JPS6074208A - Method of forming conductive paint film - 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 The present invention relates to a method of forming a conductive coating on an insulating member.

One method of imparting electrical conductivity to the surface of an insulating substrate such as a synthetic resin is to coat the surface of the substrate with a paint in which conductive fine powder of metal oxide thread is dispersed and mixed in a binder and a solvent.

The conductive coating film obtained by the above method generally has good transparency, but as the content of metal oxide fine powder is increased to increase the conductivity, the coating film gradually becomes transparent. The problem is that the quality decreases.

In order to solve the above-mentioned drawbacks, the present invention has discovered a method of obtaining high A4) electric property without increasing the content of metal oxide fine powder, and its characteristics are as follows: The purpose of this method is to further improve the surface of the conductive coating formed by applying a solvent.

The present invention will be explained in detail below.

In the present invention, the metal oxide fine powder used in the 5 conductive paints is selected from among 1-J, Zn, Ti, S11°In, S, Mo, and W. Oxidation of at least one metal These fine powders are mainly composed of gold-faced oxides of metals and/or gold-faced oxides thereof, doped with anomalous metal liquefied substances.These fine powders are electrically conductive if their average particle size is θ or µm or less. It is preferable from the point of view of transparency.

The binder may be one commonly used in conductive paints, such as water-soluble polymers (gelatin, maleic anhydride copolymers), soluble polyesters, polycarbonates, polystyrene.

Mixtures and copolymers of polyvinyl chloride, polycyclized vinylidene, polyvinyl acetate, polyacrylate, and straw can be used.

Further, the solvent may be any solvent as long as it can dissolve the binder, such as water, methyl ethyl ketone, toluene, ethyl acetate, acetone, tetrahydrofuran, nclohexanone, /, /, /-)lichloroethane, ethanol, benzene, increased methylene, - Nitropropane, torinlene,
Styrene monomers, divalent propylene, acetic acid chloride, dioxane monomers, mixtures thereof, and the like can be used.

A method of coating a conductive paint with the above composition on an insulating substrate,
Conventional application methods such as blade coating are applied. Examples of the insulating substrate include films, sheets, plates, and other various molded products made of synthetic resins such as polyvinyl chloride resin and polyester resin. In the present invention, various primers may be applied to the insulating substrate for the purpose of improving adhesion before applying the conductive paint.
A conductive paint is applied on the loquat frame substrate by the above method, and after drying, the coated surface is further treated with a solvent capable of dissolving the binder in the paint. The bath agent used here may be any bath agent as long as it can remove the binder used, and a bath agent mixed with a poor solvent for the binder may also be used.

As for the method of treating the coated surface with the above-mentioned solvent, the coating method described in section 7 above can be applied, and after applying the bath agent, the coated surface is dried. If the surface resistivity of the coating film before treatment is, for example, about 709 ohms, it can be treated with a solvent of /θ5~
/θ7 ohm.

Here, the reason why the conductivity is improved is as follows. That is, the metal oxide fine powder forming the human blood coating is usually coated with a very thin insulating material such as an inder, and this is thought to inhibit the nine-electrification property. Therefore, when the insulating material was dissolved and the conductive fine powder was exposed on the surface by the solvent treatment of the present invention, the conductivity was improved. The degree of solvent treatment and the number of treatments should be determined depending on the required conductivity; however, if the treatment is too much, the conductive fine powder may also peel off from the surface, resulting in poor performance, so choose the conditions accordingly. There is a need to.

Next, the present invention will be explained in detail using examples.

Example A conductive paint made by adding soluble polyester as a binder to fine powder mainly composed of tin oxide and dispersing it in a solvent was applied using the tire-bar coating method (bar coater #B).
The compositions shown in Table 7 were coated on the surface of an insulating substrate, and then the coated surface was dried. The drying conditions were 700° C. for 7 minutes or more in the case of polyester film, and 3θ seconds or more at GO° C. in the case of polyvinyl vinyl film. Furthermore, various solvents shown in Table 1 were applied to the above-mentioned coated surface by a tire bar coating method (bar coater #3) for treatment. that pz
It was dried at θ°C for about 3θ seconds and used as a sample. The measurement results of the surface resistivity values of each sample are shown in Table 2.
Solvent treatment PJ using the same substrate as i1x11! The measurement results for 0 and C are also shown in Table 7. Each surface resistivity value is a value measured according to JIS Ki9//i.

From Table 1, it can be seen that for sample No. 1 whose substrate is PET, the treatment with the solvent of the present invention lowers the surface resistivity on the order of 102 to /θ4Ω, and improves the conductivity. (It turns out that there are eight things.

Similarly, it can be seen that the conductivity of the samples whose substrates were made of PVC was also improved.

As described above, according to the method of the present invention, conductivity can be significantly improved by bath treatment without reducing transparency.

Furthermore, in order to obtain the desired conductivity, a small amount of fine powder can be used compared to the conventional method, and it is economical and has great applicability to electronic phase material parts.

Claims (1)

[Claims] After applying a conductive paint containing a metal oxide fine powder, a binder, and a solvent as main components onto an insulating substrate and drying it, the binder coated on the metal oxide fine powder is completely dissolved in the solvent 1. A method for forming a conductive coating film, the method comprising: removing the conductive coating film by