JP2005186597A - Method for manufacturing electrically-conductive pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a fine and thick electrically-conductive pattern with a high accuracy, efficiently, in a short time, and at a low cost. <P>SOLUTION: A series of printing processes comprising a process for feeding an ink on a cylindrical intaglio printing plate (intaglio printing plate cylinder 10), a process for transferring the ink from the intaglio printing plate to a silicone blanket 16 by bringing the silicone blanket 16 mounted on a blanket cylinder 15 into contact with the intaglio printing plate, and a process for separating the silicone blanket 16 from the intaglio printing plate to roll it in press contact with a base material 20 (a body to be transferred) and to transfer the ink onto the base material 20 from the silicone blanket 16 is practiced. After the printing process is finished one time or specified times, the silicone blanket 16 is separated from the intaglio printing plate, and a process for drying the surface of the silicone blanket 16 is practiced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a conductive pattern, and more particularly to a method for printing and forming a conductive pattern using a rotary intaglio offset printing method.

In recent years, display devices such as color televisions and computer displays have been replaced by cathode ray tubes (CRT), so-called flat panel displays (FPD) such as liquid crystal displays (LCD), electroluminescent (EL) displays, plasma displays (PDP), etc. Is used.
In this flat panel display, for example, a striped electrode pattern is mainly formed on a transparent substrate such as glass, such as a front substrate (front substrate) for PDP, a rear substrate (rear substrate), and an electrode substrate for EL display. In such an electrode substrate, a fine stripe pattern having a line width of about 10 to 500 μm is formed using an ink containing a conductive substance and about 0.1 to 10 μm. It is required to form with thickness.

  Conventionally, photolithography is mainly used as a method for forming a fine and thick conductive pattern with high accuracy, but the process is complicated, and materials and manufacturing equipment necessary for pattern formation are expensive. Therefore, there is a problem that the manufacturing cost becomes extremely high. In addition, the cost for processing harmful waste liquid generated by development processing and the like is high, and the waste liquid also has environmental problems. Moreover, in order to form a large electrode substrate by photolithography, it is necessary to increase the size of the exposure apparatus and development etching apparatus, which is extremely disadvantageous in terms of cost, so it is difficult to cope with the recent increase in size of displays. There is also.

  Therefore, research has been conducted on a method for forming a conductive pattern at low cost without causing harmful waste liquid, and the thickness of the ink pattern to be printed can be freely controlled by the depth of the recess, An intaglio offset printing method that can form a fine line pattern with a width of several tens to several hundreds of μm and can easily cope with an increase in the size of a transfer object has attracted attention as an alternative to photolithography. Among them, according to the intaglio offset printing method using a blanket (silicone blanket) using a silicone-based elastomer for the surface rubber, the ink can be transferred from the blanket to the substrate that is the transfer object by almost 100%. It becomes possible to accurately print and reproduce very fine patterns. That is, by adopting an intaglio offset printing method using a silicone blanket, the printing accuracy of the conductive pattern can be improved and the manufacturing cost can be reduced.

  However, as described in Patent Document 1, a normal intaglio plate is a flat glass substrate or metal substrate formed with recesses by etching or the like. The printing press is used. In printing with a flatbed printing press, (i) supply of ink to the intaglio with a squeegee and doctor, (ii) movement of the blanket, (iii) contact / rolling of the blanket on the intaglio, (iv) movement of the blanket, And (v) Since the blanket pressing and rolling steps on the substrate are sequentially performed, it is difficult to greatly improve the printing speed. Although a printing machine that executes the above-described steps in parallel has been proposed, the mechanism is extremely complicated, which is disadvantageous in terms of cost.

Therefore, it is difficult to mass-produce an electrode substrate having a fine and thick conductive pattern while suppressing manufacturing costs.
Japanese Patent Laid-Open No. 2002-245931 JP-A-4-33858

  An object of the present invention is to provide a method for producing a fine and thick conductive pattern with high accuracy, efficiently in a short time and at low cost.

