accuracy. Further, the supply speed of the belt 10 is preferably set to such an extent that the composition can stably exist on the belt 10. The belt 10 is not particularly limited as long as the solidified body of the composition can be peeled off. For example, the belt 10 is made of fluororesin, fluorine coating, polymethylpentene (TPX), triallyl cyanurate (TAC). And the like. The belt 10
May have a surface subjected to a release treatment, or may be reinforced with a glass cloth or the like. Among them, a glass cloth reinforced fluororesin belt is particularly preferable in terms of excellent releasability.

The supply amount of the composition from the supply pipe 14 is as follows.
It is set appropriately according to the thickness of the target sheet,
Usually, about 1 to 10 kg / min is preferable. Further, it is preferable that the composition is uniformly supplied in the width direction of the belt 10 by a uniform supply device (not shown) such as a traverser attached to the supply pipe 14.

The tunnel furnace 16 is provided with a heater (not shown) on its inner wall, so that heat can be applied to the composition on the belt 1 from all directions. The composition can be vulcanized and solidified uniformly. Further, the temperature of the heater is preferably set in a range of 100 to 180 ° C.

The method for forming the elastic heat radiation layer 43 in the present invention is not limited to the coating method shown in FIG. 4, but the elastic heat radiation layer 43 is formed using a conventionally known calender roll, extruder or the like. It is also possible. Also, the method of forming the conductive layer 44 is not limited to the spray coating method shown in FIG. 4, and may be formed by a conventionally known method such as brush coating or printing, or by laminating a conductive metal thin film. It is also possible to form a layer 44. The conductive layer 44 can be formed on both sides of the elastic heat dissipation layer 43. However, if sufficient electric conductivity can be imparted to the sheet, the conductive layer 44 may be formed on the elastic heat dissipation layer 4.
3 is preferably formed only on one side.

The thickness of the elastic heat dissipation layer 43 of the antistatic heat dissipation sheet 45 thus obtained is preferably set in the range of 0.15 to 2 mm, particularly preferably 0.20 to 0.80 mm. Range. Further, the thickness of the conductive layer 44 is preferably set in the range of 5 to 30 μm, and particularly preferably in the range of 10 to 20 μm.

The hardness (JIS) of the above antistatic heat dissipation sheet
A) is preferably set to 90 or less, particularly preferably in the range of 65 to 75. The hardness of the sheet may be measured using a micro rubber hardness meter, and a value similar to the hardness of the A type of JIS K6301 is obtained.

The antistatic heat radiation sheet preferably has a thermal conductivity of at least 0.40 w / m ° C., particularly preferably at least 0.70 w / m ° C. The antistatic heat dissipation sheet has a volume resistivity of 10 ¹² Ω.
Cm or less, particularly preferably 10 ⁶ Ω · cm or less. By setting the thermal conductivity and the volume resistivity of the antistatic heat-dissipating sheet within the above ranges, excellent heat conductivity and electric conductivity can be provided.

