KR100462511B1 - Transparent conductive ink - Google Patents

Abstract

The present invention relates to a gravure printing aptitude in a transparent conductive ink used when a transparent conductive film is formed by gravure printing on a surface of a multicolor picture or an image printed by offset printing. The present invention aims to provide a transparent conductive ink having excellent blocking resistance, stable conductivity, and excellent clarity of a picture or a color on a surface of a multicolor picture (4) formed by offset printing. It is a transparent conductive ink for forming the transparent conductive film 5 by gravure printing superimposed, It consists of acrylic thermoplastic resin whose glass transition point is 45 degreeC or more, electroconductive powder and a solvent whose average particle diameter is 1 micrometer or less, And 100 to 500 parts by weight of the conductive powder, based on 100 parts by weight of the thermoplastic resin.

Description

Transparent conductive ink

The present invention provides a transparent conductive ink for forming a transparent conductive film by gravure printing by superimposing on the surface of a multicolored picture printed by offset printing on a substrate such as paper. The printed matter imparted with conductivity by the transparent conductive ink of the present invention can be suitably used for educational picture books, educational toys, and the like.

Conventionally, there is a learning textbook printed using conductive ink. As such a teaching material, for example, a problem printed with a non-conductive ink on a base material (1), such as a study problem book (FIG. 1) disclosed in Japanese Unexamined Utility Model Publication No. 48-20540 (question) The printed matter is composed of the part 2 and the selection check mark 3 printed with conductive ink (or non-conductive ink). In this case, a plurality of answers are printed for one question, check marks are written for each question, and only the check marks for correct answers are printed with conductive ink. The learner can check the correct answer or the wrong answer by pressing the check mark with a check light pen (not shown) which causes the lamp to be turned on only when the conductive ink layer obtains electrical conduction. Therefore, the teaching material using the conductive ink has the advantage that it is possible to quickly self-check and continue to be used repeatedly.

By the way, as the conductive ink used in the above-described printed matter, carbon powder or silver powder is used as the conductive component, but there is no particular problem in printing only the check mark of the teaching material as described above, but for learning for infants requiring various image patterns When printing a picture book or the like, it is not always easy to print a multicolor picture or image freely with the conductive ink itself. Moreover, since the said electroconductive ink is opaque, even if it prints on a multicolor picture or image, a picture or image of a desired color cannot be obtained.

Japanese Laid-Open Patent Publication No. 7-57545 discloses a printing ink layer, a barrier layer, and a transparent conductive ink layer of letters or pictures in order from the printing substrate side on the printing substrate. A transparent conductive printed matter having a conductive portion formed by lamination has been disclosed, and a method of forming a transparent conductive film by gravure printing with a transparent conductive ink is superimposed on the surface of a multicolor picture formed by offset printing.

The standard operating conditions of gravure printing are characterized by high speed printing (30 to 120 sheets per minute) and low temperature and short time drying (30 seconds to 60 seconds at 60 ° C). Since the printed matter is stacked up to bookbinding (5000-10000 sheets, height 1m, bottom pressure 10kg / cm2), the transparent conductive ink provided by gravure printing is suitable for gravure printing under such working conditions. The challenges of blocking, stable conductivity, and ensuring the clarity of the picture and the color of the picture must be overcome.

In addition, as a gravure printing ink, the solvent is usually composed of toluene, and the resin of the binder is composed of toluene. Soluble resins are generally selected. The chlorinated rubber resins may cause pollution problems when the chlorine contained in the composition is incinerated.Alkyd resins are poor in dryness and require the use of initial screens. There is a problem that ketone-based or ester-based solvents, which dissolve the aqueous solution, become essential components, and the screen may be precipitated by the reduction of the ester-based or ketone-based solvents in the solvent composition during printing.

In addition, the above publication has a composition comprising 10.5% of a polyester resin, 24.5% of a mixture of tin oxide and antimony pentoxide, 50% of toluene, and 65% of a mixed solvent of 50% methyl isobutyl ketone as a transparent conductive ink. Although it is disclosed, there is a problem that the transparent conductive ink is also poor in dryness, and the solvent tends to remain in the drying ink and the viscosity change is large due to the change in solvent composition by using a mixed solvent.

