JP2000210962A - Manufacture of laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a deviation in the case of heating pressure molding by heating to fusion bond prepregs to a temperature lower than a thermosetting temperature from a melting temperature of a thermosetting resin composition at least a part of connected surfaces of the laminated prepregs, and then heating pressure molding it. SOLUTION: The laminate is obtained by superposing prepregs 1 each made of a thermosetting resin composition and a base material, disposing metal foils 2 on both sides of the prepregs 1 as needed to constitute a laminated material 5, and heating and pressurizing the material 5 to be integrally laminated. In this case, before integrally laminating the material 5, the prepregs 1 are perviously fusion bonded at least at part of connected surfaces of the laminated prepregs 1 therebetween. As a method for fusion bonding it, a method for heating by a heater or a hot air is used, and its fusion bonding temperature is a temperature lower than a thermosetting starting temperature from a melting temperature of a thermosetting resin composition in the prepregs 1. Thus, a hardening degree of the resin in the prepregs 1 is maintained constant, and hence a decrease in moldability of the laminate is suppressed.

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 manufacturing a printed wiring 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 1 was prepared, and as shown in FIG.
If necessary, a metal foil 2 such as a copper foil is disposed on one side or both sides thereof and laminated to form a laminate 5.
It was manufactured by heating and pressurizing it between.

In order to improve the productivity, the above laminated plate is
A method of obtaining a large number of laminated plates at a time by interposing a plate-shaped mold 4 or the like between them as necessary and stacking a plurality of the laminated plates between hot plates 3 and heating and pressurizing the stacked plates at a time. Used.

[0004] Since the prepreg 1 is obtained by impregnating a thermosetting resin composition into a base material and semi-curing the resin, the viscosity of the resin temporarily decreases when heated, and the resin flows. And the resin does not flow. The prepreg 1 generally has a larger amount of resin than the resin required to fill the gap in the base material forming the prepreg 1 with the resin. Therefore, when the required number of prepregs 1 are stacked, it is easy to handle because it is semi-cured, and has some fluidity during molding by heating and pressing, so that there is a slight variation in the amount of resin. This is also characterized in that a resin having a substantially constant thickness can be obtained by flowing a resin, and is generally used.

[0005]

However, the prepreg 1
In order to manufacture a laminate by sandwiching a plurality of laminated sheets between the hot plates 3 and applying heat and pressure, a plurality of laminated sheets 5 are laminated with a plate-shaped mold 4 or the like interposed therebetween. As shown in FIG. 3, when the hot plate 3 is sandwiched between the hot plates 3, when the in-plane variation in the amount of resin of the prepreg 1 is large, or when the parallelism between the hot plates 3 is low, In some cases, a gap A occurred between the prepregs 1 when flowing. When the displacement A occurs, the obtained laminated plate has a portion that is smaller than the required number of prepregs 1 at the end portion and the thickness is partially reduced, or a portion where the pressure is insufficient occurs and the laminated plate is partially formed. In some cases, the thickness is increased to cause a failure, which causes a problem of lowering the yield.

The present invention has been made to solve the above problems, and an object of the present invention is to form a laminate by stacking a plurality of prepregs each comprising a thermosetting resin composition and a base material. Alternatively, a method for producing a laminate, in which a plurality of the laminates are stacked to form a laminate, and the laminate or 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 of manufacturing a laminated board with less occurrence of misalignment.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a laminate, comprising: laminating a plurality of prepregs 1 each comprising a thermosetting resin composition and a base material; In at least a part of the surfaces to be joined, the prepregs 1 are heat-welded at a temperature equal to or higher than the melting temperature of the thermosetting resin composition and lower than the curing temperature, and then heat-pressed. .

According to a second aspect of the present invention, in addition to the structure of the first aspect, the amount of the resin in the prepreg 1 is 40 to 70 parts by weight based on 100 parts by weight of the entire prepreg 1. It is characterized by using parts by weight.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method of manufacturing a laminate according to the present invention will be described with reference to the drawings. As a substrate used in the present invention, inorganic fibers such as glass, polyesters, polyamides, polyacryls, polyimides, etc. Such as organic fibers,
A woven fabric, nonwoven fabric, paper or the like of natural fibers such as cotton can be used. A woven fabric (glass cloth) such as glass fiber is preferable because it has excellent heat resistance and moisture resistance, and the effects of the present invention can be easily obtained.

