JPS6036578A - Ultraviolet-curable electrically conductive coating composition - Google Patents

Abstract

PURPOSE:To provide a coating composition curable easily with ultraviolet radiation and capable of forming an electrically conductive coating film having excellent adhesivity to the substrate, heat-resistance and flexibility, at a relatively low cost, by compounding a Lewis acid-reacting ultraviolet-curable epoxy resin with silver powder. CONSTITUTION:The objective composition is produced by compounding (A) 100pts.wt. of a Lewis acid-reacting ultraviolet-curable epoxy resin (containing a Lewis acid salt and an epoxy resin as main components) with (B) 100-300pts.wt. (preferably 150-250pts.wt.) of silver powder. The coating composition is applied to a substrate by screen printing, etc., and cured by radiating with an ultraviolet lamp of preferably about 50-200w/cm for about 10-60sec. The Lewis acid salt is e.g. diazonium salt, iodonium salt, sulfonium salt, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides ultraviolet rays that can be easily cured by ultraviolet rays, have conductivity '11, and form a conductive coating film that has excellent Zgt properties, heat resistance, and flexibility on a substrate. The present invention relates to a curable conductive coating composition.

[Background of the invention]

In recent years, the use of electron beam or ultraviolet curable paints has been considered in place of conventional hardening agent-based paints for forming conductive circuits in parts for electric power equipment and conductive coatings for electrical shielding. has been done. Electron beam or ultraviolet ray curable paints can be rapidly cured by irradiation with electron beams or ultraviolet rays, so the manufacturing process can be streamlined.

The present inventors have developed a conductive coating composition that is easily cured by electron beams or ultraviolet rays, has conductivity, and can form a conductive coating film that has excellent adhesion to a substrate, heat resistance, and flexibility. In order to obtain this, we conducted intensive research.

As a result, a coating film was first applied using a conductive coating composition made by adding silver powder to an electron beam curable resin, and then the coating film was cured by irradiating it with electron beams, thereby forming a conductive circuit and a conductive circuit. We have developed a method to create a transparent coating film. Even if the coating film is cured with electron beams, it does not impair the effects of speeding up curing and streamlining the manufacturing process, but the installation costs of electron beam irradiation equipment are relatively high.2. Maintenance and management. However, compared to ultraviolet irradiation equipment, it is also cumbersome. However, in the conductive coating composition,
Since silver powder that blocks light is added to the composition, it was impossible to internally cure the coating film even when irradiated with ultraviolet rays.

The present inventors continued to conduct research on a method of curing the conductive coating material I11 by irradiating it with ultraviolet rays. As a result, in conductive paint compositions that use a Lewis acid-reactive ultraviolet-curing epoxy resin as a paint base and add silver powder to it, silver powder can be added by irradiating the paint film with ultraviolet light. Although it was predicted that the UV rays would be blocked from entering the coating, the unexpected phenomenon was that the coating could mysteriously harden to the inside, and furthermore, the silver powder Even though the amount added is relatively small at 100 to 300 parts by weight! p
Practical Use-1-We have discovered that it is possible to form a conductive coating film with sufficient conductivity.

[Summary of the invention]

The present invention has been made based on the knowledge described in "-", and its gist is that the present invention contains a Lewis acid-reactive ultraviolet curable epoxy resin and silver powder as main components, and that the amount of silver powder is 100 to 3 per 100 parts by weight of epoxy resin
Ultraviolet curable conductive f characterized by having 00 double ejection parts
It is in the 1mm coating film composition.

[Detailed description of the invention]

The resin used as the paint base used in the present invention is a Lewis acid-reactive ultraviolet curable epoxy resin, and has an epoxy group that undergoes a polymerization reaction due to the action of the Lewis acid, such as a Lewis acid salt that generates a Lewis acid when irradiated with ultraviolet rays. It contains an epoxy resin as an L component. The epoxy resin and Lewis acid salt may be mixed at the time of preparing the paint, or may be mixed immediately before printing. Examples of Lewis acid salts include Lewis acid diazonium salts, Lewis acid iodonium salts, Lewis acid sulfonium salts, and the like.

The silver powder used in the present invention is mainly composed of metallic silver, and is fine particles having a flake-like or lump-like shape and an average particle size of about 0.1 to IO μm. The shape and particle size of the silver powder are not particularly limited, but considering conductivity, printing work, and economy, it is better to use particles with a flake shape and a large specific surface area. In order to do this, it is desirable to select particles with small particle size.

