JPH1016100A - Preparation of laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminated sheet with little generation of deviation during heating and pressing by a method wherein a prepreg with a size a plurality of times a specified size is used and it is folded into the specified size to laminate them so as to become substantially a plane. SOLUTION: A laminated article 3 is formed by laminating a prepreg 1 consisting of a thermosetting resin compsn. and a base material and if necessary, arranging a metal foil 2 on one side or both sides and laminating them. A laminated body is formed by laminating a plurality of the laminated articles 3, if necessary, placing a mold 5, etc., between them and the laminated body is manufactured by forming it and heating and pressing the laminated body by placing them between hot plates 4 and 4 of a molding press. In this case, a method for laminating a plurality of the prepreg 1 is performed in such a way that the prepreg 1 with a size a plurality of times a specified size is used and it is folded into the specified size to laminate them so as to become substantially a plane. A number of laminated sheets can be obtd. by forming a plurality of the laminated articles 3 to form a laminated body and heating and pressing the laminated body between the hot plates 4 and 4.

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 used for manufacturing a printed wiring board is obtained by impregnating a base material such as a glass cloth with a thermosetting resin composition such as an epoxy resin, and then drying and semi-curing. A prepreg was prepared, and FIG.
As shown in FIG. 1, a required number of the prepregs 1, 1... Are stacked, and a metal foil 2 such as a copper foil is arranged on one side or both sides of the prepregs as necessary to form a laminate. Is pressed between the hot plates 4 and 4 of the forming press and heated and pressed.

In order to improve productivity, a plurality of the above laminates are stacked with a mold 5 or the like interposed therebetween as necessary.
There is also used a method in which a plurality of laminated plates are sandwiched between hot plates 4 and 4 of a forming press and heated and pressed to obtain a large number of laminated plates at one time.

[0004] Since the prepreg is obtained by impregnating a thermosetting resin composition into a substrate and semi-curing the resin, the viscosity of the resin decreases as soon as it is heated, and the resin flows. It shows the behavior that resin does not flow. The prepreg generally has a larger amount of resin than the amount of resin required to fill the gap in the base material forming the prepreg with the resin. Therefore, it is easy to handle because it is semi-cured when handling the required number of prepregs, and also has some fluidity during molding by heating and pressing, even if there is some variation in the amount of resin. It is generally used because it has the characteristic that a laminate having a substantially uniform thickness can be obtained by flowing resin.

[0005] However, when a laminate is produced by sandwiching a plurality of prepregs between hot plates of a molding press and applying heat and pressure to produce a laminate, a plurality of laminates are laminated with a mold or the like interposed therebetween. When the prepregs are sandwiched between hot plates, when the in-plane variation in the amount of resin of the prepreg is large, or when the parallelism between the hot plates is low, as shown in FIG. Of the prepreg 1, 1,... Sometimes occurred when the resin flowed. When the misalignment A occurs, the resulting laminated plate has a portion that is less than the required number of prepregs 1, 1,... In some cases, the thickness becomes thicker, resulting in a defect, which lowers the yield and poses a problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to stack a plurality of prepregs comprising a thermosetting resin composition and a base material. A method of manufacturing a laminate, in which a laminate is formed, a plurality of the laminates are stacked to form a laminate, and the laminate is sandwiched between hot plates and heated and pressed to produce a laminate. It is an object of the present invention to provide a method for manufacturing a laminated board in which the occurrence of misalignment is small.

[0007]

According to a first aspect of the present invention, there is provided a method for manufacturing a laminate, comprising forming a laminate by laminating a plurality of prepregs each comprising a thermosetting resin composition and a base material, and forming the laminate. In a method of manufacturing a laminated board in which a plurality of stacked layers are formed to form a stacked body, and the stacked body is sandwiched between hot plates and heated and pressed, a method of stacking a plurality of prepregs has a size that is a multiple of a predetermined size. The method is characterized in that the prepreg is folded to a predetermined size and overlapped so as to be substantially flat.