In order to achieve the above object, a method for producing a conductive pattern according to the present invention comprises:
Supplying ink to the cylindrical intaglio,
A step of bringing the silicone blanket attached to the blanket cylinder into contact with the intaglio and transferring ink from the intaglio to the silicone blanket;
A step of separating the silicone blanket from the intaglio and rolling it while being in pressure contact with the transfer target, and transferring the ink from the silicone blanket to the transfer target;
A series of printing processes including
After the printing step is completed once or a predetermined number of times, the step of separating the silicone blanket from the intaglio and drying the surface of the silicone blanket is performed.

  According to the method for producing a conductive pattern according to the present invention, since a conductive pattern is printed by intaglio offset printing using a silicone blanket, it is required to form a fine and thick conductive pattern. Even in this case, it can be formed with high accuracy. Furthermore, since the conductive pattern is formed by the printing method, the manufacturing cost can be significantly reduced as compared with the case where the pattern is formed by the photolithography method as in the prior art.

  Moreover, in the manufacturing method of the electroconductive pattern which concerns on this invention, the rotary intaglio offset printing method using a cylindrical intaglio is employ | adopted for the printing formation of the electroconductive pattern. Here, in printing by a flatbed printing machine, as described above, (i) supply of ink to the intaglio by a squeegee and doctor, (ii) movement of the blanket, (iii) contact and rolling of the blanket on the intaglio (V) The blanket is moved and (v) the blanket is pressed and rolled on the substrate, so that it is difficult to greatly improve the printing speed. On the other hand, according to rotary intaglio offset printing using a cylindrical intaglio, the time required for the steps (i) to (iii) can be shortened without complicating the mechanism of the printing press. . Therefore, the time required for the entire production of the conductive pattern can be greatly shortened.

  When continuous printing is performed by the intaglio offset printing method, the silicone blanket gradually swells due to the ink solvent, and eventually the ink acceptability of the silicone blanket is lowered and the shape of the printed pattern is disturbed. However, according to the method for manufacturing a conductive pattern according to the present invention, the process of drying the surface of the silicone blanket is performed once or after a predetermined number of times. Therefore, it is possible to prevent the above problem from occurring due to the swelling of the silicone blanket. In addition, the drying process of the silicone blanket is performed with the blanket separated from the intaglio, so the intaglio does not dry or rise in temperature, and the ink transfer from the intaglio to the blanket decreases accordingly. And the problem that the intaglio is expanded and the printing accuracy is lowered is not caused.

  By the way, Patent Document 2 describes a rotary intaglio offset printing machine in which a cylindrical intaglio surface comes into contact with a blanket cylinder only at the time of ink transfer. However, the invention described in Patent Document 2 is mainly intended to prevent drying of the plate cylinder, and in order to achieve this purpose, ink is always supplied to the plate, and the plate cylinder and the blanket cylinder are provided. It is only supposed to be separable. Further, although Patent Document 2 describes that the surface of the blanket is dried (see FIGS. 2 and 3 of the same document), there is nothing about the heat treatment for drying the blanket affecting the plate cylinder. Not considered.

  When the method of the present invention is employed for forming an electrode pattern (conductive pattern) on an electrode substrate of a flat panel display (FPD) by a printing method, the electrode substrate (base material) that is a printing medium is glass or the like. Therefore, rather than fixing the intaglio or blanket and moving the substrate, which is the substrate, moving the blanket while fixing the substrate (substrate) saves the space required for the printing process. can do. In recent years, since the screen of the FPD has been enlarged, and it is required to manufacture a large electrode substrate, the method of the present invention that can save the space required for the printing process is a large FPD. This is also preferable from the viewpoint that the burden of investment in manufacturing equipment associated with screen conversion can be reduced.

  The method for producing a conductive pattern according to the present invention is suitable for the purpose of producing a fine and thick film conductive pattern with high accuracy and mass production, as is apparent from the results of Examples described later. is there.

Hereinafter, embodiments of the present invention will be described in detail.
(intaglio)
The intaglio used in the present invention is used by being attached to a cylindrical or columnar plate cylinder, or one in which a concave portion corresponding to the printing pattern is directly formed on the surface of a cylindrical or columnar member (plate cylinder) Is mentioned.
In order to increase the printing accuracy of the conductive pattern, the surface smoothness of the intaglio is very important. This is because if the surface of the intaglio plate is poor, ink remains on the surface of the intaglio plate when it is filled with ink and scraped off with a doctor, resulting in the occurrence of stain (background stain) on the non-image area.

