JP3275782B2 - Manufacturing method of laminated board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated board used for electric / electronic equipment and the like.

[0002]

2. Description of the Related Art Conventionally, a laminated board having a conductor layer on its surface, which is used for manufacturing a printed wiring board, is prepared by impregnating a base material such as a glass cloth with a thermosetting resin such as an epoxy resin. The required number of prepregs manufactured by drying and semi-curing, and an inner layer plate on which a conductor circuit is formed as necessary, are laminated to form a body to be crimped, and a conductive sheet is arranged on both outer sides and laminated. The laminate is sandwiched between flat plates made of metal or the like to form a laminate, and the laminate is sandwiched between pressurizing plates of a molding press, and heated and pressed to bond the object to be compressed and the conductive sheet to produce the laminate. Have been.

In order to improve productivity, a plurality of laminates are stacked with a flat plate interposed therebetween, and the stacked products are heated and pressed by being sandwiched between pressing plates of a forming press. A method of obtaining a large number of laminates at one time is also used.

[0004] As a method of heating and pressurizing, a method in which a laminate is sandwiched between heated pressurizing plates and pressurized while heating by heat transfer from the pressurizing plate, or Japanese Patent Application Laid-Open No. Hei 8-5062.
No. 89, a method of supplying power to a conductive sheet in a state where a laminate is sandwiched between pressure plates, and performing pressure while heating by resistance heating. Note that resistance heating is a method in which a current is applied to a conductor having electric resistance and heating is performed using heat generated by the Joule effect.

As a method of applying pressure while heating by resistance heating, as shown in FIG. 3, a pressure-bonded body 32 formed by laminating a required number of prepregs 31 and the like,
By bending the conductive sheet 33 at each one end surface, the pressure-bonded members 32 adjacent to each other with the flat plate 35 interposed therebetween,
The crimped body 32, the flat plate 35, and the conductive sheet 33 are stacked so that the conductive sheet 33 is continuous between the
Is formed, and the laminated body 36 is pressed into a pressing plate 3 of a forming press.
In a state where the conductive sheet 33 is pressed between the conductive sheets 33 and 39,
In this method, each of the pressure-bonded members 32 is heated by resistance heating.

In this method, the conductive sheet 33 is disposed so as to be continuous between the pressure-bonded members 32 adjacent to each other with the flat plate 35 interposed therebetween, and when power is supplied to both ends of the conductive sheet 33, The entirety of the conductive sheet 33 where the current has flowed generates heat, and the plurality of pressure-bonded bodies 32, 32 all generate heat in substantially the same manner. Therefore, the method of heating by resistance heating has a feature that the heating time is shorter and the productivity is higher than that of the method of heating by heat transfer from the pressure plate 39, and is increasing. If the flat plate 35 disposed between the pressed bodies 32, 32 has conductivity, current flows in the flat plate 35, and current does not flow uniformly in the conductive sheet 33. Uniform resistance heat generation is difficult, and the pressure-bonded body 32 in that portion is insufficiently heated, and the characteristics of the obtained laminated board are deteriorated. Therefore, a flat plate 35 having an insulating property is used.

Since the prepreg 31 is obtained by impregnating a thermosetting resin into a base material and semi-curing the resin, the viscosity of the resin decreases as soon as it is heated, and the resin flows.
When heated further, the resin hardens and the resin stops flowing. Therefore, the prepreg 31 is semi-cured and easy to handle, and has a certain degree of fluidity during molding by heating and pressing, so that even if there is a slight variation in the amount of resin, the resin flows and is almost uniform. It is widely used because it has the characteristic that a laminated plate having a thickness of 3 mm can be obtained. However, since the resin generally has a high viscosity, it is difficult to sufficiently impregnate the resin into the inside of the base material, and bubbles are generally left inside the obtained prepreg 31. Therefore, when the resin is heated and melted, pressure is applied to cause the resin to flow to remove air bubbles, and thus a laminate is generally manufactured.

However, when the number of the pressure-bonded members 32 sandwiched between the pressing plates 39, 39 is large, there is a problem that air bubbles are likely to remain in the obtained laminated plate and the moldability is low. Therefore, it has been studied to improve the formability by interposing a sheet-like elastic body 38 having elasticity, such as cellulose paper, generally called a cushion material, between the laminate 36 and the pressing plate 39.