According to a second aspect of the present invention, in the method for manufacturing a laminate according to the first aspect, the resin content of the prepreg is 40 to 70 parts by weight based on 100 parts by weight of the prepreg. It is characterized by being.

According to the present invention, the large prepreg is folded and overlapped, so that even if a part of the overlapped prepreg tries to move due to displacement, the connected prepreg is stopped at the bent portion to stop the movement, so that the displacement is small. Become.
In addition, in order to bend so that it becomes substantially flat,
It is less likely that the thickness of the laminate is partially increased to cause a bias in the pressure, and a shift due to the bias in the pressure is less likely to occur.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a laminate according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an embodiment of a method for manufacturing a laminated board according to the present invention.

As shown in FIG. 1, the method for manufacturing a laminated board according to the present invention comprises, as shown in FIG. 1, a prepreg 1 comprising a thermosetting resin composition and a base material, and a metal foil 2 on one or both sides thereof as required. The laminate 3 is formed by arranging and laminating, and the laminate 3 is formed.
Are laminated as necessary with a mold 5 or the like interposed therebetween to form a laminate, and the laminate is heated by hot plates 4 and 4 of a forming press.
The production is performed by heating and pressurizing by sandwiching between them. At this time, it is important that the method of stacking a plurality of the prepregs 1 is a method of using the prepregs 1 having a size several times larger than a predetermined size and bending the prepregs 1 to a predetermined size to be substantially flat. .

Since the large prepreg 1 is bent and stacked, even if a part of the stacked prepreg 1 shifts and tries to move, the connected prepreg 1 is restrained at the bent portion to stop the movement, so that the shift is small. In addition, since the laminate 3 is folded and superposed so as to be substantially flat, the thickness of the laminate 3 is partially increased, so that it is difficult for the bias to occur, and the bias due to the bias hardly occurs.

In the present invention, a plurality of the laminates 3 are stacked to form a laminate, and the laminate is sandwiched between the hot plates 4 and 4 to be heated and pressurized. Is preferable.

As the base material used in the present invention, inorganic fibers such as glass, organic fibers such as polyester, polyamide, polyacryl, and polyimide, and woven fabric, nonwoven fabric, and paper of natural fibers such as cotton can be used. it can. In addition, a woven fabric (glass cloth) made of glass fiber is excellent in heat resistance and moisture resistance, and the effect of the present invention can be easily obtained. When the thickness of the base material is 40 to 300 μm, the workability of bending the base material is good, which is preferable.

The thermosetting resin composition used in the present invention may be an epoxy resin, a phenol resin, a polyimide resin, an unsaturated polyester resin, a polyphenylene ether resin, etc., alone, modified or mixed. As described above, general thermosetting resin compositions can be used.

The thermosetting resin composition contains a thermosetting resin as an essential component, and may contain a curing agent, a curing accelerator, an inorganic filler and the like of the thermosetting resin as required. it can. A thermosetting resin composition having a low self-curing property, such as an epoxy resin, needs to contain a curing agent for curing the resin.

When the thermosetting resin composition is of an epoxy resin type, the electrical properties and the adhesiveness are well balanced, which is preferable. Examples of the epoxy resin contained in the epoxy resin-based resin composition include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, bisphenol A novolak type epoxy resin,
Examples thereof include bisphenol F novolak type epoxy resin, cresol novolak type epoxy resin, diaminodiphenylmethane type epoxy resin, and epoxy resin which is made flame-retardant by halogenating a part of hydrogen atoms in these epoxy resin structures. Examples of the curing agent contained in the epoxy resin-based resin composition include amide-based curing agents such as dicyandiamide and aliphatic polyamide; amine-based curing agents such as ammonia, triethylamine and diethylamine; phenol novolak resins and cresols. Examples include phenolic curing agents such as novolak resins and p-xylene-novolak resins, and acid anhydrides.

As the inorganic filler which can be contained in the thermosetting resin composition, inorganic powder fillers such as silica, calcium carbonate, aluminum hydroxide and talc, glass fibers, pulp fibers and synthetic fibers And fibrous fillers such as ceramic fibers.

