JP2003308973A - Method of manufacturing organic el panel, and blanket for printing used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an organic EL panel excellent in mass productivity in which a detailed pattern of the organic EL element can be formed by a simple method without using expensive equipment and at a low cost, and to provide a blanket for printing which is suitable for enforcement of the method of manufacturing the organic EL panel. <P>SOLUTION: After filling up with a printing ink, which is made by dissolving or distributing with stability an organic EL element forming material such as a light-emitting layer forming material into a solvent, into a dent part of an intaglio of printing, the printing ink concerned is transferred to the blanket for printing from the dent part of the intaglio of printing, further, by transferring the printing ink transferred to the surface of the blanket for printing on a substrate 11, a light-emitting layer 14 or the like is formed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic EL panel which enables formation of extremely fine patterns, and
A blanket for intaglio offset printing suitable for the manufacturing method.

[0002]

2. Description of the Related Art An organic EL (electroluminescence) panel consumes less power because it can be driven at a low DC voltage, is a self-luminous type with high brightness, and can be thinned. Due to its characteristics, it has been expected in recent years to be applied to displays in mobile phones, PDAs (personal digital assistants), mobile personal computers, in-vehicle navigation systems and the like.

The organic EL element constituting this organic EL panel includes, for example, a transparent conductive film (ITO film, anode) on a glass substrate and a light emitting layer containing at least an organic light emitting body, and if necessary, transports holes. A single layer or a multi-layer organic material layer including a layer and an electron transport layer, and a cathode (metal electrode) are laminated. In this organic EL device, a voltage is applied between both electrodes by a DC power source, and holes injected from the transparent conductive film into the hole transport layer and electrons injected from the cathode into the light emitting layer are contained in the light emitting layer. The light is generated by exciting the organic light-emitting body by binding with.

Organic EL devices currently being researched and developed are
The light emitting body is mainly composed of a low molecular weight type organic compound, and the light emitting layer is formed by vapor deposition of the organic low molecular weight light emitting body on a substrate. Therefore, there is a limit to the size increase of the organic EL panel from the viewpoint of the vapor deposition device. On the other hand, a polymer type organic light emitting body (organic polymer light emitting body) can be freely used as an ink by dissolving itself in a solvent. Therefore, the light emitting layer can be formed by various conventionally known printing methods or ink jet methods. Moreover, the organic EL panel can be upsized by forming the light emitting layer by using the printing method or the ink jet method.

[0005]

However, in the case of forming the light emitting layer and the like by the ink jet method, it is necessary to set the viscosity of the ink for ink jet to be extremely low in order to prevent clogging of the nozzle. On the other hand, if the viscosity of the ink is low, the ink is likely to spread on the surface of the substrate or the like onto which the ink is sprayed, so that it is necessary to perform a fluorine-based surface treatment on the surface of the substrate or the like to prevent this. In addition, in the inkjet method, one of the organic EL elements is used.
It is necessary to spray ink on each pixel. Therefore,
There is a problem that the process is complicated and the productivity is low. Furthermore, since the printing accuracy of the inkjet method itself is as low as about ± 30 μm, it is difficult to improve the accuracy. On the other hand, when the light emitting layer and the like are formed by the conventional printing method, it is usually difficult to form a pattern of the order of several tens of μm required for an organic EL element, and the accuracy of the organic EL element may decrease.

Therefore, an object of the present invention is to provide a fine pattern such as a light emitting layer in an organic EL device by a simple method without using expensive equipment and at low cost, which is excellent in mass productivity. An object of the present invention is to provide a method for manufacturing an organic EL panel.

Another object of the present invention is to provide a printing blanket suitable for forming a fine pattern such as a light emitting layer in an organic EL panel by a printing method.

[0008]

Means for Solving the Problems and Effects of the Invention Organic E
The light emitting layer of the L panel is required to have an extremely thin film thickness of about 50 to 100 nm from the viewpoint of light emitting characteristics, and further, the thickness is uniform and the surface is extremely smooth. Required. Regarding other layers such as a hole transport layer and an electron transport layer which are arbitrarily formed in the organic EL panel, it is required to set the film thickness to be extremely thin, about 50 to 100 nm.

Conventionally, the vapor deposition method used for forming a light emitting layer is a very excellent method for forming a film having a uniform thickness and excellent smoothness. There is an unavoidable drawback in increasing the size of the device. On the other hand, when an organic polymer light-emitting body or the like is dissolved in a solvent and used as an ink, a film is formed by coating such as spin coating, and the film is patterned by photolithography and etching techniques or patterned by a printing method. Can be adopted. But,
In the former case, there are problems that most of the material forming the light emitting layer is wasted, the cost is high, and the waste liquid treatment after the treatment is time-consuming.

When forming a light emitting layer or the like by a screen printing method among the conventionally known printing methods, since the line width of the pattern is less than 100 μm, it is not possible to faithfully reproduce the shape, and the disconnection or the like occurs. However, there is also a problem that it is difficult to form a thin film pattern having a thickness of about 0.1 μm when dried. Further, in principle, the applied force is different between the central part and the peripheral part of the screen, and the amount of expansion is different, resulting in different pattern printing accuracy on the same back substrate. Therefore, the printing accuracy (in-plane ± 10 μm) required for the light emitting layer or the like cannot be sufficiently satisfied.

In the case of the lithographic offset printing method, the thickness of the pattern obtained by one printing is as thin as 0.5 μm or less, and if the reduction of the thickness due to the drying process is taken into consideration, it is 2 to before the drying. Overprinting must be performed until a film thickness of about 10 μm is obtained. As a result, not only the manufacturing cost increases, but also the productivity and the printing accuracy are significantly reduced. On the other hand, printing using a waterless planographic printing plate (for example, trade name "TAN" manufactured by Toray Industries, Inc.) in which silicone rubber is used for the non-image area of the transfer body is widely used, which is an improved method of the planographic offset printing method. is there. However, in the case of waterless lithographic printing as well as in ordinary lithographic printing, the film thickness of the pattern obtained by one printing is only about 0.5 μm, and therefore productivity and printing accuracy are reduced due to overprinting. ,
There is a problem such as an increase in manufacturing cost. further,
The resolution of the waterless planographic printing plate is about 50 μm, and it is impossible to print finer lines than this, and therefore it is unsuitable for pattern formation of a light emitting layer or the like which requires a fine and highly precise pattern.

The letterpress offset printing method also has the same problem as described above because the thickness of the pattern obtained by one printing is small. Further, in this case, ink squeezing out called marginal zone around the pattern is caused. Since a part is generated, it is extremely difficult to faithfully reproduce the pattern. Further, in the case of intaglio direct printing (gravure printing), the plate used for direct printing is a rigid member, so that uniform printing pressure is applied to a glass substrate that is rigid and has uneven thickness. Becomes difficult,
As a result, there is a problem that uneven transfer is likely to occur.

On the other hand, in the intaglio offset printing method,
It is possible to freely control the film thickness of the pattern by changing the depth of the recess of the intaglio plate. In addition, by using a printing blanket (transfer body) that has a surface printing layer made of a material with low surface energy such as silicone rubber, it is possible to use a rigid and slightly uneven thickness substrate or a flexible film substrate. Also, it becomes possible to transfer 100% of the ink transferred from the intaglio plate to the printing blanket. Therefore, a pattern having a sufficient thickness can be formed by printing once, and the ink separation occurs only once at the time of transfer from the intaglio plate to the printing blanket. Can have a very good shape. For the above reasons
In the method of manufacturing an organic EL panel according to the present invention, an intaglio offset printing method is adopted for the purpose of forming a pattern of an organic EL element.

That is, in the method of manufacturing an organic EL panel according to the present invention for solving the above-mentioned problems, a printing ink formed by dissolving or stably dispersing an organic EL element forming material in a solvent is filled in the concave portion of the intaglio plate. After that, the printing ink is transferred from the concave portion of the intaglio plate to the printing blanket, and further,
The printing ink transferred to the surface of the printing blanket is transferred onto a substrate.

According to the method of manufacturing an organic EL panel of the present invention, it is not necessary to use expensive equipment as in the case of forming an organic EL element by a vapor deposition method, and a simple means / method by an intaglio offset printing method is used. Efficient organic E
It is possible to form the L element, and furthermore, it is possible to form an extremely fine pattern with high accuracy. In the method for manufacturing an organic EL panel of the present invention, the “organic EL element forming material” means a material for forming a light emitting layer which is an essential constituent element of the organic EL element, and a hole transport layer provided as necessary. And a material for forming the electron transport layer.

