JP2720726B2 - Composite laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a composite laminate.

[0002]

2. Description of the Related Art Along with the cost reduction of electronic and electric equipment, it has been required to reduce the price of a printed wiring board used by incorporating the electronic and electric equipment. Low cost composite laminates have come to be used in fields where glass fiber woven substrate laminates have been used. Composite laminate (CEM
The problem (-3) is that the base material used for the core layer is a glass fiber nonwoven fabric, and the warpage after heating is larger than that of the laminate (FR-4) of the glass fiber woven fabric base material. There is. This is because the glass fiber woven fabric is obtained by uniformly weaving glass fibers, whereas the glass fiber nonwoven fabric is obtained by randomly entangled short glass fibers and has a high porosity. It is presumed that the glass fiber nonwoven fabric is warped due to non-uniform stress relief with respect to shrinkage stress when the thermosetting resin impregnated in the base material cures. In addition, composite laminates often contain an inorganic filler in the resin for the purpose of cost reduction and the like, and the proportion of the base material in the volume is low, so that the base material can suppress the stress generated in the resin. It is also believed that it will warp when it disappears.

On the other hand, the method of mounting components on a printed wiring board has shifted from insertion mounting into through holes formed in a substrate to surface mounting, and the method of soldering components on a printed wiring board also involves soldering components. From the manual method, in which only the mounting position is heated with a soldering iron, etc., to the flow solder method, in which components are mounted on a printed wiring board and passed through a jet solder bath, or the cream solder is applied to the printed wiring board, Has been shifted to a reflow method in which a heater is installed and passes through a heating furnace. In the conventional soldering method, only a part of the printed wiring board is often heated, and the whole printed wiring board is not often heated. A step of heating the whole has become essential.

[0004] In such a situation, various studies have been made to suppress the stress generated inside the composite laminate, which is easily warped by the heat treatment. The composite laminate is made by impregnating a thermosetting resin, which is a matrix resin, with a glass fiber woven fabric and a glass fiber non-woven fabric, forming a core layer with a glass fiber non-woven fabric, and forming both surface layers with a glass fiber woven fabric,
Manufactured by heat and pressure molding, for example, simply adding a flexibility-imparting agent to a thermosetting resin impregnating a glass fiber woven fabric disposed on a surface layer, or adding the added flexibility-imparting agent Studies have been made to reduce the stress by reacting with the thermosetting resin or the curing agent.

[0005]

However, according to the above-mentioned prior art, the warpage of the composite laminate after heating can be reduced, but other characteristics required for the substrate of the printed wiring board, that is, heat resistance and metal There was a problem that the peel strength of the foil was lowered. The problem to be solved by the present invention can correspond to a manufacturing process of a printed wiring board that performs high-temperature heating of the entire substrate such as surface mounting.
An object of the present invention is to provide a composite laminate suitable for use as a substrate of a printed wiring board, to suppress warpage after high-temperature heating, and to ensure heat resistance, insulation, and metal foil peeling strength.

[0006]

In order to solve the above-mentioned problems, a first composite laminate according to the present invention comprises a thermosetting resin impregnated in a glass fiber nonwoven fabric constituting a core layer, wherein the thermosetting resin is a dimer acid-modified resin. The second composite laminate according to the present invention, comprising an epoxy resin, wherein a blending amount of the dimer acid-modified epoxy resin is 50 parts or less based on 100 parts of the thermosetting resin in a solid weight ratio. The board is obtained by reacting the dimer acid-modified epoxy resin with the novolak-type phenol resin in the first invention, and the compounding amount thereof is 60 parts or less based on 100 parts of the thermosetting resin in a solid weight ratio. It is characterized by being. Third aspect of the present invention
In the composite laminate, the thermosetting resin impregnated in the glass fiber nonwoven fabric constituting the core layer contains a propylene oxide-added bisphenol A type epoxy resin, and the compounding amount of the propylene oxide added bisphenol A type epoxy resin is solid. The weight ratio is not more than 40 parts with respect to 100 parts of the thermosetting resin.

