JPH0739614Y2 - Cushion material - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cushion material used for press-molding a copper clad laminate such as a rigid printed board or a flexible printed board.

[0002]

2. Description of the Related Art Conventionally, as the above-mentioned cushion material, for example, a cushion material formed of felt made of aramid fiber and rock wool, a cushion material formed of synthetic rubber and non-woven fabric, and aramid felt or kraft paper only. There is a cushion material formed in.

[0003]

However, as shown in Table 1 below, the maximum operating temperature during press molding of each cushion material such as the above example is about 170 ° C. to about 300 ° C. It is suitable for press molding of printed circuit boards that use epoxy, phenol, etc. as the base material, but when press-molding printed circuit boards that use polyimide, Teflon, etc. as the base material, the press temperature is higher than the maximum operating temperature of each cushion material. Therefore, there is a problem that a satisfactory action and effect cannot be obtained. In addition, due to the characteristics of the materials that make up each cushion material, there are difficulties in terms of resilience, thermal conductivity, and releasability, and satisfactory cushioning properties cannot be obtained at high press temperatures. Since the restoration rate is lost due to the above, there is a problem that it cannot be used repeatedly many times.

In view of the above problems, the present invention forms a cushioning material by surrounding a single or expanded sheet of expanded graphite sheet with a protective sheet made of a metal foil or a PTFE sheet to form a cushioning material. An object of the present invention is to provide a cushioning material that can improve releasability.

[0005]

The cushioning material according to the first aspect of the present invention is characterized in that it is formed by surrounding the outer surface of the expanded graphite sheet with a protective sheet.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the cushion material has a protective sheet on the outer surface of the laminated sheet obtained by alternately laminating the expanded graphite sheet and the metal foil. It is characterized by being formed by surrounding.

The cushioning material according to a third aspect of the present invention is characterized in that the outer surface of the expanded graphite sheet is surrounded by a protective sheet made of a metal foil.

The cushioning material according to a fourth aspect of the present invention is characterized in that the outer surface of the expanded graphite sheet is surrounded by a protective sheet made of a PTFE sheet.

[0009]

In the cushioning material according to the first aspect of the present invention, the cushioning material is formed by surrounding the outer surface of the expanded graphite sheet with the metal foil according to the third aspect or the protective sheet comprising the PTFE sheet according to the fourth aspect. Then, the heat resistance, the restoring property, the thermal conductivity, and the releasability are improved due to the characteristics of the expanded graphite sheet and the metal foil.

In the cushioning material according to claim 2 of the present invention, in addition to the effect according to claim 1, the outer surface of the laminated sheet formed by alternately laminating the expanded graphite sheet and the metal foil is recited in claim 3. By forming a cushion material by being surrounded by a protective sheet made of a metal foil or the PTFE sheet according to claim 4, the cushioning property is improved as compared with the cushion material according to claim 1.

[0011]

According to the present invention, during press molding, a cushion material in which the outer surface of the expanded graphite sheet is surrounded by a metal foil or a PTFE sheet (tetrafluoroethylene resin) and the expanded graphite sheet and the metal foil are alternately arranged. Since a cushion material in which the outer surface of the laminated sheet laminated with the above is surrounded by a metal foil or a PTFE sheet is selectively used, for example,
It can be applied to press molding of a printed circuit board having epoxy or phenol as a base material or a printed circuit board having polyimide or Teflon as a base material. Moreover, the cushioning material has a higher maximum operating temperature than conventional products, and since the cushioning material is formed without using organic materials such as adhesives, the heat resistance is dramatically improved, and the restorability and thermal conductivity are improved. It also has excellent mold releasability. In addition, the cushioning material can be repeatedly used many times, and overall durability is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The cushioning material of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a cushion material 1 of a first embodiment, which is an expanded graphite sheet 2 (for example, 1.0 mm to 2.0 m thick) formed in a size and shape corresponding to a printed circuit board P.
m), the entire outer surface of which is formed of metal foil such as stainless steel or aluminum in a size and shape so as to cover the expanded graphite sheet 2.
(1 μm to 75 μm), and then each protective sheet 3, 3
The respective peripheral edge portions 3a, 3a are seam welded.