The antistatic heat radiating sheet of the present invention can be used as a heat radiating sheet for various electric appliances, but is particularly preferably used for manufacturing a liquid crystal display device as shown in FIG. This liquid crystal display device can be manufactured by using, for example, the following method using the antistatic heat dissipation sheet. That is, as shown in FIG. 5, the liquid crystal panel 1 is placed on the lower plate 3, and the TAB-ICs 2 are placed thereon at predetermined intervals. On the other hand, an antistatic heat radiating sheet 45 is stretched between the winding drum 41 and the winding drum 42, and is interposed between the heating press-bonding plate 4 and the TAB-IC 2. Next, under predetermined pressure and temperature conditions, the heat-pressed
Then, the liquid crystal panel 1 and the TAB-IC 2 are permanently joined. Thus, the TAB-IC is connected to one of the three ends of the liquid crystal panel 1 shown in FIG.
2 are joined. Next, the lower plate 3 is rotated by 90 ° C., and the antistatic heat radiating sheet 45 is fed out from the winding drum 41 to the winding drum 42 by a predetermined length. Then, in the same manner as described above, the thermocompression bonding plate 4 is pressed in the direction of arrow A, and the liquid crystal panel 1 and the TAB-IC 2 are permanently joined. Thus, the liquid crystal panel 3 shown in FIG.
The TAB-IC2 is joined to two of the two ends. Then, by performing the same operation, a liquid crystal display device in which the TAB-IC 2 is bonded to all three ends of the liquid crystal panel 1 shown in FIG. 1 can be manufactured. According to such a method, since the antistatic heat dissipation sheet 45 has excellent electric conductivity, it is possible to prevent the generation of static electricity, prevent foreign substances from adhering to the TAB-IC2, and prevent the TAB-IC2 from adhering. The destruction of the IC 2 can be prevented. Further, since the antistatic heat dissipation sheet 45 has excellent thermal conductivity, heat can be sufficiently conducted to the TAB-IC2, and the bonding property between the TAB-IC2 and the liquid crystal panel 1 is improved. Since the antistatic heat dissipation sheet 45 has excellent elasticity, the TAB-IC2 can be uniformly pressed through the heating and pressing plate 4, and the bonding between the TAB-IC2 and the liquid crystal panel 1 is improved. Further improve. As described above, when the antistatic heat dissipation sheet of the present invention is used, a liquid crystal display device can be efficiently manufactured.

Next, examples and comparative examples will be described.

[0026]

Example 1 First, the components shown in Table 1 below were blended in the proportions shown in the same table, and a composition was prepared in the same manner as described above, and an apparatus as shown in FIG. 4 was prepared. As the belt 10 used in the above apparatus, a glass cloth reinforced fluororesin sheet (approximately 1 m in width) was used.
It ran at 0 cm / min. Then, using the above composition dissolved in a solvent, the elastic heat dissipation layer 43 is manufactured under the following manufacturing conditions.
Was formed. Next, after the conductive ink was spray-coated on the surface of the elastic heat radiation layer 43, it was dried at 200 ° C. for 10 minutes using a hot air circulation oven. Thus, an antistatic heat dissipation sheet 45 (see FIG. 3) in which the conductive layer 44 was formed on one surface of the elastic heat dissipation layer 43 was produced. After that, it was cut into a predetermined shape.

[Manufacturing conditions] Supply amount of composition: 1.0 kg / min Gap between belt 10 and doctor knife 15: 0.45 mm Distance from doctor knife 15 to tunnel furnace 16: 2 m Heater in tunnel furnace 16 Temperature: 130-150 ° C Length of tunnel furnace 16: 10m

[0028]

Example 2 As shown in Table 1 below, a conductive paint was used as the conductive layer forming material instead of the conductive ink. Otherwise, the procedure of Example 1 was repeated to prepare an antistatic heat dissipation sheet.

[0029]

[Table 1]

[0030]

Comparative Example 1 The components shown in Table 2 below were blended in the proportions shown in the table to prepare compositions. Then, using this composition, a conductive sheet (thickness: 0.4) was prepared in the same manner as in Example 1.
5 mm).

[0031]

Comparative Example 2 A composition was prepared by blending the components shown in Table 2 below in the proportions shown in the table. Then, using this composition, in the same manner as in Example 1, a heat dissipation sheet (thickness: 0.45
mm).

[0032]

[Table 2]

Using each sheet thus obtained, the thermal conductivity, volume resistivity and hardness were measured according to the following criteria. The results are shown in Table 3 below.

[Thermal Conductivity] Each sheet was cut into a predetermined size to prepare a sample, and the thermal conductivity of the sample was measured according to the guarded hot plate method (steady-state method). That is,
The thermal conductivity (K) [W / m ° C] of the sample is calculated as the midpoint of the temperature of the main heater and the heat sink (Tb + Tc) / 2 [° C].
The thermal conductivity (K) [W / m ° C.] at (Tb + Tc) / 2 [° C.] is given by the following equation according to Fourier's law.

[0035]

(Equation 1)

[Volume resistivity] Measured according to JIS C 2123.

