JPH048774A - Inorganic transparent electroconductive paint composition and production of electroconductive coating film - Google Patents

Abstract

PURPOSE:To obtain the subject composition useful for an OA instrument, etc., having excellent transparency, resistance to scratch and to solvent, containing a composition of tetraalkoxytin, etc., dissolved in lower alcohol, a specific siloxane polymer and a solvent. CONSTITUTION:The objective composition contains (A) a composition composed of tetraalkoxytin or a mixture of tetraalkoxytin and trialkoxyantimony (preferably 0.1-1.0mol trialkoxyantimony to 1mol tetraalkoxytin) dissolved in lower alcohol (e.g. methanol), (B) a siloxane polymer having >=1000 weight-average molecular weight obtained by hydrolyzing-condensation of tetraalkoxysilane (using amount is preferably 5-2000 pts.wt. solid component to 100 pts.wt. the component A) and (C) a solvent (e.g. methanol). Besides, the composition is applied on a substrate face and cured to afford an electroconductive coating film having excellent resistance to solvent.

Description

[Detailed Description of the Invention] (Industrial Application Field) Himi BA relates to inorganic transparent conductive coating compositions, and more specifically, to forming highly transparent conductive films on substrates such as glass and ceramics. The present invention relates to a suitable inorganic transparent conductive coating composition and a method for producing a conductive coating film using the same.

(Prior Art) In recent years, conductive coating films have been formed on the glass surfaces of television cathode ray tubes and displays of various office automation equipment for the purpose of preventing static electricity.

This method involves applying organic substances such as alcohol polymers, higher alcohols, and surfactants, but this method has poor solvent resistance and scratch resistance, so the antistatic effect has a short lifespan and is not practical. . As another method, attempts have been made to form antistatic films using inorganic materials. For example, in Japanese Patent Application Laid-open No. 62-187188,
After hydrolyzing a hydrolyzable tin compound or an antimony-doped tin compound to obtain fine particles, water is removed.

A method of dispersing in ethanol and firing is disclosed. However, this method has the disadvantage that transparency is limited because fine particles are dispersed, and scratch resistance is poor because no binder resin is blended. Also, JP-A-6
2-252481 discloses a method using conductive tin oxide powder and a binder resin, but this method also uses fine powder and has poor transparency.
Since the tanoku inder resin is an organic polymer, it has the disadvantage of poor solvent resistance and scratch resistance.

In such conventional methods, tin oxide or antimony-doped tin oxide powder as a conductive component is first generated as fine particles by mechanically or chemically dissolving it, and it is difficult to make it into primary particles. be.

Furthermore, even if primary particles can be formed, the transparency is limited and it is difficult to prevent reagglomeration.

In addition, since an organic resin is used as a binder, it has poor scratch resistance and bath agent resistance.In addition, as an inorganic binder, monomers such as tetraethoxysilane, ethyl silicate 40 (trade name manufactured by Colcoat Co., Ltd., siloxane oligomer), etc. Even when oligomers such as those having a weight average molecular weight of about 1000 are used, they have the disadvantage of poor scratch resistance.

(Problems to be Solved by the Invention) An object of the present invention is to solve the problems of the prior art, and to provide an inorganic transparent conductive coating composition with excellent conductivity, transparency, solvent resistance, and scratch resistance. An object of the present invention is to provide a method for producing a four-electrode coating film using the present invention.

(Means for solving problems) The present invention is.

■ A composition in which tetraalkoxytin or a mixture of tetraalkoxytin and trialkoxyantimony is dissolved in a lower alcohol.

(B) An inorganic transparent conductive coating composition comprising a siloxane polymer with a weight average molecular weight larger than 1000 obtained by hydrolyzing and condensing a tetraalkoxysilane and (C) an @ agent, and coating this composition on a substrate surface. The present invention relates to a method for producing a conductive coating film that is cured.

Among the lower alcohols used in the composition of the present invention, methyl alcohol, ethyl alcohol, butyl alcohol, isopropyl alcohol, etc. are used. Two or more of these may be used in combination.

To dissolve, stir at room temperature or heat.

Use ultrasound etc.

In the present invention, it is preferable to use a mixture of tetraalkoxytin and trialkoxyantimony from the viewpoint of the electrical conductivity of the coating film.

The ratio of tetraalkoxytin and trialkoxyantimony to be used is preferably in the range of 17 mols of tetraalkoxytin to 0.1 to 1.0 mols of trialkoxyantimony, in view of the conductivity and transparency of the coating film.

Examples of the tetraalkoxytin include tetramethoxytin, tetraethoxytin, and tetrabutoxytin, and tetraethoxytin is preferred from the viewpoint of the smoothness and scratch resistance of the coating film.

Examples of trialkoxyantimony include trimethoxyantimony, triethoxyantimony, tributoxyantimony, etc., and triethoxyantimony is preferred from the viewpoint of the smoothness and scratch resistance of the coating film.

Siloxane polymer (B) fl used in the present invention.

It is a polymer having a weight average molecular weight of more than 1000 obtained by hydrolyzing and condensing tetraalkoxysilane. This hydrolytic condensation is carried out by a known method using a catalyst such as phosphoric acid. As a tetraalkoxylan, carbon number is 1
Those having ~5 alkoxide groups are used. If the weight average molecular weight of the siloxane polymer is less than 1000, the scratch resistance of the coating film will be poor. Since it has no effect on the scratch resistance of the coating film, a low molecular weight material having a weight average molecular weight of 1000 or less, which is less than 50% by weight of the total polymer, may be mixed with the siloxane polymer.