When a PTFE sheet (tetrafluoroethylene resin) is used, the entire outer surface of the expanded graphite sheet 2 is surrounded by two protective sheets 3 and 3 made of a porous PTFE sheet, and then the same. The respective peripheral edge portions 3a, 3a of the protective sheets 3, 3 are joined by, for example, a molten fluororesin film such as PFA or FEP.

Each protective sheet 3 made of metal foil 3,
In the case of seam welding No. 3 in an airtight state, it is possible that the welded part may be damaged due to thermal expansion of the sealed air when heated and pressed by the press device 20 described later, so the fine powder of the expanded graphite sheet 2 leaks to the outside. To prevent this, perform deaeration processing in a vacuum state and then perform seam welding.
Further, a pinhole (φ0.1 mm to φ1.0 mm) may be formed in a part of the protective sheet 3 surrounding the expanded graphite sheet 2.

FIG. 2 shows a cushioning material 4 of a second embodiment, in which the entire outer surface of the expanded graphite sheet 5 formed to have a suitable size and shape is made of metal foil in a size and shape to cover the expanded graphite sheet 5. After surrounding with the formed two protective sheets 6 and 6, the peripheral portions 6a and 6a of the protective sheets 6 and 6 are surrounded.
Curling on one side and then seam welding.

In this case, the same effect as that of the cushion material 1 shown in the first embodiment can be obtained, and the bent portions of the protective sheets 6 and 6 surrounding the expanded graphite sheet 5 are seam welded from one side. , Cushion material 1 of the first embodiment
Seam welding of the protective sheets 6 and 6 can be performed more easily than that of. Moreover, since the peripheral edge portions 6a, 6a of the protective sheets 6, 6 are curled, the operator is not injured when handling.

FIG. 3 shows a cushioning material 7 of a third embodiment, in which one side plane of a metal plate 8 made of stainless steel or the like and one side plane of an expanded graphite sheet 9 are closely attached to each other, and After the outer side surface is surrounded by the protective sheet 10 formed of a metal foil in an appropriate size and shape, the flat surface portion 8a of the metal plate 8 and the peripheral edge portion 10a of the protective sheet 10 are seam welded. In this case, the same action and effect as those of the cushion material 1 shown in the first embodiment can be obtained, and the cushion material 7 can be easily attached and detached because it is mounted on the press hot plate 21 of the press device 20 described later via the metal plate 8. And the efficiency of press work is significantly improved.

FIG. 4 shows a cushion material 11 according to a fourth embodiment, which is an expanded graphite sheet 12 having an appropriate size and shape.
After reinforcing material 13 such as porous rubber, felt, cloth or the like is provided around the outer peripheral portion of, the two protective sheets formed of metal foil on both upper and lower surfaces including the expanded graphite sheet 12 and the reinforcing material 13 Since 14 and 14 are attached, the same operational effect as the cushion material 1 shown in the first embodiment can be obtained.

FIG. 5 shows a cushioning material 15 of a fifth embodiment, in which four metal foils 17 each having the same shape and size are formed between four respective expanded graphite sheets 16 ... Which are appropriately sized and shaped. .. are alternately laminated to form a laminated sheet 18, and the entire outer surface of the laminated sheet 18 is surrounded by two protective sheets 19 and 19 formed of a metal foil in an appropriate size and shape, and then the protective sheets are formed. Peripheral portions 19a, 19 of the sheets 19, 19
Seam weld a.

When a PTFE sheet (tetrafluoroethylene resin) is used, each of the two protective sheets 1 in which the entire outer surface of the laminated sheet 18 is formed of a porous PTFE sheet
After being surrounded by 9, 19, the peripheral portions 19a, 19a of the respective protective sheets 19, 19 are joined by a molten fluororesin film such as PFA or FEP.