Japanese Patent Application Laid-Open No. 11-273859 discloses an invention in which a light emitting layer is formed by various printing methods such as relief printing, planographic printing, gravure printing flexographic printing and screen printing. However, the invention disclosed in the above publication uses a low molecular weight organic compound as a material (organic luminescent material) for forming an organic luminescent layer, and the printing method described above is different from the intaglio offset printing method. Both methods are difficult to form a fine pattern with high accuracy.

It should also be noted that when a light emitting layer is formed by printing using an organic polymer light emitting material, the solvent used in the ink for forming the light emitting layer causes a decrease in printing accuracy. At present, for example, a π-conjugated polymer-based compound is mainly used as an organic polymer light-emitting body for an organic EL element, and among them, polyphenylene vinylene (PP) is used.
V) has received the most attention. In recent years, a polyparaphenylene derivative having a side chain attached to PPV (MEH-PPV,
Orange) and other polyalkylthiophenes (PA
T, red), polydialkylfluorene (PDAF, blue), polyparaphenylene (PPP, blue), and various organic polymer light emitters have been developed.

These organic polymer light emitters have low solubility in organic solvents in common, and when a printing ink is prepared using the organic polymer light emitter, the solid content is 15% by weight or less, preferably. Not only needs to be kept to 10% by weight or less, but also it is necessary to use an aromatic hydrocarbon such as xylene or toluene as a solvent. An organic solvent such as an aromatic hydrocarbon easily swells the rubber layer (surface printing layer) arranged on the surface of the printing blanket used for offset printing, which greatly reduces the printing accuracy, In this case, there is a problem that the printing blanket is damaged and printing cannot be performed.

Therefore, in a preferred embodiment of the method for manufacturing an organic EL panel according to the present invention, the printing blanket used in the manufacturing method has (1) a ten-point average roughness Rz of 0.01 to 3 μm.
and a surface printing layer having a volume change rate of 40% or less when immersed in a solvent of the above printing ink at 23 ° C. for 24 hours, (2) having a thickness of 0.03 to 5.0 mm,
A surface printing layer having a hardness (JIS A) of 20 to 80 ° and a volume change rate of 40% or less when immersed in a solvent of the printing ink at 23 ° C. for 24 hours,
(3) Solubility constant 5-8 (cal / mol / cm ³ ).
^The surface tension γ _s is 5 to 35d using ^1/2 elastic body.
a surface print layer of yn / cm, or (4) an elastomer having a fluorinated polyether skeleton and a silicone cross-linking terminal group, the surface roughness is 0.01 to 3 μm in ten-point average roughness Rz. It is preferable to have a surface printing layer of.

According to the above preferred embodiment, even if the organic EL
Even if the solvent of the ink containing the element forming material causes remarkable swelling in the surface printing layer in the conventional ordinary printing blanket, the pattern of the organic EL element can be made extremely fine and with extremely high accuracy. It can be formed. In the present invention, the “solubility constant” is a so-called SP value (solubility parameter), which is a value obtained by the square root of a value obtained by dividing the heat of vaporization per mol by the volume [(cal / mol · cm ³ )
^1/2 ].

In the printing blanket described in (1) to (3) above, the surface printing layer is a silicone elastomer.
It is preferable to use a fluorine-based elastomer, butyl rubber, ethylene-propylene rubber, or a mixture thereof, from the viewpoint of further improving the accuracy of the pattern of the organic EL element. On the other hand, in the printing blanket described in (4) above, the surface printing layer has a surface roughness of 0.01 to 3 μm in ten-point average roughness Rz.
It is preferable from the viewpoint of further improving the accuracy of the pattern of the organic EL element.

In the method for manufacturing an organic EL panel according to the present invention, examples of the organic EL element forming material include organic polymer light emitting materials. In this case, the light emitting layer of the organic EL panel can be formed by transferring the printing ink obtained by dissolving or stably dispersing the organic EL element forming material in the solvent onto the substrate. As described above, organic polymer light emitters have a low solubility in organic solvents in common, the content of the solvent is large when preparing a printing ink, and the solvent is used as a normal printing blanket. Aromatic hydrocarbons such as xylene and toluene that cause significant swelling in the surface printing layer of are used. However, according to the printing blanket used in the method for producing an organic EL panel of the present invention, (i) the surface roughness of the surface printing layer and the solvent resistance of the ink (solvent resistance), (ii) the surface printing layer Thickness and hardness and resistance of ink to solvent, (iii) Solubility constant (SP value) and surface tension of surface printing layer forming surface printing layer, or (iv) Specific material forming surface printing layer and its Various characteristics related to the surface printing layer such as surface roughness, materials used, etc. are appropriately combined,
As a result, an extremely fine pattern can be printed and formed with high accuracy even in a printing ink containing an organic polymer luminescent material.

In the method for manufacturing an organic EL panel according to the present invention, the printing pressure for transferring the printing ink transferred to the surface of the printing blanket onto the substrate is 1 to 30 kgf / c.
It is preferably m. If the printing pressure is less than the above range, the surface of the transferred pattern cannot be sufficiently smoothed, and the transferability of the ink may be reduced. On the other hand, when the printing pressure exceeds the above range, the deformation of the surface printing layer becomes too large, which may reduce the printing accuracy of the pattern.

The printing blanket according to the present invention for solving the above problems is suitable for the method for manufacturing an organic EL panel of the present invention, and has (I) a ten-point average roughness Rz of 0.
A surface printing layer having a volume change of 40% or less when immersed in a solvent of a printing ink at 23 ° C. for 24 hours, and (II) having a thickness of 0.03 to 5.0.
mm, hardness (JIS A) is 20 to 80 °, and a surface printing layer having a volume change rate of 40% or less when immersed in a solvent of printing ink at 23 ° C. for 24 hours,
(III) Solubility constant of 5 to 8 (cal / mol / cm ³ ).
^The surface tension γ _s is 5 to 35d using ^1/2 elastic body.
The surface roughness is 0.01 to 10 in terms of ten-point average roughness Rz, which is provided with an yn / cm surface-printed layer or is formed using an elastomer having (IV) a fluorinated polyether skeleton and a silicone cross-linking end group. With a surface printing layer that is 3 μm.

That is, the printing blanket according to the present invention comprises: (i) the surface roughness of the surface printing layer and the resistance of the ink to the solvent (solvent resistance); (ii) the thickness and hardness of the surface printing layer and the solvent of the ink. Resistance, (iii) the solubility constant (SP value) of the material forming the surface printing layer and the surface tension of the surface printing layer, or (iv) the specific material forming the surface printing layer and its surface roughness. It is characterized by appropriately combining various properties relating to layers and materials to be used.

According to the printing blankets (I) to (IV), the combination as described above is used to ink the organic EL element forming material for the production of the organic EL panel. It is possible to exhibit the characteristic that it is extremely difficult to swell in an organic solvent such as an aromatic hydrocarbon. Therefore, by using such a printing blanket, it is possible to obtain an extremely fine pattern even when an ink using an aromatic hydrocarbon or the like as a solvent is used, such as a printing ink for forming an organic EL element. Printing can be reproduced with accuracy. Therefore, the printing blanket of the present invention is suitable for manufacturing an organic EL panel.

In the printing blankets (I) to (III), the surface printing layer is made of silicone elastomer, fluorine elastomer, butyl rubber, ethylene-propylene rubber or a mixture thereof. It is preferable in order to further improve the accuracy of the pattern of the organic EL element. In the printing blanket of (IV) above, the hardness of the surface printing layer is determined according to JIS A hardness from the viewpoint of forming an organic EL element (for example, a light emitting layer using a polymer organic light emitting body) with higher accuracy. 20 ~ 80
It is preferably °.

In the printing blanket according to the present invention, the elastomer, the rubber or the mixture thereof for forming the surface printing layer is preferably in a paste state or a liquid state in the uncured state, and the viscosity in the uncured state. Is
It is more preferably 10,000 Pa · s or less at room temperature. In this case, since the surface printing layer can be easily formed and the smoothing can be performed by self-leveling, it is extremely easy to set the surface roughness of the surface printing layer within the above range.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a method for manufacturing an organic EL panel according to the present invention and a printing blanket used therefor will be described in detail. [Manufacturing Method / Conditions for Organic EL Element] In the method for manufacturing an organic EL panel according to the present invention, the organic EL element is formed by an intaglio offset printing method (in its preferred embodiment, the above-mentioned (I ) ~ (I
V) is used).

The organic EL element is required not only to have an extremely fine pattern, but also to have a good print shape (for example, a sharp edge portion in the cross section of the pattern). Therefore, in a preferred embodiment of the method for producing an organic EL panel according to the present invention, as described above, the surface printing layer of the printing blanket has a volume when immersed in a solvent of (a) printing ink at 23 ° C. for 24 hours. A rate of change of 40% or less, (b) an elastic body having a solubility constant of 5 to 8 (cal / mol · cm ³ ) ^1/2 , or (c) a fluorinated polyether skeleton What is made of an elastomer having a silicone cross-linking terminal group, which is characterized by having extremely excellent solvent resistance.

