JPH0154173B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an improvement in a hot press device used for press forming laminated molded products such as electrical printed wiring boards and laminate boards.

(Prior art) Conventionally, a plurality of plate-shaped laminated materials such as resin-impregnated sheets, resin films or sheets, metal foils or plates are stacked on top of each other, and the stacked laminate is charged between the hot plates of a hot press machine. Then, by applying heat and pressure, the laminates are integrated and press-molded into the desired laminate molded product.For example, electrical printed wiring boards and laminate boards are made using this method. Manufactured.

By the way, in laminate molded products such as electrical printed wiring boards and laminate boards that are manufactured by press molding with such hot press equipment,
If air, water vapor, gas, etc. (hereinafter simply referred to as air, etc.) remains between the laminated materials that have been integrated by press forming, bonding failure may occur due to the air remaining between the laminated materials. Defects such as blisters, delamination, and voids occur, leading to a decline in product quality and product defects. Therefore, in this type of laminated molded product, care must be taken to prevent air from remaining between the laminated materials during press molding. It is necessary to
In particular, when the laminated molded product is an electrical printed wiring board, etc., even minute voids may significantly impede the functionality of the product, so prevent air etc. from remaining between the laminated materials as much as possible. There is a need to.

Therefore, in conventional hot press equipment, the press surface of each hot plate is formed into a curved surface that slightly protrudes at the center, and the laminate is heated and pressurized in such a state that the pressing force (surface pressure) becomes larger toward the center. Accordingly, press molding was performed. If the press surface of the hot plate is curved in this way and the laminate is heated and pressurized with the pressure increasing toward the center, the air between the laminate materials will be absorbed by the adhesive resin due to heating. As it gels, it is gradually pushed out from the center to the periphery, which effectively prevents air from remaining between the laminated materials, resulting in poor adhesion, blistering, delamination, etc. This effectively prevents defects such as voids from occurring. Furthermore, it is possible to relatively effectively prevent these defects from inhibiting the functionality of the product.

(Problem) However, although the hot press device in which the pressing surface of the hot plate is curved can effectively suppress the occurrence of defects caused by residual air, etc., the pressing surface of the hot plate itself is curved. Due to this curved shape, there are problems such as warpage and uneven thickness of the laminated press-formed product, and improvements to these problems have been desired.

(Solution Means) Here, the present invention was made in view of such circumstances, and between the back of the upper hot plate and at least one of the fixed plate or the back of the lower hot plate and the movable plate, A hollow bag member is provided in which the amount of expansion increases toward the center when fluid is supplied to the inside, and the thickness becomes uniform over the entire surface when the fluid is discharged.

(Operation/Effect) According to such a hot press device, heating and pressurizing operations are started when the volume of the bag member into which a predetermined fluid is supplied is increased, so that the pressurizing force based on the cylinder drive is applied to the laminate. is applied to the laminate in a distribution state that is maximum at the center and decreases continuously toward the periphery, and as the press operation progresses, the fluid inside the bag member is gradually discharged to increase the pressing force on the laminate. By gradually equalizing the laminate materials, water vapor and gas generated as the resin gels to bond the laminated materials together, or the air between each laminated material, can be gradually distributed from the center to the periphery. Since air, water vapor, gas, etc. between the laminated materials can be effectively expelled, it is possible to effectively prevent air, etc. from remaining between the laminated materials. Therefore, it is possible to effectively prevent defects such as poor adhesion, blistering, delamination, and voids caused by residual air, etc., and in turn, prevent product functionality from being hindered by such defects. It is also possible to effectively prevent this from occurring.

In addition, in such a hot press device, when the fluid in the bag member is discharged and the bag member is contracted, the pressing surface of each hot plate returns to a flat state, so the final stage pressing operation is performed while the bag member is contracted. By doing so, the laminate can be pressed on a flat pressing surface. Therefore, unlike the conventional hot press apparatus in which the press surface of the hot plate itself is a curved surface, warpage or uneven thickness due to the curvature of the hot plate press surface does not occur in the laminated molded product.

