KR100596215B1 - Offset printing method and offset printing ink - Google Patents

Abstract

The present invention relates to an offset printing method and a printing ink used therein, the printing ink comprising a printing blanket using a silicone-based elastomer on the surface and containing 2 to 280 parts by weight of low molecular weight polysiloxane with respect to 100 parts by weight of the resin component. use. After the printing ink is transferred to the transfer object, the surface of the printing blanket is heated by warm air from a hot air jet or the like so that its maximum temperature is 40 to 250 ° C, and the solvent of the printing ink absorbed in the blanket is evaporated. Subsequently, the cooling roller is brought into contact with the surface of the blanket for printing, and the cooling is performed such that the surface temperature of the blanket 31 is 15 to 55 ° C. Thereby, the pattern of a fine and thick film can be formed continuously with high precision.

Description

Offset printing method and printing ink using the same {OFFSET PRINTING METHOD AND OFFSET PRINTING INK}

1 is a schematic diagram showing an example of one process of the offset printing method according to the present invention,

Figure 2 is a schematic diagram showing the connection of Figure 1,

3 is a schematic diagram showing another process example of the offset printing method according to the present invention,

4 is a schematic diagram showing the connection of FIG.

Figure 5 (a) is a schematic diagram showing another example of the cooling roller,

5B is a schematic diagram showing an example of a cooling belt.

           <Explanation of symbols for the main parts of the drawings>

10, 11 offset printing press 12 hot air jet

13 Infrared irradiation device 15 Cold air jet

17 Cooling Roller 18 Cooling Belt

30 Printing plates 31 Blankets for printing

33 Subject 34 Print Ink

The present invention relates to a technique for continuously forming a thick film pattern by an offset printing method, and more particularly, an electrode pattern of a back substrate or a front substrate of a plasma display panel (PDP), and an organic thin film transistor (TFT). Of an offset printing method suitable for forming an electrode pattern of a substrate, a black matrix pattern of a color filter for a liquid crystal display (LCD), a shield pattern of a transparent electromagnetic shielding member, and an ink suitable for use in the offset printing method will be.

At present, in order to form the pattern of a thick film with high precision, the photolithographic method is mainly employ | adopted. However, the photolithography method has a problem that the manufacturing cost is very high because the process is complicated and the material, manufacturing equipment, etc. required for pattern formation are expensive. In addition, the cost of treating the waste liquid generated in the development process and the like at the time of pattern formation is high, and there is a problem in terms of environmental protection for the waste liquid.

Therefore, instead of the photolithography method, studies have been often made on a pattern formation method in which no harmful waste liquid or the like is generated at low cost. Among them, the concave plate offset printing method using a printing blanket (hereinafter referred to as a silicone rubber blanket) made of silicone rubber can form a thin line pattern of several tens to hundreds of micrometers in width, and thus is an alternative to photolithography. It is attracting attention.

However, it is pointed out that even when a pattern is formed by a concave plate offset printing method using a silicone rubber blanket, the printing pattern is deteriorated or printing accuracy is deteriorated by repeating printing.

As a cause, Japanese Patent No. 2993846 and Japanese Patent No. 3073674 have a low molecular weight silicone oil of glass that gradually grids from the inside of the silicone rubber to the surface of the silicone rubber blanket, but the oil is produced by repeating printing. This may decrease.

Therefore, as a method of repeatedly forming a thin line pattern of a thick film with high printing accuracy and maintaining the accuracy, Japanese Patent No. 2993846 discloses silicone oil having a lower interfacial tension than printing ink on the surface of a silicone rubber blanket. Japanese Patent No. 3073674 discloses a method (see claim 7 of the present publication) for applying a water repellent agent to a blanket surface.

However, it is also not possible to sufficiently solve the problem of deterioration of the shape of the print pattern or deterioration of printing accuracy over time by repeating printing by the above method.

As a cause which cannot fully solve the said problem, it is considered that the solvent of a printing ink submerges in a silicone rubber blanket, and the blanket swells gradually.

In particular, recently, when printing the PDP back substrate or the front substrate electrode pattern, the TFT substrate pattern, the transparent electromagnetic shield member shield pattern, or the like, the printing ink contains a metal powder or the like as a pattern forming material. Pastes are used, and at the same time, in order to paste these materials, for example, treatments such as high solvent content in ink or solvents that easily penetrate into silicone rubber such as aromatic hydrocarbons are employed. Therefore, the problem that the printing ink solvent causes the silicone rubber blanket to swell, and the affinity between the printing blanket and the printing ink increases to increase the line width of the pattern, resulting in a decrease in printing accuracy and the like. .

That is, in the case of printing using a silicone rubber blanket, even if the affinity with the printing ink is changed by swelling with a solvent, there is no significant change in the amount of transferred ink, so that the printing position at the center of the pattern can accurately reproduce the printing. Can be. Therefore, in the case of formation of an electrode with high precision if a predetermined conductivity is secured simply, or pattern formation of a color filter that corrects a pattern shape after printing by a planarization process, a large change in the line width and film thickness of the pattern is a problem. It may not work. However, for example, in pattern formation such as very thin line width, very large film thickness, and very high printing accuracy, such as an electrode pattern of a back substrate or a front substrate of a PDP, an electrode pattern of a substrate of a TFT, etc., It is very important to suppress changes in pattern line width and the like due to swelling of the blanket.

Therefore, the present inventors first perform heating and drying treatment such as spraying warm air on the surface of the blanket after the transfer of ink from the printing blanket to the transfer target, and then spraying cold air on the surface to lower the surface temperature of the blanket. By a cooling process, such as, a method for solving the problem of the swelling of the blanket by the solvent of the ink in a simple manner and without interrupting the flow of a series of processes of transferring the ink from the concave plate through the blanket to the transfer target. (Japanese Patent Laid-Open No. 2002-245931 / claim 1, FIG. 2, etc.).