However, when the prepreg 31 having a large variation in the amount of adhered resin is used, or when the number of the pressure-bonded members 32 sandwiched between the pressing plates 39, 39 is particularly large, etc.
Even when the amount of the elastic body 38 sandwiched between the pressure plate 6 and the pressing plate 39 is increased, there is a problem that air bubbles may remain in the obtained laminated plate. Therefore, there is a demand for a method of manufacturing a laminate that can provide a laminate having excellent moldability, even when a prepreg 31 having a large variation in the amount of adhered resin is used.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a press-bonded object having a prepreg in which a thermosetting resin is impregnated in a base material. And an insulating plate, by bending the conductive sheet at one end surface of each, so that the conductive sheet is continuous between the objects to be pressed and adjacent to each other with the insulating plate interposed therebetween, so that the object to be pressed, the insulating plate, and the conductive sheet Are laminated, a power is supplied to the conductive sheet, the laminate is heated by resistance heating, and the laminate is manufactured by pressurizing the laminate. To provide a method for manufacturing a laminated board.

[0011]

According to a first aspect of the present invention, there is provided a method for manufacturing a laminated board, comprising: a pressure-bonded body having a prepreg in which a thermosetting resin is impregnated in a base material; By bending the conductive sheet at, so that the conductive sheet is continuous between the body to be pressed and adjacent to each other with an insulating plate in between, after forming a laminate by stacking the body to be pressed, the insulating plate and the conductive sheet, Power is supplied to the conductive sheet, the laminate is heated by resistance heating, and the laminate is manufactured by pressurization. between the plate and the conductive sheet, while sandwiching the elastic member having elasticity, the pressure-bonded body, a method of forming a laminate superimposed insulating plate and the conductive sheet, further, between the insulating plate and a conductive sheet, elastic How to stack your body After the elastic body is detachably adhered to one surface of the conductive sheet, the insulating plate and the conductive sheet to which the elastic body is adhered are overlapped so that the adhered elastic body comes into contact with the insulating plate. There is a feature.

[0012]

According to a second aspect of the present invention, there is provided a method for manufacturing a laminated board according to the first or second aspect, wherein the elastic body comprises a cellulose sheet, an aramid fiber sheet, a rubber sheet, It is characterized in that it is at least one selected from composites.

In the conventional method in which the elastic body is sandwiched between the laminate and the pressing plate of the forming press, the elasticity of the elastic body is hardly transmitted to the crimped body disposed at the center, and Since the body to be pressed is hardened in a state where the variation in the resin amount of the prepreg remains, it is considered that bubbles remain in the portion where the resin amount is small. However, according to the present invention, since the elastic body is sandwiched between the insulating plate and the conductive sheet,
Even if there is a variation in the amount of resin of the prepreg in the object to be pressed placed in the center part, the elastic body interposed between the insulating plate and the conductive sheet absorbs the variation and uniformly applies pressure. It is considered that air bubbles hardly remain inside the obtained laminate.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the method for manufacturing a laminated board according to the present invention will be described with reference to the drawings. FIG. 1 illustrates a reference method relating to a method for manufacturing a laminate according to the present invention.
FIG . 2 is a diagram showing one example of a method for manufacturing a laminate according to the present invention.
It is a figure explaining an embodiment .

One embodiment of the method for manufacturing a laminated board according to the present invention comprises , similarly to the reference method shown in FIG. 1, a pressure-bonded body 2 having a prepreg 1 in which a thermosetting resin is impregnated in a base material, By bending the conductive sheet 3 at each end surface of the plate 5, the crimped bodies 2, 2 are connected so that the conductive sheet 3 is continuous between the crimped bodies 2, 2 adjacent to each other with the insulating plate 5 interposed therebetween. The laminate 6 is formed by stacking the insulating plate 5 and the conductive sheet 3. Then, the laminate 6 is sandwiched between the pressurizing plates 9 of the forming press and pressurized, and power is supplied to the conductive sheet 3 to heat the laminate 6 by resistance heating and pressurize the laminate. Manufacture boards.

It is important that the pressure-bonded member 2, the insulating plate 5 and the conductive sheet 3 are stacked while the elastic body 8 having elasticity is sandwiched between the insulating plate 5 and the conductive sheet 3. If the elastic body 8 is not sandwiched, bubbles may remain in the obtained laminated plate, which may cause a problem in moldability.