In this case, since the expanded graphite sheets 16 ... And the metal foils 17 ... Are alternately laminated, the above-mentioned first embodiment, second embodiment, third embodiment, and fourth embodiment can be used. Cushioning properties higher than those of the cushioning materials 1, 4, 7, and 11 shown can be obtained, and the thickness of the cushioning material 15 can be kept uniform.

A pressing device 20 shown in FIG. 6 is formed by using each of the cushion materials 1 and 1 of the first embodiment having the above-mentioned structure.
A method for press-molding the printed circuit board P will be described below. That is, the press hot plates 21 arranged above and below,
Each cushion material 1,1 is attached to the facing surface of 21, and each mold plate 22,22 is attached to the facing surface of each cushion material 1,1. After mounting the laminated printed circuit boards P, the upper and lower press heat plates 2
1, 21 for each cushion material 1, 1 and each mold plate 2
The printed circuit board P is pressurized through the Nos. 2 and 22, and the air remaining on the press surface is evacuated and heat-treated at an appropriate temperature.

By pressurizing and heating for a predetermined time, the heat of each press hot plate 21, 21 is conducted to the printed circuit board P through each cushion material 1, 1 and the printed circuit board P in which a large number of sheets are laminated is adhered. Can be joined. After a lapse of a predetermined time, pressurization and heating are stopped to perform cooling treatment,
After the upper and lower press heat plates 21 and 21 are relatively moved in the vertical direction and separated from each other, the printed board P is separated from the pressing surfaces of the mold plates 22 and 22, thereby press-molding one printed board P. Is completed.

Each cushion member 1, formed as described above,
As a comparative example of 4, 7, 11, and 15, for example, a test product A of an example formed of an expanded graphite sheet and a metal foil, and a test product of a comparative example 1 formed of a felt made of aramid fiber and rock wool. B, a test product C of Comparative Example 2 formed of synthetic rubber and a non-woven fabric, a test product D of Comparative Example 3 formed of aramid felt, and a test product E of Comparative Example 4 formed of glass cloth and silicone rubber. And a test product F of Comparative Example 5 formed of kraft paper are press-molded to have the same shape and dimensions and subjected to a compression test under the same conditions.

That is, the test pressure was set to 200 kg / cm ² , the test temperature was set to 180 ° C., the pressurization time was set to 16 minutes, and the depressurization time was set to 20 minutes.
B, C, D, E, F are compression tested.

Table 1 below shows each of the test products A,
The results of compression tests of B, C, D, E and F are shown.

[0028]

[Table 1]

As is clear from the above test results, the test products B, C, D, E, and F of the comparative examples have low maximum operating temperatures (about 170 ° C. to about 300 ° C.) during press molding. Although it is suitable for press molding of a printed circuit board P using epoxy, phenol or the like as a base material, satisfactory cushioning properties cannot be obtained at a press temperature higher than the maximum operating temperature.
However, since the test product A of the present invention has a high maximum working temperature (about 600 ° C.) during press molding, for example, a printed circuit board P having a base material such as epoxy or phenol and a print having a base material such as polyimide or Teflon. It can be applied to press molding of the substrate P, and each test product B, C, D,
Compared to E and F, the test product A of the present invention is superior in heat resistance and thermal conductivity.

Further, as shown in FIG.
Although the thickness change rate of C, D, and E varies, the thickness change rate of the test product A of the present invention is more stable than at the start of compression.
In addition, as shown in FIG. 8, each of the test products C, D, and F loses the restoration rate after about 2 to about 200 times.
Has a stable recovery rate from about 400 to about 500 times, and the test product A of the present invention is more durable than the test products B, C, D, E and F of the comparative examples. . Since the measured value of the rate of change in thickness of the test product F is small, the description of the measurement result is omitted.