  In order to produce an intaglio with excellent surface smoothness at low cost, it is preferable to use glass as the intaglio substrate and to form recesses by etching. However, like the intaglio used in the present invention, a cylindrical plate cylinder Manufacturing costs are incurred for those that are attached to and used for the intaglio and the intaglio itself is cylindrical. In addition, when an intaglio is manufactured with a glass cylinder, it is not suitable for practical use because it lacks mechanical strength and lacks durability.

  Accordingly, in the present invention, a concave portion is formed on the surface of a thin metal plate by photoetching, and then the surface is polished to give a mirror finish to make an intaglio plate, which is wound around a cylindrical plate cylinder. It is preferable to use it. Alternatively, the metal cylinder may be mirror-finished in advance, and a concave portion may be engraved on the surface by laser processing to form an intaglio cylinder. Here, the specific material of the metal thin plate or the metal cylinder is not limited to this, and examples thereof include 42 alloy and stainless steel. When a thin metal plate or a metal cylinder with hard chrome plating on the surface is used, the durability of the intaglio can be made excellent.

  What is necessary is just to design the depth of the recessed part of an intaglio according to the thickness of the target ink film, and it is normally set in the range of 1-50 micrometers. The transfer of ink from the silicone blanket to the transfer target (substrate) can achieve approximately 100% transfer, whereas in the transfer of ink from the intaglio to the blanket, the amount of ink transferred is the depth of the recess. It is necessary to consider that the thickness is about half of the thickness.

(Silicone blanket)
As described above, the silicone blanket used in the present invention uses a silicone elastomer such as silicone rubber as the surface rubber. Silicone rubber is roughly classified into room temperature curable silicone rubber (RTV) and heat curable silicone rubber (HTV), and any type of silicone rubber can be used in the present invention. However, it is more preferable from the viewpoint of the dimensional accuracy of the silicone blanket to use a room-temperature-curing and addition-type silicone rubber that is a type in which no by-product is generated during curing.

  If the hardness of the silicone elastomer is too high, the surface of the blanket may not be sufficiently deformed during the transfer of ink from the intaglio and the transfer of the ink pattern to the transfer target, leading to a decrease in ink transferability. It becomes. Conversely, if the hardness of the silicone-based elastomer is too low, the blanket surface deformation during transfer and transfer becomes too large, which may lead to a decrease in printing accuracy. The silicone elastomer has a JIS A hardness of preferably 20 to 70, and more preferably 30 to 60.

  The surface shape of the silicone blanket has a greater effect on printing accuracy (particularly the shape of the pattern) as the printed pattern becomes finer. In general, the surface roughness of a printing blanket is preferably as small as possible. For example, when forming a fine pattern having a line width of about 20 μm, which is required when forming a conductive pattern on an electrode substrate, the surface roughness of the silicone blanket is required. The thickness (10-point average roughness) is preferably 1.0 μm or less, and more preferably 0.5 μm or less.

Although the thickness of the surface rubber of the silicone blanket is not particularly limited, in general, when the surface rubber is thicker than 1.5 mm, the deformation of the rubber may increase and the printing accuracy may decrease, It is preferable to set within 1.5 mm.
(Printing ink)
The printing ink used in the present invention has a different composition depending on the use and required characteristics of the conductive pattern, and is therefore not particularly limited. In addition to the use and characteristics of the conductive pattern, printability and the like are considered. In addition, it may be appropriately selected from conventionally known various inks. The printing ink is produced by blending a proper amount of conductive powder, pigment and the like in accordance with the use of the conductive pattern, required characteristics, etc., in addition to the resin and solvent, and mixing and stirring with three rolls.