When the same elastic body 8 is sandwiched between the laminate 6 and the pressing plate 9 (or the amount of sandwiching is increased), there is an effect of improving the formability, but the insulating plate 5 and the conductive plate are electrically conductive. Sheet 3
The effect is small as compared with the case where it is sandwiched between the laminated sheets, and air bubbles may still remain inside the obtained laminate.

The elastic body 8 sandwiched between the insulating plate 5 and the conductive sheet 3 is formed of a sheet having elasticity and withstanding the temperature and pressure at the time of heating and pressurizing. Cellulose sheets such as paper, aramid fiber sheets, and polyester fiber sheets, etc., are formed in a sheet shape by bonding a large number of fibers with a gap therebetween,
Examples thereof include those in which a compound having elasticity such as fluororubber and butadiene styrene rubber is formed in a sheet shape, and a composite thereof. It is preferable that at least one selected from the group consisting of a cellulose sheet, an aramid fiber sheet, a rubber sheet, and a composite thereof is particularly high in elasticity, so that air bubbles hardly remain inside the obtained laminate.

The position at which the elastic body 8 is sandwiched is not limited to being sandwiched between all the insulating plates 5 and the conductive sheet 3.
According to the quantity of the pressure-bonded body 2 sandwiched between the pressing plates 9, 9,
It may be adjusted appropriately.

The conductive sheet 3 and the elastic body 8 are in direct contact with each other .

The object to be pressed 2 of the present invention has a prepreg 1 in which a thermosetting resin is impregnated in a base material on its surface and / or inside. This is a stack of substrates on which circuits are formed.

As the base material used in the present invention, woven fabric, nonwoven fabric, paper and the like of inorganic fibers such as glass, organic fibers such as polyester, polyamide, polyacryl and polyimide, and natural fibers such as cotton can be used. it can. It is preferable to use a woven fabric (glass cloth) made of glass fiber because the obtained laminate has excellent heat resistance and moisture resistance, and the effect of the present invention can be easily obtained. The thickness of the base material is generally 0.04 to 0.3 mm.

The thermosetting resin used in the present invention may be an epoxy resin, a phenol resin, a polyimide resin, an unsaturated polyester resin, a polyphenylene ether resin, or the like, alone, modified or mixed. In addition, general thermosetting resins can be used.

The thermosetting resin essentially contains a thermosetting resin, and may contain a curing agent, a curing accelerator, an inorganic filler and the like for the thermosetting resin as required. Note that a thermosetting resin having a low self-curing property, such as an epoxy resin, must also contain a curing agent for curing the resin.

The method for producing the prepreg 1 by impregnating the base material with the thermosetting resin is not particularly limited.
For example, after the thermosetting resin is varnished with a solvent, the viscosity of which is adjusted with a solvent, the base material is immersed and impregnated, and then heat-dried to produce a semi-cured product or a solid thermosetting resin at room temperature. After being impregnated into a substrate in a state where the viscosity is reduced by heating and melting, the mixture is cooled and solidified to produce a product.

The amount of the resin in the prepreg 1 is 10% by weight of the prepreg 1 (total weight of the thermosetting resin and the base material).
The amount is preferably 40 to 70 parts by weight with respect to 0 parts by weight.
If the amount is less than 40 parts by weight, the heat resistance of the obtained laminate may decrease, and if it exceeds 70 parts by weight, the thickness of the obtained laminate may vary greatly.

As the conductive sheet 3 used in the present invention, a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like can be used. Those having a thickness of 0.070 mm are generally used. The portion where the conductive sheet 3 is in direct contact with the prepreg 1 is bonded by heating and pressing, and the conductive sheet 3 becomes a conductive layer on the surface of the laminate.

The insulating plate 15 used in the present invention is not particularly limited as long as it is an insulating material capable of withstanding the temperature and pressure during heating and pressurizing. For example, metal oxide or fluorine One in which an insulating layer such as a resin is formed can be given. When the electrically insulating elastic body 8 is disposed in contact with both sides of the insulating plate 15, a metal plate having generally higher pressure strength than the insulating plate 15 is used instead of the insulating plate 15. It is also possible.

Conditions for heating and pressurizing the laminated body 6 include:
Heating and pressurizing may be performed by appropriately adjusting the conditions under which the thermosetting resin in the prepreg 1 is cured. However, if the pressurizing pressure is too low, bubbles may remain inside the obtained laminate, It is preferable to apply pressure under conditions that satisfy moldability.