However, even in this case, when a very fine pattern is formed with a very high precision, a phenomenon such as a decrease in the line width or a scattering of the pattern shape occurs by repeating printing, and the pattern shape is continuously performed with high precision. There was a difficult problem.

Accordingly, it is an object of the present invention to provide an offset printing method for forming a pattern of fine and thick films with high precision and continuously.

It is another object of the present invention to provide a printing ink suitable for forming fine and thick film patterns with high precision and continuously by an offset printing method.

Disclosure of the Invention

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, while carrying out research and heat-drying the silicone rubber blanket swollen with the solvent of a printing ink, the low molecular weight polysiloxane contained in a silicone rubber blanket according to the grade and frequency of heating. It has been found that this increase in phenomena occurs, thereby causing a problem of a decrease in printing accuracy, such as an increase in the line tension of the blanket, thereby increasing the line width of the printing pattern. In view of these facts, further research has been conducted to find an offset printing method for preventing swelling of the blanket and efficiently supplying a low molecular weight polysiloxane to the blanket, and a printing ink suitable for implementing the method. The invention has been completed.

That is, the offset printing method which concerns on this invention for solving the said subject is the offset printing method which transfers a printing ink from the printing plate to the blanket for printing, and then transfers it from the said printing blanket to a to-be-transferred body, WHEREIN: As a said blanket for printing, Using a silicone elastomer, using 2 to 280 parts by weight of low molecular weight polysiloxane with respect to 100 parts by weight of the resin component in the ink as the printing ink, transfer the printing ink from the printing blanket to the transfer target Thereafter, the surface of the printing blanket is heated so that its maximum temperature is 40 to 250 ° C, the solvent of the printing ink absorbed in the printing blanket is evaporated, and the surface temperature of the printing blanket is 15 to 55. It is characterized by cooling so that it may become ° C.

According to the offset printing method according to the present invention, since the surface of the printing blanket is made of a silicone-based elastomer, the releasability of the ink is low on the surface of the printing blanket, and the transfer of the ink image transferred from the printing plate to almost 100% is performed without separation. There is a number.

In addition, after the printing ink is transferred from the printing blanket to the transfer member, the surface of the printing blanket is heated to a predetermined temperature to increase and dry the solvent of the printing ink, thereby reducing the swelling of the surface of the printing blanket and the resulting decrease in printing accuracy. It can be significantly suppressed. Furthermore, since the surface of the blanket for printing is cooled to a predetermined temperature after heat drying, the problem that printing accuracy is lowered due to swelling of the surface of the blanket for printing due to heating can be prevented.

Furthermore, according to the offset printing method of the present invention, since a predetermined amount of low molecular weight polysiloxane is contained in the printing ink, the low molecular weight polysiloxane can be automatically supplied to the printing blanket by transferring the printing ink from the printing plate to the printing blanket. Can be. In other words, by using the specific printing ink, the low-molecular-weight polysiloxane can be reinforced on the blanket for printing even without special treatment for the loss of the low-molecular-weight polysiloxane due to the heat treatment. As a result, according to the offset printing method of this invention, even when forming a fine and thick pattern continuously, the outstanding printing precision can be maintained, without reducing line width and deterioration of a pattern shape.

(Heat treatment)

In the offset printing method of the present invention, it is preferable that the heating of the blanket surface for printing is made of at least one method selected from the group consisting of hot air jetting, infrared irradiation, and heating by a heater disposed on or inside the blanket. In the heating method of the said example, it is preferable from the viewpoint of the efficiency of heat drying, the handleability of a heating installation, etc. to perform both the blowing of warm air and the irradiation of infrared rays. That is, the apparatus for hot air spraying may share the apparatus for cold wind spraying and the injection holes of the hot air and cold wind. As a method of the heat treatment, in the above-described method, in the case of employing infrared irradiation or heating by a heater disposed inside or behind the blanket, the opportunity of blowing treatment of the offset printing process can be reduced. The effect by this is the same as the case where the contact of a cooling roller or a cooling belt is adopted as a method of cooling treatment.

In the heat processing of the blanket for printing, it adjusts so that the maximum value of the surface temperature may be in the range of 40-250 degreeC. The surface maximum temperature by this heat treatment should just be sufficient temperature for drying and drying the solvent of the printing ink absorbed by the printing blanket, and if it selects suitably in the said range within the range which does not thermally deteriorate the silicone elastomer of the printing blanket surface, good.

If the maximum temperature (surface maximum temperature) of the surface of the printing blanket does not reach the above range during the heat treatment, the printing blanket cannot be sufficiently dried. On the contrary, when the maximum temperature exceeds the above range, there is a problem that the line width of the pattern formed / transferred becomes thin due to thermal deterioration of the silicone-based elastomer or excessive heating of the blanket surface.

It is especially preferable that it is 50-250 degreeC, and, as for the highest value of the surface temperature of the blanket for printing, it is more preferable that it is 60-150 degreeC.

The temperature and injection time of the warm air during the heat treatment, the irradiation intensity and irradiation time of the infrared ray (IR), and the heating temperature and the heating time of the heater may be appropriately adjusted according to the maximum temperature of the surface of the printing blanket obtained during the heat treatment. . Therefore, although it is not specifically limited, For example, it is appropriate to set the temperature of the warm air to inject to 40-120 degreeC, and to set the injection time to 10 second-3 minutes. When the temperature of a warm air is less than 40-120 degreeC, there exists a possibility that sufficient drying effect may not be acquired. On the contrary, when it exceeds 120 degreeC, there exists a possibility that the problem of deterioration of the blanket for printing may arise.

