JPH01157821A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To remove voids contained in resin efficiently and control the generation of thin spots developed by the voids on a molded laminated sheet by pressurizing the sheet to the state of a given reduced pressure by a given initial pressure, applying zero pressure for a given period of time, and then pressurizing with a pressure lower than the initial pressure. CONSTITUTION:A laminated material is pressurized up to the state of a given reduced pressure with a given initial pressure, and then zero pressure is applied thereon, followed by an applied pressure lower than the initial pressure in the manufacturing method of a laminated sheet in which a plurality of laminated materials consisting of piled up inner layer materials, resin impregnating bases, metal foils and the like are heated and pressurized under the pressure reduced atmosphere. A plurality of laminated materials consisting of a plurality of piled up resin impregnating bases are disposed between hot platens to, vacuum atmosphere, and a laminated sheet is manufactured by heating and pressurizing under the reduced atmosphere. The degree of vacuum is around 600-100Torr and molding pressure is 5-150kg/cm<2>, while molding temperature is 100-200 deg.C and molding time is approximately 30-100min. For example, the initial pressure of 50-70kg/cm<2> is applied, and when the degree of vacuum reaches 700-300Torr, zero pressure is applied, and after 10-80sec, the pressure of 10-30kg/cm<2> is applied.

Description

[Detailed description of the invention] 【Technical field】

The present invention relates to a method for manufacturing a laminate used as a printed wiring board or the like.

[Background technology]

Conventionally, multiple sets of laminates, each consisting of an inner layer material, a resin-impregnated base material, metal foil, etc., have been placed between hot plates equipped with a vacuum enclosing press mechanism, and then heated and pressurized under reduced pressure to produce a laminate. However, due to unevenness in the resin content of the resin-impregnated base material, differences in temperature rise within the heating plate, etc., the formed laminates were prone to scratches due to voids. In order to prevent this blurring, high-pressure molding is used.
In this case, there was a problem in that the laminate would be greatly warped and twisted.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to produce a laminate plate that is free from scratches and has minimal warping, warping, and twisting.

[Disclosure of the invention]