In the reference method shown in FIG.
And between every conductive sheet 3, the elastic body 8 of approximately the same size as the insulation plate 5, <br/> that so as to overlap each other across each, between the insulating plate 5 and the conductive sheet 3, the elastic member In the present invention, for example, as shown in FIG. 2, after the elastic body 8 is detachably adhered to one surface of the conductive sheet 3, the adhered elastic body 8 is attached to the insulating plate 5. so that the side in contact with, the insulating plate 5, a shall overlap the conductive sheet 3 adhered to the elastic body 8. In the method of using the conductive sheet 3 to which the elastic body 8 is bonded, if a sheet to which the elastic body 8 is detachably bonded to one surface of the conductive sheet 3 is prepared in advance, the object to be pressed 2 and the insulating plate 5 In addition, the productivity when the laminate 6 is formed by stacking the conductive sheets 3 is excellent and is preferable .

[0032]

EXAMPLES ( Reference Example 1 ) As the thermosetting resin, a thermosetting resin comprising the following epoxy resin, curing agent and curing accelerator was used. -Epoxy resin: 80 parts by weight as a solid content of a tetrabromobisphenol A type epoxy resin having an epoxy equivalent of 500 [trade name: YDB-500, manufactured by Toto Kasei Co., Ltd.]-Curing agent: dicyandiamide [manufactured by Nippon Carbide Co., Ltd.] ] And 0.2 parts by weight of a curing accelerator: 2-ethyl-4-methylimidazole [manufactured by Shikoku Chemicals Co., Ltd.].

A varnish prepared by adding N, N-dimethylformamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a solvent to the above thermosetting resin and adjusting the viscosity thereof is coated with a 0.19 mm-thick glass cloth [manufactured by Asahi Schwebel Co., Ltd. Name 7628] as a base material, and immersion by impregnation, followed by drying by heating at a maximum temperature of 180 ° C.
A prepreg having a gel time at 150 ° C. of 150 seconds was produced. The in-plane variation of the resin amount of the obtained prepreg was measured at a measuring speed of 1 using a new wave gauge [manufactured by Yokogawa Electric Corporation].
When measured under conditions of m / min and a measurement span of 10 mm / time, the difference between the maximum and minimum was 10.7 g / m 2.

After the two prepregs are stacked to form a pressure-bonded body, a conductive sheet is formed on each end face of the pressure-bonded body and an insulating plate having an aluminum oxide layer formed on the entire surface of an aluminum plate. By folding, 10 sets of crimped bodies, 11 insulating plates and a conductive sheet (copper foil, thickness 18 μm) so that the conductive sheet is continuous between adjacent crimped bodies with an insulating plate interposed therebetween. Were laminated to form a laminate. At this time, a laminated body was formed by interposing an elastic body having elasticity between the insulating plate and the conductive sheet. As the elastic body, kraft paper of 190 g / m 2 [manufactured by Tomagawa Seisakusho Co., Ltd.] was used for each one between the insulating plate and the conductive sheet.

Next, five kraft papers similar to the above were arranged on both sides of the laminate, and were sandwiched between pressure plates of a forming press. The number of kraft paper sandwiched between the pressure plates is
The total is 30 sheets.

Then, power was supplied to the conductive sheet, and the laminate was heated at 170 ° C. for 80 minutes by resistance heating and pressed to obtain 10 double-sided copper-clad laminates having a thickness of 0.4 mm.

The magnitude of the elasticity (compression amount during pressurization) of the kraft paper (manufactured by Tomagawa Seisakusho) used as the elastic body was measured by using an autograph (manufactured by Shimadzu Seisakusho) to measure the size of the test piece. When measured under the conditions of a size of 50 × 50 mm, a load of 30 kg / square cm, and a head speed of 50 mm / min, it was 40 μm per sheet, and it was confirmed that the sheet had elasticity.

Example 2 Instead of forming a laminated body by sandwiching one elastic body having elasticity between the insulating plate and the conductive sheet to form a laminated body, reference example 1 is applied to one surface of the conductive sheet. After bonding the same elastic body as described above, an insulating plate and a conductive sheet to which the elastic body is bonded are laminated to form a laminate so that the bonded elastic body is on the side in contact with the insulating plate, and After heating and pressing, a double-sided copper-clad laminate was obtained in the same manner as in Reference Example 1 , except that the elastic body was peeled off from the conductive sheet on the laminate surface.