  Since the solvent of the printing ink is an important factor governing the printability of offset printing, it is necessary to select it in consideration of the degree of swelling with respect to the silicone blanket and the effect on the wettability of the blanket surface. In general, by using a solvent with less swelling with respect to the silicone blanket, the change in the wetting property of the surface of the blanket can be reduced, and stable printing can be realized. In particular, since the present invention assumes that the conductive pattern is continuously printed by a rotary printing press, it is preferable to use a solvent with less swelling. In continuous printing, the surface wettability changes easily as the blanket swells. As a result, the line width of the printed pattern widens, minute stains on the surface of the intaglio plate are transferred to the surface of the blanket, etc. This is because problems such as deterioration in transferability to the ink occur and stable printing becomes difficult. On the other hand, from the viewpoint of ink acceptability of the silicone blanket, it is preferable to select a solvent that can swell the silicone blanket to some extent.

  Various resins such as a thermosetting resin, an ultraviolet curable resin, and a thermoplastic resin can be used as the resin forming the printing ink. Examples of the thermosetting resin include polyester-melamine resin, melamine resin, epoxy-melamine resin, phenol resin, polyimide resin, and acrylic resin. Examples of the ultraviolet curable resin include acrylic resins. Examples of the thermoplastic resin include polyester resin, polyvinyl butyral resin, cellulose resin, acrylic resin, and the like. These resins may be used alone or in combination of two or more according to the desired printability.

  In the present invention, since a silicone blanket is used as a printing blanket, it is preferable to add silicone oil to the printing ink. The low molecular weight silicone oil component contained in the silicone blanket is extracted by contact with the printing ink, and its content decreases with time. By including silicone oil in the printing ink, the silicone oil is contained in the printing ink from the blanket. This is because the oil component can be suppressed and prevented from being extracted, and the silicone oil component can be supplied into the blanket. When the content of the silicone oil component in the silicone blanket decreases, problems such as variations in the line width of the printed pattern occur. By using printing ink that contains the silicone oil component, this problem can be prevented. Can be prevented.

In this case, the amount of silicone oil added to the printing ink is 3 to 50 parts by weight, preferably 5 to 30 parts by weight with respect to 100 parts by weight of the resin content of the ink. When the blending amount of the silicone oil is below the above range, a sufficient effect cannot be obtained. On the contrary, even if silicone oil is blended exceeding the above range, the effect is not changed, which is disadvantageous in terms of cost.
The silicone oil added to the printing ink is not particularly limited, and various modified silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, and the like can be employed.

(Transfer material)
The material to be transferred used in the present invention is not particularly limited, and may be appropriately selected from substrates that can be used for the product depending on the product to be manufactured.
When an electrode substrate for a flat panel display is formed by employing the manufacturing method of the present invention, as a material for forming the transfer object, for example, glass such as soda lime glass, low alkali glass, non-alkali glass, quartz glass, etc. May be used. In the case of forming a pattern for other uses, in addition to the glass exemplified above, polyesters such as polyethylene terephthalate (PET); polyolefins such as polyethylene, polypropylene and polystyrene; polyvinyl chloride (PVC), polyvinylidene chloride, etc. It is also possible to use a film made of a resin such as polyethersulfone, polycarbonate, polyamide, polyimide, or acrylic resin as a transfer target, or use a metal film, ceramic, or the like as a transfer target.

(Specific Embodiment of the Present Invention)
Next, the manufacturing method of the electroconductive pattern which concerns on this invention is demonstrated, referring FIG.
In the conductive pattern manufacturing method shown in FIGS. 1 (a) to 1 (c), an intaglio cylinder 10 in which a concave portion corresponding to a printing pattern is formed on the surface of a cylinder is used as an intaglio plate. A cylindrical silicone blanket 16 is wound around the surface of the body 15.

In the method for producing a conductive pattern shown in FIG. 1, first, the intaglio cylinder 10 and the blanket cylinder 15 are rotated in opposite directions, and an ink 12 is applied to a recess (not shown) on the surface of the intaglio cylinder 10 by a squeegee 11. Is supplied. The ink 12 filled in the recesses is transferred to the silicone blanket 16 mounted on the blanket cylinder 15 (FIG. 1A).
Next, the silicone blanket 16 is moved onto the base material 20 as a transfer target, and is rotated and rolled onto the surface of the base material 20, whereby ink (not shown) filled in the recesses is obtained. It is transferred to the surface of the substrate 20 [FIG. 1 (b)]. In FIG. 1B, reference numeral 16 ′ denotes a reference position of the silicone blanket 16 when ink is transferred from the intaglio cylinder 10, and reference numeral 16 ″ denotes a silicone blanket rolled on the surface of the substrate 20. 16 stop positions are shown.

