JPH04187430A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To reduce air bubbles in a laminated sheet as much as possible by a method wherein a predetermined number of sheet-like base materials are superposed one upon another while continuously transferring to form a superposed base material which is, in turn, coated and impregnated with a solventless liquid thermosetting resin and sheet-like metal foils or release film are superposed on both surfaces of the superposed base material to form a laminated sheet main body. CONSTITUTION:Sheet-like base materials 1 are superposed one upon another by a pair of laminating rolls 2 while continuously transferred to form a superposed base material (a). Copper foils 6 are superposed on both surfaces of the superposed base material (a) as sheet-like metal foils to form a laminated sheet main body (b). Next, a resin composition 4 prepared by mixing aluminum hydroxide and a curing agent with a thermosetting polyester resin is applied to and infiltrated in the superposed base material (a) by a kiss-roll 3. At this time, resin content is set to 80%. Thereafter, the copper foils 6 and release sheets are superposed on the surfaces of the superposed base material (a) by a laminating roll 5 to form a laminated sheet main body (b) which is, in turn, molded and cured in a curing oven 11. By this method, air bubbles in the laminated sheet is reduced as much as possible and quality is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a laminate used for electrically insulating substrates and the like.

<Conventional technology> Conventionally, the method for manufacturing this type of laminate using a solvent-free liquid thermosetting resin is to apply and impregnate a sheet-like base with the resin, and then mold it without pressure. However, in such a manufacturing method, in order to completely impregnate the base material with the resin, it is necessary to perform the resin coating and impregnating portion as described above in a reduced pressure environment.

However, reducing the pressure of the coating and impregnating area requires a large amount of organic solvent, which is dangerous and difficult to implement. In particular, in order to improve the impregnating property of the resin, 20To
Since it is necessary to reduce the pressure to below r r, it is very difficult to implement this equipment.

On the other hand, if the resin coating and impregnation part is not performed in a reduced pressure environment, a large amount of resin is supplied onto the base material, and the impregnating property of the resin is improved by increasing the temperature over time and during molding and curing. However, in such a method, the impregnating properties of the resin are poor and the yield of the resin is poor, compared to applying and impregnating the resin in a reduced pressure environment.

Therefore, as a manufacturing method for laminates that solves these drawbacks, it has been known that a double belt press is used to perform pressure molding and hardening. While continuously transferring the sheet-like base materials 1 of
a, then a kitsu roll 3 coats and impregnates the polymerized base material a with a solvent-free liquid thermosetting resin 4.

Thereafter, a sheet metal foil 6 or a template film or the like is superimposed on both sides of the polymerized base tr)Ja using a lamination roll 5 to form a laminate body, and then the laminate body is transferred to a double belt press 7. Then, in a heating and pressurizing molding hardening furnace 8,
The laminate body is molded and cured under conditions such as heating temperature, molding pressure, molding speed, etc. set in advance based on the curing conditions of the resin, and then it is cut with a cutting machine 8 to obtain the laminate 9. There is.

By the way, glass cloth and glass nonwoven fabric are used for the sheet-like base material 1. Although glass nonwoven fabric has good permeability and there is no particular problem with respect to resin impregnation, glass cloth has poor mechanical strength and drilling workability. Due to these physical properties, the weave density is high and the permeability is poor, resulting in poor resin impregnation. Therefore, in the above manufacturing method, Kitsu roll 3
The 0 rotation speed is increased, and a molding pressure of 5 to 301 Cg/c♂ is applied to the laminate main body in a hot-press molding and curing furnace 8, thereby improving the impregnating properties of the resin.

<Problems to be solved by the invention> However, in such conventional manufacturing methods,
Since the laminate body as described in 1 above is pressurized in the heating, pressure molding and curing furnace 8, it is inevitable that the flow of the resin coated and impregnated into the laminate body will increase. The thickness of the main body of the laminate plate varies, and the precision of the test becomes poor.

