JP2001088153A - Resin sheet heating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin sheet heating method capable of shortening the heating time of a resin sheet and capable of obtaining the resin sheet reduced in the residual amt. of a volatile component. SOLUTION: In a method for applying a solvent-containing resin compsn. 2 to a continuous moving release film 3 to semicure the formed resin compsn. layer, the release film 3 is provided with a large number of through-holes 4 having a hole size capable of suppressing the dripping of the coated resin compsn. 2. The solvent in the resin compsn. can be also volatilized on the side of the release film 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a resin sheet in which a resin composition is applied to a continuously moving release film and the resin is semi-cured.

[0002]

2. Description of the Related Art A resin sheet plate is used as an insulating substrate for a power supply. The resin sheet plate is obtained by heating a resin sheet obtained by applying a resin composition obtained by mixing a thermosetting resin such as an epoxy resin, a filler such as alumina, and a solvent onto a release film such as polyethylene terephthalate (PET), After the resin is semi-cured, it is obtained by peeling off the release film. Conventionally, as a method of heating such a resin sheet, a method of blowing hot air has been frequently used.

[0003]

With the recent diversification of electronic devices and electric appliances, the above resin sheet plates have
From the demand for further improvement of the withstand voltage, the conventional 100 to 2
From the thickness of about 00 μm, a thicker one is required. However, in the resin composition containing a solvent, the solvent in the resin composition near the release film remains because the solvent volatilizes from the surface of the resin sheet, and remains on the resin sheet plate. Resin sheet plates with a large amount of residual volatile components may cause voids when molded using the sheet plates in a subsequent process, or may cause a decrease in releasability, leading to deterioration in characteristics. Therefore, in order to reduce the residual volatile matter, the heating time of the resin sheet must be increased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to shorten a heating time of a resin sheet and obtain a resin sheet having a small residual volatile content. An object of the present invention is to provide a method for heating a resin sheet.

[0005]

The invention according to claim 1 is
In a method for heating a resin sheet, in which a resin composition containing a solvent is applied on a release film that moves continuously, and the resin is semi-cured, the release film has a range in which resin dripping of the applied resin composition can be suppressed. A plurality of through-holes having a hole diameter of As described above, since the through-hole is provided in the release film, the solvent in the resin composition can be volatilized also from the release film side.
Therefore, the above method can prevent the solvent from remaining on the resin sheet, and can shorten the heating time of the resin sheet.

According to a second aspect of the present invention, in the method for heating a resin sheet according to the first aspect, the through hole has a diameter of 30 to 30 mm.
It is characterized by a range of 100 μm. With the above, it is possible to suppress the occurrence of resin dripping of the resin composition and to realize sufficient volatilization of the solvent.

According to a third aspect of the present invention, in the method for heating a resin sheet according to the first or second aspect, the through hole is
The release film is provided at a rate of 10 to 50 holes / cm ² . As described above, the solvent can be sufficiently volatilized from the release film side.

According to a fourth aspect of the present invention, in the method for heating a resin sheet according to the second aspect, the resin composition applied to the release film has a viscosity of 1000 cps or more. The above viscosity indicates a value measured at a temperature of 25 ° C. with a B-type viscometer. The upper limit of the viscosity is not particularly limited as long as it can be applied, but is practically 50,000 cps or less. As described above, the surface tension of the resin composition functions to prevent resin dripping from the through holes.

According to a fifth aspect of the present invention, in the method for heating a resin sheet according to any one of the first to fourth aspects, the resin composition applied to the release film is irradiated with electromagnetic waves and heated. I do. As described above, since the resin composition is irradiated with electromagnetic waves and heated, heat is generated from the inside of the resin sheet, so that the heating time can be further reduced.

According to a sixth aspect of the present invention, in the method for heating a resin sheet according to the fifth aspect, the upper surface of the applied resin composition is irradiated with electromagnetic waves, and cool air is blown from the lower surface of the release film. And According to the above, by applying the cool air to the release film surface, the progress of the curing of the resin of the resin composition in the vicinity of the release film can be suppressed, so that the volatilization of the solvent from the through-holes becomes smoother. Can be done.