After the ink pattern (not shown) is transferred to the surface of the substrate 20 in this way, the silicone blanket 16 is returned to the reference position 16 ′ when transferring the ink from the intaglio cylinder 10 to execute a new printing process. can do.
After the transfer of the ink from the intaglio cylinder 10 to the silicone blanket 16 and the transfer of the ink pattern from the silicone blanket 16 to the surface of the substrate 20 (a series of printing steps), a process of drying the surface of the silicone blanket 16 Is preferably performed. As described above, this drying process may be performed every time a series of printing steps is completed once, or may be performed after repeating a predetermined number of times in consideration of the surface state of the silicone blanket 16.

  The silicone blanket 16 is preferably dried by heating. For example, as shown in FIG. Further, a heater may be disposed on the back surface of the silicone blanket 16 or inside the blanket cylinder 15 and the silicone blanket 16 may be heated with this heater. Among these, it is preferable to perform the warm air injection and the infrared irradiation in view of heating / drying efficiency and handling property of the heating equipment.

After the silicone blanket 16 is heated and dried, it is preferable to perform a process of cooling the surface of the blanket 16. The silicone blanket 16 can be cooled, for example, by spraying cold air or by bringing a roller 27 made of a material having excellent thermal conductivity such as a low temperature roller or metal into contact with the surface of the blanket 16.
In the drying process (heating and cooling process) of the silicone blanket 16, the blanket 16 is separated from the intaglio cylinder 10 (more preferably, the blanket 16 is also separated from the base plate 20 and the surface plate 21 that fixes the blanket 16). It is preferable to carry out the process from the viewpoint of preventing drying of the intaglio cylinder 10 and thermal expansion of the base material 20 and preventing deterioration of printing accuracy.

Next, the present invention will be described with reference to Examples and Comparative Examples in which a conductive pattern is printed on a substrate by the production method of the present invention.
[Print formation of conductive pattern]
(Example 1)
For the substrate on which the conductive pattern is printed, a glass plate having a length of 500 mm and a width of 2.8 mm is used. Spherical one) 1000 parts by weight and 50 parts by weight of glass frit were mixed, and a conductive paste obtained by mixing and stirring butyl carbitol acetate as a solvent at a ratio of 30 to 50 parts by weight was used.

  As the intaglio plate, a metal cylinder (width 500 mm, diameter 400 mm) subjected to hard chrome plating and further mirror-finished (polished by a polisher) on the surface was used. The conductive pattern formed by printing was a stripe pattern having a line width of 180 μm and a line interval of 360 μm, and a recess corresponding to the pattern was engraved on the surface of the metal cylinder by laser processing.

  As the silicone blanket, a PET rubber film having a thickness of 0.35 mm and a silicone rubber layer having a thickness of 0.6 mm (JIS A hardness 40, 10-point average roughness 0.1 μm) was used. The silicone rubber layer was prepared by applying room temperature curing type / addition type silicone rubber on a PET film and then curing it while smoothing by self-leveling. This silicone blanket was used by being mounted on a blanket cylinder having a width of 500 mm and a diameter of 400 mm.

  The conductive pattern was printed on the substrate by a rotary intaglio offset printing method using a cylindrical intaglio. The printing environment is a room temperature of 23 ° C. and a humidity of 55% RH. When ink is transferred from the intaglio to the silicone blanket, the linear velocity of the intaglio cylinder and the blanket cylinder is set to 50 mm / s, and the nip width of the silicone blanket is 15 mm. Adjusted. On the other hand, at the time of transfer from the silicone blanket to the transfer object, the linear velocity of the blanket cylinder was set to 200 mm / s, and the nip width of the silicone blanket was adjusted to 15 mm.