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, or the like, alone, modified or mixed. In addition, 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. Note that a thermosetting resin composition having a low self-curing property, such as an epoxy resin, needs to contain a cured product or the like for curing the resin.

[0012] It is preferable that the thermosetting resin composition is an epoxy resin-based composition because the balance between electrical properties and adhesiveness is good. Examples of the epoxy resin contained in the epoxy resin-based resin composition include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolak epoxy resin, bisphenol A novolak epoxy resin, and bisphenol F Novolak epoxy resin, cresol novolak epoxy resin, diaminodiphenylmethane epoxy resin, and brominated bisphenol A
Epoxy resins which are made flame-retardant by halogenating a part of hydrogen atoms in these epoxy resin structures, such as a type epoxy resin, are exemplified. In the epoxy resin-based thermosetting resin composition, it is preferable to mix one or more of the above epoxy resins so that the halogen weight is 15 to 20% by weight based on the total amount of the resin.

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;
Examples thereof include phenolic hardeners such as phenol novolak resin, cresol novolak resin, and p-xylene-novolak resin, and acid anhydrides. The epoxy resin-based thermosetting resin composition preferably contains 1.5 to 20% by weight of a mixture of one or more of the above curing agents.

As a curing accelerator, an imidazole compound or the like can be used. In particular, when 2-ethyl-4-methylimidazole (2E4MZ) is blended, curing of the resin composition during storage becomes difficult to proceed, and This is preferable in that the varnish life can be maintained and the varnish life can be maintained. The epoxy resin-based thermosetting resin composition preferably contains 2E4MZ in an amount of 0.01 to 0.05% by weight.

Examples of the inorganic filler that can be contained in the thermosetting resin composition include inorganic powder fillers such as silica, calcium carbonate, aluminum hydroxide, and talc; glass fibers, pulp fibers, and synthetic fibers. Examples include fibrous fillers such as ceramic fibers, and these inorganic fillers can be blended in the range of 10 to 80% by weight.

The method for producing the prepreg 1 from the thermosetting resin composition and the substrate is not particularly limited. For example, a resin varnish obtained by adjusting the viscosity of the thermosetting resin composition with a solvent is used. After impregnating by impregnation, it is obtained by heating and drying as necessary and semi-cured,
For example, when an epoxy resin-based thermosetting resin composition is used, it can be dried by heating at 130 to 200 ° C. for 3 to 15 minutes. Here, 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, and methanol. And alcohols such as ethanol, and aromatic hydrocarbons such as benzene and toluene. One or more of these solvents may be mixed in a range of 5 to 40% by weight. it can.

Here, the amount of the resin in the prepreg 1 is preferably 40 to 70 parts by weight based on 100 parts by weight of the prepreg 1 (the total weight of the thermosetting resin composition and the base material). When the amount is less than 40 parts by weight, air bubbles may remain inside the base material when the laminate 5 is subjected to heat and pressure molding, and the electrical characteristics may be deteriorated. When heating and pressing, the resin flow is large, and the variation in the plate thickness may be large.

In the method for manufacturing a laminate according to the present invention, as shown in FIG. 2, a prepreg 1 composed of a thermosetting resin composition and a base material is laminated, and metal foils 2 are arranged on both sides as necessary. A laminate is obtained by heating and pressurizing the laminated product 5 to be laminated and integrated.

In the present invention, the prepregs 1 are previously welded to each other on at least a part of the surface to be joined between the prepregs 1 to be laminated before the lamination 5 is integrated. Here, it is preferable that the welding be performed on at least one side of the peripheral portion of the surface to be joined between the prepregs 1 in a region of 10 to 100% of the length of one side. This welding may be performed over the entire area of one side of the peripheral portion of the surface to be joined between the prepregs 1. Further, the welding may be performed on the entire periphery of two, three, or four sides of the peripheral portion.
If the width of the welded portion is 1 to 50 mm, welding between the prepregs 1 can be performed with sufficient strength.
The welding may be performed over the entire surface of the prepreg 1.