According to a seventh aspect of the present invention, in the method for heating a resin sheet according to any one of the first to fourth aspects, the resin composition applied to the release film is heated by blowing hot air. The method is characterized in that hot air is blown from the upper surface of the applied resin composition and cool air is blown from the lower surface of the release film. By the above, even in the heating method in which hot air is blown, the progress of curing of the resin of the resin composition in the vicinity of the release film can be suppressed by blowing the cool air on the release film surface. The solvent can be volatilized more smoothly.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a heating apparatus showing an example of an embodiment using a method according to the first and fifth aspects of the present invention, and FIG. 2 illustrates a release film. It is a principal part expansion perspective view. The above-mentioned method comprises the steps of: a resin sheet 1 having a resin composition 2 applied on a release film 3 which moves continuously;
Is heated so that the resin of the resin sheet 1 is semi-cured. The resin composition 2 includes a thermosetting resin such as an epoxy resin, a filler such as alumina, and methyl ethyl ketone (ME
It is a mixture of solvents such as K). The release film 3 has a release property from the resin composition, and includes a polyethylene terephthalate (PET) film. The release film 3 has a thickness of 20 to 200 μm.
Those having a thickness of the order are preferred.

As shown in FIG. 1, the above-mentioned heating device has a resin sheet 1 which moves in a horizontal direction, and heaters 5 for heating the resin sheet 1 are provided vertically above and below the resin sheet 1. Examples of the heater 5 include an electrode for irradiating an electromagnetic wave, an outlet of a hot-air dryer for blowing hot air, and the like. Above all, the heating method of irradiating the heater 5 with an electromagnetic wave by using an electrode generates heat from inside the resin sheet 1.
This is preferable in that the heating time can be further reduced.

The resin sheet 1 contains a solvent-containing resin composition. Since the solvent is volatilized from the surface of the resin sheet 1, the solvent in the resin composition 2 near the release film 3 remains. easy. In particular, if the thickness of the resin sheet plate is 20
When heating a material as thick as about 0 to 400 μm, it takes time for the solvent near the release film 3 to evaporate. In the above method, a plurality of through holes 5 are provided in the release film 3 as shown in FIG. 2 in order to volatilize the solvent also from the release film 3 side. The through-hole 5 of the release film 3 has a hole diameter in a range where resin dripping can be suppressed by the surface tension of the applied resin composition. The resin composition applied to produce a thick resin sheet plate has a viscosity of 1000
Cps or more are used. In this case, the diameter of the through hole 5 of the release film 3 is suitably in the range of 30 to 100 μm. If the through hole 5 exceeds 100 μm, the applied resin composition may cause resin dripping, and
If it is less than 30 μm, the effect of volatilization of the solvent may be reduced. The number of the through holes 5 is 10 to 50 holes / cm.
Preferably, they are provided at a ratio in the range of ² .

The production of the through hole 5 is not particularly limited, and the through hole 5 can be produced by irradiating the release film 3 with a laser beam.

According to the above method, the solvent is removed from the release film 3.
Since the solvent can also be volatilized from the side, the solvent can be prevented from remaining on the resin sheet 1 and the heating time of the resin sheet 1 can be shortened. In particular, when a resin sheet having a thickness of about 200 to 400 μm is heated, the effect is remarkably exhibited.

FIG. 3 is an explanatory view of a heating apparatus showing an example of an embodiment using a method according to the sixth aspect of the present invention. Only differences from FIG. 1 will be described. The above-mentioned heating device is provided with an electrode 6 for irradiating an electromagnetic wave as a heater 5 on an upper surface 1a slightly moved away from the resin sheet 1 and a blower 7 on a lower surface 1b. I have. The heating device outputs electromagnetic waves from these electrodes 6 and irradiates the resin sheet 1 to generate heat from the inside of the resin sheet 1 and heat the resin sheet 1. The plurality of electrodes 6 are provided in the moving direction of the resin sheet 1, and the electrodes 6a, 6b, 6c,... Are arranged so that anodes and cathodes are alternately arranged. Further, the blower 7 includes a plurality of air outlets 8 in the moving direction of the resin sheet 1, and the cool air blown from these air outlets 8 cools the surface of the release film 3 of the resin sheet 1.

In the heating method, an electromagnetic wave is output from the electrode 6 and radiated to the resin sheet 1 so that the resin sheet 1
Since heat is generated from the inside of the device, the heating time can be reduced. Furthermore, the above-mentioned heating method suppresses the progress of curing of the resin of the resin composition 2 in the vicinity of the release film 3 by blowing cool air to the surface of the release film 3, so that the solvent is more volatilized from the through holes 4. It is intended to go smoothly.

The above method is not limited to the heating method of irradiating electromagnetic waves, but may be a heating method of blowing hot air.