In the present invention, the printing blanket having such a surface printing layer is used to print the light emitting layer and the like. Therefore, the solvent for the light emitting layer forming ink is aromatic carbonization such as xylene and toluene. In the case of hydrogen, deterioration of printing accuracy due to swelling of the surface printing layer hardly occurs, and the light emitting layer can be formed by printing with extremely high reproducibility even with an extremely fine pattern.

Furthermore, in the preferred embodiment of the method for manufacturing an organic EL panel according to the present invention, as described above, the surface printing layer of the printing blanket has (d) a ten-point average roughness Rz of 0.01 to 3 μm. That is, an extremely smooth object, (e) an object whose thickness and hardness are set within predetermined ranges,
Or (f) the surface tension of which is set in a predetermined range. The surface printing layer has excellent solvent resistance as described in (a) to (c) above, and as described in (d) to (f) above, the characteristics of surface roughness, thickness and hardness, and surface tension. According to the preferred embodiment of the method for manufacturing an organic EL panel according to the present invention, the organic EL element can be formed as an extremely fine pattern with extremely high accuracy. More preferable ranges of the conditions shown in (a) to (f) above will be described in detail in the detailed description of the printing blanket described later.

The surface printing layer of the printing blanket used in the present invention is characterized by having a very small surface energy, as is clear from the conditions shown in the above (a) to (f). Therefore, when the ink is transferred from the printing blanket to the substrate, a printing pressure higher than the printing pressure (about 1 to 5 kgf / cm ² ) set in normal intaglio offset printing is adopted. Further, by printing with a printing pressure higher than usual, smoothing treatment of the transferred pattern surface can be achieved at the same time.

In the present invention, the printing pressure for transferring the printing ink from the printing blanket onto the substrate is preferably set in the range of 1 to 30 kgf / cm ² , as described above. If the printing pressure is less than the above range, the transferability of the ink may be lowered, and the smoothed surface of the transferred pattern may be insufficient. On the other hand, when the printing pressure exceeds the above range, the surface printing layer may be excessively deformed and the pattern printing accuracy may be deteriorated. The printing pressure when transferring the printing ink from the printing blanket to the substrate is
Among the above ranges, ² to 30 kgf / cm ² is preferable, and ² to ²⁰ kgf / cm ² is more preferable.

(Ink for forming organic EL element) In the organic EL element, the printing ink used for forming the light emitting layer is, as described above, an organic polymer light emitting material such as a π-conjugated polymer compound in an organic solvent. It has been dissolved.

The above-mentioned organic polymer light-emitting body is not particularly limited, and the above-mentioned polyphenylene vinylene (PP) is used.
V), polyparaphenylene derivative (MEH-PPV, orange), polyalkylthiophene (PAT, red), polydialkylfluorene (PDAF, blue),
Examples include various conventionally known organic polymer light-emitting materials such as polyparaphenylene (PPP, blue). Any solvent may be used as long as it can sufficiently dissolve or stably disperse the organic polymer light-emitting body, and specific examples thereof include organic solvents such as xylene and aromatic hydrocarbons such as toluene.

The content ratio of the organic polymer luminescent material in the light emitting layer forming ink is not particularly limited and may be appropriately set according to the viscosity of the ink, the thixotropic property and the solubility of the organic polymer luminescent material. As described above, since the above organic polymer luminescent material has extremely low solubility, the content ratio (solid content) of the organic polymer luminescent material in the total luminescence forming ink is usually 15% by weight. % Or less, preferably 10% by weight or less, and more preferably 5% by weight or less.

Among the organic EL devices, the printing ink used for forming the hole transport layer and the electron transport layer uses the hole transport agent and the electron transport agent in an organic solvent such as aromatic hydrocarbon and aliphatic hydrocarbon. Examples thereof include those that are sufficiently dissolved or stably dispersed. The hole transfer material and the electron transfer material are not particularly limited, and known materials conventionally used for forming an organic EL element can be mentioned. The organic solvent is not particularly limited as long as it can sufficiently dissolve or stably disperse the hole transfer material or the electron transfer material. Specific examples of the hole transfer agent include triphenylbenzidine, polyvinylcarbazole, diphenylnaphthylamine and the like. Specific examples of the electron transfer agent include oxadiazole and perylene derivatives.

(Intaglio plate) The intaglio plate used for printing and forming the light emitting layer is not particularly limited, but it is preferable to use a material having good etching property and excellent ink releasability. . Specific examples include metal and glass. The line width and depth of the recess formed on the intaglio may be appropriately set according to the line width and thickness required for the pattern of the light emitting layer or the like.

(Transparent Substrate) Examples of the transparent substrate as a base material of the organic EL device include soda lime glass, non-alkali glass, quartz glass, low alkali glass, low expansion glass and the like. The thickness of the transparent substrate is appropriately set according to the heat resistance of the substrate and is not particularly limited, but the thickness is appropriately set within the range of 1 to 10 mm.

(Structure of Organic EL Panel, Forming Steps, Printing Conditions, etc.) In the present invention, the organic EL element constituting the organic EL panel is manufactured as shown in FIG. 1, for example. That is, first, a transparent conductive film (ITO film) 12 as an anode is formed on a glass substrate 11 by sputtering or the like (FIG. 1A), and then the transparent conductive film 12 is patterned by a photolithography method or the like ( Figure 1 (b)
), The hole transport layer 13, the light emitting layer 14 on the transparent conductive film 12.
Are formed in this order (Fig. 1 (c), (d)). Further, a cathode 15 is formed on the surface of the light emitting layer 14 or the like by a method such as vapor deposition (FIG. 1 (e)) to obtain the organic EL element 10.

Here, the light emitting layer 14 comprises the aforementioned light emitting layer forming ink containing an organic polymer light emitting body and a printing blanket having a surface printing layer formed using the aforementioned fluorinated elastomer. It is formed by the intaglio offset printing method used. The hole transport layer 13 is formed by an intaglio offset printing method using a hole transport layer-forming ink containing a hole transport agent and the above printing blanket, and is also formed, for example, by a method such as whole surface coating. You may. Reference numeral 16 shown in FIG. 1 (f) indicates a DC power supply. By applying a voltage between the transparent conductive film 12 and the cathode 15 by this DC power source, light emission occurs in the direction indicated by the white arrow in the figure.

In the present invention, the layer structure of the organic EL element is not limited to the structure shown in FIG. 1, and various conventionally known layer structures can be adopted. For example, when the glass substrate is omitted, (a) anode / light emitting layer / cathode (b) anode / hole transport layer / light emitting layer / cathode (c) anode / light emitting layer / electrons in order from the glass substrate side. Transport layer / cathode (d) A constitution in which an anode / hole transport layer / light emitting layer / electron transport layer / cathode are laminated is mentioned. The layer structure shown in FIG. 1 corresponds to the above-mentioned structure (b).

(Transfer speed during printing) In order to reproduce the pattern of the light emitting layer and the like with high accuracy and good shape, the transfer of ink from the intaglio depression to the printing blanket and the printing blanket to the substrate. It is necessary to accurately realize the ink transfer and the ink transfer. One of means for achieving such an object is to adjust the transfer speed of ink from the intaglio plate to the printing blanket and from the printing blanket to the substrate within a predetermined range.

The transfer speed of the ink from the intaglio to the printing blanket is preferably set in the range of 1 to 200 mm / s, more preferably 5 to 100 mm / s. The transfer speed of the ink from the printing blanket to the substrate is preferably set in the range of 10 to 500 mm / s, more preferably 50 to 300 mm / s.

(Pattern of Light-Emitting Layer, etc.) The pattern size (thickness and line width) of the light-emitting layer (organic polymer light-emitting layer) was formed by printing in accordance with the pixel size of the organic EL element. Volume reduction due to pattern drying (especially
The thickness reduction amount) is taken into consideration. Therefore, although not particularly limited, the thickness of the pattern after solvent drying is usually 0.02 to 0.2 μm,
The thickness is preferably 0.05 to 0.1 μm, and accordingly, the thickness of the printed pattern before drying is usually set to 1 to 20 μm, preferably 2 to 10 μm. The line width of the pattern after solvent drying is usually 20 to 200 μm, preferably 50 to 150.
It is required to be μm. The conditions for drying the printed pattern are not particularly limited because they differ depending on the solvent used for the ink, but since the solvent is an organic solvent such as xylene or toluene, a printing pattern is usually formed. It is achieved by placing the transparent substrate together with the solvent in an oven at a boiling point of the solvent to a boiling point of about -50 ° C and heating and drying.