This welding method can be performed by heating with a heater or hot air. Specifically, for example, as shown in FIG. 1, an electric heating wire heater such as a nichrome wire heater is built in the inside. Heating section 8 having a length and width equal to the size of the welded portion of prepreg 1
Are used. As shown in FIG. 2 (a), the pair of welding jigs 7 are arranged such that the heating unit 6 faces each other, and a plurality of prepregs 1 are stacked between the heating units 8. The prepreg 1 is disposed so that a peripheral portion, which is a welded portion, of the prepreg 1 is interposed between the heating portions 8. In this state, the heating unit 8 is brought into contact with the welded portion of the prepreg 1 to sandwich the welded portion, and the heating wire heater is heated to heat the welded portion. As the heating unit 8, a unit having a hot air outlet for blowing hot air is used.
As shown in (a), in a state where the heating portions 8 are arranged to face each other, the welded portion can be heated by blowing hot air from both sides toward a peripheral portion which is a welded portion of the prepreg 1. .

Here, if the welding temperature is set to a temperature equal to or higher than the melting point of the thermosetting resin composition in the prepreg 1 and lower than the thermosetting start temperature, the prepreg 1 in the laminate 5 before being subjected to the heat and pressure molding is formed. It is possible to keep the degree of curing of the resin therein uniform, suppress the deterioration of the moldability of the laminate, and prevent the occurrence of voids in the laminate to be molded. That is, for example, in the case of an epoxy resin-based thermosetting resin composition, the melting point is 80 to 90 ° C., and the thermosetting start temperature is 130 to 1
40 ° C., and is welded at a temperature of 90 ° C. or more and 120 ° C. or less. In the case of a polyimide resin-based resin composition, the melting point is 90 to 100 ° C., and the thermosetting onset temperature is 140 to 140 ° C.
It is preferable that the welding is performed at a temperature of 100 ° C. or more and 130 ° C. or less.

Then, as shown in FIG. 2, a metal foil 2 is arranged on both sides of the prepreg 1 to be welded to form a laminate 5 if necessary, and a plate-like structure is formed between the laminates 5 if necessary. A laminate 6 is formed by stacking a plurality of the laminates with a mold 4 or the like interposed therebetween, and the laminate 5 or the laminate 6 is placed on a hot plate 3 of a molding press.
The production is performed by heating and pressurizing with intervening, and laminating and integrating.

Here, as the metal foil 2, a single, alloy, or composite metal foil 2 of copper, aluminum, brass, nickel, or the like can be used. Instead of the metal foil 2, the metal foil 2 is formed on an insulating resin layer. A single-sided metal foil-clad laminate or a double-sided metal foil-clad laminate formed by lamination can also be used. The thickness of the metal foil 2 is generally 12 to 70 μm.

The conditions for heating and pressurizing the laminate 5 may be adjusted appropriately under the conditions for curing the thermosetting resin composition and heating and pressurizing. Since air bubbles may remain in the inside of the substrate and electrical characteristics may be reduced, it is preferable to apply pressure under conditions that satisfy moldability. For example, when an epoxy resin-based thermosetting resin composition is used, the temperature is 160 to 210 ° C. and the pressure is 1
0~70kg / cm ^2, it can be respectively set between the heat pressing time to 60 to 240 minutes.

When the heating and pressurizing are performed in a reduced pressure atmosphere of 300 Torr or less, the degassing generated from the resin composition during the heating and pressurizing can be promptly removed, and the residual air bubbles inside the obtained laminated board can be removed. Is preferred.

When the laminate 5 is sandwiched between the hot plates 3 of the molding press, a cushion material such as cellulose paper or aramid fiber paper, a heat conduction adjusting material,
Alternatively, heating and pressing may be performed with a smooth surface material such as a plate-shaped mold 4 interposed therebetween.