In the present invention, 100 to 300 parts by weight of silver powder is added to 100 parts by weight of a Lewis acid-reactive ultraviolet curable epoxy resin serving as a paint base.

If the amount added is less than 100 parts by weight (6:4), a printed circuit with sufficient conductivity cannot be obtained, and if the amount added is less than 300 parts by weight, the conductivity of 1fl- However, as mentioned earlier, the price of the conductive composition is high, the printing workability is 1ζ, and the finished circuit tends to be somewhat poor, and the coating film is especially flexible. When this is required, a problem arises in that flexibility is impaired and the coating film breaks when folded. Particularly preferably, the amount added is 150 to 250 parts by weight, and a conductive coating film having a conductivity of 1 min can be formed without causing the above-mentioned problems.

In the present invention, in order to adjust the form of the paint (it is also possible to add a viscosity adjusting agent, colorant, etc. to Ijl. To make a composition by adding silver powder to the resin that is the paint base) , can be obtained by uniformly and thoroughly kneading the paint by a method of preparing a paint, for example, by roll mixing.

Methods for applying the coating composition according to the present invention include coating with a hair or roller, screen printing, and the like. Among these, the screen printing method is preferable because it allows the coating film to be formed according to the required pattern. In particular, in the present invention, since the amount of silver powder added is smaller than in the conventionally disclosed technology, the sealing work tlE is good.
Suitable for use in screen printing methods.

After the coating composition according to the present invention is applied to the substrate, it is cured by irradiation with ultraviolet rays. The ultraviolet irradiation conditions are as follows:
Using an ultraviolet lamp of about 50 to 200 w/cm,
About 10 to 60 seconds is desirable.

In the paint based on the invention, the coating film is cured by ultraviolet irradiation, and then heated at a temperature of 80 to 200''C for a further 70 minutes to cure the coating film.

Heat treatment may be performed for about a minute.

Example J ADEKA ULTUUSHI NODO AD 7200 ], 00
Weight part curing catalyst a T) P33 3-pi parts were kneaded using three rolls to prepare a paint. This paint was applied onto a polyimide film with a thickness of 3071 I
+] to form a conductive coating film, which was cured by irradiating it with ultraviolet light for 30 seconds using two LKW ultraviolet lamps. Conductivity after curing'11. The coating was immersed in methyl ethyl ketone for 5 minutes. After taking it out, the paint film was rubbed vigorously, but no abnormality occurred on the paint film, and it was confirmed that the hardening had progressed well to the inside of the paint film. When the conductivity of the coating film was measured, it was found that it exhibited a resistance value of 10Ω or less. In addition, when the polyimide film on which this conductive coating was formed was bent, no abnormalities such as folding of the coating occurred, and it was confirmed that a good conductive coating was formed.
It was done.

Example 2 In Example 1, the conductive coating film was cured with ultraviolet light 11 and then heated at 150°C for 3 () minutes. The resistance value was approximately LΩ.

Comparative Example 1 The composition of the paint in Example 1 was A1'. Nox Oricomer 8 (Ji parts Ribokin Resin 20 weight: 112 parts silver 25 parts) Instead of our IE part, a conductive coating film was prepared under the same conditions as in Example 1. Although the coating surface was well cured, When the coating film was rubbed after being immersed in methyl ethyl ketone, it was found that the coating film was scratched from the paste fill, indicating that the interior of the coating had not been sufficiently cured.

As described above, the coating composition according to the present invention cures easily and quickly with ultraviolet rays, has good conductivity, and has excellent adhesion to No. 4, heat resistance, and flexibility. Since it can form a conductive coating film, it can be widely used for forming conductive circuits for electronic equipment parts and conductive coating for electrical shielding. 100 weight 111
Practical by just adding between 100 and 3001 yen to a portion -L
Since the conductive composition can exhibit high conductivity, the price of the conductive composition is relatively low, the coating process is good, the coating film is well formed, and the conductive composition has particularly good conductivity. Flexibility! I can do a lot of things.

Agent Patent Attorney Tetsuji Udai Continued from page 10 Inventor Noriko Matoba Nishiyodzuki Office, Osaka City0 Inventor Atsuko Yamamoto Inside Nishiyodzuki Office, Osaka City

Claims (1)

[Claims] ) Contains a Lewis acid-reactive ultraviolet curable epoxy resin and silver powder as main components, and the amount of silver powder is 1% of the epoxy resin.
An ultraviolet curable conductive 1:1 coating composition characterized in that the amount is 100 to 300 parts by weight based on 0.00 parts by weight.