[Printing Blanket] As described above, the printing blanket according to the present invention includes (i) the surface roughness of the surface printing layer and the resistance of the ink to the solvent (solvent resistance),
(ii) the thickness and hardness of the surface printing layer and the resistance of the ink to the solvent, (iii) the solubility constant of the material forming the surface printing layer (S
P value) and the surface tension of the surface printing layer, or (iv) a specific material forming the surface printing layer and its surface roughness, such as various characteristics relating to the surface printing layer, materials used, etc. To do.

(Surface Roughness) The surface printing layer of the printing blanket is required to have high smoothness. Specifically, the surface roughness of the surface printing layer is 0.01 to 10-point average roughness Rz.
It is preferably 3 μm. Ten-point average roughness Rz is 3 μm
If it exceeds, the printed shape of the pattern transferred by the blanket may be significantly disturbed. vice versa,
If it is less than 0.01 μm, the contact area between the blanket and the transparent substrate at the time of ink transfer becomes large, and the adhesiveness becomes too strong, so that good printing may not be realized. Further, since the total surface area of the blanket becomes too small and the ink acceptability from the intaglio plate is deteriorated, there is a possibility that pinholes or disconnections are likely to occur in the pattern. Ten-point average roughness Rz of the printed surface layer
Is particularly preferably 0.1 to 1 μm in the above range.

In order to set the ten-point average roughness Rz of the surface-printed layer in the above range, the surface of the surface-printed layer is polished with sandpaper or the like, or a mold whose surface is previously subjected to high smoothing treatment is used. It may be used to replicate the surface of the mold. When the surface printing layer is formed using an elastomer that is in paste form or liquid in the uncured state, it is possible to achieve smoothing of the surface printing layer by self-leveling by appropriately adjusting the viscosity of the elastomer. . When the elastomer is in a paste state or a liquid state in the uncured state, the surface printing layer can be formed by the coating manufacturing method or the injection manufacturing method, and the manufacturing of the printing blanket becomes easy. Viscosity of uncured elastomer is 10,000P
When it is not more than a · s, the smoothing effect by self-leveling can be sufficiently exerted on the surface printing layer formed by the coating manufacturing method or the injection manufacturing method. In the above range, the viscosity of the uncured elastomer is preferably 1000 Pa · s or less, more preferably 10 to 100 Pa · s.

(Swelling property) The surface printing layer of the printing blanket is required to have low swelling property (high solvent resistance) in the solvent of the printing ink. Specifically, the swelling property of the surface printing layer is determined by immersing in a solvent in a printing ink (for example, a light emitting layer forming ink) in which an organic EL device forming material is dissolved or stably dispersed at 23 ° C. (normal temperature) for 24 hours. It is preferable that the volume change rate (that is, the so-called swelling degree in such a solvent) at that time is set to 40% or less.

If the volume change rate of the surface printing layer under the above conditions exceeds 40%, the change in the wettability of the surface of the printing blanket becomes large, and stable printing cannot be performed. Specifically, there arises a problem that the line width of the pattern is widened. Further, if the degree of swelling with respect to the solvent is large, the deformation of the surface printing layer at the time of transferring the light emitting layer forming ink or the like from the printing blanket onto the transparent substrate becomes too large, so that the pattern printing is formed with high accuracy. Can't do it. The volume change rate of the surface printing layer under the above conditions is preferably 20% or less, and more preferably 10% or less, in the above range.

When the surface printing layer forming material described below is used for the surface printing layer of the printing blanket, the swelling property of the surface printing layer with respect to the solvent such as the light emitting layer forming ink (the above-mentioned volume change which is an index thereof). The rate) can be set within the above range.

(Thickness) In the printing blanket of the present invention, the thickness of the surface printing layer is not particularly limited, but is preferably 0.03 to 5 mm. If the thickness of the surface printing layer is less than 0.03 mm, the mechanical strength of the surface printing layer may be reduced or the apparent hardness of the surface printing layer may be increased, which may reduce the transferability of the ink. . On the other hand, when the thickness of the surface printing layer exceeds 5 mm, the apparent hardness of the surface printing layer becomes low and the deformation at the time of ink transfer becomes large. Therefore, the printing shape of the pattern transferred by the blanket becomes large. There is a risk that the printing accuracy will be degraded, such as disturbance. The thickness of the surface printing layer is preferably 0.1 to 2 mm in the above range.

(Hardness) In the printing blanket of the present invention, the hardness of the surface printing layer is not particularly limited, but the JIS A hardness is preferably 20 to 80 °. If the hardness of the surface printing layer is less than 20 ° in JIS A hardness, the deformation of the surface printing layer at the time of transferring the ink becomes large, so that the printing shape of the pattern transferred by the blanket is greatly disturbed. The accuracy may decrease. On the other hand, the hardness of the surface printing layer is JIS
If the A hardness exceeds 80 °, the transferability of the ink may deteriorate. The hardness of the surface printing layer is preferably 20 to 70 °, and more preferably 30 to 60 °, in the above range.
Is more preferable. When the above-mentioned fluorinated elastomer is used as the elastic body forming the surface printing layer, the hardness of the surface printing layer can be set within the above range.

(Solubility constant and surface tension)
An elastic body that forms the surface printing layer in a printing blanket
The solubility constant (SP value) of is not particularly limited
Is 5-8 (cal / mol · cm ³)^1/2Is
preferable. Further, the surface tension γs of the surface printing layer is particularly
Although not limited, it is 5 to 35 dyn / cm.
Is preferred.

The solubility constant of the elastic body is 5 to 8 (cal).
/ Mol · cm ³ ) ^1/2 , the swelling property of the surface printing layer against the aromatic hydrocarbon organic solvent such as xylene and toluene which is a solvent for the light emitting layer forming ink becomes extremely small. Therefore, the decrease in printing accuracy due to the swelling hardly occurs. On the other hand, if the solubility constant is out of the above range, the swelling property of the surface printing layer against the solvent such as the ink for forming the light emitting layer becomes large, and the shape of the print pattern particularly when the organic polymer light emitting layer is continuously formed by printing. May be disturbed or the surface printing layer itself may be damaged.

When the SP value of the elastic body is set within the above range, the swelling property of the surface printing layer with respect to the solvent such as the ink for forming the light emitting layer can be suppressed to be low, but the acceptability of the ink may be deteriorated. There is. However, when the surface tension γs of the surface printing layer is 5 to 35 dyn / cm, the swelling is extremely small, but the ink acceptability is good. Therefore, when the printing blanket having the above-mentioned surface printing layer is used, an extremely fine pattern of the organic EL element can be printed with high reproducibility.

The SP value of the elastic body forming the surface printing layer is
Within the above range, especially 5 to 7 (cal / mol · cm
³ ) ^1/2 is preferable. Further, the surface tension γs of the surface printing layer is 5 to 25 dyn / in particular within the above range.
It is preferably cm. In order to set the SP value of the elastic body forming the surface printing layer in the above range, the elastomer material exemplified above may be used as the elastic body. When an elastomer having the above-mentioned fluorinated polyether skeleton and a silicone cross-linking end group is used as the elastic body forming the surface printing layer, the surface tension γs of the surface printing layer should be set within the above range. You can In addition,
For fine adjustment of the surface tension γs and the like, surface treatment (for example, treatment for increasing the hydrophilicity of the surface by UV irradiation) may be performed.

(Material for forming surface printing layer) In the present invention,
The elastic body used for forming the surface printing layer of the printing blanket includes, for example, silicone elastomer, fluorine elastomer, rubber or elastomer material such as butyl rubber, ethylene-propylene rubber, and a mixture thereof. Generally, by using these rubber or elastomer materials, or a mixture thereof, a surface printing layer for a solvent of a printing ink (for example, a light emitting layer forming ink) obtained by dissolving or stably dispersing an organic EL device forming material In addition to the swelling property, various properties (for example, ink acceptability, releasability, etc.) required for a printing blanket in print formation of an organic EL element (for example, a light emitting layer) can be satisfied. Therefore,
In order to perform stable print formation of the light emitting layer and the like, it is preferable to use the above-mentioned rubber or elastomer material or a mixture thereof as a material for forming the surface print layer.