[0007]

The composite laminate according to the present invention uses a dimer acid-modified epoxy resin or a propylene oxide-added bisphenol A-type epoxy resin for the core layer, without deteriorating the characteristics required for a substrate of a printed wiring board. And to reduce warpage after high-temperature heating. The presence of the low elasticity dimer acid-modified epoxy resin or propylene oxide-added bisphenol A type epoxy resin in the thermosetting resin absorbs and alleviates the internal stress of the laminate caused by the curing shrinkage of the thermosetting resin. When the dimer acid-modified epoxy resin is reacted with a novolak-type phenol resin, the amount of unreacted dimer acid-modified epoxy resin can be reduced, which is more preferable in suppressing a decrease in heat resistance. When the dimer acid-modified epoxy resin having low elasticity is used in combination with a thermosetting resin impregnated in a glass fiber woven fabric disposed on the surface layer of the composite laminate, the aliphatic skeleton of the dimer acid-modified epoxy resin is used. In this case, the heat resistance of the laminate and the adhesive strength of the metal foil integrally attached to the surface during the formation of the laminate are reduced. When the propylene oxide-added bisphenol A-type epoxy resin is used in combination with a thermosetting resin impregnated in a glass fiber woven fabric disposed on the surface layer of the composite laminate, the propylene oxide-added bisphenol A-type epoxy resin is used. , The insulation resistance on the surface of the laminate is degraded, and the corrosion resistance is reduced. Therefore, the dimer acid-modified epoxy resin or the propylene oxide-added bisphenol A type epoxy resin is blended with the thermosetting resin impregnating the glass fiber nonwoven fabric disposed on the core layer. However, when the mixing ratio of the dimer acid-modified epoxy resin is large, the glass transition temperature of the laminate decreases, and the heat resistance and the moisture-resistant insulation properties decrease. Also, if the proportion of the propylene oxide-added bisphenol A type epoxy resin is large, the glass transition temperature of the laminated board is lowered, and the heat resistance and the moisture-resistant insulating properties are lowered.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The glass fiber non-woven fabric used in the present invention includes glass-paper mixed non-woven fabric. The thermosetting resin that is the matrix resin is an epoxy resin, a phenol resin,
Urea resin, polyimide, polyester, or the like can be used as appropriate. These thermosetting resins include inorganic fillers (A) for the purpose of improving quality, improving workability, and reducing costs.
l ₂ O ₃ , Al ₂ O ₃ .H ₂ O, Al ₂ O ₃ .3H ₂ O, talc, MgO, SiO _2, etc.). The novolak type phenol resin is obtained from phenols such as phenol, alkylphenol, dihydric phenol and polyhydric phenol as raw materials. The composite laminate according to the present invention includes a laminate for a multilayer printed wiring board in addition to a laminate for a normal printed wiring board. The dimer acid-modified epoxy resin used in the composite laminate according to the present invention is, for example, one represented by (Chemical Formula 1).
The propylene oxide-added bisphenol A type epoxy resin is, for example, one represented by the following formula (2).

[0009]

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[0010]

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Examples 1-2, Comparative Example 1 Novolak type phenol resin (Bliofen VH-4170 manufactured by Dainippon Ink) was used as a curing agent for 80 parts by weight of bisphenol A type epoxy resin (Epiclon 855 manufactured by Dainippon Ink). 20 parts by weight, 0.5 parts by weight of a curing accelerator 2-ethyl-4-methyl-imidazole and 50 parts by weight of an inorganic filler SiO ₂ were blended to prepare a bisphenol A type epoxy resin varnish (A). Varnish (A),
Dimer acid-modified epoxy resin (YD-17 manufactured by Toto Kasei)
1) was dissolved in the diluting solvent methyl ethyl ketone at the compounding amount (weight of the solid resin) shown in Table 1 to prepare a varnish (B). A varnish (B) is impregnated and dried into a glass fiber nonwoven fabric having a unit weight of 50 g / m ² , and the resin adhesion amount including a filler is 8
4% by weight of prepreg (I) was obtained. The separately prepared bisphenol A epoxy resin varnish (C) was impregnated and dried in a glass fiber woven fabric having a unit weight of 205 g / m ² to obtain a prepreg (II) having a resin adhesion amount of 40% by weight. Six layers of prepreg (I) were stacked, one ply of prepreg (II) was placed on each side, and a copper foil having a thickness of 18 μm was placed on both sides. Was obtained.