The method for producing the prepreg from the thermosetting resin composition and the substrate is not particularly limited,
For example, the base material is obtained by immersing the thermosetting resin composition in a varnish whose viscosity has been adjusted with a solvent, impregnating the base material, and, if necessary, drying by heating and semi-curing. Solvents that can be used for adjusting the viscosity of the thermosetting resin composition include amides such as N, N-dimethylformamide, ethers such as ethylene glycol monomethyl ether, ketones such as acetone and methyl ethyl ketone, methanol, and ethanol. And aromatic hydrocarbons such as benzene and toluene.

The amount of resin of the prepreg is not more than the weight of the prepreg (the total weight of the thermosetting resin composition 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, bubbles may remain inside the substrate when the laminate is heated and pressed, and the electrical characteristics may be reduced.If the amount exceeds 70 parts by weight, the laminate is heated and pressed. The resin flow is large, and the variation in the plate thickness may be large.

The metal foil which can be used in the present invention includes copper, aluminum, brass, nickel and the like alone,
An alloy or composite metal foil can be used. Instead of the metal foil, a single-sided metal-clad laminate or a double-sided metal-clad laminate formed by laminating and forming a metal foil can also be used. The thickness of the metal foil is generally 0.012 to 0.070 mm.

The conditions for heating and pressurizing the laminate may be adjusted appropriately under the conditions under which the thermosetting resin composition is cured, and heating and pressurizing may be performed. In some cases, air bubbles may remain and electrical characteristics may be reduced. Therefore, it is preferable to apply pressure under conditions that satisfy moldability. Note that it is preferable that the heating and pressurizing be performed in a reduced-pressure atmosphere of 300 Torr or less, because the amount of bubbles remaining in the obtained laminate is reduced.

When the laminate is sandwiched between hot plates of a molding press, a cushioning material such as cellulose paper or aramid fiber paper, a heat conduction adjusting material, and a surface smoothing material such as a mold may be used, if necessary. Heating and pressurizing may be performed with an intervening member or the like interposed therebetween.

The method for manufacturing a laminate according to the present invention comprises:
By using a prepreg of multiple times the predetermined size,
The present invention is not limited to stacking only the prepregs bent to a predetermined size, but may include an inner layer substrate, a prepreg cut to a predetermined size, and the like at the same time.

[0025]

【Example】

(Example 1) As a thermosetting resin composition, a thermosetting resin composition comprising the following epoxy resin, a curing agent and a curing accelerator was used. -Epoxy resin: 80 parts by weight of a tetrabromobisphenol A-type epoxy resin having an epoxy equivalent of 500 [trade name: YDB-500, manufactured by Toto Kasei Co., Ltd.] as a solid content-Curing agent: dicyandiamide [manufactured by Nippon Carbide Co., Ltd.] 3 parts by weight Curing accelerator: 0.2 parts by weight of 2-ethyl-4-methylimidazole [manufactured by Shikoku Chemicals Co., Ltd.]

As a base material, a glass cloth having a thickness of 0.19 mm and a width of 1 m [trade name 76 manufactured by Asahi Schwebel Co., Ltd.]
28], the thermosetting resin composition was impregnated by immersion in a varnish having the viscosity adjusted by adding N, N-dimethylformamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a solvent. The resultant was dried by heating at a temperature of 180 ° C. to prepare a prepreg having a resin amount of 45% by weight, a gel time at 170 ° C. of 110 seconds, a length of 2 m and a width of 1 m.

The obtained prepreg is bent at the center,
Two sheets were superimposed and planarized to a length of 1 m and a width of 1 m. Then, a thickness of 18 μm is provided on both outer sides of the folded prepreg.
m copper foils were arranged and laminated to form a laminate. Further, 10 sets of the laminate were sandwiched between a mold having a thickness of 1 mm to form a laminate. Next, the laminated body is sandwiched between hot plates of a forming press with kraft paper interposed therebetween, and a maximum temperature of 180 ° C.
Molding was performed under the conditions of a pressure of 3 MPa and a time of 120 minutes to obtain a double-sided copper-clad laminate having a thickness of 0.4 mm and a size of 1 m square.