As the above-mentioned silicone elastomer,
For example, methyl silicone rubber [KE series manufactured by Shin-Etsu Chemical Co., Ltd., TSE series manufactured by Toshiba Silicone Co., Ltd.], vinyl methyl silicone rubber [KE series manufactured by Shin-Etsu Chemical Co., Ltd., manufactured by Toshiba Silicone Co., Ltd.] T
SE series], fluorosilicone rubber [FE series manufactured by Shin-Etsu Chemical Co., Ltd., T manufactured by Toshiba Silicone Co., Ltd.]
SE series] and the like. It should be noted that, although not particularly limited, among the types such as the heat curing type (HTV) and the room temperature curing type (RTV), the room temperature curing type addition type silicone rubber does not generate a by-product at the time of curing. In addition, the dimensional accuracy is excellent, which is preferable.

Examples of the above-mentioned fluorine-based elastomer include elastomers having a fluorinated polyether skeleton and silicone cross-linking end groups [SIF manufactured by Shin-Etsu Chemical Co., Ltd.
EL (R) ", one having a fluoroether structure, uncured viscosity 10 to 10,000 Pa · s], vinylidene fluoride rubber [" Daiel (R) "manufactured by Daikin Industries, Ltd.,
"Viton (R)" manufactured by Showa Denko / Dupont, tetrafluoroethylene propylene rubber [Aflas (R) manufactured by Asahi Glass Co., Ltd.], tetrafluoroethylene perfluoromethyl vinyl ether rubber [Dupont] Kalrez (R) manufactured by the company
], Phosphazene-based fluororubber [a rubber obtained by thermally decomposing a trimer of dichlorophosphonitrile, which is peroxide-crosslinked. "EYPEL-F (R)" manufactured by Daikin Industries, Ltd.], fluoropolyether, fluoronitroso rubber, perfluoroalkylene triazine, and the like.

Examples of the butyl rubber include "JSR BUTYL" manufactured by Japan Synthetic Rubber Co., Ltd., "EXXON BUTYL" manufactured by Exxon Co., Ltd., and halogenated butyl rubber [for example, "JSR CTY manufactured by Japan Synthetic Rubber Co., Ltd."
HLOROBUTYL "," JSR BROMOBUT
YL "and the like]. Examples of the ethylene-propylene rubber (EPM) include EP series manufactured by Nippon Synthetic Rubber Co., Ltd., “Esprene” series manufactured by Sumitomo Chemical Co., Ltd., and the like. This EPM has ethylene-
Includes propylene-diene rubber (EPDM).

Among the above materials for forming the surface printing layer, an elastomer having a fluorinated polyether skeleton and a silicone cross-linking terminal group [for example, the above-mentioned trade name "SIFEL"
(R) ”] is very suitable for a printing blanket for forming an organic EL element, since it has a good balance between solvent resistance and printing characteristics. The above-mentioned "fluorinated polyether skeleton and silicone cross-linking end group" is specifically represented by the following formula
It is represented by (1).

[0064]

[Chemical 1]

(In the formula (1), n represents the number of repeating units.)

[0066]

EXAMPLES The present invention will be described with reference to Examples and Comparative Examples.

[Formation of Light Emitting Layer] In the following Examples and Comparative Examples, the transparent substrate and the transparent conductive film had a thickness of 0.
On the surface of a 7 mm glass substrate (soda lime glass),
ITO film (anode) with a thickness of 0.1 μm by vacuum evaporation method
Was used. As the hole transport material, a coating liquid containing polyethylene dioxythiophene as a hole transport agent [polyethylene dioxythiophene-polystyrene sulfonate (PEDT / PSS), trade name “Baytron P” manufactured by Bayer Co., Ltd.] Using.
Poly (9,9′-dialkylfluorene) [PDAF] was used as the organic polymer light-emitting material. This PDAF was dissolved in a solvent (xylene) so that the solid content concentration was 2% by weight and used as a printing ink for forming a light emitting layer.

Example 1 After UV-ozone cleaning was applied to the surface of the base material to remove organic substances and other deposits, the hole transporting material was applied to the surface of the base material on the ITO film side by spin coating. Was applied and dried at 70 to 80 ° C. to obtain a hole transport layer. Next, a pattern of the light emitting layer was formed on the surface of the hole transport layer by the intaglio offset printing method.

In the printing formation of the light emitting layer, the printing plate is
An intaglio plate having a concave portion (stripe pattern) formed on the surface of a soda lime glass substrate by etching, the concave portion having a line width of 100 μm and a depth of 10 μm was used. The printing blanket has a fluorosilicone rubber surface printing layer [Shin-Etsu Chemical Co., Ltd. product number "F
E351U "] was used. This surface-printed layer is used as a solvent (xylene) for the ink for forming the light-emitting layer.
The volume change rate when immersed at 3 ° C. for 24 hours was 8%, and the ten-point average roughness (Rz) of the surface was 0.1 μm. Furthermore, this surface-printed layer has a thickness of 0.5 mm, a hardness (JIS A hardness) of 50 °, and a solubility constant (SP value).
Was 7 (cal / mol · cm ³ ) ^1/2 and the surface tension γs was 18 dyn / cm.

To form the light emitting layer by printing, first, the above intaglio plate, the printing blanket and the glass substrate with the ITO film were mounted on a flatbed printing machine, and the above ink for forming a light emitting layer was applied to the recess of the intaglio plate by doctoring. After filling, the transfer speed of the ink from the intaglio plate to the printing blanket is 50 mm / s, the transfer speed of the ink from the printing blanket to the glass substrate is 150 mm / s, and the printing at the time of transferring the ink to the glass substrate is performed. The printing pressure was set to ² kg / cm ² for each blanket.

The thickness of the ink printed on the above hole transport layer (before drying) was 6 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 30 minutes was 0.12 μm. After the light emitting layer is dried, calcium is deposited on the surface by a vacuum deposition method, and then aluminum is deposited to give a total thickness of 0.1.
An organic EL panel was obtained by forming a Ca / Al layer (cathode layer) of μm.

(Example 2) A mark used for print formation of a light emitting layer
As a printing blanket, the surface printing layer is made of tetrafluoroethylene.
Perfluoromethyl vinyl ether rubber [Dupont
Made of fluorocarbon rubber, trademark "Kalrez"]
Was used. This surface printing layer is an ink for forming a light emitting layer.
When immersed in the solvent (xylene) at 23 ℃ for 24 hours
The volume change rate is 5%, and the ten-point average roughness (R
z) was 0.3 μm. Furthermore, this surface printing layer
Has a thickness of 1.0 mm and a hardness (JIS A hardness) of 40
°, solubility constant (SP value) 6.5 (cal / mol ·
cm ³)^1/2, The surface tension γs is 10 dyn / cm
It was For the intaglio, etch on the surface of the soda lime glass substrate
The width of the recess is 50 μm and the depth is 10 μm.
A lime pattern was used. ITO film
Glass substrate, hole transporting material, and light-emitting layer forming layer
The same thing as in Example 1 was used as the ki.

After forming a hole transport layer on the surface of the glass substrate with the ITO film in the same manner as in Example 1, a light emitting layer was formed on the hole transport layer using the printing blanket and the intaglio plate. Printed. Example 1 was used for print formation of the light emitting layer.
Using the same flatbed printing machine as above, the transfer speed of the ink from the intaglio to the printing blanket is 30 mm / s, and the transfer speed of the ink from the printing blanket to the glass substrate is 1
The printing pressure was set to 50 mm / s and the printing pressure of the printing blanket during the transfer of the ink to the glass substrate was set to ² kg / cm ² , respectively. The thickness of the ink printed on the hole transport layer (before drying) was 5 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 30 minutes was 0.
It was 1 μm. After drying the light emitting layer, an organic EL panel was obtained in the same manner as in Example 1.

Comparative Example 1 A glass substrate with an ITO film and the same hole transport material as in Example 1 were used, and a hole transport layer was formed on the surface of the glass substrate in the same manner as in Example 1. . Next, a pattern of the light emitting layer was formed on the surface of the hole transport layer by screen printing.

When the light emitting layer is formed by printing, the width of the image area is 100.
Using a screen plate having a stripe pattern of μm, the intaglio plate and the above-mentioned glass substrate with an ITO film were mounted on a flatbed printing machine. The same light emitting layer forming ink as in Example 1 was used. The thickness of the ink printed on the hole transport layer (before drying) was 10 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 30 minutes was 0.2 μm.

Comparative Example 2 A glass substrate with an ITO film and the same hole transport material as in Example 1 were used, and a hole transport layer was formed on the surface of the glass substrate in the same manner as in Example 1. . Next, a pattern of the light emitting layer was formed on the surface of the hole transport layer by a lithographic printing method.