When the laminated board is manufactured as described above, it is possible to prevent the occurrence of the displacement A between the prepregs 1 when the resin of the prepreg 1 flows during the heating and press molding, and the resulting laminated board can be prevented. However, a portion smaller than the required number of prepregs 1 is generated at the end portion and the thickness is partially reduced, or a portion where the pressure is insufficient is generated and the thickness is partially increased so that a failure occurs. It can prevent things from happening.

[0028]

The present invention will be described below in detail with reference to examples.

Example 1 As a thermosetting resin composition,
A thermosetting resin composition comprising the following epoxy resin, curing agent and curing accelerator was used. Epoxy resin: a tetrabromobisphenol A type epoxy resin having an epoxy resin equivalent of 500 [YDB-500, trade name, manufactured by Toto Kasei Co., Ltd.] having a solid content of 8
0 parts by weight. Curing agent: 3 parts by weight of dicyandiamide [manufactured by Nippon Carbide Co., Ltd.] -Curing accelerator: 0.2 part by weight of 2-ethyl-4-methylimidazole [manufactured by Shikoku Chemicals Co., Ltd.].

As a substrate, 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 immersing the thermosetting resin composition in a resin varnish of which viscosity was adjusted by adding N, N-dimethylformamide (manufactured by Mitsubishi Gas Chemical Company) as a solvent, After heating and drying at a maximum temperature of 180 ° C. for 10 minutes, the resin amount is 45% by weight, and the gel time at 170 ° C. is 11%.
A prepreg 1 having a length of 1 m and a width of 1 m was prepared for 0 second.

Two prepregs 1 produced as described above are superimposed on each other, sandwiched by a welding jig 7 having a heating wire heater shown in FIG.
By heating under the condition of a second, a portion having a width of 1 mm on one side of the peripheral portion of the prepreg 1 was welded over the entire length of one side.

A copper foil having a thickness of 18 μm was arranged on both outer sides of the welded prepreg 1 and laminated to produce a laminate 5. Further, a stack 6 was formed by stacking 10 sets of the stack 5 with a plate-shaped mold 4 having a thickness of 1 mm interposed therebetween. Next, the laminated body 6 is sandwiched between hot plates 3 of a forming press with kraft paper interposed therebetween, and the maximum temperature is 180 ° C., the pressure is 3 MPa, and the time is 12 hours.
Molding was performed under the condition of 0 minutes to obtain a double-sided copper-clad laminate having a size of 1 m × 1 m × 0.4 mmt.

Example 2 Same as Example 1 except that prepreg 1 having a resin amount of 50% by weight was prepared using a resin varnish prepared by changing the amount of a solvent added to the thermosetting resin composition. To obtain a double-sided copper-clad laminate.

Example 3 The same procedure as in Example 2 was carried out except that the number of prepregs 1 was three.

(Example 4) The welded portion of the prepreg 1 was
Of the rim of the prepreg 1, two opposing sides,
A double-sided copper-clad laminate was obtained in the same manner as in Example 3 except that the width was 1 mm.

(Example 5) The welded portion of the prepreg 1 was
1 m width on the four sides of the periphery of the prepreg 1
A double-sided copper-clad laminate was obtained in the same manner as in Example 3, except that the portion was m.

(Embodiment 6) The welding portion of the prepreg 1
Except that the length along each side was 100 mm,
In the same manner as in Example 5, a double-sided copper-clad laminate was obtained.

Embodiment 7 A welding jig 7 having a hot air outlet shown in FIG. 2 is used as a welding jig. In welding, the welding jig 7 is arranged on both sides of a welding portion and heated by hot air. A double-sided copper-clad laminate was obtained in the same manner as in Example 6, except for the above.

Comparative Example 1 A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that the prepreg 1 was not welded.

Comparative Example 2 A double-sided copper-clad laminate was obtained in the same manner as in Example 2 except that the prepreg 1 was not welded.

Comparative Example 3 A double-sided copper-clad laminate was obtained in the same manner as in Example 3 except that the prepreg 1 was not welded.

Comparative Example 4 A double-sided copper-clad laminate was obtained in the same manner as in Example 5, except that welding between the prepregs 1 was carried out at 170 ° C., which is higher than the curing temperature of the thermosetting resin composition. .