From the viewpoint of scratch resistance and conductivity, the blending ratio of the above-mentioned prison component and component (B) is such that the solid content of component (B) is 5 to 2000 parts by weight per 100 parts by weight of the solid content of component (1). It is preferable to use the range.

Solvents (C) used in the present invention include methyl alcohol, ethyl alcohol, inpropyl alcohol, phthyl alcohol, diacetone alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, calpitol, ethylene glycol, and diethylene glycol sodium alcohol. solvents, acetone, methyl ethyl ketone,
Ketone solvents such as methyl isobutyl ketone, ethyl acetate.

Examples include ester solvents such as butyl acetate, various chlorogenic solvents, and these can be used alone or in combination. Among these, ethyl alcohol is preferred.

The solid content of the inorganic transparent conductive coating composition of the present invention is as follows.

From the point of view of conductivity, it is preferable to use 0.01% by weight or more, so the amount of the solvent (C) used is such that the solid content of the two compositions is 0.01% by weight or more. be done.

The inorganic transparent conductive coating composition of the present invention is coated onto a substrate surface such as glass or ceramic by a general coating method such as spin cord, spray coating, roll coating, or tip coating at a temperature of, for example, 120°C or higher. It hardens in 10 minutes or more to form a conductive coating. The film thickness at this time is that of crack resistance. ) is preferably 20 μm or less.

(Example) The present invention will be explained in detail with reference to nine examples below.

Parts in the examples mean parts by weight.

Example 1 (1) Preparation of conductive liquid A Tetraethoxytin 26.919 (0.09 mol).

Triethoxyantimony Z579 (0.01 mol) and 560 g of ethanol were placed in a three-bottle flask (No. 11) and dissolved by stirring at 30° C. for 2 hours.

The solid content concentration of this melt was determined at 160° C. for 30 minutes and was found to be 3.0%.

(2) Synthesis of siloxane polymer solution B Tetraethoxysilane 359 and ethyl alcohol 150 gk50
Three 0mg flasks were charged and stirred. This and water 12
A mixed solution of 9 and phosphoric acid O, sg was added dropwise over a period of about 30 minutes, and after one drop was completed, reflux was performed for about 1 hour to obtain a siloxane polymer solution B having a weight average molecular weight of about 6,000.

The weight average molecular weight was determined by high performance liquid chromatography (Pump: C-6000, Rr detector C-3300, manufactured by Hitachi, Ltd.).
, data processor: D-2520) using a low-molecular column (polystyrene equivalent).

The solid content concentration of this solution B was measured at 160° C. for 30 minutes and was found to be 120%.

Conductive liquid A6.79. obtained above. Paint A was obtained by mixing and stirring 6.7 g of furoxane polymer i1MB and 86 g of ethyl alcohol.

Comparative Example 1 30 g of antimony-doped tin oxide powder T-1 (trade name manufactured by Mitsubishi Metals) and 270 g of ethyl alcohol were charged into an attritor filled with 300 d of glass beads having a diameter of 1.0 mm, and mixed for about 10 hours. A T-1 dispersion was obtained.

Paint B was obtained by mixing and stirring 20 g of this T-1 dispersion, 86.79 g of the siloxane polymer solution of Example 1, and 919 g of ethyl alcohol.

Comparative Example 2 Conductive liquid A6.79 of Example 1. Tetraethoxysilane 6
．． Paint C was obtained by mixing and stirring 79 and ethyl alcohol 869.

Comparative Example 3 Conductive liquid A6.79. Ethyl silicate 40 (trade name, manufactured by Colcoat Co., Ltd., siloxane oligomer, weight average molecular weight approximately 1000) 6.79 and ethyl alcohol 869 were mixed and stirred to obtain a paint.

<Test example> The obtained paints A-D were applied on a glass plate at 60 rpm at 25 rpm.
Spin coded for seconds and then cured at 160° C. for 60 minutes. Using the obtained test piece, surface resistance, transmittance at 550 nm, pencil hardness, and ethyl alcohol resistance were evaluated. The results are shown in Table 1.

Table 1 (Effects of the Invention) The inorganic transparent conductive coating composition of the present invention has excellent transparency because the conductive component is not a dispersion of metal oxide particles, and also uses a high molecular weight ethyl silicate polymer as a binder. Because of this, it is possible to obtain a coating film with excellent scratch resistance and solvent resistance.

≠1 Measured with a Yokogawa Hewlett-Based Card Co., Ltd. High Resistance Meter.

Absorbance at 550 nm was measured using an Ao2 UV absorption photometer.

Training 3: Conducted in accordance with JIS C3003.

%4 Immersed in ethyl alcohol at room temperature for 24Uj.

Changes in appearance were visually observed.

From Table 1, the inorganic transparent conductive coating composition of the present invention is highly transparent, and the resulting conductive coating film has low surface resistance.
Excellent scratch resistance due to hard pencil hardness, -! It is shown that it has excellent solvent resistance.

Claims (3)

[Claims] 1. (A) a composition in which tetraalkoxytin or a mixture of tetraalkoxytin and trialkoxyantimony is dissolved in a lower alcohol; (B) a siloxane polymer with a weight average molecular weight greater than 1000 obtained by hydrolyzing and condensing tetraalkoxysilane; and (C) an inorganic transparent conductive coating composition comprising a solvent. 2. 2. The inorganic transparent conductive coating composition according to claim 1, wherein the trialkoxyantimony content is 0.1 to 1.0 mol per mol of tetraalkoxytin. 3. 2. The inorganic transparent conductive coating composition according to claim 1, wherein the solid content of component (B) is 100 to 2000 parts by weight relative to 100 parts by weight of component (A). 4. A method for producing a conductive coating film, which comprises coating the inorganic transparent conductive coating composition according to claim 1 on a substrate surface and curing the composition.