When the light emitting layer is formed by printing, the width of the image area is 50 μm.
Using a waterless planographic plate having a stripe pattern of m (trade name "TAP plate" manufactured by Toray Industries, Inc.) and the same printing blanket as in Example 1, the planographic printing plate and the ITO film were used in a flatbed printing machine. Each glass substrate was attached. The same light emitting layer forming ink as in Example 1 was used. The ink transfer rate from the lithographic plate to the printing blanket was set to 30 mm / s, and the ink transfer rate from the printing blanket to the glass substrate was set to 150 mm / s. The thickness of the ink printed on the hole transport layer (before drying) was 0.5 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 30 minutes was 0.01 μm.

Comparative Example 3 A glass substrate with an ITO film and the same hole transport material as in Example 1 were used, and a hole transport layer was formed on the surface of the glass substrate in the same manner as in Example 1. . Next, a pattern of the light emitting layer was formed on the surface of the hole transport layer by gravure printing (intaglio direct printing).

The light emitting layer was printed by using a gravure plate having a recess (stripe pattern) having a line width of 100 μm and a depth of 10 μm, and the gravure plate and the above-mentioned glass substrate with an ITO film were mounted on a flatbed printing machine. I did it.
The same light emitting layer forming ink as in Example 1 was used.
The transfer speed of the ink from the gravure plate to the glass substrate was set to 150 mm / s. The thickness of the ink printed on the hole transport layer (before drying) was 1.0 μm, and
The thickness of the light emitting layer after drying at 0 ° C. for 30 minutes is 0.05 μm.
It was m.

[Evaluation of Printability] Regarding Examples 1 and 2 and Comparative Examples 1 to 3 described above, the flatness of the surface of the light emitting layer after drying, linearity, suitability of line shape, presence of pinholes and presence of disconnection Then, the printability was evaluated by confirming whether or not there was a change in the line width of the pattern or a change in the film thickness when the light emitting layer was continuously formed by printing. The above results are shown in Table 1.

[0081]

[Table 1]

In Table 1, "PDAF" in the column "Printing ink for forming light emitting layer" means poly (9,
9'-dialkylfluorene) is shown. "Intaglio" in the "Printing method" column is the intaglio offset printing method, "Screen"
Indicates a screen printing method, “lithographic” indicates a lithographic printing method, and “gravure” indicates a gravure printing method. Among the materials in the "Blanket surface printing layer" column, "Fluoro" indicates fluorosilicone rubber, and "TFE" indicates tetrafluoroethylene perfluoromethyl vinyl ether.
The "volume change rate (%)" in the same column indicates the volume change rate when the surface printing layer was immersed in xylene, which is a solvent for the light emitting layer forming ink, at 23 ° C for 24 hours (see the following formula). Volume change rate (%) = [(volume after immersion)-(volume before immersion)] / (volume before immersion) × 100

As is clear from Table 1, intaglio offset printing was performed using a printing blanket having a surface printing layer made of a specific material having good solvent resistance and having a surface roughness set in a predetermined range. According to Examples 1 and 2 in which the light emitting layer was formed by the method, the line width and thickness of the pattern of the light emitting layer could be set within the range suitable for the organic EL device. Particularly, in Example 2, the line width of the pattern of the light emitting layer was set to 5
It was possible to make it as thin as 0 μm. On the other hand, in Comparative Example 1 in which the screen printing method is adopted, the pattern shape is disturbed, in Comparative Example 2 in which the lithographic printing method is adopted, the pattern is broken, and in Comparative Example 3 in which the gravure printing method is adopted, Since the adhesion between the plate and the material to be printed was insufficient, the pattern could only be formed partially. Therefore, Comparative Examples 1 to 3 were all improper in printability.

[Formation of Light-Emitting Layer] (Example 3) As a printing blanket used for print-forming the light-emitting layer, vinylidene fluoride-based fluororubber [registered trademark "DAIEL" of Daikin Corp.] was used for the surface printing layer. What was used was used. The surface printing layer had a volume change rate of 7% when immersed in a solvent (xylene) for the light emitting layer forming ink at 23 ° C. for 24 hours and had a thickness of 0.5 m.
m, and the hardness (JIS A hardness) was 50 °. Furthermore, this surface-printed layer has a surface ten-point average roughness (Rz) of 0.2 μm and a solubility constant (SP value) of 7 (cal / mo).
l · cm ³ ) ^1/2 and the surface tension γs were 12 dyn / cm.

Glass substrate with ITO film, hole transport material,
The same ink as used in Example 1 was used for the light emitting layer forming ink and the intaglio plate. On the surface of the glass substrate with the ITO film,
After forming the hole transport layer in the same manner as in Example 1, the light emitting layer was printed on the hole transport layer by using the printing blanket and the intaglio plate. The transfer speed and the printing pressure of the printing blanket at the time of print formation of the light emitting layer are the same as those in Example 2.
The same conditions were set. The thickness of the ink printed on the hole transport layer (before drying) was 5 μm, and the thickness was 3 at 80 ° C.
The thickness of the light emitting layer after drying for 0 minutes was 0.1 μm. After drying the light emitting layer, an organic EL panel was obtained in the same manner as in Example 1.

(Example 4) As a printing blanket used for print formation of the light emitting layer, a phosphor layer of phosphazene type [trademark "EYP" manufactured by Daikin Co., Ltd.
EL ”] was used. The surface printing layer had a volume change rate of 5% when immersed in a solvent (xylene) for the light emitting layer forming ink at 23 ° C. for 24 hours, had a thickness of 1.0 mm and a hardness (JIS A hardness). Was 60 °. Further, this surface-printed layer has a surface ten-point average roughness (Rz) of 0.3 μm and a solubility constant (SP value) of 7 (c).
al / mol · cm ³ ) ^1/2 , surface tension γs is 15 dy
It was n / cm.

Glass substrate with ITO film, hole transport material,
The same ink as used in Example 1 was used for the light emitting layer forming ink and the intaglio plate. On the surface of the glass substrate with the ITO film,
After forming the hole transport layer in the same manner as in Example 1, the light emitting layer was printed on the hole transport layer using the printing blanket and the intaglio plate. The transfer speed during printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Example 2. The thickness of the ink printed on the hole transport layer (before drying) was 5 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 3 minutes was 0.1 μm. After drying the light emitting layer, an organic EL panel was obtained in the same manner as in Example 1.

(Comparative Example 4) The printing blanket used for printing and forming the light-emitting layer had a surface printing layer having a thickness of 6 mm, a volume change rate when immersed in xylene at 23 ° C. for 24 hours, and a surface. Printing layer hardness (JIS A), ten-point average roughness Rz, solubility constant (SP value) and surface tension γs
Which was the same as in Example 1 was used. The same glass substrate as in Example 1 was used for the glass substrate with the ITO film, the hole transport material, the light emitting layer forming ink and the intaglio plate.

After forming a hole transport layer on the surface of the glass substrate with the ITO film in the same manner as in Example 1, a light emitting layer was formed on the hole transport layer using the printing blanket and the intaglio plate. Printed. The transfer speed during printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Example 2. The thickness of the ink printed on the hole transport layer (before drying) was 5 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 30 minutes was 0.1 μm. After drying the light emitting layer, an organic EL panel was obtained in the same manner as in Example 1.

(Comparative Example 5) The thickness of the surface printing layer was 1.0 m in the printing blanket used for printing the light emitting layer.
m, the hardness of the surface printing layer (JIS A) is 85 °, the volume change rate when immersed in xylene at 23 ° C. for 24 hours, the ten-point average roughness Rz, the solubility constant (SP value) and the surface The same tension γs as in Example 1 was used. The same glass substrate as in Example 1 was used for the glass substrate with the ITO film, the hole transport material, the light emitting layer forming ink and the intaglio plate.

After forming a hole transport layer on the surface of the ITO film-coated glass substrate in the same manner as in Example 1, a light emitting layer was formed on the hole transport layer using the printing blanket and the intaglio plate. Printed. The transfer speed during printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Example 2. The thickness of the ink printed on the hole transport layer (before drying) was 0.5 μm, and the thickness was 30 at 80 ° C.
The thickness of the light emitting layer after drying for 0.01 minute was 0.01 μm.

(Comparative Example 6) As a printing blanket used for printing and forming the light emitting layer, a printing blanket made of acrylonitrile-butadiene rubber (NBR) for the surface printing layer was used. This surface-printed layer has a volume change rate of 150% when immersed in xylene at 23 ° C. for 24 hours, a thickness of the surface-printed layer of 6 mm, and a hardness (JIS A hardness) of 85 °.
Furthermore, the ten-point average roughness Rz of the surface printing layer is 0.4 μm,
Solubility constant (SP value) is 7 and surface tension γs is 18d
It was yn / cm.