(Evaluation Test) Examples 1 to 7 and Comparative Example 1
Regarding the double-sided copper-clad laminates obtained in Nos. To 4, the size of the deviation A, the number of occurrences of wrinkles, and the variation of the plate thickness were evaluated.

Before the heating and pressing, the size of the deviation A is determined by adding the prepreg 1 to the kraft paper sandwiched between the laminate 6 and the hot plate 3.
The position of the end is displayed, and the length of the difference between the position of the end of the prepreg 1 after heating and pressurization and the position displayed on the kraft paper is measured, and the maximum value of each of the ten laminated boards is shifted. A size.

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 variation in plate thickness 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, the results are shown in Examples 1-7.
As compared with Comparative Examples 1 to 3, it was confirmed that the occurrence of the shift A was small, the number of wrinkles was small, and the variation in the plate thickness was small. In addition, in Examples 1 to 7, it was confirmed that generation of voids was suppressed and moldability was improved, as compared with Comparative Example 4 in which welding was performed at a temperature equal to or higher than the curing temperature of the resin.

[0048]

[Table 1]

[0049]

As described above, the method for producing a laminated board according to the first aspect of the present invention comprises the steps of: laminating a plurality of prepregs each comprising a thermosetting resin composition and a base material;
In at least a part of the surface to be bonded between the prepregs, the prepregs are heat-welded at a temperature equal to or higher than the melting temperature of the thermosetting resin composition and lower than the curing temperature, and then subjected to heat-press molding. At the time of molding, it is possible to prevent the occurrence of displacement between the prepregs when the resin of the prepreg flows, and the obtained laminated plate has a portion at the end where a portion smaller than the required number of prepregs occurs. It is possible to prevent the thickness from becoming thinner or the portion where the pressure is insufficient to be prevented from being partially thickened and defective. In addition, it is possible to keep the degree of curing of the resin in the prepreg before being subjected to the heat and pressure molding uniform, suppress the deterioration of the moldability of the laminate, and prevent the occurrence of voids in the molded laminate. You can do it.

According to a second aspect of the present invention, in the method for manufacturing a laminate, the amount of resin in the prepreg is set to 40 to 70 parts by weight based on 100 parts by weight of the entire prepreg. Prevents bubbles from remaining inside the laminated board obtained when molding, suppresses the deterioration of the electrical characteristics, and prevents the resin flow during heating and pressurization from becoming too large, thereby preventing the occurrence of sheet thickness variations. It can be suppressed.

[Brief description of the drawings]

1A and 1B show an operation of an example of an embodiment of the present invention, wherein FIG. 1A is a perspective view and FIG. 1B is a front view.

FIG. 2 is a schematic front view illustrating a method for manufacturing a laminated board.

FIG. 3 is a view for explaining a conventional method of manufacturing a laminated board;
It is an outline front view showing signs that a gap has occurred between prepregs.

[Explanation of symbols]

 1 prepreg

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/00 H05K 3/00 R // B29K 105: 06 F term (Reference) 4F072 AA04 AA07 AA09 AB03 AB04 AB05 AB06 AB07 AB09 AB28 AD13 AD23 AD27 AD28 AD29 AD31 AD33 AD38 AD42 AD45 AE01 AE02 AE03 AE04 AF03 AF04 AF06 AF26 AF27 AF28 AF29 AF30 AG03 AG17 AH02 AJ04 AK02 AL13 4F100 AB17 AB33 AG00 AH02H AH03H 012 EJ422 EJ82A EJ82B GB43 JB13A JB13B JK14 YY00A YY00B 4F204 AA36 AA39 AB03 AB19 AD03 AD04 AD16 AG03 AH36 AR06 EB01 EB22 EF01

Claims (2)

[Claims] 1. A prepreg comprising a thermosetting resin composition and a base material, a plurality of prepregs are laminated, and the prepregs are melted with each other on at least a part of a surface to be joined between the laminated prepregs. A method for producing a laminate, comprising: heat-welding at a temperature equal to or higher than the curing temperature and lower than the curing temperature; 2. The method according to claim 1, wherein the amount of the resin in the prepreg is 40 to 70 parts by weight based on 100 parts by weight of the whole prepreg.