(Cooling)

In the offset printing method of the present invention, the cooling of the blanket surface for printing is preferably performed by at least one method selected from cold air spraying, air cooling and water cooling on the back surface of the blanket, and contact of the cooling roller and the cooling belt to the blanket surface. Do. In the cooling method of the said example, it is preferable to employ the injection of cold wind from a viewpoint of a cooling efficiency, the handleability of a cooling installation, etc. That is, the apparatus for cold wind spraying may share the apparatus for hot wind spraying, and the injection hole of the cold wind and warm wind. As a method of the cooling treatment, in the case of adopting the contact of the cooling roller and the cooling belt to the blanket surface in the above-described method, the opportunity of the blowing treatment in the offset printing process can be reduced. In the printing formation of precision parts, it is necessary to sufficiently prevent foreign matter such as dust from adhering to the product, so that the burden on the dustproof treatment can be reduced by reducing the chance of blowing. In addition, in a device such as a member of a printing plate or an ink roller, it is necessary to prevent problems such as change in transferability and deterioration of ink caused by evaporation of a solvent, thereby reducing related opportunities by reducing the chance of blowing. The burden to prevent can be reduced. In addition, by abutting the cooling roller or the cooling belt, it is difficult to generate cooling stains on the surface of the blanket for printing.

In the cooling treatment of the blanket for printing, the surface temperature of cooling is reduced so that the surface temperature of cooling may be in the range of 15-55 degreeC from a viewpoint of preventing the fall of the printing precision by the thermal expansion thermal contraction of the blanket for printing. The surface temperature of the blanket for printing after the cooling is appropriately set in accordance with the surface maximum temperature of the blanket set by the aforementioned heat treatment, the room temperature of the clean room in which printing is performed, or the surface temperature of the printing plate or the printed object as described later. For example, in the case where the surface maximum temperature of the printing blanket is set to 40 ° C by the above-described heat treatment, if the surface temperature of the printing blanket after cooling is set within a range of less than 40 ° C regardless of the above range, good. In such a case, it is preferable to specifically set the surface temperature of the blanket for printing after cooling so that room temperature, such as a clean room, or the surface temperature of a printing plate or a to-be-printed object may become equal.

If the surface temperature of the blanket for printing has been cooled only to the extent exceeding the above range, there is a high possibility that the state in which the blanket is thermally expanded cannot be returned to its original state, and as a result, there is a problem that the printing accuracy is lowered. On the contrary, when cooling to the extent that the surface temperature of the blanket for printing falls below the said range, heat shrink will generate | occur | produce in a blanket, but the problem which degrades printing precision rather arises. It is preferable that it is 15-50 degreeC, and, as for the surface temperature of the blanket for printing after a cooling process, it is more preferable that it is 20-40 degreeC.

In addition, although it does not specifically limit in this invention, In order to improve the printing precision of the pattern (print pattern) formed by printing, the printing plate which supplies printing ink to the surface temperature (T _B ) of the printing blanket after a cooling process, and a contact blanket. The difference between the surface temperature (T _p ) of the (concave plate), the surface temperature of the blanket for printing after the cooling treatment, and the printed object receiving the printing ink from the blanket (PDP or TFT electrode pattern, LCD black matrix pattern, and transparent electromagnetic shielding member) In the case of forming the shield pattern, it is preferable that the difference between the surface temperature T _g of the substrate made of glass or the like is ± 5.0 ° C. as shown in the following formulas (iii) and (ii).

T _p -T _B | ≤5.0 (℃) (ⅰ)

T _g -T _B | ≤5.0 (° C) (ii)

In general, since the temperature in the clean room for manufacturing PDP, TFT, LCD, transparent electromagnetic shielding member, etc. is about 23 ° C, even if the surface temperature T _B of the blanket for printing after cooling treatment is in the range of 15 to 55 ° C, the printing plate It is also assumed that the difference between the surface temperature T _p and the difference between the surface temperature T _{g and} the surface to be printed does not satisfy the ranges of the formulas (i) and (ii). In this case, when the printing precision of the printing pattern is set more precisely, it is preferable to heat or cool the surface of the printing plate or the printed object so that the | TP-TB | and | TG-TB | are set to 5.0 degrees C or less.

The blanket for printing obtained after the cooling treatment for the temperature and injection time of the cold wind during the cooling treatment, the air cooling / water cooling temperature and cooling time from the back surface of the blanket, the surface temperature of the cooling roller / cooling belt which contacts the blanket surface, and the time for contacting the blanket surface, etc. What is necessary is just to adjust suitably according to surface temperature, etc. Therefore, although it is not specifically limited, For example, it is preferable to set the temperature of the cold wind to inject into temperature lower about normal temperature or about several degrees Celsius lower than normal temperature, and to set spray time to time shorter than between heating process by warm wind. If the temperature of the warm air is extremely low, there may be a problem of deterioration of the blanket for printing.

As a method of the cooling treatment, in the case of employing a cooling roll to the blanket surface or abutting of the cooling belt, the cooling roller and the cooling belt are preferably cooled at a portion other than the contact portion with the blanket for printing, as a method of the cooling treatment. Do. Thus, by performing water cooling with respect to a cooling roller or a cooling belt, the cooling efficiency of the surface of the blanket for printing can be improved.

(Printed version)

In the offset printing method of the present invention, the printing plate is preferably a concave plate. When the printing plate is a concave plate, it is possible to easily control the film thickness of the pattern by changing the depth of the concave plate concave portion, and finer than the flat plate (or flat plate without water) offset printing or the convex plate offset printing depending on the selection of the concave plate forming material. High-precision printing can be realized.

Although it does not specifically limit about the formation material of a recessed plate, etc., In terms of price, it is preferable to form a line part (concave part) by etching using metals, such as 42 alloy and stainless steel, and glass, such as soda-lime glass. From the viewpoint of durability of the recessed plate, a metal recessed plate is more preferable. In the field where very high length precision is required, alkali-free glass may be used, and in particular, when excellent durability is required, hard chromium plating may be applied to the surface. What is necessary is just to set the width | variety of the line pattern of a recessed board | substrate according to the object of printing, the kind of ink used, etc. Although the depth of this pattern is set according to the object of printing, the kind of ink to be used, the width of a pattern, etc., what is necessary is just to set normally in the range of 3-40 micrometers.