Glass substrate with ITO film, hole transport material,
The same ink as used in Example 1 was used for the light emitting layer forming ink and the intaglio plate. On the surface of the glass substrate with the ITO film,
After forming the hole transport layer in the same manner as in Example 1, the light emitting layer was printed on the hole transport layer using the printing blanket and the intaglio plate. The transfer speed in printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Comparative Example 4. The thickness of the ink printed on the hole transport layer (before drying) was 1 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 30 minutes was 0.02 μm.

[Evaluation of Printability] The printability of Examples 3 and 4 and Comparative Examples 4 to 6 was evaluated in the same manner as in Examples 1 and 2. The results are shown in Table 2 together with the results of 1 and 2 above.

[0095]

[Table 2]

In Table 2, "PDAF", "Fluoro", "T"
The FE "and the" volume change rate (%) "are the same as those in Table 1. Also," PVDF "indicates a vinylidene fluoride rubber and" foss "indicates a phosphazene fluororubber, respectively. As is clearer, a light-emitting layer is formed by an intaglio offset printing method using a printing blanket having a surface printing layer made of a specific material having good solvent resistance and having a thickness and hardness set in a predetermined range. According to Examples 1 to 4 in which the light emitting layer was formed, the line width and thickness of the pattern of the light emitting layer could be set within a range suitable for the organic EL element. The line width could be made extremely thin as 50 μm.

On the other hand, in Comparative Example 4 in which the thickness of the surface printing layer of the printing blanket was too large, the shape of the pattern was disturbed, and in Comparative Example 5, the hardness of the surface printing layer was too hard. A disconnection occurred. In Comparative Example 6, since the thickness of the surface printing layer was too large and the hardness was too hard, the pattern shape was disturbed and
Pinholes and disconnections also occurred. Therefore, Comparative Examples 4 to 6 were all improper in printability.

[Formation of Light-Emitting Layer] (Comparative Example 7) As a printing blanket, the material of the surface printing layer was acrylonitrile-butadiene rubber (NBR), and the solubility constant (SP value) of the surface printing layer was 8.8.
(Cal / mol · cm ³ ) ^1/2 , surface tension γs is 38
Dyn / cm, thickness 0.5 mm, hardness (JIS A hardness) 50 °, and ten-point average surface roughness (Rz) 2 μm were used. In addition, the glass substrate with the ITO film, the hole transport material, the ink for forming the light emitting layer and the intaglio plate were prepared in
Used the same.

After forming a hole transport layer on the surface of the glass substrate with the ITO film in the same manner as in Example 1, the organic blank layer was formed on the hole transport layer using the printing blanket and the intaglio plate. Printed. The transfer speed during printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Example 1. The thickness of the ink printed on the hole transport layer (before drying) was 2 μm, and the thickness was 30 at 80 ° C.
The thickness of the light emitting layer after drying for a minute was 0.04 μm.

(Comparative Example 8) As a printing blanket,
The material of the surface printing layer is chloroprene rubber (CR),
The solubility constant (SP value) of the surface printing layer is 9.0 ((c
al / mol · cm ³ ) ^1/2 ), surface tension γs is 40d
The one having a yn / cm and a thickness of 0.5 mm was used.
The same glass substrate as in Example 1 was used as the glass substrate with the ITO film, the hole transport material, the light emitting layer forming ink and the intaglio plate.

After forming the hole transport layer on the surface of the glass substrate with the ITO film in the same manner as in Example 1, the organic light emitting layer was formed on the hole transport layer by using the printing blanket and the intaglio plate. Printed. The transfer speed during printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Example 1. The thickness of the ink printed on the hole transport layer (before drying) was 1.5 μm, and the thickness of the light emitting layer after drying at 80 ° C. for 30 minutes was 0.03 μm.

(Comparative Example 9) As a printing blanket,
The material of the surface printing layer is urethane rubber (UR)
The solubility constant (SP value) of the surface printing layer is 10.0 ((ca
l / mol · cm ³)^1/2), Surface tension γs is 45 dy
An n / cm film having a thickness of 0.5 mm was used. Well
Intaglio, glass substrate with ITO film, hole transport material and
The same ink as in Example 1 was used as the ink for forming the light-emitting layer.
I used it.

After forming a hole transport layer on the surface of the glass substrate with the ITO film in the same manner as in Example 1, an organic light emitting layer was formed on the hole transport layer using the printing blanket and the intaglio plate. Printed. The transfer speed during printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Example 1. The thickness of the ink printed on the hole transport layer (before drying) was 1 μm, and the thickness was 30 at 80 ° C.
The thickness of the light emitting layer after drying for a minute was 0.02 μm.

(Comparative Example 10) As a printing blanket, the material of the surface printing layer was tetrafluoroethylene (PTFE).
And the solubility constant (SP value) of the surface printing layer is 5.
5 ((cal / mol · cm ³ ) ^1/2 ), surface tension γs
Was 4 dyn / cm and the thickness was 0.5 mm. Further, the same inks as in Example 1 were used as the intaglio plate, the glass substrate with the ITO film, the hole transport material and the light emitting layer forming ink.

After forming a hole transport layer on the surface of the glass substrate with the ITO film in the same manner as in Example 1, an organic light emitting layer was formed on the hole transport layer using the printing blanket and the intaglio plate. Printed. The transfer speed during printing formation of the light emitting layer and the printing pressure of the printing blanket were set to the same conditions as in Example 1. The thickness of the ink printed on the hole transport layer (before drying) was 0.5 μm. 8
After drying at 0 ° C. for 30 minutes, many wire breakages occurred, so that the film thickness could not be measured.

[Evaluation of Printability] The printability of each of Comparative Examples 7 to 10 was evaluated in the same manner as in Example 1. The results are shown in Table 3 together with the results of Examples 1 and 2 above.

[0107]

[Table 3]

In Table 3, "PDAF", "Fluoro", "T"
FE "is the same as in Table 1. Also," NBR "
Is acrylonitrile-butadiene rubber, "CR" is chloroprene rubber, "UR" is urethane rubber, and "PT" is
FE "represents tetrafluoroethylene, respectively. As is clear from Table 3, surface printing made of a specific material having good solvent resistance and having SP value and surface tension of the material set in a predetermined range. According to Examples 1 and 2 in which the light emitting layer was formed by the intaglio offset printing method using the printing blanket having the layer, the line width and thickness of the pattern of the light emitting layer were set within the range suitable for the organic EL device. In particular, in Example 2, the line width of the pattern of the light emitting layer was 5
It was possible to make it as thin as 0 μm.

On the other hand, the surface printing layer has insufficient resistance (solvent resistance) to the solvent of the light emitting layer forming ink, or the SP value or the surface tension value is out of the preferable range. In Comparative Examples 7 to 9 formed by using, the pattern shape was disturbed, and it was not possible to repeatedly print and form a fine pattern with high accuracy. Further, in the printing blanket of Comparative Example 10, although the SP value of the surface printing layer was a sufficiently low value, the surface tension was too low and the ink acceptability was poor.
There is a problem that a pattern having a sufficient thickness cannot be formed. Therefore, Comparative Examples 7 to 10 were all improper in printability.

[Production of Printing Blanket] (Production Example 1) Fluorine rubber as an elastomer having a fluorinated polyether skeleton and a silicone cross-linking terminal group on a PET film as a support [perfluoropolyether in the main chain] Those having a structure and having a silicone cross-linking end group, trade name "SIFE" manufactured by Shin-Etsu Chemical Co., Ltd.
L (R) 3500 ", viscosity 300 Pa.s] is applied and cured while being smoothed by self-leveling to have a thickness of 0.3 mm and a surface ten-point average roughness (R
z) A printing blanket having a thickness of 0.1 μm and a hardness (JIS A hardness) of 40 ° was obtained. The surface printing layer of this printing blanket is coated with a solvent (xylene) for the light emitting layer forming ink.
The volume change rate when immersed at 3 ° C. for 24 hours was 10%. Furthermore, this surface-printed layer has a solubility constant (SP
Value) is 7 (cal / mol · cm ³ ) ^1/2 , surface tension γ
s was 18 dyn / cm.

[Formation of Light Emitting Layer] In the following Examples and Comparative Examples, the transparent substrate and the transparent conductive film had a thickness of 0.
On the surface of a 7 mm glass substrate (soda lime glass),
ITO film (anode) with a thickness of 0.1 μm by vacuum evaporation method
Was used. Poly (9,9′-dialkylfluorene) [PDAF] was used as the organic polymer light-emitting material. This PDAF was dissolved in a solvent (xylene) so that the solid content concentration was 2% by weight and used as a printing ink for forming a light emitting layer.

(Example 5) UV on the surface of the glass substrate
-After ozone cleaning to remove organic substances and other deposits,
A pattern of the light emitting layer was formed on the surface by the intaglio offset printing method. When the light emitting layer is formed by printing, the printing plate is an intaglio plate in which a recess (stripe pattern) is formed by etching on the surface of a soda lime glass substrate, and the line width of the recess is 100 μm and the depth is 10 μm. used. As the printing blanket, the one obtained in Production Example 1 above was used.