In other words, according to the hot press apparatus according to the present invention, the thickness is uniform, the flatness is high, and there is almost no air remaining inside (between the laminated materials).
This allows you to obtain high-quality laminate molded products.
In particular, it is used in the manufacture of laminate molded products such as electrical printed wiring boards, where the product function may be significantly inhibited by residual air, etc., to ensure high quality products are stably produced. There are some advantages that you can get.

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

First, FIG. 1 shows an example of a hot press apparatus according to the present invention, in which 10
is a stationary plate and is fixed to the upper end of a plurality of tie rods 14 erected on the flange 12 of the cylinder 18. Reference numeral 16 denotes a movable platen, which is fixed to a ram 20 fitted into the cylinder 18 so as to be movable up and down, so that it can be moved up and down as the ram 20 expands and contracts. An upper heating plate 26 and a lower heating plate 28 are disposed below the fixed platen 10 and above the movable platen 16, respectively, with a rubber bag 22 and a heat insulating plate 24 in between.

Here, the upper heating plate 26 and the lower heating plate 28 each have a flat plate shape with a flat upper and lower surface,
A plurality of brackets 30 are provided on the sides thereof.
The fixed platen 10 is fixed by bolts 32 which are slidably inserted through the brackets 30.
The movable platen 16 is connected to the movable platen 16 in such a manner that it is prevented from being separated from the movable platen 16 by more than a predetermined distance.

On the other hand, the bags 22, 22 each have a planar shape corresponding to the upper hot plate 26 and the lower hot plate 28,
The internal space is connected to a pneumatic device (not shown) via a hose 34. Air is supplied and discharged from the pneumatic device into the interior through the hose 34. In addition, the expansion ratio of these bags 22, 22 is increased toward the center, and as shown in FIG. 1, when air is discharged, the entire surface takes on a plate-like shape with an even thickness. However, as shown in FIG. 2, when the volume into which air is supplied increases, the amount of bulge, that is, the thickness, increases toward the center. When the volume increases, as shown in FIG. 2, the upper hot plate 26 and the lower hot plate 2
The lower surface 36, which is the press surface of the upper hot plate 26, and the upper surface 38, which is the press surface of the lower hot plate 28, are respectively formed into curved surfaces with their central portions protruding. There is.

On the other hand, a movable hot plate 40 is supported between the upper hot plate 26 and the lower hot plate 28 so as to be movable in the vertical direction by a support mechanism (not shown).
6, the predetermined laminates 42, 42 can be heated and pressurized between the facing hot plates. Note that the laminate 42 is made by laminating a plurality of plate-shaped laminated materials such as resin-impregnated sheets, resin films or sheets, metal foils or plates,
Although they are constructed by stacking them, the laminated materials differ depending on the intended laminated molded product. Incidentally, if the laminate molded product is an electrical printed wiring board, a substrate, copper foil, resin sheet (prepreg), etc. will be employed as the laminate material.

Next, using such a hot press device,
Laminates 42, 42 inserted between each facing hot plate
The case of press molding will be explained.

That is, each laminate 42, 42 is inserted and placed between each hot plate with the movable platen 16 in the lowered state, but when the laminate 42 is placed between each hot plate, first , cylinder 18 is driven, and each laminate 4
The movable platen 16 is raised until the movable platen 16 reaches a position where the hot plates 2 and 42 are lightly pressed between the hot plates or a position just before that. At the raised position of the movable platen 16, air is forced into the bags 22, 22, and as shown in FIG. The central portions of 28 are respectively projected toward the movable hot plate 40. As a result, the lower surface 36 and the upper surface 38, which are the pressed surfaces, are curved to protrude toward the center, and the surface pressure (pressure force) on each laminate 42, 42 is applied to the center. It is set so that it becomes larger as the size increases. Next, a pressurizing force based on the driving of the cylinder 18 is applied via the bags 22, 22 in a distributed state in which the maximum is at the center of each laminate and the pressure decreases continuously toward the periphery.
Note that the maximum surface pressure for each of the laminates 42, 42 is generally set at a relatively low pressure called contact pressure, usually ^about 1 to 5 kg/cm2.