(Blanket for printing)

In the offset printing method of the present invention, the silicone elastomer on the surface of the blanket for printing is preferably a liquid or paste-like silicone rubber at the time of uncuring. In this case, when hardening and forming the silicone rubber layer of the blanket surface for printing, the said layer can be smoothed by self-leveling. Therefore, a blanket for printing having a very small surface roughness which is more preferable for high-precision pattern formation can be formed by a simple method.

About the surface hardness of the blanket for printing, since the deformation | transformation at the time of transfer becomes small when it hardens | cures, it leads to the fall of ink transfer property. On the contrary, when too soft, the deformation during transfer becomes large, which leads to a decrease in printing accuracy. In the present invention, the surface hardness of the blanket for printing is not particularly limited, but in view of the above, it is preferable to set it to 20 to 70 with JIS A hardness, and to set it to 30 to 60.

As for the surface roughness of the blanket for printing, the finer the printing pattern, the greater the influence on the printing shape. In the present invention, the surface roughness of the blanket for printing is not particularly limited, but when used for forming a fine pattern having a line width of about 20 μm, for example, the surface roughness is set to 1.0 or less with a 10-point average roughness. It is preferable to set it, and it is more preferable to set so that it may be 0.5 micrometer or less. Although it does not specifically limit about the thickness of the silicone elastomer which forms the blanket for printing, It is preferable to set the deformation | transformation at the time of transfer in an appropriate range, and to set it to 1.5 mm or less.

(Print Ink)

The printing ink according to the present invention for solving the above problems has a resin, a solvent and a low molecular weight polysiloxane, and the content of the low molecular weight polysiloxane is 2 to 200 parts by weight based on 100 parts by weight of the resin.

According to the printing ink of the present invention, when the transfer plate is transferred from the printing plate to the surface of the printing blanket, the low molecular weight polysiloxane can be appropriately supplied to the printing blanket. Therefore, the printing ink of the present invention is very suitable for the use of forming fine and thick film patterns with high precision and continuously by the offset printing method.

In the printing ink of the present invention and the printing ink used in the offset printing method of the present invention, the content of the low molecular weight polysiloxane is determined by the kind of the low molecular weight polysiloxane, the use of the printing ink, and the degree of heating and drying treatments for the blanket for printing. (Degree of loss of low molecular weight polysiloxane due to heating), degree of penetration into the blanket of low molecular weight polysiloxane, and the like. By setting the content of the low molecular weight polysiloxane in the above range, the diffusion effect of the low molecular weight polysiloxane when the printing ink is transferred from the printing plate to the blanket for printing can be properly maintained.

When the content of the low molecular weight polysiloxane in the printing ink is less than the above range, the effect of replenishing the low molecular weight polysiloxane with the blanket for printing becomes insufficient. On the contrary, when content exceeds the said range, supply of low molecular weight polysiloxane will become excess and the problem which causes the fall of printing precision rather arises. It is preferable that it is 5-150 weight part with respect to 100 weight part of resin components in a printing ink especially, and, as for content of low molecular weight polysiloxane, it is more preferable that it is 10-30 weight part. In addition, the low molecular weight polysiloxane in the printing ink penetrates into the blanket for printing while the solvent of the printing ink penetrates into the blanket for printing (and thus the contact blanket swells).

In the printing ink of the present invention and the printing ink used in the offset printing method of the present invention, the molecular weight of the low molecular weight polysiloxane contained in the printing ink is preferably from 100 to 100,000. By using the polysiloxane whose molecular weight is in the relevant range, the effect of the present invention of replenishing the low molecular weight polysiloxane component lost from the blanket for printing by heat treatment and maintaining the printing accuracy of the blanket can be further ensured. It is especially preferable that it is 500-15000, and, as for the molecular weight of low molecular weight polysiloxane, it is still more preferable that it is 3000-10000.

It is preferable that the low-molecular-weight polysiloxane used for this invention is 0.65-100000 mm <2> / s (= cSt) in the dynamic viscosity. By satisfy | filling the said range, kinematic viscosity can make favorable the permeability to the printing blanket surface, and can fully exhibit the effect of maintaining the ink release property of a printing blanket. It is preferable that especially the kinematic viscosity of low molecular weight polysiloxane is 10-5000mm <2> / s among the said ranges.

In addition, when the said low molecular weight polysiloxane hardens | cures a printed pattern, it softens, and it is set as a desired pattern, it is preferable to carry out evaporation or thermal decomposition. Accordingly, it is possible to prevent a problem that the polysiloxane component adversely affects, for example, the back electrode pattern for the PDP, which is finally formed.

Examples of the low molecular weight polysiloxane usable in the present invention include, but are not limited to, dimethyl silicone oil (e.g., product name "KF96 series" of Shinwol Chemical Co., Ltd., product name "TSF451 series of GE Copper Silicon Co., Ltd.). "," TSF456 series ", etc.], methyl phenyl silicone oil [For example, the product names" KF50 "," KF54 "of Shin-Wol Chemical Co., Ltd.," TSF431 "," TSF433 ", etc. of GE Co., Ltd.] , Methylhydrogen polysiloxane [for example, the product name "KF99" of Shinwol Chemical Co., Ltd.], methylhydrogen silicone oil (for example, the product name "TSF484" of GE Copper Silicon, etc.], cyclic dimethyl Polysiloxane [For example, the product name "KR995" of Shinwol Chemical Co., Ltd.) etc. are mentioned.

The resin and the solvent used to prepare the printing ink of the present invention are not particularly limited. However, the choice of the resin is important in controlling printing aptitude in offset printing. In practice, it may be appropriately selected and used as a resin and a solvent for an ink colorant according to the use of a printing ink.

