JPS5918769A - Paste for transparent conductive film formation - Google Patents

Abstract

PURPOSE:To obtain titled paste capable of forming film, on an insulated base such as of glass, of low electrical resistance and high transparency and adhesiveness, by incorporating a paste containing an organometallic compound convertible to transparent conductive metallic oxide by sintering, with a high- temperature sublimable organic dye sparingly soluble to organic solvents. CONSTITUTION:The objective paste can be obtained by incorporating a mixture comprising (A) an organometallic compound convertible to transparent conductive metallic oxide by sintering [e.g., trisacetyl acetonate indium (III)], (B) an organic solvent (e.g., terpineol), and (C) a binder (pref. a deacidified nitrocellulose) with (D) an organic dye sparingly soluble to organic solvents, with nearly all of it sublimed at <=300 deg.C, little remained at >=300 deg.C, and no residue at >=500 deg.C (e.g., butyl carbitol). USE:Semiconductor elements, liquid crystal displays, electrochromic displays, conductive films for deicing window glass, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method of forming a transparent reproducible film made of a flexible oxide with excellent N-density onto an insulating substrate such as glass or ceramics into a desired shape by screen printing and firing. The present invention relates to a paste for forming a transparent 24-diameter film.

In formed on an insulating substrate such as glass or ceramics,
It is well known that oxide plate films of Sn, Sb, Cd, etc. have high transmittance and good conductivity, and are used in semiconductor devices, liquid crystal display devices, electrochromic display devices, etc. In recent years, the range of its applications has been expanding more and more, such as being used as an anti-icing Ichikawa conductive film for window glass and the like. Methods for forming such a transparent metal oxide coating include chemical spraying, vacuum evaporation, dipping, and
There is a double printing method, etc.

The chemical spray method is advantageous for obtaining a ruptured film with a relatively large area, but it is not suitable for obtaining a film with a fine and complex shape.
Extra work such as etching 1'! not necessary and economical. The vacuum evaporation method has recently developed the mask evaporation method, eliminating the need for etching treatment (l-1'), but the process is batch-type, making it difficult to mass-produce. However, the properties of the film formed are significantly inferior to those of the former method, and etching treatment is also required, making it impractical.On the other hand, the screen printing method does not have such problems;
It has the advantage that it can be obtained in the desired shape by printing and firing, and there is no need for waste liquid treatment associated with photo-treatment of eratin. However, in the past, the stability of the paste itself for forming a transparent turtle-conducting film was not good, and the workability during screen printing was also poor, resulting in the inability to stably print particularly fine patterns on gold.

In other words, conventionally, this yuzu paste was made using occhi/L/
rx'l Indium C (CyHsCOt)s In)
Organic acid indium soap and other organic metal compounds with strong ionic bonding properties were used. However, they are easily hydrolyzed, and when made into a paste, they gel quickly, chemically change relatively easily, and the paste itself is not stable.
This caused poor workability during screen printing. My father used to use ethyl cellulose as the binder for the paste using the organometallic compound.
When fired at 0°C, the binder does not burn completely, and as a result, the specific resistance of the glands formed increases, resulting in a film with weak film formation strength.The present inventors have made every effort to eliminate these drawbacks. As a result of repeated research, we have found that, for example, acetylacetone (Hacac) is a compound that forms a metal oxide film by firing.
trisacetylacetonatoindium (g
(In(acac), ) or other coordinated organic indium complexes or resistance value? As a frequently used tin compound,
For example, dimethyltinacedope ((CHII)!5n
It has been found that good results can be obtained by increasing the stability of the paste by using a coordinated organotin complex such as (acac). or,
We have found that by using nitrocellulose as the cellulose compound used as a binder, a film with high adhesion strength and low resistance can be obtained.

However, when nitrocellulose was used, the paste life was shorter than when ethylcellulose was used, and problems with workability during screen printing still remained. Therefore, the present inventors have found that properties can be improved by using nitrocellulose that has been further deoxidized and a mixed solvent of butylcarpitol, butylcellosolve, benzyl acegate, and dimethylphthalate V-) as an organic solvent. I tried to improve the printability, but 1 was not enough, especially.
There remained a problem in printability when performing full screen printing of a fine pattern of about 0.1 mm. In order to solve all of these problems, the present inventors created a paste containing a whole organic compound, an organic solvent, and a binder. '+1' Characteristics can be greatly improved by adding methyl group-substituted monoazo-based Myotsuki pigments that are poorly soluble in organic solvents, burn almost completely at high temperatures of around 400°C, and do not contain alkali ions or metal components. I discovered that.

As for the properties required of such organic pigments, it is desirable that they meet all of the following conditions. That is, (1) It is poorly soluble in the organic solvent used for paste preparation, and its solubility is about 0.2 wt% or less.

■ The weight starts to change by 1v before 300°C, and there is very little residual content as a strong proboscis at 300°C, and there is no residual content at 500°C.

■ Items that have poor reactivity with the paste composition.

■ Alkaline ion, violet component Kinnomiya 1 Numono.

It is. It has been found that it is easy to satisfy all of the conditions (■, ■, and ■) in the Ail organic pigment, and the characteristics as described above are improved, but since the condition (■) is not completely satisfied, the M machine The characteristics were slightly inferior to those of a film formed from a paste to which no pigment was added.

゛ The present invention eliminates the above-mentioned drawbacks and provides good coating properties,
In other words, the coating 1+Q has low resistance and good transparency and adhesion.
The present invention was made with the object of providing a base If for forming a transparent conductive film which has good paste stability, fine pattern printability, and printing workability as in the past.