The present invention provides stable gravure printing aptitude, blocking resistance, and conductivity in a transparent conductive ink used for forming a transparent conductive film by gravure printing on the surface of a multi-colored picture or image printed by offset printing. And it is a subject to provide the transparent conductive ink which is excellent in the vividness of a picture and an image color body.

The transparent conductive ink of the present invention is a transparent conductive ink for forming a transparent conductive film by gravure printing overlaid on the surface of a multicolored figure formed by offset printing. The transparent thermoplastic ink has a glass transition point of 45 DEG C or more and an average particle diameter. It is composed of a conductive powder and a solvent of 1㎛ or less and characterized by containing 100 to 500 parts by weight of the conductive powder with respect to 100 parts by weight of the thermoplastic resin.

2 is a cross-sectional view of the conductive printed article according to the embodiment using the present invention conductive ink. That is, the transparent conductive layer 5 is formed on the surface of the printing layer 4 on the base material 1 using the conductive ink of the present invention.

The acrylic thermoplastic resin of the present invention is a methylacrylic acid resin, an ethylacrylic acid resin, an isobutylacrylic acid resin, a butylacrylic acid resin, a methylmethacrylic acid methylmethacrylic acid resin, ethylmethacrylic acid resin, isobutylmethacrylic acid resin, butylmethacrylic acid resin, ethylmethacrylic acid-ethylacrylic acid ) Copolymer resin, methylmethacrylic acid-styrene copolymer, methylmethacrylic acid-ethylacrylic acid copolymer resin, urethane modified acrylic resin, polyester ) Modified acrylic resin etc. are illustrated and glass transition point (Tg) is 45 degreeC or more. That is, when glass transition point (Tg) is less than 45 degreeC, blocking will generate | occur | produce but this blocking cannot be prevented completely even if it uses a antiblocking agent together. In addition, the glass transition point (Tg) is preferably 105 ° C. or lower, and when the temperature exceeds 105 ° C., the coating becomes soft, which is not preferable.

As the conductive powder, a powder in which tin oxide is used as a main component and doped with a metal having a different valence value, such as antimony, aluminum, or boron, and the composition is used as the substance, for example, mica powder, potassium titanate, and silica. ) Conductive powders such as powder coated with powder, zinc antimonate, indium tin oxide, gold, silver, and copper. The particle diameter of the electroconductive powder needs to be 1 micrometer or less from a transparency point, and it is preferable that a refractive index is small.

The content of the conductive powder is 100 parts by weight to 500 parts by weight, preferably 180 parts by weight to 300 parts by weight with respect to 100 parts by weight of the acrylic resin in order to ensure transparency and conductivity of the coating film. When the conductive powder is less than 100 parts by weight, it exhibits conductivity of 10 ¹⁰ Pa / □ or more and is not suitable for use in the present invention. Moreover, when it exceeds 500 weight part, the transparency of a coating film (evaluated by soaking) will be lost by excess of electroconductive powder, and it will become difficult to obtain a vivid color when it prints on the surface of a picture and a figure.

Examples of the solvent include toluene, xylene, xyl acetate, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, ethyl cellosolve, and the like. You may use it. Toluene-xylene mixed solvent is preferable in view of printability when the temperature is high in gravure printing.

What is necessary is just to mix and disperse | distribute acrylic resin, electroconductive powder, and a solvent using a disperser, such as a ball mill, a sand mill, and three roll mills, as a manufacturing method of the conductive ink of this invention. For small quantities, a paint maker can be used.

Moreover, in this invention, in order to improve the dispersibility of electroconductive powder further, dispersing aids, such as a silane coupling agent and a back surface active agent, can be used together. Moreover, in order to improve blocking resistance and abrasion resistance, wax, fine silica, a fluorine powder, etc. which are generally used for printing inks can be used together.

The conductive ink prepared in this way is gravure printing on the surface of a multi-colored drawing or pattern layer printed on a base paper, synthetic paper including polypropylene, polystyrene, polyvinyl chloride, and synthetic resin film such as polyethyleneterephthalic acid. And, when drying, a conductive film having a film thickness of 0.8 m to 5 m is formed.