The surface of the blanket for printing is in contact with the solvent of the printing ink during printing, but at that time, the solvent of the printing ink swells the blanket, thereby changing the wettability of the surface. If a swelling agent is used as the solvent of the printing ink, the change in the wettability of the surface of the blanket for printing can be suppressed. Therefore, when continuous printing is carried out, if the line width of the pattern is to be strictly controlled, a slight contamination of the surface of the printing plate is transferred. When it wants to prevent strictly, it is preferable in etc. On the other hand, it is preferable that the grade of swelling by a solvent is a little big from the viewpoint of the hydraulic property of ink.

The printing ink is, for example, (a) forming an electrode pattern of a back substrate or a front substrate of a PDP (hereinafter referred to as "ink for forming a PDP electrode pattern") or (b) an electrode pattern of a substrate of a TFT. (Hereinafter referred to as &quot; TFT electrode pattern forming ink &quot;), the metal powder such as silver powder can be uniformly dispersed in the printing pattern and can be lost when the printing pattern is soft. What is necessary is just to combine the resin component, the solvent which can disperse | distribute and melt | dissolve the resin component, and a metal powder uniformly, and can volatilize at the time of softening a printing pattern. In the case where the printing ink is (c) forming a black matrix of the liquid crystal color filter (hereinafter referred to as "black matrix forming ink"), carbon black or metal powder is uniformly dispersed and maintained in the printing pattern. What is necessary is just to combine the resin component which may be lost at the time of softening of a printing pattern, the solvent component which disperse | dissolves the resin component, carbon black, etc. uniformly, and may volatilize at the time of softening of a printing pattern. If the printing ink is (d) for forming the shield pattern of the electromagnetic shield member (hereinafter referred to as "shield pattern forming ink"), the fine conductive metal powder is uniformly dispersed and maintained in the printing pattern. The resin component which may be lost when the printed pattern is soft, the resin component and the conductive metal powder may be uniformly dispersed and dissolved, and a solvent which may be volatilized when the printed pattern is soft may be combined.

When the printing ink is the ink for forming the PDP electrode pattern of (a) or the ink for forming the TFT electrode pattern of (b), the resin of the printing ink is, for example, acrylic resin, methacryl resin, ethyl cellulose resin. Etc. are preferable. As the solvent of the printing ink, for example, higher alcohol [product name "Diador (R)" of Samjun Chemical Co., Ltd., butyl carbitol, etc. are preferable. In the related case, the content of the low molecular weight polysiloxane in the printing ink is particularly preferably 10 to 30 parts by weight based on 100 parts by weight of the resin component of the printing ink.

In the case where the printing ink is the black matrix forming ink of the above (c), the resin of the printing ink is, for example, a polyester resin, a melanin resin, a polyether resin [polyether ether ketone (PEEK), a polyether sulfone ( PES) etc.], urethane resin, acrylic resin, etc. are preferable. As the solvent of the printing ink, for example, higher alcohols (such as "Diador (R)" of evaporation), butyl carbitol acetate, butyl carbitol, triethylene glycol, acryl and the like are preferable. In the related case, the content of the low molecular weight polysiloxane in the printing ink is particularly preferably 5 to 150 parts by weight, more preferably 10 to 30 parts by weight based on 100 parts by weight of the resin component of the printing ink.

When the printing ink is the shield pattern forming ink of the above (d), the resin of the printing ink is, for example, a polyester resin, a melanin resin, a urethane resin, an acrylic resin, a polyether resin [polyether etherkene (PEEK) ), Polyether sulfone (PES) and the like] are preferable. As the solvent of the printing ink, for example, higher alcohols (such as "Dyador (R)", butyl carbitol acetate, butyl carbitol, triethylene glycol, etc.) are preferable. In the related case, low molecular weight in the printing ink It is preferable that content of polysiloxane is 3-150 weight part with respect to 100 weight part of resin components of a printing ink especially in the range mentioned above, and it is more preferable that it is 5-30 weight part.

The printing ink used in the present invention is not limited to this, but is appropriately mixed with a resin solvent and a low molecular weight polysiloxane, and optionally mixed with an electrically conductive powder, a pigment, etc., if necessary, mixed and stirred with three rolls or the like. It can be manufactured by.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are schematic diagrams showing an example of one step of the offset printing method according to the present invention.

The offset printing apparatus 10 shown in FIGS. 1 and 2 includes a blanket 31 for printing, a heating means (hot air jet nozzle 12 and an infrared irradiation device 13) for the surface thereof, and cooling means for the surface thereof. (Cold air injector 15), a printing plate (concave plate) 30, and a surface plate 16 formed by placing the object to be transferred 33 are provided.

As shown in Fig. 1 (a), the printing ink 34 is filled in the wire portion (concave portion) of the printing plate (concave plate) 30 by using 0 skim (rubber) 35, and the same drawing ( As shown in b)-(c), by moving the surface plate 16 and rotating the blanket copper, the printing ink 34 from the printing plate 30 to the printing blanket 31 is transferred. Also, as shown in Figs. 2 (d) to (e), the blanket for printing is moved by moving the surface plate 16 and rotating the blanket copper 32 while contacting the blanket for printing 31 on the transfer member 33. The printing ink from 31 to the transfer object 33 is transferred, and a print pattern 34a is formed on the transfer object 33 (same figure f). In this way, after completing a series of transfer processes, as shown in FIG. 2 (f), the jet of hot air from the hot air jet nozzle 12 and the infrared ray (IR) from the infrared irradiation device 13 are shown on the blanket 31 for printing. Heating and drying treatment by irradiation) is performed, followed by cooling treatment by injection of cold wind from the cold wind jetting port 15.

3 and 4 are schematic diagrams showing another process example of the offset printing method according to the present invention.