Example 3 70 parts by weight of the dimer acid-modified epoxy resin in Example 1, 30 parts by weight of a novolak phenol resin, and 0.5 parts by weight of 2-ethyl-4-methyl-imidazole were blended.
The reaction was carried out at 80 ° C. for 5 hours to prepare a preliminary reaction product of a dimer acid-modified epoxy resin and a novolak-type phenol resin. Varnish (D) was prepared by dissolving the varnish (A) used in Example 1 and the pre-reacted product in the dilution solvent methyl ethyl ketone in the amounts shown in Table 1 (weight of resin solid component). A glass fiber nonwoven fabric having a unit weight of 50 g / m ² was impregnated with varnish (D) and dried to obtain a resin adhesion amount including a filler of 84 g.
% By weight of prepreg (III) was obtained. Prepreg (III)
6 ply, prepreg (II) is placed on each side by 1 ply, copper foil of 18 μm thickness is placed on both sides, and 1.6 mm thick composite copper clad A laminate was obtained.

[0013]

[Table 1]

Examples 4-5, Comparative Example 2 The varnish (A) used in Example 1 and the propylene oxide-added bisphenol A type epoxy resin (BPP-350 manufactured by Sanyo Chemical Co., Ltd.) (Resin solid component weight) and dissolved in a diluting solvent methyl ethyl ketone to prepare a varnish (E). The varnish (E) was impregnated and dried into a glass fiber nonwoven fabric having a unit weight of 50 g / m ² to obtain a prepreg (IV) containing a filler and having a resin adhesion amount of 84% by weight. Six layers of prepreg (IV) are stacked, one ply of prepreg (II) is arranged on each side, and a thickness of 18 μm is formed on both sides.
m, and a 1.6 mm thick composite-type copper-clad laminate was obtained by heat-press lamination.

[0015]

[Table 2]

Conventional Examples 1 to 3 The varnish (C) used in Example 1 and the dimer acid-modified epoxy resin or propylene oxide-added bisphenol A type epoxy resin are mixed in the amounts shown in Table 3 (resin solid component weight). ) To prepare a varnish (F). A varnish (F) is impregnated and dried in a glass fiber woven fabric having a unit weight of 205 g / m ^{2 to} prepare a prepreg (V) having a resin adhesion amount of 40% by weight.
I got The varnish (A) used in Example 1 was impregnated and dried in a glass fiber nonwoven fabric having a unit weight of 50 g / m ² to obtain a prepreg (VI) containing a filler and containing 84% by weight of a resin. Six layers of prepreg (VI) are stacked, and one ply of prepreg (V) is arranged on each side, and a copper foil having a thickness of 18 μm is placed on both sides.
A 1.6 mm thick composite copper-clad laminate was obtained.

[0017]

[Table 3]

Table 4 shows the characteristics of the laminates of the above-mentioned examples, comparative examples and conventional examples. In the table, the warpage after heating is the average value measured after applying a load of 500 g to a test piece (size: 340 × 255 mm, n = 12) and floating it in a 260 ° C. solder bath for 10 seconds. The solder heat resistance was 300
The time until blistering occurred on the surface floating in a solder bath was measured. The copper foil peel strength was measured by the JIS method. The insulation resistance was measured by pressure cooker treatment (121
° C, 2 atm, 6 hr).

[0019]

[Table 4]

[0020]

As described above, the composite laminate according to the present invention was able to secure the heat resistance, the metal foil peeling strength, and the moisture insulation resistance in addition to the suppression of the warpage after heating. It is suitable as a substrate for a printed wiring board compatible with a high-temperature heating process. By securing moisture-resistant insulation, it is possible to provide through holes with a narrow pitch, and it is possible to manufacture a printed wiring board with a higher density than before.

Claims (1)

(57) [Claims] (1) a sheet-like substrate of a surface layer is made of a woven glass fiber fabric;
The sheet-like base material of the core layer is a glass fiber non-woven fabric, and these are impregnated with a thermosetting resin and are integrated with a metal foil placed on the surface by heat and pressure molding. Bisphenol with propylene oxide added only to thermosetting resin impregnated in glass fiber nonwoven fabric
Including A-type epoxy resin, propylene oxide-added
A composite laminate comprising a phenolic epoxy resin in an amount of 40 parts by weight or less based on 100 parts of the thermosetting resin in terms of a solid weight ratio.