On the other hand, before and after this air pumping operation, the heating operation of each hot plate is started, and gelation of the resin layer for adhering the laminated materials in the laminates 42, 42 to each other is started. Then, as the gelation of the resin layer progresses, the pressing force by the cylinder 18 is gradually increased. Further, at the same time as this press force increases, the air inside each bag 22, 22 is gradually discharged, and the degree of curvature of the upper hot plate 26 and the lower hot plate 28 is gradually reduced. With this, each laminate 42, 42
The area on which the maximum surface pressure acts is gradually expanded while the maximum surface pressure on the laminates 42, 42 is gradually equalized. Finally, all the air in the bags 22, 22 is discharged, and both the upper hot plate 26 and the lower hot plate 28 return to the flat plate shape, that is, the surface pressure on each laminate 42, 42 is reduced to that level. The pressing operation is performed with sufficient pressing force in a state that the entire surface is uniform.

In this way, at the beginning of the heating operation for each laminate 42, 42, the surface pressure acting on the laminates 42, 42 is made larger toward the center thereof, and the adhesive resin layer in each laminate material is Depending on the progress of gelation, these laminates 42, 42
By gradually equalizing the surface pressure against the laminates from the center toward the periphery, air, water vapor, gas, etc. between each laminate material can be prevented from gelling the resin layer and against each laminate material 42, 42. As the surface pressure is equalized, the laminated materials 42, 42 are gradually pushed out from the center toward the periphery, and eventually are almost completely ejected from between the laminated materials. . Therefore, laminated molded products press-formed using this method may have defects such as poor adhesion between laminated materials, blistering, delamination, or voids due to residual air or gas. There are almost no such defects, and it is possible to very effectively prevent product functionality from being inhibited due to these defects.

Moreover, each laminate 42, 42, as mentioned above,
The final pressing operation is performed between each hot plate that has returned to its flat plate shape, with the surface pressure being uniform over the entire surface, so the laminate is pressed between the hot plates with curved pressing surfaces. Unlike conventional hot press machines that tighten, there is no possibility of warping or uneven thickness of the laminated molded product.

In addition, during the heating operation, the resin layer first gels at the center of each laminate 42, 42, and as the surface pressure on each laminate 42, 42 becomes equal, the gelation progresses toward the periphery. In the past, it was effective to gradually expand the air between the laminated materials, and to do so,
Heating means such as electric heaters and heating medium distribution channels for heating each hot plate may be provided closer to the center of each hot plate, or heating means for heating the periphery of each hot plate may be provided separately from the heating means for heating the periphery of each hot plate. It is desirable to provide a heating means capable of independently heating the heat plate, and to actively raise the temperature of the central portion of each hot plate higher than that of the peripheral portion at the initial stage of the heating operation. In particular, if the central part of the hot plate can be heated by a heating means independent from the heating means that heats the peripheral part of the hot plate, the surface pressure on the laminate 42 can be evenly distributed without complicating the hot plate so much. It has the advantage that the gelation of the resin layer can be controlled easily and with high precision depending on the temperature.

In addition, in the process of equalizing the surface pressure on each laminate 42, in order to improve the quality of the laminate molded product, as mentioned above, the maximum surface pressure is maintained at a relatively low pressure and approximately constant. It is desirable to do so. In the process of equalizing this surface pressure, if the surface pressure is increased more than necessary, not only air and gas, but also gelled resin will be pushed out to the periphery, causing distortion in the laminate molded product. This is because fear arises.