The offset printing machine 11 shown in FIGS. 3 and 4 is provided with cooling rollers 17a to 17c in place of the cold air jetting port 15 as the cooling means. It is provided with the heating means (the hot-air jet nozzle 12 and the infrared irradiation apparatus 13), the printing plate 30, and the to-be-transferred body 33 like the offset printing machine 10. As shown in FIG.

In the printing using the offset printing machine 11, first, as shown in Figs. 3A, 3B, and 3C, the printing ink 34 from the printing plate 30 to the printing blanket 31 is formed. Is transferred. This transfer step is the same as the case shown in Figs. 1 (a) to (c), respectively. Subsequently, as shown in FIGS. 4D and 4E, a printing pattern 34a is formed on the transfer object 33. The transfer (pattern forming) process here is the same as the case shown in Figs. 2 (d) and (e), respectively. Furthermore, after completing a series of transfer processes, as shown in FIG. 4 (f), the hot air jet from the hot air jet nozzle 12 and the infrared (IR) jet from the infrared device 31 are applied to the blanket 31 for printing. Heat-drying treatment is performed, and then cooling treatment is performed by bringing the cooling rollers 17a to 17c into contact with the surface of the blanket 31 for printing.

In the offset printing method according to the present invention, as a method of heating the surface of the blanket 31 for printing, in addition to spraying warm air or infrared rays, a blanket for printing (with a heater disposed inside the blanket copper 32) It is also possible to employ a method of heating (not shown) from the back surface of 31 or by a heater disposed inside the printing blanket 31 itself.

On the other hand, in the offset printing method according to the present invention, as a method of heating the surface of the blanket 31 for printing, air cooling is performed from the inside of the blanket copper 32 in addition to spraying cold air or abutting a cooling roller. Alternatively, a method of cooling (not shown) by performing water cooling to cool the back surface of the blanket 31 for printing may be employed. One set of cooling rollers 17 (a) to 17 (c) shown in FIG. 4 (f) may be, for example, one cooling roller 17 as shown in FIG. 5 (a), and the same drawing (b). Cooling belt 18 as shown in FIG.

Since the cooling roller and the cooling belt need to be rapidly de-heated by contact with the blanket for printing, it is preferable to use a material having high thermal conductivity as the material for forming this. Specifically, engineering plastics such as metals such as copper, stainless steel, nickel, aluminum, iron, or alloys thereof, polyimide, polyamideimide, polyether ether ketone (PEEK), polyether surone (PES), and the like Can be mentioned.

As a method of water-cooling a cooling roller or a cooling belt in the site | parts other than the contact part with a blanket for printing, the method of air cooling or water cooling from a cooling roller or a cooling belt inside, for example is mentioned.

The metal belt may be, for example, a so-called caterpillar type product formed by forming a linkage by connecting a flat sleeve manufactured by an electroforming method or a flat metal sheet extending in the axial direction of the blanket copper. have.

The hot air jetting port 12 of the hot air jetting apparatus as the heating / drying means on the surface of the blanket for printing and the cold air jetting port 15 of the cold air jetting apparatus may be used as cooling means.

Example

Next, an Example and a comparative example are given and this invention is demonstrated.

[Application to Backside Electrode Printing Machine for PDP]

Examples and comparative examples when the present invention is applied to pattern formation of the back electrode of a plasma display panel (PDP) are shown below.

Example 1

(I) Preparation of Printing Ink

To 100 parts by weight of acrylic resin, 2000 parts by weight of silver powder, 10 parts by weight of glass frit, 30 parts by weight of higher alcohol as a solvent, and 10 parts by weight of silicon oil as low molecular weight polysiloxane were added, followed by stirring and mixing. The printing ink for electrode formation was obtained.

Among the various materials used for the production of printing ink, the acrylic resin product name "KP-1700" and the silver powder the product name "AgC-1561" by Futian Metal Powder Industry Co., Ltd. The product name "FJ-101" of Nippon Ferro Corporation was used, and the product name "Dayador 7 (R)" of Samjun Chemical Co., Ltd. was used as a solvent (higher alcohol), respectively. In addition, dimethyl silicone oil (product name "KF-96", kinematic viscosity 200-300 mm <2> / s) of Shinwol Chemical Co., Ltd. was used for silicone oil.

(II) Formation of back electrode

Using the printing ink of (I), printing of the back electrode pattern of the PDP was performed by the concave plate offset printing method.

As the printing plate, a concave plate having a stripe patterned recess formed by etching was used. The opening width of the recess was 180 µm, the depth was 30 µm, the pitch of the pattern was 360 µm, the total length of the pattern was 400 mm, and the total number of patterns was set to 1000. As a blanket for printing, the silicone rubber blanket provided with the silicone rubber whose JIS A hardness is 0.6 degree of thickness 40 degree on the surface was used. This blanket is made by Shinwol Chemical Co., Ltd. one-component RTV silicone rubber (addition type, product name "KE-1603", uncured viscosity of 80 Pa.s) on a film of polyethylene terephthalic acid (PET) with a thickness of 0.35 mm After application, it was produced by smoothing and curing by self-leveling. As a to-be-transferred body, the soda-lime glass plate of thickness 1.5mm, length, and width 500mm was used.

The printing plate (concave plate) 30, the printing blanket (silicone rubber blanket) 31 and the transfer object (soda lime glass plate) 33 are arranged as shown in Fig. 1 (a), and the transfer member 33 is placed on the transfer body 33. Printing ink (back electrode forming ink) 34 was printed. Printing is carried out in an environment of room temperature 23 ° C. and humidity 55%, and when transferring from the printing plate 30 to the blanket 31 for printing, the transfer speed is 15 mm / s, and the nip width of the blanket for printing 31 is 12 mm. Was adjusted to Moreover, at the time of transferring from the printing blanket 31 to the to-be-transferred body 33, the transfer speed was adjusted to 200 mm / s and the nip width of the printing blanket 31 to 12 mm.

