JP5499822B2 - Method for producing functional thin film - Google Patents

Description

  The present invention relates to a manufacturing method for printing a functional thin film with high quality.

  In recent years, attempts have been made to use a known printing method that is excellent in mass productivity and can reduce the manufacturing cost in forming a fine thin film pattern. In particular, in the display field, in order to cope with an increase in screen size and cost, studies are being made to form a functional thin film by a printing method.

  As specific printing methods, offset printing, gravure printing, gravure offset printing, letterpress printing, and the like are being studied.

Among these various printing methods, the resin letterpress printing method is a printing using a letterpress made of resin, an ink roll engraved with fine recesses (cells) on the surface called an anilox roll, and solvent-drying ink. This method is widely used for printed materials such as wrapping paper. This resin relief printing is particularly suitable for forming a thin and stable printing layer having a film thickness of about 0.01 to 0.2 μm.
Resin letterpress printing enables printing at a very low printing pressure, called kiss touch, so printing on a glass substrate or a substrate on which a transparent electrode or the like whose characteristics are easily destroyed by applying high pressure is formed The printing method is particularly suitable for pattern formation of electronic parts such as displays.

Next, a general letterpress printing apparatus will be described with reference to FIG.
As shown in FIG. 2, this relief printing apparatus includes an anilox roll 201 having a cell for supplying ink to the plate surface of the relief plate 204, an ink chamber 208 for supplying ink to the anilox roll, and an under-cushion cushion 203. It has a rotary plate cylinder 205 on which a relief plate 204 for pattern formation is mounted, a substrate surface plate 206 on which a substrate 207 to be printed is placed, and a doctor blade 202 that performs doctoring to scrape off ink. ing.
Next, the flow of printing when using the printing machine of FIG. 2 will be described.
First, after the substrate to be printed is placed on the substrate surface plate 206, the substrate is moved to just below the plate cylinder 205. When the substrate surface plate 206 moves, the plate cylinder 205 rotates in synchronization with the operation of the substrate surface plate 206, and ink is supplied to the relief plate 204 from the anilox roll 201 operating at the same speed as the plate cylinder 205. Immediately after the ink is supplied to the relief plate 204, the relief-form ink is transferred to the printing substrate 207 and the printing operation is completed.

Here, the doctor blade 202 is generally pushed to the anilox roll with a pressure of about 20 kPa in order to push the ink uniformly into the anilox roll cell by scraping off excess ink from the ink applied on the anilox roll 201. Hit.
For this reason, both the anilox roll and the doctor blade are worn, and there is a problem that the scraped portion is mixed into the ink.

  Since an anilox roll and a doctor blade are generally made of a metal oxide or a resin, they are mixed into the ink as foreign matters.

  Conventionally, it is not a big problem if it is a general printed matter that is mainly targeted by the resin letterpress printing method, but it is for electronic parts for the purpose of fine patterning of functional thin films such as organic semiconductor thin films and organic light-emitting thin films. In printing, defects such as product defects due to scraped foreign matter, or short-circuiting due to electrical conduction occur when the foreign matter is metal.

As described above, as a means for scraping off the ink on the conventional anilox roll, a doctor blade is mainly used. However, as shown in Patent Document 1, a doctor roll technique in which rubber or the like is processed on a roll is also available. It is used.
By using the doctor roll method, the generation of foreign matter as generated by the doctor blade method can be suppressed to a low level, but the scratching property is inferior to that of the doctor blade, and sufficient ink is applied to the anilox roll cell. It was impossible to push in, and it was difficult to pattern fine thin films with high quality.

JP 2001-083495 A

As described above, the conventional resin relief printing method is a printing method having excellent characteristics, but to obtain a high-quality printed material, such as doctoring and reducing the occurrence of foreign matter affecting the printed material, It did not meet the required characteristics.
Accordingly, an object of the present invention is to solve such problems and to provide a method for producing a functional thin film that is advantageous in printing the functional thin film with high quality and less foreign matter.

