JPS61263752A - Manufacture of laminated board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a laminate used for electrically insulating substrates and the like.

[Background technology]

The following methods are available as continuous forming methods for laminated plates. First, a strip-shaped base material is continuously impregnated with liquid resin while being transferred. A laminate is produced by continuously overlapping the obtained strip-shaped resin-impregnated substrates with a strip-shaped metal foil or release film on one or both sides, if necessary. Thereafter, the laminate is passed through a double belt press (endless belt) and heated and pressurized, or passed through a heating furnace and heated under no pressure, etc., to continuously transfer and cure. Next, the cured laminate is cut into a desired size using a cutter or the like to obtain a laminate.

This method has high production efficiency because the laminate is not subjected to heat-pressure curing by applying it to a press one by one, but is cured while being continuously transferred using a double belt press or heating furnace.

However, the laminates obtained by this continuous method often have many air bubbles (voids) inside.

This is mainly due to the following reasons. In other words, the penetration of the resin into the base material is insufficient, the resin-impregnated base material swells and sucks air after the resin-impregnated base materials are overlapped, and the metal foil is not applied to a predetermined sheet of the resin-impregnated base material. When they are stacked on top of each other, air is trapped between them. The second cause will be explained in detail. As shown in FIG. 2, the resin-impregnated base material 1 is usually laminated by passing it between a pair of upper and lower rolls (squeeze rolls) 2. The resin-impregnated base material l is a pair of upper and lower rolls 2.
When passing through, pressure is applied to fit each resin-impregnated base material 1 closely together, so the resin-impregnated base material 1 is pressed down so that its thickness is reduced. Next, when passing through a pair of rolls 2, this pressure is removed, so the resin-impregnated base l
It swells. At this time, air is sucked in.

If there are many bubbles inside the laminate, the thermal conductivity will decrease, resulting in poor heat dissipation properties and poor heat resistance.
Alternatively, problems such as blistering may occur when heat is applied during the processing process.

When manufacturing a metal foil-clad laminate, the following steps are taken to prevent air from becoming trapped between the metal foil and the resin-impregnated base material. The overlapping of metal foils is usually done in the third
As shown in the figure, a metal foil 3 is placed on one or both sides of a laminate 1' in which resin-impregnated base materials are stacked, and the metal foil 3 is passed between a pair of upper and lower rolls 4. It is being done. Then, the resin 5 is supplied to a position immediately before the metal foil 3 and the laminate 1' are overlapped to prevent air from entering between the metal foil 3 and the laminate 1'. New resin is always supplied to replace old resin. this is,
This is because the resin gradually contains air bubbles due to vibrations caused by the rotation of the roll 4.

However, in this case, as shown in FIG. 3, the resin 5' protrudes from the end of the laminate 6 and the end of the metal foil 3 is contaminated. A problem arises in that the laminate 6 becomes meandering due to adhesion of the resin. Further, there arises a problem that the amount of resin consumed increases and the cost increases.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a laminate that can produce a laminate with very few air bubbles inside.

[Disclosure of the invention]

In order to achieve the above objectives, the inventor has conducted repeated research. As a result, it has been found that metal foil or release film must be laminated on both sides of a predetermined number of resin-impregnated base materials, and resin impregnation and lamination of each base material are performed in separate vacuum chambers under a reduced pressure environment. We discovered that this is a good idea, and here we completed this invention.

Therefore, this invention creates a resin-impregnated base material by continuously impregnating a belt-shaped base material with resin while transferring it,
A predetermined number of the obtained resin-impregnated base materials are continuously stacked, and a strip-shaped metal foil or release film is continuously stacked on both sides to obtain a laminate, and this laminate is continuously transferred. The gist of the method is a method for manufacturing a laminate, which is characterized in that resin impregnation and lamination of each base material are performed in separate vacuum chambers under a reduced pressure environment in order to obtain a laminate by curing. The present invention will be explained in detail below.

The method for manufacturing a laminate according to the present invention is carried out using, for example, an apparatus as shown in FIG. As shown in the figure, this device has decompression chambers 73 to 7d. Decompression chamber 7a
, 7b, and 7c are provided with an inlet 8a through which the base material 13 passes without impairing the airtightness of the room, and a resin-impregnated base material l.
Each outlet 8b is provided through which the water passes. The inlet and outlet are installed, for example, by installing a pair of rotating rolls made of an elastic material in the opening in the wall so as to maintain airtightness in the room. In this case, the base material, metal foil, and laminate are passed between two rotating rolls. Further, the inlet and outlet may be formed of slits or the like whose edges are made of an elastic material.Resin tanks 9 are provided in the decompression chambers 7a and 7b, and resin dripping means 10 is provided in the decompression chamber 7C. is provided.