In order to achieve this object, the present invention provides a paste containing an organometallic compound, an organic solvent, and a binder that is sparingly soluble in the organic solvent, most of which disappears by sublimation at a temperature of 300°C or lower, and at a temperature of 500°C. It is characterized by the addition of a sublimable organic dye that has zero residue, has poor reactivity with the paste composition, and does not contain alkali ions or metal components.

That is, in the case of organic pigments where the process of disappearance due to temperature is combustion, it is difficult to achieve a final state of zero residue, and this is considered to have an adverse effect on the properties of the coating. The present invention focuses on this and significantly improves the film properties by hypersensitively adding a sublimable organic dye that can be easily produced in a state of zero residue.

The paste to which all the sublimable organic dyes are added is prepared as follows. That is, a prudent indium compound such as In(acac)1 which is soluble in an organic solvent and becomes an oxide after firing, and (CH,) and 5n(acac) for adjusting the resistance value.
An organic tin compound such as , an organic solvent, and an inder are mixed respectively.Then, the sublimable organic dye is added.The organic dye must be added before adding the inder. Good too.

Examples of organic solvents include low-boiling point alcohols such as terpineol, 2-ethylhexanol, and benzyl alcohol, boiling point esters such as benzyl acetate, carpitol acetate, and dimethyl phthalate, and high-boiling point alcohols such as butyl cellosolve, calpitol, and butyl carpitol. Alcohol ethers, etc. are used. Further, as the binder, deoxidized nitrocellulose is suitable.

A more detailed explanation will be given below based on examples.

Example 1 In order to examine the relationship between the type of sublimable organic dye added to the paste and printability and film properties, a mixed organic solvent of each sublimable organic dye (butyl carbitol: butyl cellosolve: benzyl acetate: dimethyl phthalate = 4 :2:2:
2) was investigated. Next, in order to create a paste for examining printability and film characteristics, In(aca
c) 32.69wt, (CH,,)2Sn(acac
), o, 31 wt %, the above-mentioned mixed organic solvent in the bath medium, and 13.8 wt % kumquat in the deacidified cellulose 80 seconds as the binder, and the solubility of the sublimable Miso dye ( (wt) Add 11 wt % to make a complete paste. On the other hand, a 0.1 dragon pattern is created on a 250-mesh screen plate made of stainless steel net. The prepared paste il-screen printing was performed using the screen plate, the printability was examined, and further 150
The film was pre-dried at 500° C. for 20 minutes and fired at 500° C. for 30 minutes, and the characteristic sound of the resulting film was examined. The solubility, A1i++ properties, and film characteristics are summarized in Table 1 below. The solubility test in the figure was conducted at room temperature, and a
Those with 98% or more are marked with ◎, those with 95 to 98% are marked with ○, those with 90 to 95% are marked with Δ, and those with less than 90% are marked with X. For comparison purposes, a sublimable organic dye whose thermal conditions are not satisfied and a combustion type Reli are shown in Comparative Example 1 for the former, and Comparative Examples 2 and 3 for the latter. Furthermore, Comparative Example 4 shows an example in which no organic dye or the like was added.

y Bottom margin As is clear from this table, it can be seen that the properties obtained when all of the sublimable organic dye of Example 1 was used were excellent. The reason for this is that the solubility of the organic dye in organic solvents is relatively low in terms of printability, and the fact that the M4 cutting dye almost scatters in a trench at 300 degrees Celsius. This can be explained by the fact that the residue becomes completely zero at 500°C. To explain the latter more clearly, we investigated the thermal behavior of each organic dye and pigment, and the results are shown in the figure. In addition, this combustion test was conducted at a heating rate of 1! lt5
It was carried out at ℃/min. As is clear from this figure, the organic pigment of Comparative Example 3 had a considerable amount of residue at 500° C., and it can be seen that the film properties were all quite poor. On the other hand, in the other three cases, the residual l ratio at 500°C is zero, but 30
Comparing all the residues at 0°C, the order is Example 1 followed by Comparative Example 2 (Comparative Example 1). This difference is considered to influence the properties of the formed film. This is because film formation is 300
This is because CAiJ (starts from +). Therefore, the results in Table 1 are supported by the results in the figure. It was found that the paste properties were significantly improved by adding dye.

Example 2 In the above example, a sublimable organic dye was selected that satisfies the conditions for universal use in the pasting wave film forming paste. Paste 7 was prepared with almost the same composition as in Example 1, but the amount of organic dye added in Example 1 was completely changed, and each item was examined in the same manner as in the previous example. The results are shown in Table 2.

Table 2 From this table, it is clear that mv, addition @ 1.0 to 10 wl gives excellent printability and film properties.

The present invention has the above-mentioned simple structure, has good paste stability, can print fine patterns, has good confectionery properties, is transparent with good coating properties, and is resistant to 1Plj breakage. A forming paste can be provided.

[Brief explanation of the drawing]

The figure is a combustion characteristic diagram comparing the combustion characteristics of a sublimable organic dye according to an example of the present invention and a conventional combustible organic pigment. Ge? (': Losing weight (°C)

Claims (1)

[Claims] (1) A paste containing an organometallic compound, an organic bath medium, and a binder that becomes a transparent conductive metal oxide by firing,
A paste for forming a transparent tetragonal film, which is characterized by the total addition of an organic dye that is sparingly soluble in the M solvent and sublimes at high temperatures. (2. In claim 1, most of the organic dye that sublimes at high temperatures is scattered at temperatures below 300°C;
A paste for forming a transparent 24-diameter film, characterized in that the residue is almost zero at temperatures higher than 00°C, and the residue is zero at least at 500°C.