The heating, drying, and cooling treatments for the printing blanket 31 perform a cycle of transferring the printing ink 34 from the printing plate 30 to the transfer object 33 via the printing blanket 31. It was done every time.

The heating and drying of the blanket 31 for printing was performed simultaneously by the injection of the warm air from the warm air jet nozzle 12 and the irradiation of infrared rays by the IR irradiation device (infrared heater) 13. The conditions of heating and drying process were adjusted so that the maximum temperature of the surface of the blanket for printing might be 120 degreeC.

On the other hand, cooling of the blanket 31 for printing was performed by the injection of the cold air from the cold air injection port 15. As shown in FIG. The conditions of the cooling process were adjusted so that the surface temperature of the blanket for printing 31 might return to 40 degreeC.

Under the printing conditions, continuous printing was performed on 500 sheets of the transfer object (soda lime glass plate), and the pattern of the formed back electrode forming printing ink was dried by heating at 100 캜 for 30 minutes. At the time of continuous printing, it sampled every 10 prints, and the evaluation test shown to the following (III) was done. Further, the print pattern of the sampled print product was softened at 550 ° C., and the evaluation test shown in the following (IV) was performed on the pattern of the back electrode thus obtained.

(III) Performance Evaluation of Ink Patterns

a) calculation of line width change

The printed pattern of the sampled print product was observed with an electron microscope, and line widths (mu m) were measured for 15 measurement points in the printing surface. The average value of the data thus obtained is taken as the line width data, and linear regression calculation is performed based on the line width data of the sample obtained for every 10 prints. It was calculated as. In the case of forming the back electrode of the PDP, it is possible to determine that the line width change amount (µm / sheet) determined by the regression number (regression gradient) is within ± 0.05, preferably within ± 0.02.

b) calculation of capability index Cp

The change range (tolerance) of the line width was set to ± 15 µm, and the capability index Cp value was calculated. The Cp value is

Cp value = 15 × 2 / (6 × δ)

Obtained by In the formula, δ represents the standard deviation. In the case of forming the back electrode of the PDP, the Cp value can be determined to be 1.33 or more, preferably 1.4 or more.

c) evaluation of printing geometry

The print pattern of the sampled print product was observed with an electron microscope to determine the overall linearity of the pattern.

d) evaluation of printing precision

The printing pattern of the sampled printed product was observed with an electron microscope, and the quality of printing precision was determined based on the deviation of the position of the pattern and the alignment mark position. In the case of forming the back electrode pattern of the PDP, it can be found that the printing accuracy is within ± 20 μm.

(Ⅳ) Performance Evaluation on Back Electrode Pattern

e) adhesion to the substrate

The test was carried out according to the method (testing method) described in 8.4 "Pencil Scratch Value" of JIS K 5400, and the adhesion between the back substrate pattern and the soda lime glass substrate obtained by softening the printed pattern was evaluated. As the back electrode pattern of the PDP, it can be determined that the pencil scratch value is 4H or more (> 4H), preferably 5H or more (> 5H).

F) electrical resistance

The resistivity p (Ω /?) Of the pattern was measured in accordance with JIS K 7194 "Resistivity test method by the four-needle method of conductive plastic" which evaluates the electrical property of the back electrode pattern obtained by softening a printing pattern. Samjun Chemical Co., Ltd. low resistivity meter (product name "Loresta-GP") was used for the measurement. As the back electrode pattern of the PDP, a resistivity p of 15? /? Or less, preferably 9? /? Or less can be obtained.

(V) Overall evaluation

The performance evaluation of the ink pattern of (III) and the performance evaluation of the back electrode pattern of (IV) were collectively judged to evaluate whether or not it was suitable as a method of forming the back electrode pattern of the PDP. Evaluation criteria are as follows.

A +: The performance evaluation was very good.

A: The performance evaluation was favorable.

A-: Although the evaluation was low in some items, there was no problem in practical use.

B: The performance evaluation was low and practically insufficient.

The above results are shown in Table 1.

Example 2

The cooling means of the blanket for printing 31 was replaced with the cooling rollers 17a to 17c instead of cold air spraying (see Fig. 4 (f)). An electrode pattern was formed. That is, the same thing as what was obtained by (I) of Example 1 was used as a printing ink. In addition, performance evaluation was performed similarly to (III)-(IV) of Example 1. The results are shown in Table 1.

(Examples 3 and 4)

All of the examples except that the amount of the low molecular weight polysiloxane (dimethylsilicone oil) to be mixed with the printing ink (content of 100 parts by weight of the resin powder) was 50 parts by weight in Example 3 and 270 parts by weight in Example 4. In the same manner as in (I) of 1, a printing ink for forming a back electrode of a PDP was obtained. A back electrode pattern was formed in the same manner as in (II) of Example 1 except that the related printing ink was used, and performance evaluation was performed in the same manner as in (III) to (IV) of Example 1. The results are shown in Table 1.

(Comparative Examples 1 and 2)

The amount of the low molecular weight polysiloxane (dimethylsilicone oil) blended into the printing ink (content of 100 parts by weight of the resin powder) was changed to 1 part by weight in Comparative Example 1 and 300 parts by weight in Comparative Example 2. In the same manner as in Example (I) of Example 1, a printing ink for forming a back electrode of a PDP was obtained. A back electrode pattern was formed in the same manner as in Example (II) except that the related ink was used, and performance evaluation was performed in the same manner as in (III) to (V) of Example 1. The results are shown in Table 1.

Table 1

In Table 1 and Table 2 and Table 3, "ⅰ" in the "cooling means" column represents the injection of cold wind, and "ii" represents the contact of the cooling roller.