Reference Example 3 Double-sided copper-clad in the same manner as in Reference Example 1 except that one sheet of a 3 mm-thick fluororubber cushion material [trade name: FF20M, manufactured by Yamauchi Co., Ltd.] was used instead of kraft paper. A laminate was obtained. When the magnitude of elasticity of this cushion material was measured in the same manner as in Reference Example 1 , it was 150 μm.
And it was confirmed to have elasticity.

(Comparative Example 1) A double-sided copper-clad laminate was obtained in the same manner as in Reference Example 1 except that the elastic body was stacked so as to be in direct contact with the insulating plate and the conductive sheet without sandwiching them.

(Comparative Example 2) An elastic body was stacked so as to be in direct contact with an insulating plate and a conductive sheet without being sandwiched between the insulating plate and the conductive sheet, and fifteen kraft papers similar to the above were disposed on both sides of the laminate. A double-sided copper-clad laminate was obtained in the same manner as in Reference Example 1 except for the above. In this case as well, the number of kraft papers sandwiched between the pressure plates is 30 in total, as in Reference Example 1 .

(Evaluation and Results) The moldability of the double-sided copper-clad laminates obtained in each of the Reference Examples, Example 2, and Comparative Examples was evaluated. The method is such that after the copper foil of the double-sided copper-clad laminate obtained from the fifth and sixth sets of pressed bodies from the upper side is entirely etched, the presence or absence of bubbles in the laminate is visually observed, The number of residues was counted.

The results are as follows: 0 and 0 in each of Reference Examples and Example 2, 8 and 10 in Comparative Example 1, 2 and 3 in Comparative Example 2, and Example 2 Compared with the example, the number of bubbles in the laminated plate was small, and it was confirmed that the moldability was excellent.

[0044]

According to the method of manufacturing a laminate according to the present invention, a laminate is formed by stacking an object to be pressed, an insulating plate and a conductive sheet while sandwiching an elastic body having elasticity between the insulating plate and the conductive sheet. Therefore, even when a prepreg having a large variation in the amount of adhered resin is used, a laminate having excellent moldability can be obtained.

[Brief description of the drawings]

FIG. 1 is a reference relating to a method for manufacturing a laminate according to the present invention.
It is a figure explaining a method .

FIG. 2 shows one embodiment of a method for manufacturing a laminated board according to the present invention.
It is a figure explaining a state .

FIG. 3 is a diagram illustrating a conventional method for manufacturing a laminated board.

[Explanation of symbols]

 Reference Signs List 1,31 Prepreg 2,32 Crimping object 3,33 Conductive sheet 5 Insulating plate 6,36 Laminated body 8,38 Elastic body 9,39 Pressing plate 35 Flat plate

──────────────────────────────────────────────────の Continuation of the front page (56) References JP-A-62-233213 (JP, A) JP-A-61-255849 (JP, A) JP-T 8-506289 (JP, A) JP-T 7- 508940 (JP, A) Table 8-8-501991 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 15/08 B29C 43/00-43/34 B32B 31/20

Claims (2)

(57) [Claims] 1. A pressure-bonded body (2) having a prepreg (1) in which a thermosetting resin is impregnated in a substrate, and an insulating plate (5).
By bending the conductive sheet (3) at each end surface, the conductive sheet (3) becomes continuous between the pressure-receiving bodies (2) adjacent to each other with the insulating plate (5) interposed therebetween. (2) After stacking the insulating plate (5) and the conductive sheet (3) to form a laminate (6), power is supplied to the conductive sheet (3), and the laminate (6) is heated by resistance heating. In a method of manufacturing a laminate by pressurizing, the method of forming a laminate (6) by laminating the pressure-bonded body (2), the insulating plate (5), and the conductive sheet (3) is as follows. The body to be pressed (2), the insulating plate (5), and the conductive sheet (3) are stacked while sandwiching the elastic body (8) having elasticity between the conductive sheet (3) and the conductive sheet (3) to form a laminate (6). Oh in a way that
And between the insulating plate (5) and the conductive sheet (3).
The method of superposing the elastic body (8) on the conductive sheet (3)
After the elastic body (8) is removably adhered to one surface of the insulating plate (5), the insulating plate (5) and the elastic body (5) are arranged such that the adhered elastic body (8) is in contact with the insulating plate (5). method of manufacturing that <br/> laminate to features a method to overlay the adherent conductive sheet (3) and 8). Wherein the elastic body (8) is, claims, characterized in that the cellulose sheet, aramid fiber sheet, is at least one selected from the rubber sheet and these complexes
A method for producing a laminate according to claim 1 .