JPS61193843A - Manufacture of silica steel plate base copper lined 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 the production of highly reliable silicon steel plate-based copper-clad laminates with excellent adhesion strength and heat resistance of insulating layers. In detail, in metal-based copper-clad laminates used as printed wiring boards for small electronically controlled motors, silicon steel sheets (JISC2) with excellent electromagnetic properties are used as the metal plate.
552), conventionally, to prevent overcurrent and prevent rust, the coating of magnesium phosphate, etc., previously formed on the surface of the silicon steel plate was left as is, and an insulating layer was placed on top of it. In order to improve the drawbacks of this method, we have developed a method of bonding copper foil to the roughened surface using sandpaper, sandblasting, etc., and then bonding copper foil to the roughened surface via an insulating layer. However, the present invention involves forming, on the surface of a silicon steel plate, an electrically conductive rust-preventing film that is galvanized and chromate-treated or phosphate-treated, rather than an insulating film, and then removing this. By adhering copper foil on top of this via an insulating layer, we have created a highly reliable silicon steel plate-based copper clad with high rust prevention effect and film strength, and excellent properties such as heat resistance, moisture resistance, and withstand voltage. It manufactures laminates.

[Industrial application field]

Copper-clad laminates based on silicon steel sheets, which have excellent anti-rust film strength and heat resistance, are used in small-sized devices such as video tape recorders and floppy disks, which have been increasingly used in recent years.
It is used in drive circuits for electronically controlled motors and printed circuit boards that require electromagnetic characteristics such as 8 rotation speed and position detection. In recent years, electronic devices have become lighter, WI-type, and more dense, and the transistors and integrated circuits (ICs) used in these devices have become lighter.
Or electronic components such as resistors and capacitors are miniaturized,
The density has been increased and the output has been increased. Along with this,
The amount of heat generated per unit surface area of these electronic components is increasing significantly, and the printed wiring boards to which these components are attached are also required to have excellent heat resistance. For this reason, demand has begun for copper-clad laminates for printed wiring boards in which copper foil is bonded to a metal plate with good heat dissipation through an insulating layer with good heat resistance, such as epoxy or polyimide. The silicon steel plate-based copper clad laminate of the present invention, which has excellent insulating film adhesion strength and heat resistance, will greatly promote the future miniaturization and higher density of electronic devices as described above, and will also improve its insulation and heat resistance. It is used to greatly enhance the confidence of people such as the public.

[Conventional technology and problems]

As mentioned above, with the recent miniaturization and high output of electronic components, aluminum with excellent heat dissipation is used on one side or inside of the TELINT wiring board as a means to improve the heat resistance of the printed wiring board on which these electronic components are attached. There is an increasing trend to use metal plates such as copper, iron, etc. In particular, silicon steel sheets are beginning to be used for small electronic motors and printed wiring boards for detecting rotational speed and position in order to further improve their electromagnetic properties. Although this silicon steel sheet has excellent electromagnetic properties, it has poor corrosion resistance and is prone to rusting, especially in summer or in high humidity.

In order to prevent this and to prevent the loss of electricity [1M], silicon steel sheet manufacturers use inorganic substances such as magnesium phosphate and magnesium dichromate, and some organic substances such as acrylic, styrene, and vinyl acetate, on the surface. The company manufactures and sells a structure with a coating that combines anti-corrosion and insulation coating. In order to use this silicon steel plate for a copper-clad laminate for printed wiring boards, conventionally a silicon steel plate 1 with a coating 6 on both sides as shown in FIG. As shown, an insulating layer 4 of epoxy or the like is formed on the film 6.
Copper foil 5 is bonded through.

However, when a laminated plate with such a configuration is punched, peeling is likely to occur between the silicon steel plate 1 and the coating 6. This is a phenomenon that cannot be observed in the case of only a normal insulating film 6 as shown in FIG. 1, and as shown in FIG. This is a phenomenon that can only be seen during configuration. At this time, even if the material of the film 6 is changed to magnesium phosphate, magnesium dichromate, etc., the thickness of the film is reduced, or organic matter is added to this film, as shown in Figure 2. When using the multilayer configuration shown in
The phenomenon that tends to cause peeling remains unchanged. On the other hand, copper clad laminates.

To ensure long service life at operating temperatures.

We conduct long-term accelerated heating tests at temperatures several dozen degrees higher than the operating temperature, and high-temperature humidification tests.

High-temperature heat shock tests, high-temperature water intrusion tests, etc. are performed, and even in these accelerated life tests, when the multi-layer structure shown in FIG. A phenomenon of slippage occurs between the insulating layer 40 and the insulating layer 40. All of these are caused by the low and insufficient adhesion between the silicon steel plate 1 and the layer film 6, and the insufficient surface treatment of the film 6.

Recently, as an improvement on this, as shown in Fig. 3, after polishing off the film on one side of the silicon steel plate with sand vapor or Scotch prite, an insulating adhesive layer 4 of epoxy or the like is directly formed on the surface of the silicon steel plate, and then a layer of copper foil 5 is applied to this. A method has been devised and implemented (Japanese Unexamined Patent Publication No. 148390/1983). In addition, this method has the drawbacks of unevenness on the surface and a reduction in the withstand voltage characteristics of the thin insulating adhesive layer 4. In order to improve this, this film is removed by a sandblasting method in which metal balls, ceramic balls, etc. are sprayed to roughen the surface. A method has been proposed in which a copper foil 5 is bonded via an insulating layer 4 after the film has been formed (Japanese Patent Laid-Open No. 59-148392). The addition of the removal process increases manufacturing costs, and due to fluctuations in the removal process, the surface condition of the silicon steel plate is not constant, resulting in unstable adhesion and low reliability of the insulating layer to be formed on it. .

For this reason, in reliability tests, the insulation layer tends to peel off during accelerated heating tests at high temperatures, high-temperature humidification tests, or high-temperature water penetration tests, and this phenomenon can be expected to cause accidents when the insulation layer peels off during actual use. In the worst case, electronic components attached to the printed wiring board may come off and fall, causing a fatal accident. In addition, since the film on the silicon steel plate is removed, the anti-corrosion effect, which is one of the purposes of this film, is lost, and as a result, rust is generated during high-temperature humidification tests, and due to this rust, the insulation layer This may lead to the surface rising or falling. Furthermore, since the silicon steel sheet from which the coating has been removed has poor corrosion resistance, it tends to rust during summer or high humidity, and a copper-clad laminate must be manufactured immediately after the coating is removed, which poses a problem in terms of process. Furthermore, in the case of single-sided copper-clad laminates, the back side, which is not covered with copper foil, is easily scratched during processing and handling, and the thin coating of magnesium phosphate, etc., which is usually about 0.5 to 2 μm thick on this surface, is easily scratched. The underlying silicon steel plate is exposed and rust is likely to occur.

[Purpose of the invention]

The present invention was made in view of the current situation, and the purpose of the present invention is to form a rust-preventing film on the surface of a silicon steel plate, which has high adhesion to the silicon steel plate, and further treat the surface of this film to form a rust-preventive film on the surface of the silicon steel plate. The object of the present invention is to manufacture a silicon steel plate-based copper-clad laminate that has improved adhesion to the insulating adhesive layer to be formed.

The present invention has made it possible to manufacture a highly reliable silicon steel plate-based printed wiring board that does not produce hollowing during processing such as cutting and punching, and has excellent heat resistance, moisture resistance, and rust prevention properties. Conventionally, the adhesion of the surface film of silicon tone plates was not sufficient.

Although its excellent electromagnetic properties could not be fully utilized for printed wiring boards, the present invention enables silicon steel sheets to be used as metal plate-based printed wiring boards with excellent electromagnetic properties, such as printed wiring boards for small electronic motors and rotation speed detection circuit boards. will be actively utilized.

[Disclosure of the invention]

In other words, the gist of the present invention is to form a galvanized conductive film with a high rust prevention effect on the surface of a silicon steel plate in place of the conventional insulating/rust preventive film such as magnesium phosphate, thereby improving the adhesion to the silicon steel plate. Furthermore, in order to increase the adhesion with the insulating layer formed on top of this, the surface is subjected to an appropriate amount of chromate treatment or phosphate treatment, and the copper foil is placed on top of it through the insulating layer without removing this. It is used to glue. Below 1
Detailed explanation of the present invention 0 As the galvanizing applied to the surface of the silicon steel plate in the present invention, the galvanizing used for ordinary iron plates is sufficient, but the amount of plating is 5 to 10 g/r.
d is desirable; if it is less than 5 g/m2, there is no rust prevention effect, and the film thickness is extremely low, so rust is likely to occur due to scratches during processing or handling. Furthermore, if the plating is over 70 g/rr1, the plating will easily peel off due to the impact force during punching, and it will not be suitable for bending, drawing, or other processes. This increases corrosion resistance and improves adhesion with the insulating layer formed thereon. In this case, the chromate treatment is preferably 10 to 50 .mu./rrr.

If it is less than 10■/m2, the effect of the treatment will not be recognized and 50■/m2
If rrr is exceeded, the adhesion between the chromate-treated layer and the insulating layer is poor, and the chromate layer peels off during a life test at high temperatures. In addition, in the case of phosphate treatment, it is desirable that the rate is 1 to 5 g/rd, 1 g/n (below, the phosphoric acid treatment is less effective, and above 5 g/1 cd, the adhesion between the phosphate treatment and the insulating layer is poor). Cracks are likely to occur.

The film formed on the silicon steel plate in this manner is electrically conductive, unlike the conventional film, and even if minute scratches occur on the surface, the electrochemical phenomenon prevents the growth of rust. In addition, since it is directly bonded to the silicon steel plate by electrochemical force, it has good adhesion to the steel plate, and the appropriate amount of chromate treatment and phosphate treatment provides excellent adhesion to the insulating layer. Therefore, silicon steel plate-based copper-clad laminates, in which copper foil is bonded via an insulating layer while leaving this film on, have greatly improved the drawbacks of conventional products and ensured high reliability and long service life. The present invention will be described below with reference to the drawings. As shown in FIG. without removing it.

A copper foil 5 is bonded thereon via an insulating layer 4 to produce a silicon steel plate-based copper-clad laminate.

The type of silicon steel plate is JIS C2552 5-18.
In the case of the above high grades, the adhesion with zinc tends to be poor due to the high silicon content, so the surface of the silicon steel plate is treated by polishing, sandblasting, or chemical solution as shown in Figure 5. It is desirable to form a film of zinc plating 2 and chromate treatment or phosphate treatment 3 on the silicon steel plate 1 whose surface has been roughened, and to apply an insulating layer 4 thereon without removing the film. The silicon steel plate-based copper-clad laminate produced by adhering the copper foil 5 has further excellent corrosion resistance, punching workability, heat resistance, and moisture resistance. Note that the insulating layer used in the present invention may be applied to the above-treated silicon steel plate with a resin liquid such as epoxy resin, phenolic resin unsaturated polyester resin, or polyimide resin, or may be applied to copper foil, or these resins may be applied to glass fiber, polyimide resin, or the like. An adhesive prepreg sheet is made into an adhesive prepreg sheet reinforced with a base material such as polyester fiber 8 paper, and copper foil is laminated via these resins and pressurized to produce a laminate. Further, although the embodiment shows an example in which copper foil is bonded to one side of a silicon steel plate, it may be bonded to both sides. Note that as the heating and pressing method, a lamination press is usually used, but a continuous pressing steel belt or a roll press may also be used.

The present invention will be described in more detail below based on two examples.

1'4 I, r' ([Example 1] After polishing a silicon steel plate (S-18) without a coating with 9600 sandpaper, electrolytic galvanizing was applied at 20 g/rrr.Furthermore, 25 mg/rrr was applied on top of the zinc plating. A chromate-treated silicon steel plate with a thickness of m2 was prepared.An epoxy resin solution was applied to a 35μ copper foil and dried to produce a 50μ copper foil with an insulating layer, which was laminated on the silicon steel plate.

A single-sided copper-clad laminate based on a silicon steel plate was obtained by heating and pressing under the conditions of 30 kg/cal teo°C and 2 hours.

[Example 2] - A silicon steel plate-based single-sided steel clad laminate was obtained in the same manner as in Example 1, using a silicon steel plate that had been subjected to 3 g/rrf of phosphate treatment instead of chromate treatment in Example 1. .

[Example 3] A silicon steel plate (S-30) without a coating was electrolytically galvanized at 20 g/rd in the same manner as in Example 1 without polishing.

[Comparative Example 1] Zinc plating amount of 100 g/n in the silicon steel sheet of Example 1
A single-sided copper-clad laminate was obtained in the same manner as in Example 1, except for the following steps.

[Comparative Example 2] The amount of chromate treated in the silicon steel plate of Example 1 was 80a.
A single-sided copper-clad laminate was obtained in the same manner as in Example 1, except that w/rr1 was carried out.

[Comparative Example 3] A single-sided copper-clad laminate was obtained in the same manner as in Example 1 using a silicon steel plate without an insulating film, polished with #600 sandpaper, and then electrolytically galvanized at 25 g/min.

[Comparative Example 4] The silicon steel plate of Example 2 was treated with phosphate at 10 g1
A single-sided steel-clad laminate was obtained in the same manner as in Example 1, except that 0f was carried out.

[Comparative Example 5] A copper-clad laminate was obtained in the same manner as in Example 1 using a silicon steel plate (S-12) surface-treated with magnesium phosphate and having a thickness of about 1 μm.

[Comparative Example 6] One side of the silicon steel plate of Comparative Example 5 was polished with #180 sandpaper, and the copper foil with an insulating layer shown in Example 1 was superimposed on this polished surface, and a single-sided copper foil was prepared in the same manner as in Example 1. A laminate was obtained.

Examples 1-3. And the punching workability of the silicon steel plate-based copper clad laminates obtained in Comparative Examples 1 to 6 using a shear or press,
Withstand voltage (JISC2110), 300℃ soldering heat resistance (
Furthermore, after removing the copper foil from each single-sided copper-clad laminate by etching, a heating test at a high temperature of 190°C was conducted to evaluate the adhesion, and the results are shown in Table-1. Table 1 also shows the corrosiveness results of silicon steel plate by 72 hours of 5% concentration salt water spray test at 35°C.
Shown below.

As can be seen from the blank examples below, according to the present invention, it was possible to obtain a silicon steel plate-based copper-clad laminate that was free from peeling during back processing, had excellent voltage resistance and heat resistance, and had good corrosion resistance on the silicon steel plate surface on the back side. .

〔Effect of the invention〕

As is clear from the above invention, according to the present invention, (1) there is no step of removing the insulating anti-rust coating on the surface of the silicon steel plate, and (2) the surface of the silicon steel plate is a stable galvanized coating, so that the anti-corrosion effect is high.

■ Zinc plating is in close contact with the silicon steel plate by electrochemical force, so it has high adhesive strength (no peeling during processing,
Even if it gets scratched during pressurization, rust will not develop due to the rust-preventing effect of galvanizing.■ Since it is rust-resistant, it can be stored for a long time, so there is no time constraint in the process of making copper-clad laminates. ■ Galvanized surface The insulating layer is treated with appropriate amounts of chromate and phosphate, so it has high adhesion with the insulating layer formed on it. ■The insulating layer has excellent processability, heat resistance, and moisture resistance, and has a long service life. It has characteristics. ■It is possible to expand the uses of printed wiring boards that take advantage of the excellent electromagnetic properties of silicon steel sheets, and it is also possible to increase the operating temperature.

It has the following effects, and its industrial value is extremely large.

In particular, in the future, as the surface temperatures of electronic components become increasingly smaller, more dense, and more powerful, the printed wiring boards to which these components are attached will be required to have high heat resistance, as well as low electromagnetic loss. It is highly effective in applications that require electromagnetic shielding from adjacent circuits and electromagnetic wave generators.

[Brief explanation of drawings]

The drawings show examples and comparative examples of the present invention. Figure 1 shows a generally commercially available silicon steel plate with an insulating and rust-preventing film on its surface, and Figure 2 shows a silicon steel plate that is generally commercially available. The figure shows Comparative Example 5, in which copper foil is bonded on a silicon steel plate through an insulating layer, and Figure 3 shows a comparison in which only the film on the top surface of the silicon steel plate is removed with sandpaper, and copper foil is bonded to this. Example 6 is shown, and Figure 4 shows Example 3, in which a silicon steel plate is galvanized, a film is further treated with chromate or phosphate, and copper foil is bonded without removing this film. , Figure 5 shows a silicon steel plate that has been roughened, then galvanized, and then chromate-treated or phosphate-treated to form a film.
Examples 1 and 2 are shown in which the copper foil was bonded without removing it. Explanation of symbols 1 Silicon steel plate 2 Galvanized 3 Treated surface 4 Insulating layer Fig. 1

Claims (1)

[Claims] 1. Forming a conductive anti-rust film on the surface of a silicon steel plate by galvanizing and further forming a film by chromate treatment or phosphate treatment, and then laminating copper foil on top of this with an insulating layer interposed therebetween. A method for producing a silicon steel plate-based copper-clad laminate, characterized by: 2. The amount of zinc plating applied to silicon steel plate is 5 to 70 g/m^2
A method for producing a silicon steel plate-based copper-clad laminate according to claim 1. 3. The method for manufacturing a silicon steel sheet-based copper-clad laminate according to claim 1, wherein the amount of chromate treatment is 10 to 50 mg/m^2. 4. The method for manufacturing a silicon steel sheet-based copper-clad laminate according to claim 1, wherein the amount of phosphate treatment is 1 to 5 g/m^2. 5. Manufacturing a silicon steel sheet-based copper-clad laminate according to claim 1, characterized in that the surface of the silicon steel sheet is roughened by polishing, sand blasting, chemical treatment, etc. and then galvanized. Method.