In this way, a stripe pattern (conductive pattern) made of a conductive paste is formed on the surface of the substrate, and then this is heated and cured at 200 ° C. for 30 minutes in a clean oven, whereby a line width of 180 μm and a film thickness (cured) Later) An electrode pattern of 5 μm was obtained.
Each time a series of printing steps by the rotary intaglio offset printing method was completed for one cycle, the silicone blanket and the intaglio were separated from each other, and the silicone blanket was dried. Specifically, the surface of the silicone blanket was dried by simultaneously spraying hot air and irradiating infrared rays, and heating the surface. At that time, the degree of heating was adjusted so that the surface temperature of the silicone blanket was 120 ° C. After the heat treatment, a metal roll having a diameter of 100 mm and a width of 500 mm was brought into contact with the surface of the silicone blanket to cool the surface of the silicone blanket. The surface temperature of the blanket after the cooling treatment was adjusted to 40 ° C.

(Comparative Example 1)
The same substrate, printing ink and silicone blanket as those used in Example 1 were used for printing the conductive pattern.
On the intaglio, 42 alloy plates with a width of 500 mm and a length of 500 mm are plated with chrome, and the surface is mirror-finished What gave (polishing with a polisher) was used. The conductive pattern formed by printing was a stripe pattern having a line width of 180 μm and a line interval of 360 μm, and the concave portions corresponding to the pattern were engraved by photolithography-etching.

  The conductive pattern was printed on the substrate by intaglio offset printing using a flat intaglio. The printing environment was the same as in Example 1. At the time of ink transfer from the intaglio to the silicone blanket, the ink transfer speed was set to 15 mm / s, and the nip width of the silicone blanket was adjusted to 12 mm. On the other hand, at the time of transfer from the silicone blanket to the transfer medium, the transfer speed of the ink pattern was set to 200 mm / s, and the nip width of the silicone blanket was adjusted to 12 mm.

In this way, a stripe pattern (conductive pattern) made of a conductive paste is formed on the surface of the substrate, and this is heated and cured in the same manner as in Example 1 to obtain a line width of 180 μm and a film thickness (after curing) of 5 μm. An electrode pattern was obtained.
Each time a series of printing steps by the intaglio offset printing method was completed for one cycle, the silicone blanket was dried (heating and cooling) in the same manner as in Example 1.

[Performance evaluation]
About the said Example and comparative example, the time (printing time) required in order to manufacture an electroconductive pattern with respect to 10 base materials was measured.
Moreover, about the 10th base material, the electroconductive pattern (before hardening) formed in the surface was observed with the microscope, and the printing shape was evaluated. The evaluation of the printed shape was mainly performed after confirming the linearity of the pattern and the smoothness of the pattern surface, and (i) the printed shape was good, and (ii) the linearity and smoothness were somewhat inferior. However, the evaluation was made in three stages: no problem in practical use, or (iii) inferior linearity and smoothness and inappropriate in practical use.

  The results are shown in Table 1.

As is clear from Table 1, in Example 1 in which the conductive pattern was printed by the rotary intaglio offset printing method, the printing time could be shortened to about 1/3 compared with Comparative Example 1. Moreover, the printed shape of the conductive pattern was good.
Therefore, according to the method for producing a conductive pattern according to the present invention, for example, in a use for forming a fine and thick conductive pattern like an electrode substrate for a flat display panel, while maintaining the printing accuracy of the pattern. The time required for forming the pattern can be greatly reduced, and mass production can be realized.

  The present invention is not limited to the above description, and various design changes can be made within the scope of the matters described in the claims.

It is a schematic diagram which shows one Embodiment of the manufacturing method of the electroconductive pattern which concerns on this invention.

Explanation of symbols

10 Intaglio cylinder 15 Blanket cylinder 16 Silicone blanket 20 Base material

Claims (1)

Supplying ink to the cylindrical intaglio,
A step of bringing the silicone blanket attached to the blanket cylinder into contact with the intaglio and transferring ink from the intaglio to the silicone blanket;
A step of separating the silicone blanket from the intaglio and rolling it while being in pressure contact with the transfer target, and transferring the ink from the silicone blanket to the transfer target;
A series of printing processes including
A method for producing a conductive pattern, comprising: performing the step of separating the silicone blanket from the intaglio and drying the surface of the silicone blanket after finishing the printing step once or a predetermined number of times.

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