In order to solve the above-mentioned problems, the present inventors conducted extensive research. As a result, the peripheral speed V1 of the anilox roll surface during doctoring, the viscosity η of the ink used, and the surface tension σ, Ca = By setting the range of the numerical value represented by ηV / σ to 0.002 ≦ Ca ≦ 0.03, we found the doctoring conditions necessary for obtaining high-quality printed matter and the doctoring conditions that do not cause the generation of foreign matters that impair the function of the thin film. .
In addition, when the numerical value Ca is below the range of 0.002 ≦ Ca ≦ 0.03, it is necessary to use an ink that has a large surface tension and a low viscosity and is liable to cause poor coating, and it is necessary to further reduce the peripheral speed. This is disadvantageous in that it affects the operational stability of the apparatus, and if it exceeds the range of 0.002 ≦ Ca ≦ 0.03, it is disadvantageous in that streaky irregularities occur on the doctoring surface, resulting in poor doctoring.

The present invention has been made on the basis of such knowledge, the invention according to claim 1 for solving the above problems, a cylindrical plate cylinder comprising a relief plate on which the printing pattern is formed on the outer periphery, An anilox roll that supplies ink to the relief plate, an ink supply device that supplies ink to the anilox roll, a doctor roll that scrapes off excess ink on the anilox roll, and a positioning surface plate on which a substrate is placed A functional thin film manufacturing method for manufacturing a functional thin film by transferring the relief printing ink to the printing material using a printing apparatus, wherein the excess ink on the anilox roll is scraped off by the doctor roll. When the peripheral speed of the anilox roll surface is V1, the viscosity of the ink is η, and the surface tension of the ink is σ, Ca = ηV The numerical value range expressed by 1 / σ is in the range of 0.002 ≦ Ca ≦ 0.03.
The invention according to claim 2 is characterized in that V2> V1 is satisfied when the peripheral speed of the anilox roll when transferring ink from the anilox roll onto the relief plate is V2. It is a manufacturing method of a functional thin film.

  By applying the manufacturing method of the present invention, it is possible to easily form a printed pattern having a uniform film thickness, and to reduce the generation of foreign matters that impair the function of the thin film. Therefore, the resin relief printing method can be applied as a fine patterning technique for electronic members and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining the outline of the relief printing apparatus which has a doctor roll applied to the manufacturing method of the functional thin film of embodiment. It is drawing explaining the outline of the relief printing apparatus which has a doctor blade which shows a prior art example. It is a figure which shows the evaluation result of Example 1 and Comparative Examples 1 and 2. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that. The present invention is not limited to this.

An embodiment of the present invention will be described focusing on an ink supply mechanism 109 composed of an anilox roll 101 in the resin relief printing press shown in FIG.
The resin letterpress printing machine shown in FIG. 1 is a cylinder type copper plate 105 on which a pattern forming letterpress 104 is mounted, an anilox roll 101 for supplying ink in contact with the letterpress 104, and an ink chamber 108 for supplying ink to the anilox roll. The printing apparatus includes a doctor roll 102 that scrapes off excess ink on the anilox roll 101, and a substrate surface plate 106 on which the substrate is placed.

In other words, the above-described resin relief printing press (printing device) includes a cylindrical plate cylinder 105, an anilox roll 101, an ink chamber 108 (ink supply device), a doctor roll 102, and a substrate surface plate 106 (positioning surface plate). ).
The cylindrical plate cylinder 105 includes a relief plate 104 on which a printing pattern is formed on the outer peripheral portion.
The anix roll 101 supplies ink to the relief plate 104.
The ink chamber 108 supplies ink to the anilox roll 101.
The doctor roll 102 performs doctoring to scrape off excess ink on the anilox roll 101.
The substrate surface plate 106 is for placing a substrate that is a substrate to be printed.

  As an anilox roll 101 that can be used for resin letterpress printing of the present invention, a ceramic obtained by patterning a chromium oxide film formed by plasma spraying chromium oxide on a core roll made of a SUS material by laser engraving Either a roll or a core roll after copper plating is applied, a resin is applied, laser patterning is performed, and then a corrosion treatment is performed, and the resulting pattern is subjected to chrome plating.

  In addition, as a pattern formed on the aniloc roll, any pattern such as a helical pattern, an FM pattern, a honeycomb pattern, a diamond pattern, and an ART pattern can be used.

These patterns may be appropriately angled to prevent moire.
After these patterns are formed, the surface of the anilox roll 101 is desirably polished to prevent scratching the doctor roll 102 side. Specifically, it is desirable to polish the anilox roll pattern bank so as to eliminate protrusions of 4 μm or more.
As a mechanism for rotating the anilox roll 101, it is desirable to perform direct drive with a servo motor capable of controlling the rotation with high accuracy, since uneven rotation speed greatly affects printed matter. Further, when using a speed reduction mechanism to obtain the required torque, it is desirable to use a backlashless mechanism.

