JPS5891777A - Electrically conductive clear paint - 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 coating material that is transparent, electrically conductive, and capable of forming a coating film having antistatic properties.

In recent years, there has been a rapid increase in the number of cases in which static electricity prevention is required for IC storage containers, other electronic and electrical equipment components, and architectural components such as carpets, flooring materials, and wall materials. Additionally, there is an increasing demand for conductive paints to prevent electromagnetic interference caused by microwaves.

In the past, in response to these demands, paints containing conductive materials such as carbon powder, metal powder, or carbon fibers or metal fibers were applied. Organic substances have been applied to nonconductors to make them conductive and prevent static electricity, but in the former case, the color tone of the applied film becomes gray or blackish, so In the case of the latter, it is possible to form a transparent film with antistatic properties by coating, but the antistatic properties cannot be achieved unless the humidity is high. It had the disadvantage that it was not effective and was easy to peel off.

From the above-mentioned viewpoints, the present inventors have discovered that the coating film itself has transparency that does not impair the color tone of the base, has excellent coating film adhesion, and has good electrical conductivity. ,
As a result of repeated research to obtain a paint that imparts good conductivity and exhibits sufficient antistatic ability when applied to immovable objects, we have found that (a) tin oxide (hereinafter referred to as 5nO7) powder is
It is white in color and has electrical conductivity, but when antimony (sb) is added to it, the electrical conductivity is further improved, and it is also thermally stable.

(b) In order to ensure that the transparency and color tone of the paint are not impaired even when the powder is mixed in, it is necessary that the powder to be mixed in does not absorb light, that is, it has a white color, and that its optical refractive index is the same as that of the paint. Optical refractive index of main element resin: 1.6-1.7
or the average particle size of the powder is 0.4
It must be smaller than μm, that is, smaller than the wavelength of visible light, and must have little light scattering.

(C) The SnO2 powder containing the above sb is 2.0 to 2.0.
It has a light refractive index of 1, so it can be used as a paint.
When mixed for the purpose of imparting conductivity without impairing the color tone, especially transparency, the average particle size should be 0.4 μm.
It is necessary to miniaturize the size to less than m.

(d) Average particle size of item (C) above: 0.4 μm JJ
When mixing sb-containing 5N02 fine powder having the following properties into a paint, if the amount of the mixed powder is less than 50% by weight relative to the resin, which is the main component of the paint, it can be mixed uniformly with good dispersibility. On the other hand, the amount of contamination is 50% at the same ratio.
If it exceeds % by weight, the dispersibility deteriorates and it becomes difficult to mix uniformly, but in this case, before mixing into the paint, the fine powder is soaked in an alkaline aqueous solution adjusted to a pH of 7 to 11 for a predetermined period of time. When the pretreatment for maintaining dispersion is performed, the dispersibility of the fine powder in the paint is significantly improved, and even if the amount of the fine powder mixed exceeds 50% by weight at the same ratio, it will be uniformly dispersed in the paint. thing.

The findings shown in sections (a) to (d) above have been obtained.

This invention was made based on the above findings, and has a composition containing Sb: 0.1 to 20% by weight, with the remainder consisting essentially of 5n02, and having an average particle size of 0.4 μm or less. the conductive fine powder having a diameter;
5 to 90% by weightMain component of paint based on fat: By containing it at a ratio of 95 to 10% by weight, it has good conductivity and antistatic ability, and is transparent and does not affect the color tone of the base. It is characterized in that it is a paint that can form a coating film.

In addition, in general transparent paints, acrylic, vinyl, carbonate, polyester, urethane, epoxy, and polypropylene resins are used as the main component of the paint. The transparent paint is made of these transparent paints containing a predetermined amount of the above-mentioned conductive fine powder.

That is, the transparent paint of this invention first contains the above resin,
It is produced by mixing with a solvent such as alcohol, ester, ketone, ether, water, etc., and then adding and mixing the above-mentioned conductive fine powder. , anionic surfactants such as sodium phosphate, sodium sulfonate, sodium oleate, sodium stearate, and sodium citrate; silane coupling agents such as alkylsilane and alkoxysilane;
Furthermore, a titanate coupling agent such as alkynovititanate or acrylic titanate may be mixed and contained.

Further, the transparent paint of the present invention can be applied by a general paint application method, but good results can be obtained when applied by a spray method, a bar code method, or a doctor blade method.

Next, the reason why the sb content, average particle size, and mixing ratio of the conductive fine powder in the transparent paint of the present invention are limited to the above-mentioned values will be explained.