The transparent conductive film according to the present invention, a surface resistance (25 ℃) is 10 ⁹ Ω / □ or fewer, preferably 10 currently being put to practical use it is possible to ensure good conductivity of 1 x 10 ⁷ Ω / □ or fewer ⁹ It can be adapted to the check light pen that detects the / ■ and below and the 10 ⁹ Ω / ■ and above.

In addition, the transparent conductive film in the present invention may be 40 or less, preferably 20 or less, as the soaking material (transparency of the coating film).

The transparent conductive ink layer may be beta printed when gravure is printed on the surface of a multicolored dream or a drawing layer, but a line width of 100 μm to several hundred μm or a net point of 50% or more By printing at any), the transparency can be maintained and the picture can be made clear.

In addition, the transparent conductive film in this invention may be gravure printed on the surface of the offset-printed multicolored figure or pattern through a transparent primer layer. The transparent primer layer can provide a barrier effect that prevents the plasticizer and the like contained in the picture or the design layer from transferring to the transparent conductive ink layer, or provide a flat and smooth printing surface with little variation in forming the transparent conductive ink layer. Can be. In order to form such a transparent primer layer, a gravure varnish, an OP varnish for offset, etc. may be used, and the dry film thickness should just be 1 micrometer-10 micrometers.

The transparent conductive ink of the present invention is a transparent conductive ink that is excellent in gravure printing aptitude, blocking resistance, stable conductivity, and vividness of pictures and image color bodies. It is made possible to provide.

Hereinafter, the present invention will be described according to the examples. In addition, the solvent component in the acrylic thermoplastic resin used in the Example is toluene.

(Example 1)

The following composition was added together with 200 g of glass beads (manufactured by Toshiba Barrotini) in a 1 L glass bottle for 4 hours, and dispersed in a paint shaker to an average particle diameter of 1 탆 or less.

● Acrylic thermoplastic resin solution (copolymer of ethyl methacrylic acid and ethyl acrylic acid, Tg 75 ℃, solid content 30%) ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 100 Weight part ● Tin oxide powder (containing antimony pentoxide, average primary particle diameter 0.2㎛) ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ ‥‥‥‥‥‥‥‥‥‥‥ 90 parts by weight

● Toluene ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 70

The obtained transparent conductive ink was measured in toluene with a cup No. 3, adjusted to 20 to 25 seconds, and evaluated using a gravure printing calibrator for each paper.

For evaluation, a printed material (Groscote paper of 148g / m 2 was used) was formed using offset printing, and a part of which was formed with a multi-colored drawing was used. A dry film thickness of about 3 μm) was formed to obtain a test piece.

Using this test piece, evaluation of the conductivity of the drawing part, the vividness of the picture, and the blocking property when the pictures were left to overlap were evaluated, and the results are shown in Table 1.

(Example 2)

Example 1 Replace the entire amount of the acrylic thermoplastic resin solution of the ink with an acrylic resin (isobutyl methacrylate, Tg 50 ° C., solid content 30%), and prepare a transparent conductive ink and a test piece in the same manner as in Example 1. It evaluated and the result was shown in Table 1. Although blocking resistance was inferior to Example 1, it was a practical level.

(Example 3)

Example 1 The total amount of the acrylic thermoplastic resin solution of the ink was replaced with acrylic resin (methyl methacrylate, Tg 105 ° C., solid content 30%), and transparent conductive ink and test pieces were prepared in the same manner as in Example 1 to evaluate the test pieces. The results are shown in Table 1. From Table 1, it turned out that blocking resistance is favorable similarly to Example 1.

(Example 4)

Example 1 In the ink, the total amount of toluene for diluting the thermoplastic resin solution was replaced with xylene. The solvent composition is a mixture of 70 parts by weight of toluene and 70 parts by weight of xylene and is set in anticipation of the printing of high temperature season. In the same manner as in Example 1, a transparent conductive ink and a test piece were prepared to evaluate the test piece and the printability at 30 ° C. The results were excellent in printability at temperature 30, as shown in Table 1.