Next, as a doctor roll 102 that can be used, a core roll made of SUS material, etc., nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, acryliconitrile rubber, ethylene Propylene rubber, urethane rubber, or the like may be wound around the rubber roller, or a heat-shrinkable tube made of a PFA tube may be wound around these rubber rollers. These rubber materials are selected from the resistance to the solvent used as the ink.
These rubber rolls preferably have an arithmetic surface roughness Ra of 0.1 μm or less and a maximum height Rz of 1 μm or less. By satisfying these conditions, a low dust generation and smooth doctoring surface can be obtained.

Next, as the hardness of the doctor roll 102 that can be used, any of the JIS-A hardnesses in the range of 30 ° to 70 ° can be used.
As the mechanism to rotate the doctor roll 102, since uneven rotation speed has a large effect on the printed matter, it is desirable to use a servo motor that can control the rotation with high precision, and to perform direct drive, synchronized with the rotation of the anilox roll. It is desirable to have a system that can be controlled in a rotatable manner.

Next, the actual operation when this printing press is used will be described.
After placing the glass substrate 107 on the substrate surface plate 106, a printing operation is started by a print start instruction.
During this time, ink is supplied onto the anilox roll 101, doctoring is continuously performed, and a smooth doctored surface is always held. The speed of doctoring is determined according to the present invention.
That is, when the surplus ink on the anilox roll 101 is scraped off by the doctor roll 102, the peripheral speed of the anilox roll 101 surface is V1, the ink viscosity is η, and the ink surface tension is σ, and Ca = ηV1 / σ. The peripheral speed V1 on the surface of the anilox roll 101 is set so that the range of numerical values represented is in the range of 0.002 ≦ Ca ≦ 0.03.
For example, if the ink has a viscosity of 60 mPa · s and a surface tension of 30 mN / m, the peripheral speed V1 on the surface of the anilox roll 101 is set between 1 and 15 mm / s.
Next, after the substrate surface plate moves directly below the plate cylinder, ink is transferred onto the plate from the anilox roll 101, and then printing is performed on the glass substrate 107 placed on the substrate surface plate 106 in synchronization with the plate cylinder rotation. . That is, the functional thin film is manufactured by transferring the ink of the relief plate 104 to the glass substrate 107.
The speed at which the ink is transferred from the anilox roll 101 onto the relief plate 104 may be equal to the doctoring speed. However, if the doctoring speed is low, it takes time to transfer, so the transfer speed may be increased. . However, when the transfer speed is increased, it is necessary to adjust so that the doctoring surface obtained under the doctoring condition of the present invention is transferred to the relief plate 104.
By performing the above operation, a high-quality printed material can be obtained. That is, it is advantageous in printing the functional thin film with high quality and less foreign matter.
In other words, when the peripheral speed of the anilox roll 101 when the ink is transferred from the anilox roll 101 onto the relief plate 104 is V2, the ink transfer speed from the anilox roll 101 to the relief plate 104 is satisfied by satisfying V2> V1. Speed up. Therefore, it is advantageous in obtaining a high-quality printed matter while increasing the transfer speed of the ink to the glass substrate 107.

Example 1
Examples of the present invention will be described. In addition, this invention is not limited to an Example, The improvement, deformation | transformation, etc. in the range which can achieve this invention do not deviate from the meaning of this invention.

  In this embodiment, an example in which a polymer type organic light emitting material is printed on glass is shown.

  As the printing machine, the printing machine shown in FIG. 1 is used.

  A chrome roll was used as the anilox roll 101 used in this example. The pattern formed on the roll is a diamond pattern in which square cells with a side of 65 μm are formed at a pitch of 72.5 μm, and these patterns are formed inclined by 60 ° from the horizontal line of the roll.

  Next, as the doctor roll 102 used in this example, urethane rubber having a hardness of JIS-A 50 ° was wound on a SUS core and processed into a columnar shape so as to be within 0.5 mm with respect to the target diameter. A PFA heat-shrinkable tube was wound on the processed urethane rubber roll, and then polishing was performed so that Ra was 0.05 μm and Rz was 1 μm.

The doctor roll 102 was installed so as to be pushed into the anilox roll 101 by 50 μm.
The installed anilox roll 101 and doctor roll 102 are each driven by a servo motor.

  Next, a plate material used as the relief plate 104 will be described.