The method for producing a laminate of the present invention is a method for producing a laminate in which a plurality of sets of laminates, each consisting of an inner layer material, a resin-impregnated base material, a metal foil, etc., are pre-heated and pressed in a reduced pressure atmosphere, and the method comprises: It is characterized by pressurizing until it reaches a predetermined reduced pressure state, then opening and unpressurizing at a predetermined time, and then pressurizing at a pressure lower than the initial pressure, and with this configuration, the above object is achieved. . In the present invention, the resin-impregnated base material includes paper, cloth made of organic fibers, nonwoven fabric, or cloth made of inorganic fibers such as glass and asbestos alone or in a blend, or nonwoven fabric, which is dipped in a resin face and impregnated with resin. It is formed by drying. The base material preferably has a thickness of 0.10-0.
A glass cloth having a thickness of 30 a+m and a weight of 100 to 300 g/n2 is a glass cloth, and glass cloth having a thickness other than this specific thickness and weight has poor resin impregnation properties and contains many air bubbles. As the resin for the resin face, thermosetting resins such as epoxy resins, polyimide resins or modified products thereof, 7-ether resins, and unsaturated polyester resins can be used. In this case, the resin is impregnated into the base material under reduced pressure by reducing the pressure in the festival tank.
Alternatively, in the case of 6 pressurization, which is carried out by passing the base material between two upper and lower rolls arranged in a festival tank and then removing the pressure, for example, there are three rolls and impregnation is carried out under a pressure of 10 kg/am2. The amount of resin impregnation is 35 to 65% by weight in terms of solid content.
It is. By carrying out the process under reduced pressure or increased pressure, the entrainment of air bubbles into the base material in the festival tank can be reduced. Of course, the impregnation may be carried out under normal pressure. A plurality of carcasses 8 made by stacking a plurality of resin-impregnated base materials are placed between heating plates, the space between the heating plates is enclosed in a so-called vacuum, and a laminate is formed by heating and pressurizing in a reduced pressure atmosphere. The degree of vacuum is about 600 to 100 Torr, and the molding pressure is about 5 to 1
50 kg/cm2, the molding temperature is 100 to 200°C, and the molding time is about 30 to 100 minutes. For example, the initial pressure is 5.
Pressure is applied to 0 to 70 kg/cm2, and the degree of vacuum is 700 to 700.
After reaching 300 Torr, the pressure is reduced to zero and after 10-80 seconds, the pressure is increased to 10-30 kg/am2. In this case, a metal foil may be placed on the outermost layer of the laminate. # as a member of the club! Metal foil, aluminum foil, brass foil, nickel foil, stainless steel copper foil, iron foil, etc. can be used, and an adhesive layer may be provided on one side of this metal foil to improve adhesiveness. Alternatively, the laminate may be one in which a resin-impregnated base material is arranged on both sides of an inner layer material, and a metal foil is layered on the outermost layer. The thus obtained metal foil-clad laminate is formed with an outer layer circuit pattern by a conventional method and is put to practical use as a printed wiring board or a multilayer printed wiring board. Next, examples of the present invention will be specifically described. (Example 1) A plurality of resin-impregnated base materials obtained by impregnating glass cloth with epoxy resin and drying them are stacked, and these are placed between heating plates as a set, and the initial pressure is set at a temperature of 165 to 175°C. 6
After pressurizing at 0 kg/cm2, when the degree of vacuum reached 300 Torr, it was set to no pressure (Okg/cm") and 30 to 6
After 0 seconds, pressure was applied at 20 kg/am2 to obtain a laminate with a thickness of 1.6 mm. The degree of vacuum is 100T. r", the molding time was about 120 minutes (! @ see figure 1)
. The rate of occurrence of scratching on this laminate, warpage in normal conditions of the 1mX1w product, and variation in board thickness were measured. The results are shown in Table 1. (Example 2) A laminate was produced in the same manner as in Example 1, except that the pressure was turned off when the degree of vacuum reached 400 Torr. The same measurements as in Example 1 were also performed on this laminate. The results are shown in Table 1. (Example 3) A laminate was manufactured in the same manner as in Example 1 except that the pressure was turned off when the degree of vacuum reached 500 Torr. The same measurements as in Example 1 were also performed on this laminate. The results are shown in the tjSi table. (Comparative Example) A laminate was manufactured in the same manner as in Example 1 except that the degree of vacuum was 100 Torr and the pressure was 60 kg/cm2 (f
f! (See Figure 2). The same measurements as in Example 1 were also performed on this laminate. The results are shown in Table 1. Example Comparative example Fading occurrence rate 0 0 4 5 (%) Warpage 88815 (+ui) Plate thickness variation width 0.07 G, 07 0.08 G
, 015 Theory All of the examples of the present invention have a higher blurring occurrence rate than the comparative example,
It can be seen that the variations in warpage and plate thickness are small. and,
It is understood that these characteristics are better as the degree of vacuum is lower when the initial pressure is released. This is due to the increased pressure reduction effect.

【Effect of the invention】

The present invention is a method for producing a laminate in which a plurality of laminates, each consisting of an inner layer material, a resin-impregnated base material, a metal foil, etc., are heated and pressurized in a reduced pressure atmosphere, and the method is to heat and press a plurality of laminates in a reduced pressure atmosphere at a predetermined initial pressure until a predetermined reduced pressure state is reached. Pressure is applied, then there is no pressure for a predetermined period of time, and then the pressure is applied at a pressure lower than the initial pressure, so the initial pressure is released and the pressure is reduced while the resin in the resin-impregnated base material is melted.
It can efficiently remove the voids contained in the resin and suppress the occurrence of scratches due to voids on the molded laminate. Furthermore, since the voids can be removed more efficiently, the molding pressure can be lowered accordingly. This reduces the warpage of the laminate and the variation in plate thickness.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between pressure and vacuum degree in an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between pressure and vacuum degree in a conventional example. Agent Patent Attorney Ishi 1) Ai 7 Figure 1 Figure 2

Claims (4)

[Claims] (1) A method for manufacturing a laminate in which multiple sets of laminates, each consisting of an inner layer material, a resin-impregnated base material, metal foil, etc., are heated and pressurized in a reduced pressure atmosphere, and the method is to heat and press a plurality of laminates at a predetermined initial pressure until a predetermined reduced pressure state is reached. 1. A method for manufacturing a laminate, which comprises applying pressure, then leaving it unpressurized for a predetermined period of time, and then applying pressure at a pressure lower than the initial pressure. (2) The method for manufacturing a laminate according to claim 1, wherein the laminate is formed by stacking a plurality of resin-impregnated base materials and overlapping a metal foil on the outermost layer. (3) The method for manufacturing a laminate according to claim 1, wherein the laminate is formed by disposing resin-impregnated base materials on both sides of an inner layer material and overlapping metal foil on the outermost layer. (4) The method for manufacturing a laminate according to claim 1, wherein the laminate is formed by stacking a plurality of resin-impregnated base materials.