(Example 5)

Example 1 90 weight part of tin oxide powder of the ink was reduced to 30 weight part, the transparent conductive ink and the test piece were produced like Example 1, and the test piece was evaluated. As a result, as shown in Table 1, the surface resistance value was 10 ⁹ kPa / square band.

(Example 6)

Example 1 90 weight part of tin oxide powder of the ink was extended to 120 weight part, the transparent conductive ink and the test piece were produced like Example 1, and the test piece was evaluated. As a result, as shown in Table 1, the surface resistance showed 10 ⁵ mA / square band. Compared with Example 1, surface resistance did not show a big difference, but immersion (transparency of a coating film) and the vividness of the drawing fell, but were practical levels.

(Comparative Example 1)

Example 1 The acrylic thermoplastic resin of the ink was substituted with the acrylic resin (ethyl methacrylate, Tg40 degreeC, solid content 30%), the transparent conductive ink and the test piece were produced like Example 1, and the test piece was evaluated. As a result, as shown in Table 1, the blocking resistance was somewhat poor.

(Comparative Example 2)

Example 1 90 weight part of tin oxide powder of the ink was reduced to 25 weight part, the transparent conductive ink and the test piece were produced like Example 1, and the test piece was evaluated. As a result, as shown in Table 1, the surface resistance showed 10 ¹¹ Ω / □ band. Compared with Example 5, the surface resistance value was rather poor, and the surface resistance value below the practical level was shown.

In addition, the evaluation method of a test piece is as follows.

(1) Surface resistance value (Ω / □)

Measured using Hirester IP HT-210 (manufactured by Yuhwa Electronics Co., Ltd.).

(2) sharpness of pictures

Comparison was made with the picture where no transparent conductive layer was formed with the eyes. The double circle (◎) is more vivid than the cause (○; 印 印).

(3) blocking resistance

In the atmosphere of 50 ° C to 80% RH, the pictures of printed matter were superimposed on each other, and a load of 5 Kg / cm 2 was applied and left standing for 20 hours. After that, the load was removed and the degree of adhesion between the printed matters was evaluated. The double circle (◎) is not fixed, the cause (○; 丸 印) is slightly fixed but the picture is not damaged, and the triangle (△) is fixed and detached when the picture is damaged.

(4) Gravure printing aptitude

Each paper was evaluated using a gravure printing calibrator (Type D tester). The double circle (?) Indicates that continuous printing is possible for 2 hours or more, the cause (○) indicates that continuous printing is possible for 1 to 2 hours, and the triangle (△) indicates that continuous printing is possible for 0.5 to 1 hour.

TABLE 1

Next, the surface resistance value was obtained in the same manner as in Example 1 by applying the transparent conductive ink prepared in Example 1 to a dry coating film having a thickness of about 1 μm using a barcode on a polyethylene terephthalic acid film (125 μm in thickness). In addition, Table 2 shows the results of measurement of soaking in the following manner.

(5) soak

It measured using the direct-type haze computer (made by Suga Test Machine Co., Ltd.).

TABLE 2

The transparent conductive ink of the present invention is a transparent conductive ink which is excellent in gravure printing aptitude, blocking resistance, stable conductivity, and vividness of a picture or an image color, and provides freely and multi-products having high conductivity with high productivity. To make it possible.

1 is a plan view of a teaching aid printed using a conventional conductive ink.

Fig. 2 is a diagram showing a cross-sectional film layer of a printed matter produced using the transparent conductive ink of the present invention.

Explanation of symbols on main parts of drawing

1: base material,

2: Problem (question) printed with non-conductive ink,

3: check mark for selection printed with conductive ink and non-conductive ink,

4: picture printing layer, 5: transparent conductive layer.

Claims (1)

A transparent conductive ink for forming a transparent conductive film by gravure printing by superimposing on the surface of a multicolor picture printed by offset printing, wherein the acrylic thermoplastic resin having a glass transition point of 50 ° C to 105 ° C differs from the valence number. At least one average particle diameter of 1 micrometer or less selected from a metal-coated stone oxide, an anti zinc oxide, and an indium oxide stone consists of transparent conductive powder and a solvent which is at least one kind of toluene and xylene, 100-500 weight part of said electroconductive powders with respect to the transparent conductive ink characterized by the above-mentioned.

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