[Hardness] The hardness was measured using a micro rubber hardness meter (micro rubber hardness meter MD-1, manufactured by Kobunshi Keiki Co., Ltd.).

[0038]

[Table 3]

From the results shown in Table 3, the antistatic heat-dissipating sheet of the example has an appropriate hardness, a high thermal conductivity and excellent thermal conductivity, and a small volume resistivity and excellent electrical conductivity. You can see that there is. In contrast, the conductive sheet of Comparative Example 1 has a small volume resistivity and excellent electrical conductivity, but has a low thermal conductivity and is inferior in thermal conductivity. In addition, it can be seen that the heat dissipation sheet of Comparative Example 2 has high thermal conductivity and excellent heat conductivity, but has high volume resistivity and poor electric conductivity.

Next, the liquid crystal display device shown in FIG. 1 was manufactured by the method shown in FIG. 5 using each sheet obtained as described above. As a result, when the sheet of the example product is used, the generation of static electricity can be prevented.
-It is possible to prevent foreign substances from adhering to IC2,
-Destruction of IC2, etc. could be prevented. Also, TA
The heat was able to be uniformly and sufficiently conducted to the B-IC2, and the bonding between the TAB-IC2 and the liquid crystal panel 1 was improved.

On the other hand, when the conductive sheet of Comparative Example 1 was used, heat was not sufficiently conducted to the TAB-IC 2, which hindered the joining between the TAB-IC 2 and the liquid crystal panel 1. When the heat radiation sheet of Comparative Example 2 was used, static electricity was generated due to poor electric conductivity, and TAB-I
Problems such as the adhesion of foreign matter to C2 and the destruction of TAB-IC2 occurred.

[0042]

As described above, the antistatic heat dissipation sheet of the present invention comprises an elastic heat dissipation layer made of a composition containing a silicone polymer and a conductive layer formed on at least one surface of the elastic heat dissipation layer. It is a configuration provided. Therefore, it has excellent properties of both thermal conductivity and electric conductivity, and can be suitably used for manufacturing the above-described liquid crystal display device. The antistatic heat radiating sheet is vulcanized and solidified while continuously supplying the composition containing the silicone polymer to the surface of the release belt to form an elastic heat radiating layer. Then, at least one surface of the elastic heat radiating layer is formed. It can be manufactured by forming a conductive layer on the substrate. Therefore, it is possible to continuously manufacture the antistatic heat radiating sheet, thereby improving the manufacturing efficiency and increasing the productivity.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an example of a liquid crystal display device.

FIG. 2 is an explanatory view showing a method of manufacturing the liquid crystal display device of FIG.

FIG. 3 is a sectional view of a main part showing an example of an antistatic heat dissipation sheet of the present invention.

FIG. 4 is an explanatory view showing one example of a continuous production method of the antistatic heat radiation sheet of the present invention.

FIG. 5 is an explanatory view showing a method for manufacturing a liquid crystal display device using the antistatic heat dissipation sheet of the present invention.

[Explanation of symbols]

 43 elastic heat dissipation layer 44 conductive layer 45 antistatic heat dissipation sheet

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 9:00

Claims (5)

[Claims] 1. An antistatic heat dissipation sheet comprising: an elastic heat dissipation layer made of a composition containing a silicone polymer; and a conductive layer formed on at least one surface of the elastic heat dissipation layer. 2. The antistatic heat dissipation sheet according to claim 1, wherein the conductive layer is formed from at least one of a conductive paint and a conductive ink. 3. The antistatic heat radiation sheet according to claim 1, wherein the hardness (JIS A) of the sheet itself is set to 90 or less. 4. The antistatic heat dissipation sheet according to claim 1, wherein the antistatic heat dissipation sheet is used for manufacturing a liquid crystal display device. 5. A step of preparing a composition containing a silicone polymer and a release belt, a step of supplying the composition to a surface of the release belt while continuously running the release belt, Vulcanizing and solidifying an elastic heat dissipation layer; and forming a conductive layer on at least one surface of the elastic heat dissipation layer.