JPH0212461B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to indium trisalkyl acetoacetate useful for forming transparent conductors and a method for producing the same.

BACKGROUND OF THE INVENTION In recent years, indium oxide films have come to be used as transparent conductive films for liquid crystal devices, and the range of applications has been expanding to take advantage of the properties of indium as a metal.

Methods for forming such an oxide film include a chemical spray method, a vacuum evaporation method, a screen printing method, and the like. Although the chemical spray method is advantageous in obtaining a film with a relatively large area, it is economically disadvantageous because extra steps such as etching are required to obtain a film with a fine and complex shape. The vacuum evaporation method has recently developed into a mask evaporation method and no longer requires etching, but since it is a batch method, it is not suitable for mass production. The screen printing method has the advantage that it does not have the above-mentioned problems, that it can easily obtain the desired shape by printing and firing, and that there is no need for waste liquid treatment associated with the etching process.

However, conventional pastes for forming transparent conductive films containing indium compounds do not have good stability themselves, resulting in poor workability during screen printing, and the conductivity of the formed films also varies widely. There was a drawback.

That is, conventional indium compounds for forming transparent conductors include organic acid indium such as indium octylate [(C ₇ H ₁₅ CO ₂ ) ₃ In],
Indium trisacetylacetonate [In
(acac) ₃ ] is used.

Indium organic acids are generally easy to hydrolyze;
In addition, when made into a paste, it has the disadvantage of being relatively easily chemically changed, such as promoting gelation of the paste.For this reason, the life of the paste containing indium organic acid is short, and the workability during screen printing is It is a cause of deterioration.

Problems to be Solved by the Invention The present invention eliminates the drawbacks of conventional indium compounds for forming transparent conductors, that is, provides an indium compound with excellent chemical stability and easy screen printing operation, and The present invention provides a method for manufacturing the same.

Means to solve the problem The above problem is solved by the following structural formula (1): In the above formula, R represents an alkyl group having 5 to 12 carbon atoms.

In addition, the above indium trisalkyl acetoacetate has the following structural formula (2): Indium triisopropylate represented by and the following structural formula (3): [In the above formula, R is as defined above] It is produced by the method of the present invention, which is characterized by reacting with an alkyl acetoacetate represented by the following.

Effects and Examples Indium trisalkyl acetoacetate according to the present invention has good chemical stability and good solubility in organic solvents. For this reason, indium trisalkyl acetoacetate,
For example, it can be uniformly dissolved at a high concentration in an organic solvent such as benzene or ethyl acetate, and the resulting paste can be used for forming a transparent conductor, such as a film.

The indium trisalkyl acetoacetate of the present invention has pentyl (amyl), hexyl, heptyl, octyl, nonyl,
It can have decyl, undecyl or dodecyl (lauryl) groups; preferred compounds include indium trisoctylacetoacetate and indium trislaurylacetoacetate.

In the method of the present invention, 1 mole part of indium triisopropylate is reacted with 3 mole parts of alkyl acetoacetate to obtain 1 mole part of indium diacetylacetonate moisopropylate.

Alkyl acetoacetate has pentyl (amyl), hexyl, heptyl,
It has an octyl, nonyl, decyl, undecyl, or dodecyl (lauryl) group. Preferred alkyl acetoacetates include octyl acetoacetate and lauryl acetoacetate.

In the above reaction, a desired amount of indium triisopropylate may be dissolved in an organic solvent, and a predetermined amount of alkyl acetoacetate may be added dropwise to this solution. Alternatively, predetermined amounts of indium triisopropylate and alkyl acetoacetate may be dissolved separately in an organic solvent, and these two solutions may be mixed.

In any of the above reaction operations, the reaction system is maintained at a predetermined temperature and stirred until the reaction is completed. Once the reaction is complete, the organic solvent and the produced isopropyl alcohol are removed from the reaction system under normal pressure.
Alternatively, the target compound is obtained by distilling and removing under reduced pressure.

In the above reaction, the reaction temperature is not particularly limited, but generally a temperature of room temperature or higher and 100°C or lower is preferred. Even if the reaction temperature is made higher than 100°C, there is no particular effect and it becomes economically disadvantageous. Within the above reaction temperature range, the reaction time is from several minutes to several hours.

The solvent used in the reaction of the method of the present invention is particularly one that has poor chemical reactivity with indium triisopropylate, alkyl acetoacetate, and indium trisalkyl acetoacetate and has excellent solubility. Although there is no limitation, it is generally preferable to use at least one selected from benzene, toluene, xylene, and the like.

As mentioned above, after the reaction is completed, the organic solvent and isopropyl alcohol are distilled off from the reaction system under normal pressure or reduced pressure. The boiling point of the solvent used is
When the temperature is higher than the decomposition point of indium trisalkyl acetoacetate, the distillation removal operation is preferably carried out under reduced pressure at a temperature lower than the decomposition point of the target compound.