Therefore, in order to solve the above problems, conventionally,
The flow was reduced by increasing the viscosity of the resin, but as the viscosity of the resin was increased in this way, the impregnability of the resin decreased by one level, and air bubbles were still generated inside the laminate. In addition, problems such as deterioration of the quality of the laminate occurred.

The present invention has been made in view of the above problems, and its purpose is to reduce air bubbles inside the laminate as much as possible.

<Means for Solving the Problems> In order to achieve the above object, the present invention continuously transfers a predetermined number of sheet-like base materials and overlaps these sheet L base materials to form a polymerized base material. After that, this polymerized base material is coated and impregnated with a solvent-free liquid thermosetting resin, and sheet metal foil or release film is laminated on both sides of the polymerized base material to form the laminate body. A method for producing a laminate in which a laminate body is molded and hardened in a curing furnace is characterized in that the laminate body is subjected to ultrasonic vibration in a reduced pressure environment during molding and hardening of the laminate body.

<Function> According to the present invention, the ultrasonic vibration heats and vibrates the laminate body in a short period of time, promotes resin infiltration into the laminate body, and actively generates bubbles, while the reduced pressure environment The air bubbles are removed to the outside of the laminate body.

<Example> Hereinafter, an example of the method for manufacturing a laminate according to the present invention will be described in detail using FIGS. 1 and 2.

Note that the same parts as the conventional ones are given the same reference numerals.

What is shown in FIG. 1 shows an apparatus to which this manufacturing method is applied, in which reference numeral 1 denotes four sheet-like base materials, and these sheet-like base materials 4 are continuously transferred, and As a result of the pair of mating rolls 2 being superimposed, a polymerized substrate a is formed.

Reference numeral 3 denotes a kit roll 3 which is in contact with the polymerization base material a and is driven to rotate, and this kit roll 3 forcibly applies a solvent-free liquid thermosetting resin 4 to the surface of the polymerization base material a.

Reference numeral 5 denotes a laminating roll, and this laminating roll 5 laminates a copper foil 6 as a sheet-shaped metal foil on the surface of the polymerized base material a to form a laminate main body.

Reference numeral 11 denotes a curing furnace for molding and hardening the laminate main body, and this curing furnace 11 is divided into first to third zones in order from the direction in which the sheet-like substrate 1 moves. The zone 12 of the sealing roll 1 as shown in FIG.
3a and 13b, and is configured to create a reduced pressure environment via a vacuum pump 14. In this first zone 12, there are two ultrasonic vibrators 15 and 15 on the side of the sealing roll 13a. is installed.

By the way, in the first zone, the ultrasonic vibrator 15.
15 heats and vibrates the resin applied to the main body of the laminate in a short period of time, promotes penetration of the resin, and actively generates bubbles and the like. On the other hand, the reduced pressure environment removes the air bubbles to the outside of the laminate body and improves the impregnating property of the resin.

In this way, the viscosity of the resin is reduced and it is impregnated into the main body of the laminate, and since the resin is coated with a constant thickness using the dust roll 3 as described above, the impregnating property is further improved.

Therefore, the reduced pressure environment in item 1 may be 150 Torr or less, and specifically, the value is determined by the type of sheet-like base key 1 and the resin 4.
It is preferable to set it based on the viscosity, etc.

Further, this first zone 12 is provided with a guide roll 16 that guides the laminate body, and a pair of temperature adjustment rolls 17, 17 that also serve as the guide rolls.
This pair of temperature adjustment rolls 17 prevents the generation of new bubbles by suppressing the rapid exothermic reaction of the resin, and can change the temperature of the rolls themselves.
It is constructed so that the thickness of the laminate body can be adjusted by changing the clearance between the rolls from outside the furnace.

Incidentally, it is preferable that the above-mentioned clearance is set to be slightly narrower than the thickness of the laminate body, thereby preventing the pruning phenomenon of the laminate body.

The pair of temperature adjustment rolls 17 described in - are preferably those having excellent thermal conductivity, for example, those having copper plating or the like applied to the outer peripheral surface of each roll.