The light emitting layer is formed by printing. First, the intaglio plate, the printing blanket and the glass substrate with the ITO film are mounted on a flatbed printing machine, and the ink for forming the light emitting layer is doctored in the recess of the intaglio plate. After filling, the transfer speed of the ink from the intaglio plate to the printing blanket is 50 mm / s, the transfer speed of the ink from the printing blanket to the glass substrate is 150 mm / s, and the printing at the time of transferring the ink to the glass substrate is performed. The printing pressure was set to 15 kg / cm ² for each blanket. The thickness of the pattern composed of the light emitting layer forming ink printed on the glass substrate (before drying) was 3 μm, and the thickness of the organic polymer light emitting layer after drying at 80 ° C. for 30 minutes was 0.15 μm. .

After drying the organic polymer light emitting layer, aluminum was vapor-deposited on the surface by a vacuum vapor deposition method to give a total thickness of 0.1.
An organic EL panel was obtained by forming an Al layer (cathode layer) having a thickness of μm. When a DC voltage was applied to the organic EL panel thus obtained, very good light emission was obtained. Moreover, the pattern of the light emitting layer has excellent continuity,
It was confirmed that both the line width and the film thickness were stable.
This result did not show any particular change even when the print formation of the light emitting layer was repeated.

(Comparative Example 11) U was formed on the surface of the glass substrate.
After V-ozone cleaning was performed to remove deposits such as organic substances, a pattern of a light emitting layer was formed on the surface by lithographic offset printing.

When the light emitting layer is formed by printing, the printing plate is
A waterless planographic plate [trade name “TAP version” manufactured by Toray Industries, Inc.] was used. This waterless planographic printing plate has a stripe pattern with a line width of 100 μm. The printing blanket used had a surface printing layer formed of NBR rubber and a surface ten-point average roughness (Rz) of 0.1 μm. The surface printing layer of this printing blanket had a volume change rate of 250% when immersed in a solvent (xylene) for the light emitting layer forming ink at 23 ° C. for 24 hours. Furthermore, this surface-printed layer has a thickness of 0.3 mm, a hardness (JIS A hardness) of 50 °, and a solubility constant (SP value).
Is 9.5 (cal / mol · cm ³ ) ^1/2 , surface tension γ
s was 40 dyn / cm.

The light emitting layer is formed by printing by first using a flatbed printing machine, the waterless planographic printing plate, the printing blanket and the IT.
Each glass substrate with an O film was attached, and the lithographic plate was filled with the above-mentioned light-emitting layer forming ink by doctoring. Then, the transfer speed of the ink from the lithographic plate to the printing blanket was set to 50 mm / s, and the glass from the printing blanket to the glass plate. The transfer speed of the ink to the substrate was set to 150 mm / s, and the printing pressure of the printing blanket during the transfer of the ink to the glass substrate was set to 40 kg / cm ² .

The thickness of the pattern composed of the ink for forming a light emitting layer printed on the glass substrate (before drying) was 1 μm, and the thickness of the organic polymer light emitting layer after drying at 80 ° C. for 30 minutes was 0.01 μm. Met. According to the method of Comparative Example 11, although a good light emitting layer could be formed in the early stage of printing, the NBR rubber (surface printing layer) of the printing blanket swelled as the printing was repeated,
Since the print shape is disturbed, only 100 panels could be printed.

(Comparative Example 12) U was formed on the surface of the glass substrate.
After performing V-ozone cleaning to remove deposits such as organic substances, a pattern of a light emitting layer was formed on the surface by an ink jet method. As a result, the ink spreads on the surface of the glass substrate, and finally the line width is 100 to 1
Problems such as variations in the range of 50 μm occurred. That is, it was not possible to form a fine light emitting layer pattern with high accuracy.

(Comparative Example 13) As a printing blanket, the surface layer was formed by using acrylonitrile-butadiene rubber, and the ten-point average roughness (Rz) of the surface was 0.4 µm and the hardness was 85 ° in JIS A hardness
The pattern formation of the light emitting layer was attempted in the same manner as in Example 5 except that the above was used. As a result, there is a problem in that it is not possible to form a pattern having a good print shape, such as the sharpness is lost from the edge of the pattern of the light emitting layer due to the low ink releasability of the printing blanket.

Further, the swelling of the surface printing layer due to the solvent of the ink was remarkable, and repeated printing could not be performed.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of an organic EL element and a method for manufacturing the same.

[Explanation of symbols]

10 Organic EL panel 11 Transparent substrate 12 Transparent conductive film (ITO film) 13 Hole transport layer 14 Light-emitting layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 33/14 H05B 33/14 A (72) Inventor Hiromasa Okubo 3-6 Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo No. 9 Sumitomo Rubber Industries, Ltd. (72) Inventor Shin Sugitani 3-6-9 Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo Sumitomo Rubber Industries Ltd. F-term (reference) 2H113 AA04 BA03 BB09 BC05 CA17 DA46 DA55 DA64 DA66 EA06 EA07 EA25 FA02 2H114 AA02 CA04 CA05 DA46 DA58 DA62 FA02 FA06 3K007 AB18 DB03 FA01

Claims (15)

[Claims] 1. A printing ink obtained by dissolving or stably dispersing an organic EL device forming material in a solvent is filled in the concave portion of the intaglio plate, and the printing ink is transferred from the concave portion of the intaglio plate to a printing blanket, and further, A method for manufacturing an organic EL panel, which comprises transferring the printing ink transferred to the surface of the printing blanket onto a substrate. 2. The printing blanket has a ten-point average roughness Rz of 0.01 to 3 μm, and a volume change rate of 4 when immersed in a solvent of the printing ink at 23 ° C. for 24 hours.
A surface-printed layer having a content of 0% or less is provided.
A method for manufacturing the organic EL panel described. 3. The printing blanket has a thickness of 0.0
A surface printing layer having a hardness of 3 to 5.0 mm, a hardness (JIS A) of 20 to 80 °, and a volume change rate of 40% or less when immersed in a solvent of the printing ink at 23 ° C. for 24 hours. The method for manufacturing an organic EL panel according to claim 1, wherein 4. The printing blanket has a solubility constant of
5-8 (cal / mol / cm³) ^1/2Of elastic body
Surface tension γ_sIs a surface mark of 5 to 35 dyn / cm
The organic EL panel according to claim 1, further comprising a printing layer.
Manufacturing method. 5. A ten-point average roughness Rz of 0.01 to 3 in which the printing blanket is made of an elastomer having a fluorinated polyether skeleton and a silicone cross-linking end group.
The method for manufacturing an organic EL panel according to claim 1, which comprises a surface printing layer having a thickness of μm. 6. The method for manufacturing an organic EL panel according to claim 1, wherein the organic EL element forming material is an organic polymer light emitting material. 7. The printing pressure when transferring the printing ink transferred to the surface of a printing blanket onto a substrate is 1 to 30 kgf.
/ Cm is the organic EL according to any one of claims 1 to 6.
Panel manufacturing method. 8. A printing method comprising a surface printing layer having a ten-point average roughness Rz of 0.01 to 3 μm and a volume change rate of 40% or less when immersed in a solvent of printing ink at 23 ° C. for 24 hours. Blanket. 9. Thickness of 0.03 to 5.0 mm, hardness (JI
S A) is 20 to 80 °, and the volume change rate is 40% when immersed in a solvent of printing ink at 23 ° C. for 24 hours.
A printing blanket comprising a surface printing layer that is: 10. A solubility constant of 5 to 8 (cal / mol /
The surface tension γ _s of the elastic body of cm ³ ) ^1/2 is 5
A printing blanket with a surface printing layer of ~ 35 dyn / cm. 11. The printing blanket according to claim 8, wherein the surface printing layer is made of a silicone elastomer, a fluorine elastomer, butyl rubber, ethylene-propylene rubber or a mixture thereof. . 12. A printing comprising a surface printing layer formed by using an elastomer having a fluorinated polyether skeleton and a silicone cross-linking end group, and having a surface roughness of 0.01 to 3 μm in ten-point average roughness Rz. Blanket. 13. The printing blanket according to claim 12, wherein the surface printing layer has a JIS A hardness of 20 to 80 °. 14. The printing blanket according to claim 8, wherein the elastomer, the rubber or the mixture thereof is in a paste state or a liquid state in an uncured state. 15. The uncured viscosity of the elastomer, rubber or mixture thereof is 10,000 Pa at room temperature.
The printing blanket according to claim 14, which is s or less.