JPH0675717U - Cushion material - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a cushioning material capable of improving durability during press molding. [Composition] During press molding, a cushion material in which one side or the whole surface of the expanded graphite sheet is surrounded by a metal foil or a PTFE sheet, and one side or the whole surface of a laminated sheet formed by alternately stacking the expanded graphite sheet and the metal foil Foil or P
Since the cushion material surrounded by the TFE sheet is selectively used, it can be applied to, for example, 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. Compared with conventional products, the maximum operating temperature of the cushioning material is higher, the heat resistance is dramatically improved, and the restorability, thermal conductivity, and releasability are also excellent, and overall durability is improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cushion material used when press-molding a copper clad laminate such as a rigid printed board or a flexible printed board.

[0002]

[Prior art]

 Conventionally, as the above-mentioned cushion material, for example, a cushion material made of felt made of aramid fiber and rock wool, a cushion material made of synthetic rubber and non-woven fabric, and a cushion made of only aramid felt or kraft paper. There are materials.

[0003]

[Problems to be solved by the device]

 However, as shown in Table 1 below, each cushion material such as the above example has a maximum operating temperature of about 170 ° C to about 300 ° C during press molding. Therefore, for example, epoxy or phenol is used as the base material. It is suitable for press-molding printed circuit boards, but when press-molding a printed circuit board that uses polyimide, Teflon, etc. as a base material, the press temperature is higher than the maximum operating temperature of each cushion material, so it is satisfactory. There is a problem in that various operational effects cannot be obtained. Moreover, due to the characteristics of the materials that make up each cushioning material, there are difficulties in restoration, thermoconductivity, and releasability, and sufficient cushioning cannot be obtained at high press temperatures. There is also a problem that it cannot be used repeatedly many times because the restoration rate is lost after each time.

In view of the above problems, the present invention forms a cushion 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 conductivity and releasability.

[0005]

A cushion material according to claim 1 of the present invention is characterized in that it is formed by surrounding an outer surface of an expanded graphite sheet with a protective sheet.

A cushioning material according to a second aspect of the present invention is, in addition to the structure according to the first aspect, a protective sheet for protecting an outer surface of a laminated sheet obtained by alternately laminating the expanded graphite sheet and a metal foil. It is characterized by being formed by surrounding with.

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.

A cushion material according to a fourth aspect of the present invention is characterized in that the expanded graphite sheet is formed by surrounding the outer surface of the expanded graphite sheet with a protective sheet made of a PTFE sheet.

[0009]

[Action]

 In the cushion material according to claim 1 of the present invention, the cushion material is formed by surrounding the outer surface of the expanded graphite sheet with the protective sheet made of the metal foil according to claim 3 or the PTFE sheet according to claim 4. The properties of the expanded graphite sheet and the metal foil improve heat resistance, restorability, thermal conductivity, and releasability.

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 the cushion material by being surrounded by the protective sheet made of the metal foil or the PTFE sheet according to the fourth aspect, the cushioning property is improved as compared with the cushion material according to the first aspect.

[0011]

[Effect of device]

 According to this invention, at the time of press molding, a cushion material surrounded by a metal foil or a PTFE sheet (tetrafluoroethylene resin) on the outer surface of the expanded graphite sheet and the expanded graphite sheet and the metal foil are alternately laminated. Since the cushioning material in which the outer surface of the laminated sheet is surrounded by a metal foil or a PTFE sheet is selectively used, for example, a printed circuit board using epoxy or phenol as a base material or a print material using polyimide or Teflon as a base material. It can be applied to press molding of substrates. In addition, the maximum operating temperature of the cushioning material is higher than that of 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 heat conduction are improved. Excellent in mold release and releasability. In addition, the cushioning material can be used many times, which improves overall durability.

[0012]

【Example】

 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 outer surface of an expanded graphite sheet 2 (for example, a thickness of 1.0 mm to 2.0 mm) formed in a size and shape corresponding to a printed circuit board P. After the whole is surrounded by two protective sheets 3 and 3 (for example, a thickness of 30 μm to 75 μm) formed of a metal foil such as stainless steel or aluminum in a size and shape that covers the expanded graphite sheet 2. The peripheral edges 3a, 3a of the protective sheets 3, 3 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 peripheral portions 3a and 3a of the protective sheets 3 and 3 are joined by a molten fluororesin film such as PFA or FEP.

When the protective sheets 3 and 3 made of metal foil are seam-welded in an airtight state, when they are hot-pressed by a press device 20 described later, the welded parts are damaged due to thermal expansion of the sealed air. Therefore, in order to prevent the fine powder of the expanded graphite sheet 2 from leaking to the outside, deaeration is performed in a vacuum state and then seam welding is performed. Also, 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 in an appropriate size and shape has a size and shape such that the expanded graphite sheet 5 is covered with a metal foil. After being surrounded by the two protective sheets 6 and 6 formed in, the peripheral portions 6a and 6a of the protective sheets 6 and 6 are curled on one side and then seam welded.

In this case, the same effect as 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. Therefore, compared with the cushioning material 1 of the first embodiment, seam welding of the protective sheets 6 and 6 can be performed more easily. Moreover, since the peripheral portions 6a, 6a of the protective sheets 6, 6 are curled, the operator is not injured when handling.

FIG. 3 shows the cushioning material 7 of the third embodiment, in which one side plane of the metal plate 8 formed of stainless steel or the like and one side plane of the expanded graphite sheet 9 are in close contact with each other. After enclosing the outer side surface with 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 since the metal plate 8 is mounted on the press hot plate 21 of the press device 20 which will be described later, the cushion material 7 is detached. And the efficiency of press work is significantly improved.