The wall of the decompression chamber 7d is provided with an inlet 8e through which the resin-impregnated base material 1 passes, an outlet 8d through which the laminate 6 passes, and an inlet 8e through which the metal foil 3 passes, without impairing the airtightness of the room. . Inside the decompression chamber 7d, a first pair of upper and lower rolls (
squeeze roll) 11 and a second pair of upper and lower rolls (
A laminating roll) 12 is provided respectively.

The method for manufacturing a laminate according to the present invention is carried out using this apparatus, for example, as follows. First, the pressure inside the decompression chambers 7a to 7d is reduced using a vacuum pump.
Next, the three strip-shaped base materials 13, which are preferably 15 Torr or more and 20 Torr or less, are placed at the entrance 8, respectively.
The base material 13 is impregnated with the resin by passing it through the decompression chambers 7a to 7C from a and immersing it in the resin bath 9 or dropping the resin from the dripping means 10. When resin impregnation is performed in a reduced pressure environment, air bubbles in the resin are drawn out, air in the base material is expelled, and the impregnating property of the resin is improved, so a resin-impregnated base material with fewer air bubbles can be obtained.

As the base material, inorganic fiber cloth such as glass cloth, inorganic fiber nonwoven fabric such as glass nonwoven fabric, glass mat organic fiber cloth, organic fiber nonwoven fabric, etc. are used. Examples of the resin include unsaturated polyester resin.

It is used in the form of an unsaturated resin face made by diluting an unsaturated resin with unsaturated bonds, such as diallyl phthalate resin or vinyl ester resin, with a crosslinking agent such as vinyl monomer, and adding a polymerization initiator. Also, epoxy resin,
For thermosetting resins such as polyester resin, diallyl phthalate resin, polyimide resin and polybutadiene resin,
If necessary, a curing agent or a curing accelerator may be appropriately blended and used, or an ultraviolet curable resin may be used.

Each resin-impregnated base material 1 obtained as described above is inserted into the inlet 8c.
The first pair of upper and lower rolls 11 are passed through the decompression chamber 7d.
Continuously overlap each other while making a transition. Since the resin-impregnated base material 1 is overlapped under M pressure, even if the pressing force is removed after passing through the roll 11 and the resin-impregnated base material 1 swells, there is a very high risk that air will enter the resin-impregnated base material 1 and create bubbles. There are few. Next, the metal foil 3 is passed through the inlet 8e into the decompression chamber 7d, and a second upper and lower pair of rolls 12 are used to continuously stack the metal foil 3 on both sides of the three resin-impregnated base materials l to form a laminate. Get 6. Copper foil, aluminum foil, etc. are used as the metal foil. Since the metal foils 3 are stacked under reduced pressure, there is very little possibility that air will enter between the metal foils 3 and the laminate 6. The obtained laminate 6 is taken out of the decompression chamber 7d from the outlet 8d. Since both sides of the laminate 6 are covered with metal foil 3, there is very little risk that air will enter inside even if it goes outside the decompression chamber 7d.

Thereafter, the laminate is continuously transferred and cured by passing it through a double belt press and heating and pressurizing it, or passing it through a heating furnace and heating it under no pressure. When an ultraviolet curable resin is used, it is cured by irradiating it with ultraviolet rays under no pressure or under pressure. Next, the cured laminate is cut into a desired size using a canter or the like to obtain a laminate. Examples of double belt presses include the following devices. That is, a pair of endless belt heating means and a pressure means are provided facing each other, and the laminate is transferred between the two rotating endless belts, and the heating means heats the stack through the endless belt, while applying air pressure, etc. This device uses the pressure means used to press both endless belts toward the laminate.

The laminate thus obtained has very few bubbles.

In the method for manufacturing a laminate according to the present invention, each base material is impregnated with resin in a separate vacuum chamber, and the resin-impregnated base material and metal foil are laminated in a vacuum chamber separate from these vacuum chambers. That's what I do. By doing so, it is possible to reduce the size of each depressurizing chamber, thereby achieving the effect that the pressure in the chamber can be quickly depressurized and a high vacuum can be created. It also becomes possible to use different vacuum conditions during resin impregnation and lamination.