(Example 2) A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that a prepreg having a resin amount of 50% by weight was prepared using a varnish in which the amount of a solvent to be added was changed.

(Example 3) A prepreg having a resin amount of 50% by weight was prepared using a varnish in which the amount of a solvent to be added was changed, and a prepreg having a length of 3 m and a width of 1 m was prepared by changing a cutting size. Example 1 except that the obtained prepreg was bent at one-third portions from both sides of the obtained prepreg, and three sheets were stacked and flattened to a size of 1 m in length and 1 m in width.
(Comparative Example 1) A prepreg having a length of 1 m and a width of 1 m was prepared in the same manner as described above.
A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that two sheets were stacked.

Comparative Example 2 A prepreg having a length of 1 m and a width of 1 m was prepared, and a double-sided copper-clad laminate was obtained in the same manner as in Example 2 except that two prepregs were stacked.

(Comparative Example 3) A prepreg having a length of 1 m and a width of 1 m was prepared, and a double-sided copper-clad laminate was obtained in the same manner as in Example 3 except that three prepregs were stacked.

(Evaluation and Results) Examples 1 to 3 and Comparative Example 1
With respect to the double-sided copper-clad laminates obtained in Nos. 1 to 3, the size of the displacement, the number of wrinkles generated, and the variation in the plate thickness were evaluated.

Before the heating and pressing, the position of the end of the prepreg is indicated on kraft paper sandwiched between the laminate and the hot plate, and the position of the end of the prepreg after the heating and pressing, The length of the difference from the position indicated on the kraft paper was measured, and the maximum value of each of the ten laminated boards was defined as the size of the deviation. The number of wrinkles was determined by visually observing the surface of the copper foil of the laminate, and evaluating the number of wrinkle-shaped recesses in each of the ten laminates. The thickness variation was determined by measuring the four corners of each of the five laminated boards with a micrometer, and measuring the difference between the maximum value and the minimum value.

As shown in Table 1, it was confirmed that Examples 1 to 3 produced less deviation than Comparative Examples 1 to 3. In addition, it was confirmed that the number of occurrences of wrinkles was small in Examples 1 to 3 and the variation in plate thickness was small compared to Comparative Examples 1 to 3.

[0035]

[Table 1]

[0036]

According to the method for manufacturing a laminated board of the present invention, the method of laminating a plurality of prepregs is performed by using a prepreg having a size several times larger than a predetermined size and bending the prepreg to a predetermined size to form a substantially flat surface. Since the overlapping method is adopted, the displacement is suppressed at the bent portion, and according to the method for manufacturing a laminated plate of the present invention, a laminated plate with little occurrence of the displacement can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a method for manufacturing a laminated board according to the present invention.

FIG. 2 is a view for explaining a conventional method for manufacturing a laminated board;
(A) shows a state where there is no shift, and (b) shows a state where a shift has occurred.

[Explanation of symbols]

 Reference Signs List 1 prepreg 2 metal foil 3 laminate 4 hot plate 5 mold A misalignment

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08J 5/24 CEZ B29C 67/14 G // B29K 101: 10 105: 06 B29L 9:00

Claims (2)

[Claims] 1. A laminate is formed by laminating a plurality of prepregs each composed of a thermosetting resin composition and a base material, forming a laminate by laminating the laminates, and sandwiching the laminate between hot plates. In a method of manufacturing a laminated board manufactured by heating and pressing, a method of stacking a plurality of prepregs is performed by using a prepreg having a size several times larger than a predetermined size, bending the prepreg to a predetermined size, and forming a substantially flat surface A method of manufacturing a laminated board, which is a method of overlapping. 2. The method according to claim 1, wherein the amount of the prepreg resin is 40 to 70 parts by weight based on 100 parts by weight of the prepreg.