As is clear from Table 1, in Examples 1 to 4 where printing was carried out using a printing ink containing an appropriate amount of low molecular polysiloxane (dimethyl silicone oil), the line width variation was very small, the printing precision was very good, and the process capability index was also shown. Very high results were obtained. In particular, in Example 2, in which the printing blanket was cooled by abutment of the cooling roller, the line width change amount was further reduced, and the processability index Cp was further reduced, compared to Example 1, in which the cooling treatment was performed by injection of cold air. Could be enlarged.

In contrast, in Comparative Example 1 in which the low molecular weight polysiloxane was not blended in the printing ink, the line width change rate was large, and the process capability index was insufficient. Conversely, in Comparative Example 2 in which the compounding amount of the low molecular polysiloxane in the printing ink was too large, a problem in which the line width was too small occurred, and the process performance index was insufficient.

(Comparative Example 3)

A back electrode pattern was formed in the same manner as in Example (II) except that the heating, drying and cooling treatments for the blanket for printing were not performed. That is, the same thing as what was obtained by (I) of Example 1 was used as a printing ink. In addition, performance evaluation was performed similarly to (III)-(IV) of Example 1. The results are shown in Table 2.

(Examples 5 and 6)

Except for setting the maximum temperature of the surface of the blanket for printing during the heating and drying process to 160 DEG C in Example 5 and 240 DEG C in Example 6, the case of the back electrode pattern was the same as in Example (II) of Example 1 Formation was performed. As the printing ink, the same one as obtained in Example (I) of Example 1 was used. In addition, performance evaluation was performed similarly to (III)-(IV) of Example 1. The results are shown in Table 2.

(Comparative Example 4)

A back electrode pattern was formed in the same manner as in Example (II) except that the maximum temperature of the printing blanket surface at the time of heating and drying was 300 ° C. That is, the same thing as what was obtained by (I) of Example 1 was used as a printing ink. In addition, performance evaluation was performed similarly to (III)-(V) of Example 1. The results are shown in Table 2.

Table 2

As is clear from Table 2, in Examples 1, 5, and 6 in which the heating, drying, and cooling treatments for the blanket for printing were carried out in an appropriate temperature range, the line width variation was very small, the printing accuracy was very good, and the capability capability index. Also very high results were obtained.

In contrast, in Comparative Example 3 in which the heating, drying, and cooling treatments were not performed, the line width change rate was very large, the process capability index was very low, and the printing shape was deteriorated.

On the contrary, in Comparative Example 4 in which the surface temperature of the blanket for printing of the heating and drying treatment was too high, problems such as excessively small line width or deterioration of printing shape were issued, and the process capability index was insufficient.

(Examples 7 and 8)

The back electrode pattern was formed in the same manner as in Example (II) except that the surface temperature of the printing blanket after cooling treatment was set to 20 ° C. in Example 7 and 50 ° C. in Example 8. As the printing ink, the same one as obtained in Example (I) of Example 1 was used. In addition, performance evaluation was performed similarly to (III)-(V) of Example 1. The results are shown in Table 3.

(Comparative Examples 5 and 6)

The back electrode pattern was formed in the same manner as in Example (II) except that the surface temperature of the printing blanket after cooling treatment was set to 10 ° C in Comparative Example 5 and 60 ° C in Comparative Example 6. As the printing ink, the same one as obtained in Example (I) of Example 1 was used. In addition, performance evaluation was performed similarly to (III)-(V) of Example 1. The results are shown in Table 3.

Table 3

As is clear from Table 3, in Examples 1, 7, and 8 in which the heating, drying, and cooling treatments for the blanket for printing were carried out at an appropriate temperature range, the line width variation was very small, the printing accuracy was very good, and the capability capability index. Also very high results were obtained.

In contrast, in Comparative Example 5 in which the surface temperature of the blanket for printing was excessively reduced in the cooling treatment, the process capability index tends to be low. In addition, a problem arises in that the printing shape is deteriorated, and the accuracy of the printing position is changed to decrease.

Conversely, in Comparative Example 6 in which the surface temperature of the blanket for printing was not sufficiently lowered in the cooling treatment, although the line width change amount and the process capability index were sufficient, the printing position precision was lowered due to the thermal expansion of the blanket for printing. There was a problem.

As described above, according to the present invention, a pattern of fine and thick films can be continuously formed with high precision.

Claims (8)

In offset printing in which a printing ink is transferred from a printing plate to a blanket for printing, and then transferred from the printing blanket to a transfer object, As the blanket for printing, one using a silicone-based elastomer on its surface is used, As the printing ink, one containing 2 to 280 parts by weight of low molecular weight polysiloxane based on 100 parts by weight of the resin component in the ink, After transferring the printing ink from the printing blanket to the transfer member, the surface of the printing blanket is heated to have a maximum temperature of 40 to 250 ° C, and the solvent of the printing ink absorbed in the printing blanket is evaporated. Subsequently, the surface of this printing blanket is cooled so that the surface temperature may be 15-55 degreeC. The offset printing method characterized by the above-mentioned. The method of claim 1, And cooling the surface of the blanket for printing by at least one method selected from the group consisting of cold wind spraying, air cooling and water cooling on the rear surface of the blanket, and abutment of the cooling roller and the cooling belt to the surface of the blanket. The method of claim 2, Offset printing method characterized in that the cooling roller and the cooling belt is water-cooled and air-cooled at a portion other than the contact portion with the blanket for printing. The method according to any one of claims 1 to 3, And the heating of the surface of the printing blanket comprises at least one method selected from the group consisting of hot air spraying, infrared irradiation, and heating by a heater disposed on or inside the blanket. The method according to any one of claims 1 to 3, And the printing plate is a concave plate. The method according to any one of claims 1 to 3, And the silicone elastomer is a liquid or paste silicone rubber when uncured. The method according to any one of claims 1 to 3, Offset printing method, characterized in that the molecular weight of the low molecular weight polysiloxane is 100 ~ 100,000. delete

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