In the above example, three base materials are used, but the number of base materials is not limited to three. The number of vacuum chambers in which resin impregnation is performed is the same as the number of base materials. do. Also,
In the above embodiments, the resin is impregnated into the base material by immersing it in a resin bath or dropping it from above, but it may be unified to either one. In addition, the resin impregnation method is not limited to the two methods. Metal foils are placed on both sides of the laminate to obtain a double-sided metal foil-covered laminate, but instead of one metal foil, a strip A metal foil-clad laminate may be obtained by arranging a release film on one side, or a laminate without metal foil may be obtained by arranging strip-shaped release films on both sides. Yes, the overlapping of the predetermined sheets of resin-impregnated base material and the overlapping of the metal foil are performed using separate upper and lower pairs of rolls, but it is preferable to arrange the metal foils on both sides of the predetermined sheet of the resin-impregnated base material. Alternatively, both may be overlapped at the same time using one pair of upper and lower rolls.

As shown in FIG. 1, the resin 14 is supplied between the resin-impregnated base materials 1 and between the resin-impregnated base materials 1 and the rolls 11 immediately before the overlapping position of the first pair of upper and lower rolls 11. By doing so, it is possible to further reduce the risk of air entering into the resin-impregnated base materials 1 or between the resin-impregnated base materials 1, and to improve the adhesive strength between the resin-impregnated base materials 1. If the resin 15 is supplied between the resin-impregnated base material 1 and the metal foil 3 immediately before the overlapping position of the second upper and lower pair of rolls, air may enter between the resin-impregnated base material 1 and the metal foil 3. This has the effect of further reducing the adhesive strength between the resin-impregnated base material 1 and the metal foil 3.Since the pressure is reduced, there is little risk that the supplied resin will contain air bubbles.Therefore, it is possible to always use new It is not necessarily necessary to supply resin. In addition, even if the resin protrudes from the edge of the laminate due to this resin supply, when the laminate leaves the decompression chamber, the resin will be sucked into the room due to the pressure difference between the indoor and outdoor areas, so problems caused by the protruding resin will be greatly reduced. .

In addition, if the base material is impregnated with resin under reduced pressure,
Since the permeability of the resin is improved, it becomes possible to use even base materials that are difficult for the resin to permeate, such as high-density base materials or thick base materials (glass nonwoven fabric, glass cloth, etc.). By using a high-density base material, it is possible to obtain a laminate with almost no warping or twisting.

〔Effect of the invention〕

The method for manufacturing a laminate according to the present invention involves continuously impregnating a strip-shaped base material with resin while transferring it to create a resin-impregnated base material, and continuously stacking a predetermined number of sheets of the obtained resin-impregnated base material. At the same time, a strip of metal foil or a release film is continuously laminated on both sides to obtain a laminate, and this laminate is continuously transferred and cured to obtain a laminate, and each base material is impregnated with resin. Since the lamination and lamination are carried out under a reduced pressure environment in separate reduced pressure chambers, it is possible to obtain a product with very few air bubbles inside.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the structure of an apparatus used in an embodiment of the method for manufacturing a laminate according to the present invention, and FIG. 2 is an explanatory diagram of the state in which resin-impregnated base materials are overlapped in a conventional method for manufacturing a laminate.
FIG. 3 is an explanatory diagram showing how metal foils are laminated on both sides of a predetermined number of resin-impregnated substrates in a conventional method for manufacturing a laminate. 1... Resin-impregnated base material 3... Metal foil 7a to 7d.
...Decompression chamber 11.12...Pair of upper and lower rolls 13
···Base material

Claims (2)

[Claims] (1) A resin-impregnated base material is created by continuously impregnating a belt-shaped base material with resin while transferring it, and a predetermined number of sheets of the obtained resin-impregnated base material are continuously overlapped, and a belt-shaped base material is formed on both sides of the base material. Metal foils or release films are continuously stacked to obtain a laminate, and this laminate is continuously transferred and cured to obtain a laminate. The resin impregnation and lamination of each base material are performed under separate vacuums. A method for producing laminates, which is characterized by being carried out indoors under a reduced pressure environment. (2) The method for manufacturing a laminate according to claim 1, wherein the reduced pressure environment is 15 Torr or more and 20 Torr or less.