Next, like the first zone 12, the second zone 18 has a guide roll 16 and a pair of temperature adjustment rolls 17, and one of the third zones has a guide roll 16 and a For curing purposes, this zone is kept at a higher temperature than other zones.

Incidentally, although the curing furnace 11 is divided as described above, it is sufficient that only the first zone 12 can maintain a reduced pressure environment;
Zone 18 and one third zone need only be temperature divided.

9 is a cutting machine similar to the conventional one, and this is a hardening furnace 1.
The laminate body formed and cured in step 1 is cut into a predetermined length, thereby obtaining a laminate 16.

Next, a laminate was manufactured using the apparatus configured as described above, and the presence or absence of air bubbles inside the laminate was evaluated.

By the way, the above-mentioned laminate uses two glass cloths (width 1050 mm, thickness 0.20 mm) and three glass mats (thickness 0.3 mm) as sheet-like substrates 4, which are laminated together by roll 2. Polymerization base material a was obtained by drying the thermosetting polyester resin (X-683
5. Hitachi Chemical (trade name) 100 parts of aluminum hydroxide (Hasilite 42M).

Using a mixture of 85 parts of Hitachi Chemical (trade name) and 1 part of a curing agent (Perbutyl ZT curing agent 2 (trade name of Hitachi Chemical Co., Ltd.)), this resin 4 is applied to the polymerized substrate a using a Kitsu roll 3. Impregnated. At this time, the resin content was 80%.

Thereafter, a copper foil 6 (thickness: 35 μm) and a release sheet were laminated on the surface of the polymerization base material 8 using a lamination roll 5 to form a laminate body, which was then molded and cured in a curing furnace 11. “At this time, in the first zone 12 of the curing furnace 11, the reduced pressure environment is 5 Q Torr, the zone temperature is 100°C, the output of each ultrasonic vibrator is 1.5 parts w, and the vibration width is 20~ 3
0 μm, and the temperature of the pair of temperature adjustment rolls 17 was maintained at 105°C.

In addition, in the second zone, the temperature in the zone was maintained at 115°C and the temperature of the temperature adjustment roll was maintained at 105°C, and in the third zone, the temperature in the zone was maintained at 150°C, and the line speed was set at 4 m/min. Set.

When the copper foil portion of the thus obtained laminate was removed by etching and inspected, no air bubbles were found inside the laminate.

In addition, for comparison purposes, a laminate was manufactured without creating a reduced pressure environment in the first zone 12 and without using the ultrasonic vibrator 15, but this laminate was subjected to the same tests as above. As a result, minute bubbles were present.

Furthermore, using the same sheet-like base H and resin as above, a laminate was manufactured using the apparatus shown in FIG. 3. On this occasion,
The conditions of the heating and pressure molding curing furnace are a molding temperature of 120°C1.
Molding pressure 10KgI'/ctR, line speed 3m
/ minute. As a result, it was found that such a laminate was free of air bubbles. Therefore, it can be seen that bubbles do not occur unless the viscosity of the resin is intentionally increased.

Therefore, according to the embodiment described in item 1, the ultrasonic vibrator heats and vibrates the laminate body in a short time, promotes resin infiltration into the laminate body, and actively generates air bubbles. At the same time, the reduced pressure environment removes the air bubbles to the outside of the laminate body, so the air bubbles can be efficiently removed.

Although glass cloth and glass mat are used as the sheet-like base material, glass cloth and glass nonwoven fabric may be used instead, and other chemical fibers, such as nylon, polyester, polypropylene, etc., or carbon Fibers and inorganic fibers may also be used. By the way, the thickness of the sheet-like base material is 0.05~
The thickness is preferably 0.25 mm, and if it is thicker than this, the reduced pressure environment may be set to 20 Torr or less in consideration of resin impregnation.

In addition, the resin is mainly epoxy resin, but instead of this, it may be mainly thermosetting vinyl ester resin that is liquid at room temperature, or thermosetting polyester resin that is liquid at room temperature, and these three resins may be used. A modifier may be added to the combination. However, all resins are limited to fast-curing, solvent-free liquid thermosetting resins.

