JPS61120863A - Coating resin composition - Google Patents

Abstract

PURPOSE:To provide a resin compsn. which can be cured in a very short time and even when interposed between an electronic part and a substrate, by bleeding cobalt naphthenate and methyl ethyl ketone peroxide with an ultraviolet- curable epoxy acrylate resin. CONSTITUTION:A resin compsn. is obtd. by blending 0.02-0.5pts.wt. cobalt naphthenate and 0.1-3pts.wt. methyl ethyl ketone peroxide with 100pts.wt. base resin composed of an ultraviolet curable epoxy acrylate resin. When the quantity of methyl ethyl ketone peroxide exceeds 3pts.wt., the pot life of the resin compsn. is shortened and workability is greatly lowered, though characteristics after curing are substantially the same, while when the quantity is less than 0.1pt.wt., curing time is prolonged. When the quantity of cobalt naphthenate is less than 0.02pts.wt., curing time for space 7 extends for over one month, while when the quantity exceeds 0.5pts.wt., pot life is shortened and workability is greatly lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a resin composition for coating circuit boards used in radio receivers, videotape recorders, television receivers, and the like.

Conventional technology Conventionally, circuit boards used in television receivers, etc., are copper-clad laminates and thin-film/thick-film ceramic circuit boards, on which discrete and chip-type electronic components constituting a predetermined electric circuit are soldered. There is one implemented in. In addition, when using these electronic components with them mounted,
In order to further improve the reliability (moisture-proof insulation and mechanical/thermal shock resistance) of these circuit boards, they are sometimes coated with resin.

The resin composition used for the coating is thermosetting,
Solvent evaporation type and ultraviolet curing type resin materials are used. Examples of thermosetting resin compositions include Epokin resin CV53031 manufactured by Matsushita Electric Works Co., Ltd. and Nippon Soda Co., Ltd.
Examples include polybutadiene resin B C1000 manufactured by Hitachi Chemical Co., Ltd. and TF 2270 manufactured by Hitachi Chemical Co., Ltd. Examples of solvent-volatile resin compositions include acrylic TF11 manufactured by Hitachi Chemical Co., Ltd.
There are 41° urethane TFI I E50, etc. Examples of UV-curable resin compositions include Cv7oOO series manufactured by Matsushita Electric Works Co., Ltd. and TF3340 manufactured by Hitachi Chemical Co., Ltd.
, UR9500 manufactured by Mitsubishi Rayon Co., Ltd., etc.

When using these coating resin materials,
After coating a predetermined circuit board by a spray method, dipping method, brush coating method, or roller method, curing is performed by a predetermined curing method. For thermosetting type, 60°C
It takes a curing time of 1 hour to 120°C for 1 hour, and in the case of a solvent-volatile type, it takes 6 to 10 minutes to harden to the touch.
In the case of ultraviolet curing type, 15 seconds to 1.5 minutes are required.

Problems to be Solved by the Invention However, in the case of the second heat curing type, a long curing time is required, particularly at high temperatures, resulting in the inconvenience that the heat resistance of the electronic components used must be increased.

However, in the case of the solvent volatilization type and the ultraviolet curing type, the resin material that has entered the space 7 between the electronic component and the board is difficult to volatilize in the former case, so the latter In this case, the ultraviolet rays will be in the shadow of the electronic components and will not be irradiated, resulting in an uncured state. Therefore, there was a problem in that the wire resistance deteriorated in a high temperature and high humidity environment of 60''C and 90%.

The present invention solves these conventional problems, and is reliable and can cure resin in an extremely short time.
Furthermore, it is an object of the present invention to provide a resin composition capable of curing resin that has entered a space between an electronic component and a substrate.

Means for Solving the Problems According to the present invention, 100% by weight of a base resin consisting of a purple one-line curable epoxy/acrylate resin is added to the cobalt naphthenate composition (total 0.02 to 0% of cobal naphthenate). .6 parts by weight,
It is characterized by containing methyl ethyl ketone perogizite in a proportion of 0.1 to 3 parts by weight.