(a) Sb content If the Sb content is less than 0.1% by weight, the electrical resistance is high and the desired good conductivity cannot be secured, and the antistatic ability is also insufficient. If it is contained in the powder, the white color of the fine powder will be lost and it will become bluish, and when it is mixed into paint, the color tone and transparency will be impaired, so its content should be reduced to zero. The amount was limited to .1 to 20% by weight.

(1) Average particle size If the average particle size exceeds 0.4 μm, the transparency of the paint will be impaired when it is mixed into the P1 paint, which scatters a lot of visible light. 4μm
The average particle size must be as follows.

Incidentally, the average particle size of the conductive fine powder in the transparent paint of the present invention is as follows: First, the average particle size of the conductive fine powder in the transparent paint of this invention is as follows:
In a cc polyethylene cylindrical container, the fine powder: 5
I and 40 cc of water were inserted together with 50 sintered alumina balls of approximately 10 diameters, and the container was heated to 40 Or.
After rotating at a rotation speed of p and m for 10 hours, the contents except the sintered alumina balls were placed in a container of a centrifugal sedimentator,
The powder is sedimented while changing the rotation speed and rotation time of the centrifugal sedimentator, the weight of each sedimented powder is measured, a particle size distribution is created based on the measurement results, and the cumulative value of 50% of this particle size distribution is averaged. It was determined by the particle size method.

If the proportion of the fine powder mixed with the resin, which is the main component of the paint, is less than 5% by weight, the relative proportion of the resin is 95% by weight.
If it becomes too high, the electrical resistance of the coating film formed is high, and the desired good conductivity and antistatic ability cannot be obtained. On the other hand, when it exceeds 90% by weight, the relative proportion of resin is 1
If the amount is less than 0% by weight, the transparency of the resin will be impaired.
90% by weight, resin: 95-10% by weight.

Moreover, the conductive fine powder of this invention is alcohol.

A solution of tin chloride (hereinafter referred to as 5nC14) and antimony chloride (hereinafter referred to as 5bC43) dissolved in one or more mixtures of hydrochloric acid and acetone is added to heated water, and sb It can be manufactured by a method of precipitating gold-containing SnO2. In addition, Sn
The sb-containing 5N02 powder manufactured by known methods such as the method of firing O2 powder and the sb compound, or the method of mixing the Sn compound and the sb compound and then firing, all have an average diameter exceeding 0.4 μm. It has a particle size,
Therefore, in these known methods, the 0.
It is not possible to produce conductive fine powder with an average particle size of 4 μm or less.

Next, the conductive transparent paint of the present invention will be specifically explained with reference to Examples.

Example water: 3000 cc was heated and maintained at a temperature of 90°C,
While vigorously stirring, 8nC14 and 5bcz in the amounts also shown in Table 1 were added to a solution consisting of one or more of alcohol, hydrochloric acid aqueous solution, and acetone respectively shown in Table 1. and are slowly injected over a period of 4 hours to precipitate sb-containing 5N02 powder, and then the sb-containing SnO2 powder is separated by F, washed, and subsequently improved in crystallinity. In the air, at a temperature of 500°C.
The conductive fine powder obtained as a result of time-holding heat treatment is subjected to pretreatment under the conditions shown in Table 1, and then blended into the paint composition shown in Table 1, 1
Coatings according to the invention 1 to 5 were each prepared by mixing for 09- hours.

Next, the resulting paints 1 to 5 of the present invention were applied to the surface of the nonconductor shown in Table 1 to a thickness also shown in Table 1, and the surface resistance of the resulting coating film was measured. At the same time, we observed its properties.

From the results shown in Table 1, it can be seen that coatings 1 to 5 of the present invention all have excellent conductivity and therefore have excellent antistatic ability, and can form coatings that do not impair the color tone of the nonconductor. It is clear that it is possible to form a

”As in the series, the paint of this invention has excellent conductivity,
In addition, it is possible to form a coating film that has antistatic ability and transparency that does not impair the color tone of the base material. When used in applications such as this, it exhibits extremely superior performance.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuo 11-

Claims (1)

[Claims] A conductive fine powder containing 0.1 to 20% by weight of antimony, with the remainder substantially consisting of tin oxide, and having an average particle size of 0.4 μm or less is used as the conductive fine powder. :
A conductive transparent paint characterized by containing 5 to 90% by weight of resin, which is a main component of the paint, and 95 to 10% by weight.