Furthermore, it is preferable to use a filler in the resin that can sufficiently satisfy the properties of the laminate and reduce costs; however, the impregnability of the resin should be taken into account. Then, select a filler that does not increase the viscosity of the resin by as much as possible. Further, a curing initiator, an effect accelerator, etc., which vary depending on the type of the resin, are added to the resin, but the effective time of the resin should be as short as possible, taking into consideration the length of the curing furnace and productivity.

Also, although two ultrasonic vibrators are provided, the number is not limited to this, and of course one may be used, but for example, if the line speed is high, it is preferable to provide multiple ultrasonic vibrators. .

<Effects of the Invention> The method for manufacturing a laminate according to the present invention causes the laminate body to undergo ultrasonic vibration in a reduced pressure environment during molding and hardening of the laminate body, so that the ultrasonic vibrations cause the laminate body to vibrate in a short time. While actively generating air bubbles by heating and vibrating and promoting resin infiltration into the laminate body, a reduced pressure environment removes air bubbles to the outside of the laminate body, effectively removing air bubbles. can. As a result, the laminate body after molding and hardening, as well as each laminate cut from it, have as few internal air bubbles as possible.
And the quality is good.

Moreover, the same effects as described above can be obtained also in the inventions according to claims 2 to 7.

In particular, according to the invention set forth in claim 8, since a plurality of ultrasonic vibrators are used, bubbles can be efficiently removed even when the line speed of the laminate manufacturing process is increased, for example.

Furthermore, in the invention set forth in claim 8, since the guide roll is formed as a temperature adjustment roll, it is possible to suppress the rapid exothermic reaction of the resin and prevent the generation of new bubbles.

[Brief explanation of the drawing]

Figure 1 is a simplified cross-sectional view of the device to which this manufacturing method is applied;
The figure shows an enlarged sectional view of the first zone in this manufacturing method, and
The figure is an explanatory diagram illustrating a conventional manufacturing method. 1... Sheet-like base material 4... Resin 6... Copper foil 10... Laminate plate 11... Curing furnace 12... First zone 15... Ultrasonic vibrator 17...・Temperature adjustment roll 18...Second zone 19...Third zone a...Polymerization base material b...Laminated board main body

Claims (1)

[Scope of Claims] 1. After a predetermined number of sheet-like base materials are continuously transferred, these sheet-like base materials are superimposed to form a polymerized base material, and then a solvent-free liquid is applied to this polymerized base material. A laminate that is coated and impregnated with a thermosetting resin, then laminated with sheet metal foil or release film on both sides of the polymerized base material to form a laminate body, and then molded and hardened this laminate body in a curing furnace. A method for manufacturing a laminate, characterized in that the laminate body is ultrasonically vibrated in a reduced pressure environment during molding and curing of the laminate body. 2. The method for manufacturing a laminate according to claim 1, wherein each of the sheet-like substrates uses a glass cloth and a glass nonwoven fabric. 3. The method for manufacturing a laminate according to claims 1 and 2, wherein the resin is a thermosetting epoxy resin that is liquid at room temperature. 4. The method for manufacturing a laminate according to claims 1 and 2, wherein the resin is a thermosetting vinyl ester resin that is liquid at room temperature. 5. The method for manufacturing a laminate according to claims 1 and 2, wherein the resin is a thermosetting polyester resin that is liquid at room temperature. 6. The method for manufacturing a laminate according to claim 1, wherein the reduced pressure environment is 160 Torr or less. 7. The curing furnace is characterized in that it is divided into first to third zones in order from the direction in which the sheet-like base material moves, and that an ultrasonic vibrator is installed in the first zone. A method for manufacturing a laminate according to claim 1. 8. The method for manufacturing a laminate according to claim 7, wherein the ultrasonic vibrator includes a plurality of ultrasonic vibrators. 9. The method for manufacturing a laminate according to claim 1, wherein the curing furnace is provided with a guide roll that comes into contact with the laminate body, and the guide roll is formed as a temperature adjustment roll.