[0020]

EXAMPLES In order to confirm the effects of the present invention, resin sheet plates of the following Examples and Comparative Examples were prepared and measured.

Example 1 The release film had a thickness of 25 μm.
m PET film, pore size (diameter) 30 μm, average 1
The one provided with through holes at a ratio of 5 holes / cm ² was used.
The resin composition used was a mixture of 12 parts by weight of an epoxy resin (Epiclon 850S, manufactured by Dainippon Ink Co., Ltd.) and 88 parts by weight of alumina, and diluted with MEK.
This resin composition had a viscosity of 1000 cps and a volatile content of 7.0%.

After the resin composition was applied on the PET film at a thickness of 400 μm, it was heated for 10 minutes by a hot-air drying device maintained at a temperature of 90 ° C. to semi-cure the resin.

The residual volatile matter of the resin sheet after heating was measured at a temperature of 163 ° C. for 15 minutes and found to be 1.00%. It was confirmed that the solvent was sufficiently volatilized.

Example 2 The release film had a thickness of 25 μm.
A PET film having a diameter of 100 μm and an average of 40 holes / cm ² in the PET film was used. Except for the release film, in the same manner as in Example 1, the resin composition was applied at a thickness of 400 μm, and then heated for 10 minutes with a hot-air drying device maintained at a temperature of 90 ° C. to cure the resin in a semi-cured manner. . The residual volatile matter of the resin sheet after the heating was measured at a temperature of 163
It was 1.05% when measured at 15 ° C. for 15 minutes. It was confirmed that the solvent was sufficiently volatilized.

Example 3 The release film had a thickness of 25 μm.
m PET film, 10 μm pore size, average 40 pores /
The one provided with through holes at a rate of cm ² was used. Except for the release film, in the same manner as in Example 1, the resin composition was applied at a thickness of 400 μm, and then heated for 10 minutes with a hot-air drying device maintained at a temperature of 90 ° C. to cure the resin in a semi-cured manner. . The residual volatile matter of the resin sheet after the heating was measured at a temperature of 163
It was 1.50% when measured at 15 ° C. for 15 minutes.

(Comparative Example 1) A 25-μm-thick PET film having no through-hole was used as a release film. Except for the release film, in the same manner as in Example 1, the resin composition was applied at a thickness of 400 μm, and then heated for 10 minutes with a hot-air drying device maintained at a temperature of 90 ° C. to cure the resin in a semi-cured manner. . The residual volatile matter of the resin sheet after the heating was measured at a temperature of 1
It was 1.75% when measured at 63 ° C. for 15 minutes.

Comparative Example 2 The release film had a thickness of 25 μm.
A PET film having a hole diameter of 130 μm and an average of 15 holes / cm ² was provided on a PET film having a thickness of m. When the same resin composition as in Example 1 was applied, resin dripping occurred from the through hole.

(Evaluation) Compared to Comparative Example 1, the Example had less volatile components. In particular, in Example 1 in which the hole diameter of the through-hole of the release film was 30 μm and in Example 2 in which the hole diameter was 100 μm, it was confirmed that the solvent was sufficiently volatilized.

[0029]

[Table 1]

Example 4 The heating of the resin sheet was performed by a method of irradiating an electromagnetic wave. After applying the resin composition to a thickness of 400 μm in the same manner as in Example 1, the first 180
Electromagnetic waves were emitted from the electrodes at an output of 1.2 kW for seconds and 2.0 kW for 180 seconds thereafter. At this time, the temperature of the resin sheet is 60 to 75 ° C. for the first 180 seconds,
The temperature rose slowly to 20 ° C. The residual volatile matter of the resin sheet after heating was measured at a temperature of 163 ° C. for 15 minutes, and was 1.20%.

Example 5 The heating of the resin sheet was carried out by irradiating an electromagnetic wave. After applying the resin composition to a thickness of 400 μm in the same manner as in Example 2, the first 180
Electromagnetic waves were emitted from the electrodes at an output of 1.2 kW for seconds and 2.0 kW for 180 seconds thereafter. At this time, the temperature of the resin sheet is 60 to 75 ° C. for the first 180 seconds,
The temperature rose slowly to 20 ° C. The residual volatile matter of the resin sheet after heating was measured at a temperature of 163 ° C. for 15 minutes, and was 1.30%.