  A black oil-based dye was applied to the surface of a SUS304 plate having a thickness of 0.2 mm as a reflection suppressing layer by a die coating method so as to have a thickness of 1.5 μm. A negative photosensitive resin mainly composed of polyamide was applied to the surface of this laminate so that the total thickness was 0.1 mm, and this was used as the base of the plate.

  After that, a negative pattern having a pattern on the stripe (effective area opening 106 μm × 50 mm, non-opening space 392 μm × 50 mm, total effective number of 64 lines as a group, 1 cm horizontally and 2 cm vertically) A proximity gap of 50 μm was opened using a chromium mask of 6 × 2), and exposure was performed with an aligner. After the exposure, development was performed while pouring warm water to form a relief plate 104 having a projection height of 90 μm, a projection line width of 10 4 μm, and a space of 392 μm. The prepared relief plate 104 was attached to a plate cylinder 105 of a printing machine using a printing cushion tape having a thickness of 0.5 mm.

  Next, the ink will be described.

An organic light-emitting ink was prepared by dissolving a polyphenylene vinylene derivative, which is a polymer organic light-emitting material, in anisole to a concentration of 2%.
When the viscosity of the prepared ink was measured, it was 60 mPa · s, and the surface tension was 34 mN / m. Thereafter, the ink was put into the ink chamber 108 of the printing press.

  Printing was performed on 300 mm square and 0.7 mm thick soda glass using the above apparatus, letterpress 104, and organic light emitting ink (light emitting material ink). Printing was performed at a tact time of 60 s, the doctoring speed was 5 mm / s, the printing speed was 100 mm / s, and the numerical value Ca was 0.01 in the range of 0.002 ≦ Ca ≦ 0.03.

(Comparative Example 1)
In Comparative Example 1, printing was performed in the same manner as in Example 1 except that the doctoring speed in Example 1 was 100 mm / s, and the numerical value Ca was 0.2 exceeding the range of 0.002 ≦ Ca ≦ 0.03.

(Comparative Example 2)
In Comparative Example 2, a doctor blade was used without using the doctor roll 102 in Example 1, and the doctoring speed was 100 mm / s. Otherwise, printing was performed in the same manner as in Example 1.

The following evaluation was performed about the board | substrate with which the organic light emitting layer obtained in Examples 1, 2 and Comparative Examples 1, 2 was formed.
-Evaluation of in-plane variation of PL emission intensity in a state where the printed matter is subjected to PL emission-Evaluation of unevenness by visual observation-Evaluation of foreign matter evaluation in one panel is shown in FIG.

In Example 1, the in-plane emission intensity variation was as small as 5%, and no specific unevenness was observed. Furthermore, the number of foreign objects was as small as 16 pieces.
That is, a functional thin film having high quality and few foreign matters could be obtained.

  In Comparative Example 1, although the number of foreign matters was relatively good at 33, oblique streak unevenness was confirmed throughout and the emission intensity variation was very large at 28%.

  In Comparative Example 2, unevenness and emission intensity variation were the same as in Example 1, but the number of foreign matters was increased to 1500.

101 Anilox Roll
102 Doctor Roll
103 version cushion
104 letterpress
105 version cylinder
106 Substrate surface plate
107 Printed circuit board
108 Ink chamber
109 Ink supply mechanism
201 Anilox Roll
202 doctor blade
203 Cushion
204 letterpress
205 Version
206 Substrate surface plate
207 Printed circuit board
208 Ink chamber
209 Ink supply mechanism

Claims (2)

A cylindrical plate cylinder having a relief printing plate formed on the outer periphery, an anilox roll that supplies ink to the relief plate, an ink supply device that supplies ink to the anilox roll, and excess ink on the anilox roll A method for producing a functional thin film by producing a functional thin film by transferring ink of the relief printing onto the printing material using a printing apparatus comprising a doctor roll for scraping off the ink and a positioning surface plate on which the printing material is placed Because
When scraping excess ink on the anilox roll with the doctor roll, the peripheral speed of the anilox roll surface is V1, the viscosity of the ink is η, and the surface tension of the ink is σ, and Ca = ηV1 / σ A method for producing a functional thin film, characterized in that a range of numerical values represented is in a range of 0.002 ≦ Ca ≦ 0.03.   2. The method for producing a functional thin film according to claim 1, wherein V2> V1 is satisfied, where V2 is a peripheral speed of the anilox roll when ink is transferred from the anilox roll onto the relief printing plate.

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