As shown by the above test results, at the time of press molding, each of the expanded graphite sheets 2, 5, 9 and 12 is covered with a metal foil or a PTFE sheet as a protective sheet 3, 6, 10 or. Each cushion material 1, 4, 7, 11 surrounded by 14 and each expanded graphite sheet 16 ... And each metal foil 17 ... Since the cushioning material 15 surrounded by the protective sheet 19 is selectively used, it can be applied to, for example, press molding of the printed circuit board P having epoxy or phenol as a base material and the printed circuit board P having polyimide or Teflon as a base material. You can

Moreover, the maximum operating temperature of each cushion material 1, 4, 7, 11, 15 is higher than that of the conventional product, and the heat resistance during press molding is dramatically improved, and the restorability and thermal conductivity are improved. It also has excellent mold releasability. Moreover, each cushion material 1, 4, 7, 11, 15 can be used repeatedly many times, and the durability is improved overall.

The present invention is not limited to the configuration of the above embodiment.

For example, the cushion sheets 4, 7, 11 shown in the second, third, and fourth embodiments may be formed by using the laminated sheet 18 shown in the fifth embodiment.
Each expanded graphite sheet 2, 5, 9, 12 is made of metal foil or PT
A laminated sheet formed by alternately laminating each cushion material 1, 4, 7, 11 surrounded by each protective sheet 3, 6, 10, 14 made of an FE sheet, each expanded graphite sheet 16 ... And each metal foil 17 ... A cushion material 15 in which 18 is surrounded by a protective sheet 19 made of a metal foil or a PTFE sheet can be selectively used according to the press molding.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a cushion material according to a first embodiment.

FIG. 2 is a vertical sectional side view showing a cushion material according to a second embodiment.

FIG. 3 is a vertical cross-sectional side view showing a cushion material according to a third embodiment.

FIG. 4 is a vertical sectional side view showing a cushion material according to a fourth embodiment.

FIG. 5 is a vertical sectional side view showing a cushioning material of a fifth embodiment.

FIG. 6 is a side view showing a pressed state of a printed circuit board by a press device.

FIG. 7 is a characteristic diagram showing the rate of change in thickness of a test product.

FIG. 8 is a characteristic diagram showing a restoration rate of a test product.

[Explanation of symbols]

 P ... Printed circuit board 1 ... Cushion material 2 ... Expanded graphite sheet 3 ... Protective sheet 4 ... Cushion material 5 ... Expanded graphite sheet 6 ... Protective sheet 7 ... Cushion material 8 ... Metal plate 9 ... Expanded graphite sheet 10 ... Protective sheet 11 ... Cushion Material 12 ... Expanded graphite sheet 13 ... Reinforcement material 14 ... Protective sheet 15 ... Cushion material 16 ... Expanded graphite sheet 17 ... Metal foil 18 ... Laminated sheet 19 ... Protective sheet 20 ... Pressing device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuhiko Otata Kazuhiko Otata 1 541, Shimuchi Shinji, Uchiba, Sanda City, Hyogo Prefecture Japan Pillar Industry Co., Ltd. Mita Factory (72) Yoshikatsu Tokutake Yodogawa, Osaka City, Osaka Prefecture 2-11-48 Minami, Nonaka, Japan Pillar Industry Co., Ltd.

Claims (4)

[Scope of utility model registration request] 1. A cushion material used when press-molding an appropriate number of laminated printed circuit boards, wherein the cushion material is formed by surrounding the outer surface of an expanded graphite sheet with a protective sheet. 2. The cushion material according to claim 1, wherein the expanded graphite sheet and the metal foil are alternately laminated to each other, and the outer surface of the laminated sheet is surrounded by a protective sheet. 3. The cushion material according to claim 1, wherein the protective sheet is made of a metal foil. 4. The cushioning material according to claim 1, wherein the protective sheet is made of a PTFE sheet.