As explained above, according to the hot press apparatus of this embodiment, when heating and pressurizing the laminates 42, 42, by controlling the supply and discharge of air to and from the bags 22, 22, and as needed. By actively controlling the gelation of the adhesive resin layer, air, etc. can be effectively discharged from between the laminated materials composing these laminates 42, 42, and the thickness is uniform and the flatness is high, and the quality is good. It is possible to obtain a laminated molded product, and particularly when used in press molding of electrical printed wiring boards, etc., it has the advantage that defects in the molded product can be significantly reduced and the yield can be significantly improved.

Although one embodiment of the present invention has been described above, this is merely an example, and it goes without saying that the present invention should not be interpreted as being limited to the above-mentioned specific example.

For example, in the embodiment described above, the air is forced to be fed to the bags 22, 22 after the movable platen 16 has been raised to a predetermined position. 1
It is also possible to carry out the operation prior to the upward drive of 6, and furthermore, it is also possible to carry out the operation during the upward movement. Also, those bags 22,
The fluid supplied to and discharged from 22 does not necessarily have to be air, but may be other gas such as nitrogen gas or liquid.

In addition, in the above embodiment, the bags 22, 22 were made of rubber, but the upper heating plate 26 and the lower heating plate 2
However, if the bags 22 and 22 are made of heat-resistant resin or the like, they can be placed behind the upper heating plate 26 and the lower heating plate 28. They may be placed in direct contact with each other. Further, the bags 22, 22 do not necessarily have to be provided on the upper hot plate 26 and lower hot plate 28 sides, but can also be provided on the movable hot plate 40 side. However, in this case, the movable hot plate 40 has a structure in which the bag 22 is sandwiched between two hot plates in a sandwich-like manner.

Furthermore, in the embodiment, one movable hot plate 40 is disposed between the heat insulating plate 24 and the lower hot plate 28.
Although the present invention has been applied to a tiered hot press device, the present invention can also be applied to a multi-stage hot press device having three or more tiers, and can also be applied to a laminate 42 between an upper hot plate and a lower hot plate.
It is also possible to apply it to a one-stage hot press device in which the material is directly press-molded.

In addition, in the embodiment described above, the laminate 42 was press-molded in a state exposed to the external space, but the present inventor previously filed a patent application filed in 1983-
As proposed in No. 71844, the laminate 42 is housed in a deformable and volume-variable bag-shaped container, and the inside of the container is vacuum degassed.
It is also possible to reduce the air, etc. between each of the laminated materials 42 in advance, and then press-form the laminate 42 together with its container by the same method as in the above embodiment. In this way, it is possible to further reliably reduce residual air between the laminated materials of the laminate molded product, and the product quality of the laminate molded product is further improved.

Although not listed in detail, it goes without saying that the present invention can be implemented with various changes, modifications, improvements, etc. without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is an explanatory sectional view showing one mode of operation of an embodiment of the present invention, and FIG. 2 is an explanatory sectional view of essential parts showing a different mode of operation of the embodiment. 10: Fixed plate, 12: Flange, 14: Tie rod, 16: Movable plate, 18: Cylinder, 20: Ram, 22: Bag, 24: Heat insulation plate, 26: Upper heating plate, 2
8: lower hot plate, 40: movable hot plate, 42: laminate.

Claims (1)

[Claims] 1 A plurality of tie rods are erected on the flange of a cylinder, a fixed plate is fixed to the upper end of the plurality of tie rods, and a movable plate is attached to the upper end surface of a ram fitted into the cylinder so as to be movable up and down. A plurality of hot plates are provided between the movable plate and the fixed plate so that they can be opened and closed or clamped by the vertical movement of the movable plate, and a plurality of hot plates are provided between the movable plate and the fixed plate, and a A hollow bag member is disposed between the back of the plate and at least one of the movable plates, and the bulging amount becomes larger in the center when fluid is supplied inside, and the thickness becomes uniform over the entire surface when the fluid is discharged. A hot press device that is characterized by: