JPH05116248A - On-base copper-clad laminated board using uv resin - Google Patents

Abstract

PURPOSE:To obtain the title laminated board, which has excellent heat resistance and insulating properties and in which a shearing blade and a die are hardly abraded even at the time of shearing and punching, by adopting an ultraviolet-curing vinyl ester resin as an insulating resin layer between a steel plate and a copper foil layer. CONSTITUTION:An ultraviolet-curing vinyl ester resin is superposed on the surface of a steel plate 1 as an electrical insulating layer 2, and the layer of a copper foil 3 is formed as the upper layer of the ultraviolet curing resin, thus preparing an iron-base copper-clad laminated board 4. The intensity of ultraviolet rays applied and curing conditions must be controlled accurately for ensuring the adhesion of the ultraviolet-curing vinyl ester resin and the copper foil 3 at that time. The copper foil 3 side is coated with an epoxy resin, and an epoxy resin layer is formed as the upper layer of the vinyl ester resin as the insulating layer 2. Accordingly, heat resistance is improved by a vinyl ester resin layer having excellent heat resistance on the steel plate side while the adhesion of the steel plate 1 and the insulating layer 2 is enhanced by the epoxy resin layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper clad laminate (iron printed circuit board) based on iron (steel plate) having excellent characteristics.
The present invention can be applied to parts for which a copper-clad laminate based on a steel plate has been conventionally used, such as a brushless motor.

[0002]

2. Description of the Related Art When manufacturing a copper clad laminate based on a steel plate, as shown in FIG. 1, an electric insulating layer 2 formed of a synthetic resin mainly containing an epoxy resin is provided on the surface of the steel plate 1. The copper-clad laminate 4 is manufactured by adhering the copper foil 3 to each other, but in the conventional example, an intermediate layer that functions as an insulating layer and an adhesive layer (adhesion between the steel plate 1 and the copper foil 2) is formed. Many of the resin layers have relatively excellent heat resistance,
In addition, an epoxy resin has been often used because of its excellent adhesiveness to a steel plate.

In recent years, the heat resistance required of iron-based copper-clad laminates has become more and more severe, and heat resistance at 320 ° C. for 30 seconds or more is required. With conventional epoxy resins, such severe heat resistance cannot be obtained, and measures have been taken such as adding inorganic fillers such as alumina and silica to the resin. However, the addition of such an inorganic filler has drawbacks such as large abrasion of shear blades and dies during processing such as shearing and punching of the iron-based copper-clad laminate, and deterioration of insulation due to addition of the inorganic filler. ..

[0004]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, that is, by joining a steel sheet and a copper foil with an insulating resin having excellent heat resistance, It is an object of the present invention to provide an iron-based copper-clad laminate having excellent insulation properties and having a small abrasion of shear blades and dies during shearing and punching.

[0005]

A feature of the present invention is that a vinyl ester type ultraviolet curable resin is used for the insulating resin layer for the first time as an iron-based copper clad laminate. Since vinyl ester resins are excellent in heat resistance, they have been widely used in various engineering plastic parts (eg, pipes, tanks, ducts) requiring heat resistance. By paying attention to the heat resistance of the system resin, the above object is achieved by applying a vinyl ester-based ultraviolet curable resin as an insulating layer to the iron-based copper-clad laminate.

The present invention will be described in detail below. Among the properties required for iron-based copper-clad laminates, heat resistance is one of the most important properties. This is because when various semiconductors, coils, resistors, etc. are mounted on the wiring, they are joined by solder, and when the heat resistance is poor, the heat of the solder causes the resin layer, which is an insulating layer, to It deteriorates and peels off between the steel plate and the insulating layer. Therefore, until now, various electronic components have been made into iron-based copper-clad laminates by decreasing the solder bath temperature, reducing the thermal shock to the insulating resin layer, or improving the thermal conductivity of the resin. When mounting, it is devised so that peeling does not occur between the steel plate and the resin layer.

However, the method of lowering the solder bath temperature and the thermal shock to the insulating resin layer is not a preferable method because it lowers the mounting speed of electronic parts and thus the productivity. Further, as described above, the method of adding silica or alumina to the resin layer to improve the thermal conductivity also has the drawback of abrading the blade during punching or shearing. Therefore, it can be said that the method of improving the heat resistance of the insulating resin used is the most excellent method. However, resins having excellent heat resistance are generally not applied to iron-based copper-clad laminates because they have poor adhesion to steel plates.

As a result of studying various heat-resistant synthetic resins, the present inventors have found that the above vinyl ester UV-curable resin has excellent heat resistance and good adhesion to a steel plate, and is an iron-based copper-clad laminate. It has been found that the insulating resin layer has excellent characteristics. As the vinyl ester UV curable resin, acrylic acid is used as the acid component,
Methacrylic acid and the like, and as the epoxy component, bisphenol type epoxy resin, tetrapromobisphenol type epoxy resin, phenol novolac type epoxy resin, brominated cresol novolac type epoxy resin,
As the polymerizable cross-linking agent, styrene, chlorostyrene vinyltoluene, methyl methacrylate and the like can be further modified with an elastomer component, if necessary.
A usual peroxide can be used as the curing accelerator.

In the case where all the insulating resin layers of the present invention are made of vinyl ester UV resin (invention of claim 1), the curing condition of the vinyl ester UV resin is strict in order to secure the adhesion with the upper copper foil. Need to manage. Therefore, it is necessary to control the intensity of the ultraviolet rays to be irradiated and the irradiation time within a predetermined range. In order to expand the control range of this ultraviolet curing condition, it is sufficient to apply an epoxy resin to the copper foil side as in the conventional case and to use a vinyl ester ultraviolet resin as the lower layer (invention of claim 2). Can be improved. That is, it is a steel sheet base copper-clad laminate in which the first layer on the steel sheet side is a vinyl ester UV curable resin, the second layer is an epoxy resin, and the uppermost layer is a copper foil. Compared with the case where the insulating layer is only epoxy resin, this film structure has a vinyl ester UV resin layer with excellent heat resistance on the steel sheet side, so it has excellent heat resistance and does not peel the steel sheet and insulating resin layer. ..

The present invention is not particularly limited to the type and thickness of the steel sheet and the thickness of the insulating resin layer, but the following can be said as a general range of application. First, as for the type of steel sheet, a normal low carbon cold rolled steel sheet and a silicon steel sheet are used. Particularly, when high magnetic flux density and low iron loss are required, a silicon steel plate (Si 0.5% or more) is preferable. Further, the plate thickness of about 0.15 to 1.2 mm is most often used. Next, the insulating resin layer has a thickness of 20 μ or more and 100
A value of μ or less is common. This is because a withstand voltage of 3 kV or more cannot be ensured when the thickness is 20 μm or less, and a heat conductivity of the resin layer deteriorates and a heat resistance of the steel sheet base copper clad laminate deteriorates when the thickness is 100 μm or more. Examples of the present invention will be described below.

[0011]

【Example】

[Example 1] Low carbon cold-rolled steel sheet having both sides electroplated and chromate-treated on both sides (zinc plating amount 20 g /
m ² and a chromate amount of 50 mg / m ² ) on the upper surface of a vinyl ester UV curable resin with a roll coater to a thickness of 20 to 20
Paint in the range of 60 μm, and then UV (lamp output 80 to 160 W / cm, distance 100 from lamp steel plate)
mm), and a commercially available copper foil (one surface of which has a roughness adjusted to ensure adhesion. Thickness of 35 μm) is bonded to the steel plate with a heating roll. At this time, the temperature of the heating roll is about 150 to 180 ° C.