FIG. 4 shows a cushion material 11 of a fourth embodiment, in which, for example, a reinforcing material 13 such as porous rubber, felt, cloth or the like is provided on the outer peripheral portion of an expanded graphite sheet 12 having an appropriate size and shape. After surrounding, the two protective sheets 14 and 14 made of metal foil are attached to both upper and lower surfaces including the expanded graphite sheet 12 and the reinforcing material 13, so that it is equivalent to the cushion material 1 shown in the first embodiment. The effect of is obtained.

FIG. 5 shows a cushion material 15 of a fifth embodiment, in which four metal foils 1 each having the same shape and size are formed between four respective expanded graphite sheets 16 ... Which are appropriately sized and shaped. 7 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 metal foil in an appropriate size and shape. The peripheral edges 19a, 19a of the protective sheets 19, 19 are seam welded.

When a PTFE sheet (tetrafluoroethylene resin) is used, the entire outer surface of the laminated sheet 18 is surrounded by two protective sheets 19 and 19 made of a porous PTFE sheet, and then the same. The peripheral portions 19a and 19a of the protective sheets 19 and 19 are joined by, for example, 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 applied. A cushioning property higher than that of each cushion material 1, 4, 7, 11 shown is obtained, and the thickness of the cushion material 15 can be kept uniform.

A method of press-molding the printed circuit board P by the press device 20 shown in FIG. 6 using the cushion materials 1 and 1 of the first embodiment configured as described above will be described. That is, the cushion members 1 and 1 are attached to the facing surfaces of the press hot plates 21 and 21 arranged above and below, and the mold plates 22 and 22 are attached to the facing surfaces of the cushion material 1 and 1 respectively. After mounting a large number of printed circuit boards P between the pressing surfaces of the mold plates 22 and 22, the upper and lower press heat plates 21 and 21 interpose the cushion materials 1 and 1 and the mold plates 22 and 22, respectively. Then, the printed circuit board P is pressurized, and the air remaining on the press surface is evacuated, and is heated to an appropriate temperature.

By pressurizing and heating for a predetermined time, the heat of the press hot plates 21 and 21 is conducted to the printed circuit board P via the cushion materials 1 and 1, and a large number of printed board P are stacked. Can be closely joined. After a lapse of a predetermined time, the pressurization and heating are stopped to perform cooling treatment, and the upper and lower press heat plates 21 and 21 are relatively moved in the vertical direction to be separated from each other, and then the mold plates 22 and 22 are heated. By separating the printed circuit board P from between the pressure surfaces, press molding of one printed circuit board P is completed.

As a comparative example of the cushion materials 1, 4, 7, 11, and 15 formed as described above, for example, a test product A of an example formed of an expanded graphite sheet and a metal foil, an aramid fiber, and a lock. Specimen B of Comparative Example 1 made of felt made of wool, Specimen C of Comparative Example 2 made of synthetic rubber and non-woven fabric, Specimen D of Comparative Example 3 made of aramid felt, and glass cloth The test product E of Comparative Example 4 formed of and the silicon rubber and the test product F of Comparative Example 5 formed of kraft paper are press-molded to have the same shape and dimension 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 the results of compression testing of each of the test products A, B, C, D, E and F under the above conditions.

[0028]

[Table 1]

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

Further, as shown in FIG. 7, the thickness change rate of each of the test products B, C, D, E varies, but the thickness change rate of the test product A of the present invention is different from that at the start of compression. stable. Moreover, as shown in FIG. 8, the restoration rate of each of the test products C, D, and F is lost after about 2 to about 200 times, but the restoration rate of the test product A of the present invention is up to about 400 to about 500 times. Is stable, 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 example. Since the measured value of the thickness change rate 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 has a protective sheet 3, 6 and 10 formed on one side or the whole side of a metal foil or a PTFE sheet. , 14, each cushion material 1, 4, 7, 11 and each expanded black lead sheet 16 ... And each metal foil 17 ... are alternately laminated on one side or the whole surface of the metal foil or PTFE sheet. Since the cushioning material 15 surrounded by the protective sheet 19 made of is selectively used, for example, for press molding of the printed circuit board P using epoxy or phenol as a base material and the printed circuit board P using polyimide or Teflon as a base material. Can be applied.

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 heat conduction are improved. Excellent in mold release and releasability. In addition, 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-described 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. Cushion materials 1, 4, 7, 11 in which the expanded graphite sheets 2, 5, 9, 12 are surrounded by protective sheets 3, 6, 10, 14 made of metal foil or PTFE sheet, and expanded graphite sheets. A laminated sheet 18 obtained by alternately laminating the sheets 16 and the respective metal foils 17 can be selectively used in accordance with the press molding with a cushion material 15 surrounded by a protective sheet 19 made of a metal foil or a PTFE sheet. .

[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 Ota 1 541, Shimouchi-jinji-bata, Mita-shi, Hyogo Prefecture Mita Plant, Japan Pillar Industry Co., Ltd. (72) Yoshikatsu Tokutake Nonaka, Yodogawa-ku, Osaka City Minami 2-chome 11-48 Japan Pillar Industry Co., Ltd.

Claims (4)

[Scope of utility model registration request] 1. A cushion material used when press molding a proper 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 cushioning material according to claim 1, wherein the expanded graphite sheet and the metal foil are alternately laminated so that 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.