Example 6 The heating of the resin sheet was performed by a method of irradiating an electromagnetic wave. After applying the resin composition to a thickness of 400 μm in the same manner as in Example 3, the first 180
Electromagnetic waves were emitted from the electrodes at an output of 1.2 kW for seconds and 2.0 kW for 180 seconds thereafter. At this time, the temperature of the resin sheet is 60 to 75 ° C. for the first 180 seconds,
The temperature rose slowly to 20 ° C. The residual volatile matter of the resin sheet after heating was measured at a temperature of 163 ° C. for 15 minutes, and was 1.80%.

(Comparative Example 3) The heating of the resin sheet was performed by a method of irradiating an electromagnetic wave. After applying the resin composition to a thickness of 400 μm in the same manner as in Comparative Example 1, the first 180
Electromagnetic waves were emitted from the electrodes at an output of 1.2 kW for seconds and 2.0 kW for 180 seconds thereafter. At this time, the temperature of the resin sheet is 60 to 75 ° C. for the first 180 seconds,
The temperature rose slowly to 20 ° C. The residual volatile matter of the resin sheet after heating was measured at a temperature of 163 ° C. for 15 minutes, and was 2.05%.

(Evaluation) In the heating method using an electromagnetic wave, the volatile components of Examples 4 to 6 were smaller than those of Comparative Example 3. In particular, in Example 4 in which the hole diameter of the through hole of the release film was 30 μm and in Example 5 in which the hole diameter was 100 μm, it was confirmed that the solvent was sufficiently volatilized.

[0035]

[Table 2]

[0036]

According to the first aspect of the present invention, since the release film has the through holes, the solvent in the resin composition can be volatilized from the release film side. Therefore,
The above method prevents the solvent from remaining on the resin sheet,
The heating time of the resin sheet can be shortened.

According to the second aspect of the present invention, since the diameter of the through-hole is in the range of 30 to 100 μm, it is possible to prevent the resin composition from dripping and to make the solvent more volatile. And the effect of the present invention can be enhanced.

[0038] In the invention according to claim 3, in particular, the through hole is
Since the release film is provided on the release film at a rate of 10 to 50 holes / cm ^2, the solvent can be sufficiently volatilized from the release film side.

In the invention according to the fourth aspect, the surface tension of the resin composition functions, and it is possible to prevent the resin from dripping from the through-hole, and to enhance the effect of the present invention.

In the invention according to claim 5, since the resin composition is irradiated with electromagnetic waves and heated, heat is generated from the inside of the resin sheet, so that the heating time can be further reduced.

According to the invention of claim 6, in particular, by blowing cool air to the release film surface, the progress of curing of the resin of the resin composition in the vicinity of the release film can be suppressed. Solvent can be more smoothly volatilized.

In the invention according to claim 7, the curing of the resin of the resin composition in the vicinity of the release film is promoted by blowing cold air to the release film surface, even in the heating method of blowing hot air. Can be suppressed, so that the solvent can be more smoothly volatilized from the through holes.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a heating device showing an example of an embodiment using the present invention.

FIG. 2 is an enlarged perspective view of a main part illustrating a release film.

FIG. 3 is an explanatory view of a heating device showing an example of another embodiment using the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin sheet 2 Resin composition 3 Release film 4 Through hole 5 Heater 6, 6a, 6b, 6c electrode

Claims (7)

[Claims] 1. A method for heating a resin sheet, in which a resin composition containing a solvent is applied on a release film that moves continuously and the resin is semi-cured, wherein the release film comprises a resin of the applied resin composition. A method for heating a resin sheet, comprising providing a plurality of through holes having a hole diameter in a range in which dripping can be suppressed. 2. The through hole having a diameter of 30 to 100 μm.
The method for heating a resin sheet according to claim 1, wherein 3. The number of the through holes is 10 to 50 holes / cm ^2.
The method for heating a resin sheet according to claim 1, wherein the resin sheet is provided on the release film at a ratio of: 4. The method for heating a resin sheet according to claim 2, wherein the viscosity of the resin composition applied to the release film is 1000 cps or more. 5. The method according to claim 1, wherein the resin composition applied to the release film is irradiated with electromagnetic waves and heated.
The method for heating a resin sheet according to any one of claims 4 to 4. 6. The method for heating a resin sheet according to claim 5, wherein an electromagnetic wave is irradiated from an upper surface of the applied resin composition, and cool air is blown from a lower surface of the release film. The method for heating a resin sheet according to the above. 7. Heating the resin composition applied to the release film by blowing hot air onto the resin composition, wherein hot air is blown from the upper surface of the applied resin composition and cool air is blown from the lower surface of the release film. The method for heating a resin sheet according to claim 1, wherein air is blown.