Through the above steps, an iron-based copper-clad laminate having a layer structure of copper foil / vinyl ester UV curable resin / steel plate can be obtained. However, in this state, the vinyl ester UV-curable resin is in a semi-cured state, and the adhesiveness and heat resistance are insufficient. Therefore, the iron-based copper-clad laminate obtained in the above step is heated in a heating furnace (temperature 150 to Hold at 200 ° C. for 4 hours to completely cure the resin.

Table 1 shows the evaluation results of the iron-based copper-clad laminates manufactured under various conditions.

[0014]

[Table 1]

(1) Copper foil peel strength after soldering ... After the iron-based copper-clad laminate produced in the above process was sheared to 100 mm square,
It is immersed in boiling distilled water for 60 minutes and then cooled with tap water at 20 ° C. After that, the plate is dried, and the copper foil surface is used as the lower surface (solder bath side) at a solder bath of 280 ° C. (Pb 90% / S
n10%), float for 30 seconds. After that, apply the copper foil to JI
Evaluation is performed according to the peeling strength measurement method of S-6481. (2) Solder heat resistance: The iron-based copper-clad laminate produced in the above process is cut into 50 mm square pieces, immersed in boiling distilled water for 60 minutes, and subsequently cooled with tap water at 20 ° C. Then, the plate is dried and floated on a solder bath (Pb 90% / Sn 10%) having different temperatures for 30 seconds with the copper foil surface as the lower surface (solder bath side). After that, the copper foil is etched (JIS C-
After completely removing the swelling (according to 6481), swelling between the insulating resin layer and the steel sheet (peeling between the steel sheet and the resin can be visually confirmed) is visually observed, and swelling is observed. Not the highest temperature (test is 1
Since it is carried out in steps of 0 ° C, 300 ° C means 300 ° C.
No swelling was observed, but it means that swelling was observed at 310 ° C. ) Is the solder heat resistance.

[Embodiment 2] A silicon steel plate (Si 3.0%) having both surfaces electroplated and chromate-treated on both surfaces.
(Zinc plating amount 3 g / m ² , chromate amount 50 mg /
m ² ), an unsaturated polyester UV curable resin is applied on the upper surface of m ² ) with a roll coater in a thickness range of 20 to 50 μm, and then UV (lamp output 80 to 160 W /
cm, the distance between the lamp and the steel plate is 100 mm), and then 30 μ of commercially available epoxy resin is applied to this steel plate.
The copper foil coated with m (the epoxy resin is coated in a semi-cured state on only one surface) is bonded with a heating roll. At this time, the temperature of the heating roll is about 150 to 180 ° C.
Is.

Through the above steps, an iron-based copper-clad laminate having a layer structure of copper foil / epoxy resin / vinyl ester UV-curable resin / steel plate can be obtained. However, in this state, as in Example 1, the epoxy resin and the vinyl ester UV-curable resin are in a semi-cured state, and the adhesiveness and heat resistance are insufficient, so that the iron-based copper-clad resin obtained in the above step is insufficient. The laminated plate is held in a heating furnace (temperature 150 to 200 ° C.) for 4 hours to completely cure the resin.

Table 2 shows the evaluation results of the iron-based copper-clad laminate produced under various conditions.

[0019]

[Table 2]

As shown in Tables 1 and 2, the iron-based copper-clad laminate of the present invention is superior in heat resistance to the commercially available iron-based copper-clad laminate using only epoxy resin.

[0021]

The iron-based copper clad laminate obtained by the present invention has excellent heat resistance. By using the product of the present invention, mounting at high temperature becomes possible, and the mounting speed on the printed wiring board can be increased.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of an iron-based copper-clad laminate.

Claims (2)

[Claims] 1. An iron-based copper-clad laminate characterized in that a vinyl ester-based ultraviolet curable resin as an insulating layer is provided on the surface of a steel sheet, and a copper foil layer is provided thereon as an upper layer. 2. An iron-based copper clad having a vinyl ester ultraviolet curing resin as an insulating layer, an epoxy resin as an upper layer on the surface of a steel sheet, and a copper foil layer on the insulating layer. Laminated board.