The indium tris-alkyl acetoacetate of the present invention is easily dissolved in an organic solvent and a highly concentrated paste can be easily obtained, so this paste is particularly suitable for forming a transparent conductive film of a liquid crystal element.

In order to obtain such a paste for forming a transparent conductive film, the indium trisalkyl acetoacetate of the present invention may be dissolved in an organic solvent such as benzene, ethyl acetate, or methyl ethyl ketone at a concentration of 2 to 10% by weight. . At this time, if an organic complex compound of tin, such as dibutyltin acetate, is added to the above paste as a resistance value adjusting agent so that the atomic ratio of tin to indium is 5 to 30%, it is possible to conduct a transparent conductive material with a lower resistance value. A transparent film, such as an electrode, is obtained.

Example 1 A 500ml four-necked flask with a stirrer, thermometer,
A dropping funnel and a cooling tube with a drying tube were installed, and 35.05 g (120 mmol) of indium triisopropylate and benzene were placed in this flask.
300 ml was added, and while stirring at room temperature, 97.35 g (360 mmol) of lauryl acetoacetate was added dropwise from the dropping funnel over 5 minutes. After the dropwise addition was completed, the reaction mixture was heated to 80°C and refluxed for 30 minutes, then the insoluble matter was filtered off, the benzene and the produced isopropyl alcohol were distilled off, and the filtrate was concentrated under reduced pressure to remove the residue. 106.33 g (yield: 96.1%) of indium trislaurylacetoacetate was obtained. The NMR measurement results of this product were as follows. ¹ H NMR (CDCl ₃ ) δ (ppm) 0.88 (t, 9H) 1.26 (brs, 60H) 1.96 (s, 9H) 4.02 (t, 6H) 4.83 (s, 3H) Also, the indium content of this product is 12.7% as determined by chelate titration (theoretical value 12.43)
%), and its infrared characteristic absorption was as follows.

Chelate C=O structure: 1602 cm ^-1 Chelate C=C structure: 1518 cm ^-1 Example 2 The same operation as in Example 1 was performed. However, indium triisopropylate and lauryl acetoacetate were separately dissolved in 150 ml of benzene,
Both solutions were mixed and reacted in a flask.

The yield of the obtained product was 96%, and this product showed the same NMR measurement results, indium content, and infrared characteristic absorption as described in Example 1.

Example 3 A 500ml four-necked flask with a stirrer, thermometer,
A dropping funnel and a cooling tube with a drying tube were attached, and 35.05 g (120 mmol) of indium triisopropylate and 300 ml of benzene were placed in this flask, and while stirring at room temperature,
From the dropping funnel, 77.15 g of octyl acetoacetate.
(360 mmol) was added dropwise over 5 minutes. After the dropwise addition was completed, the reaction mixture was heated to 80°C and refluxed for 30 minutes, then the insoluble matter was filtered off, the benzene and the produced isopropyl alcohol were distilled off, and the filtrate was concentrated under reduced pressure. 89.14 g (yield 98.5%) of indium trisoctylacetoacetate was obtained as a residue. The NMR measurement results for this product were as follows. ¹ H NMR (CDCl ₃ ) δ (ppm) 0.89 (t, 9H) 1.27 (brs, 36H) 1.96 (s, 9H) 4.08 (t, 6H) 4.87 (s, 3H) In addition, the indium content of this product is 15.4% as measured by chelate titration (theoretical value 15.21
%). Further, its infrared characteristic absorption was as follows.

Chelate C=O structure: 1602 cm ^-1 Chelate C=C structure: 1518 cm ^-1 Effects of the invention The indium trisalkyl acetoacetate of the present invention exhibits good stability and solubility in organic solvents, and is therefore suitable for forming transparent conductive films. It is useful for

Claims (1)

[Claims] 1. Structural formula (1) below: [However, in the above formula, R represents an alkyl group having 5 to 12 carbon atoms.] Indium trisalkyl acetoacetate. 2. Indium trislaurylacetoacetate in the compound according to claim 1. 3. Indium trisoctylacetoacetate in the compound according to claim 1. 4 Structural formula (2) below: Indium triisopropylate represented by and the following structural formula (3): [However, in the above formula, R represents an alkyl group having 5 to 12 carbon atoms] The following structural formula (1) is characterized by reacting with an alkyl acetoacetate represented by: [However, in the above formula, R is as defined above.] A method for producing indium tris-alkyl acetoacetate. 5. The method of claim 4, wherein the alkyl acetoacetate is selected from lauryl acetoacetate and octyl acetoacetate. 6. The method of claim 4, wherein the reaction of the indium triisopropylate with the alkyl acetoacetate is carried out at a temperature from room temperature to 100°C.