Effect: Coating the surface of a circuit board on which electronic components are mounted with the oil composition of the present invention [7] By irradiating it with ultraviolet rays, it can be cured in a very short time, and the coating resin can be cured in the area irradiated with ultraviolet rays. The composition is also curable.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings and tables. In this example, ultraviolet curing type Evokin acrylic 1-
Base resin made of resin, such as UR9500 manufactured by Mitsubishi Rayon Co., Ltd., cV7300 manufactured by Matsushita Electric Works Co., Ltd.100
In the weight part, naphthenate covert, for example, new car paint (
Naphthorite til ketone peroxide (MEK)
PO), for example [] produced by Hon Yushi Co., Ltd., 'io. 1 to 5 parts by weight were added and mixed, and mixed and stirred.

Next, a circuit board of approximately 45πW x 80mm on which the chip-shaped electronic component 4 shown in FIG.
- Curing was carried out using a 4KW ultraviolet lamp placed 10 screens from the bottom. For the prepared sample Y1, the curing time, the time taken for curing the resin located in the unirradiated space 7 between the chip-shaped electronic component 4 and the substrate 1, and the connection strength of the chip-shaped electronic component 4 were measured. did. Reliable moisture-proof insulation is achieved by forming a 1.27-tone pinched comb-shaped conductor pattern on the substrate 1 (after coating with the above-mentioned resin composition, performing the ultraviolet curing as described above, and determining the insulation resistance value after curing). and 6
The insulation resistance value was measured after 500 hours under conditions of 0"Q, 90%, and 100V applied, and the following results were obtained (not shown in the table).

As is clear from the table of the first topsoil excavation, the curing time in the ultraviolet irradiated area is very long when using only the base resin (sample number 12), and the resin in the room area 7, which has not been irradiated with ultraviolet rays, remains uncured even after two months. It was a state. In fact, in the case where cobalt naphthenate was added to the base resin, the resin in the space 7 of the unirradiated part remained unhardened even after 2 months. MEKPO was added to the base resin (test tracker number 10.1)
1) is used to harden the resin in the space 7 that is not exposed to ultraviolet rays.
It took 1.5 months.

On the other hand, in the branch I resin composition of the present invention, the curing time in the ultraviolet irradiation area is extremely short, and the resin in the ultraviolet irradiation space 7 is cured for 1 day or more.
Hardens in 3 weeks. Furthermore, significance was also found in the moisture-proof insulation cell 1: and the connection strength of the parts. However, if the amount of MEKPO added to the resin composition of the present invention exceeds 3 parts by weight, the properties after curing will be equivalent, but the pot life of the blended resin composition will be shortened and workability will be significantly reduced. . If the amount of MEKPO added is less than 0.1 parts by weight, the curing time becomes longer.

If the amount of cobalt naphthenate added is less than 0.02 parts by weight, the curing time of the space 7 will be more than 1 month. Workability will be significantly reduced.

Note that the same effect can be obtained even with a circuit board on which the discrete electronic component 8 shown in FIGS. 3 and 4 is mounted.

Figure 1 shows a substrate coated with the resin composition of the present invention and cured, and Figure 2 shows the state before coating. Solder resist, 3 solder, 4 chip type electronic components, 5 coating resin, 6 times [conductor circuit]. Figure 3.

Figure 4 shows discrete electronic components 8 on a copper-clad V-laminated board.
[1' in the figure is a copper-clad laminate board.

As described above, by coating the circuit board on which electronic components are mounted with the caustic composition of the present invention and curing it with ultraviolet rays, the area irradiated with Shiyu 1 rays can be cured in an extremely short time. Furthermore, the resin in the space between the electronic component and the board can be cured, which is extremely advantageous in terms of production. In addition, the connection strength of the parts is improved, and the moisture-proof insulation has the same performance, so it has a great effect on improving reliability and is extremely advantageous in practice.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a circuit board with chip-type electronic components mounted on the circuit board and coated with the resin of the present invention, Figure 2 is a cross-sectional view of a circuit board with chip-type electronic components mounted on the circuit board, and Figure 3. 4 is a cross-sectional view of a circuit board with discrete electronic components mounted on it and coated with the resin of the present invention.
Figure 5 is a perspective view of a circuit board on which chip components are mounted.
... Coating resin, 7. Space of electronic parts, 8.
・Discrete electronic components. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
-Series of cuttings 7---4e1f'Pffo=a? J'u' Part 1 Figure 2 Figure 3 R Figure 5

Claims (1)

[Claims] 0 cobalt naphthenate was added to 100 parts by weight of the base resin made of ultraviolet curable epoxy acrylate resin.
．． 1. A coating resin composition comprising: 0.02 to 0.5 parts by weight and 0.1 to 3 parts by weight of methyl ethyl ketone peroxide.