JP2009144086A - Black paste composition and method for producing black film using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a black film having higher shielding ratio and a pattern with no line disarrangement, to improve utilization efficiency of a paste material, and to reduce complication of conventional production processes using a photolithographic method for simplifying production processes. <P>SOLUTION: The black paste composition, which is used for producing black films 16b and 24 on a front glass substrate 11 constituting a PDP 10 by an offset printing method, comprises 10-50 mass% of black oxide powder, 5-30 mass% of glass powder, and the rest of an organic vehicle, and viscosity of the composition is 0.5-30 Pa s. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a black paste composition suitable for producing black films for bus electrodes and black stripes on a windshield substrate of a plasma display panel (hereinafter referred to as PDP) by an offset printing method, and The present invention relates to a method for producing a black film using the composition.

  PDP applies voltage to the electrode pair of the discharge cell, which is a sealed space filled with gas, generates plasma discharge, and irradiates the phosphor applied in the discharge cell with ultraviolet rays generated from the gas, thereby exciting the phosphor. It is a display device that displays information by causing it to emit light.

  The image display method of the PDP will be further described below with reference to FIG. In the PDP, a partition wall 13 is provided between the front glass substrate 11 and the rear glass substrate 12 to suppress the spread of the discharge to a certain region and to perform display in a prescribed cell, and to ensure a uniform discharge space. . A bus electrode 16 is provided on the inner surface of the front glass substrate 11, and an address electrode 17 is provided on the inner surface of the rear glass substrate 12 so as to face the bus electrode 16. Both substrates 11 and 12 are partitioned by a partition wall 13. Gas is sealed in the partitioned interior, and a discharge space 14 is formed. The PDP generates plasma discharge between the bus electrode 16 and the address electrode 17 that are opposed to each other in the discharge space 14, so that ultraviolet rays generated from the gas sealed in the discharge space 14 are generated in the discharge space 14. The display is performed by being applied to the phosphors 18G, 18B, and 18R provided in.

  In recent years, there has been a demand for higher image quality of PDP, and one of the countermeasures is high contrast. Conventionally, the contrast of a PDP has been lower than that of a cathode ray tube television, but one of the causes for lowering the contrast is the high reflection luminance of room light.

  The room light is visible light, but the reflectance of the visible light to the phosphor in the discharge cell that constitutes the PDP is high, so that the room light reflected by the phosphor enters the viewer's eyes and the light emitted from the phosphor is visible. Cause the weakening.

  For this reason, in recent PDPs, as a measure for solving a decrease in contrast due to reflection of room light, the room light is prevented from entering the discharge cells constituting the PDP by improving the room light shielding rate on the front substrate. The method is adopted. The first method is a method of shielding and lowering the external light reflectance by forming the black stripes 24 at the positions of the barrier ribs 13 that create the discharge spaces, that is, the portions of the panel that are not discharged. In the second method, a black electrode 16b is first formed by applying a black paste to a bus electrode that has been conventionally composed of only one white layer mainly composed of silver or the like, and the white layer 16a is formed thereon. In this method, the bus electrode 16 is formed by stacking two layers of black and white 16a and 16b.

  A light comprising a heat-resistant black pigment, an organic binder, a photopolymerizable monomer, a photopolymerization initiator, and organic beads as a material for forming a black film such as the black stripe or the black layer of the bus electrode. A PDP front substrate is proposed in which a curable resin composition and a black layer and a black matrix (black stripe) are formed of the photocurable resin composition (see, for example, Patent Document 1). ). A photolithography method is used to form a black layer and a black matrix constituting a bus electrode made of the photocurable resin composition disclosed in Patent Document 1.

Specifically, first, a photocurable resin composition is applied to the entire surface of the front glass substrate on which the transparent electrode is formed, and dried to form a tack-free black layer. A photomask having a bus electrode and a black matrix pattern is superimposed on the formed black layer and exposed. Next, a highly conductive composition containing conductive powder such as Ag is applied to the entire surface of the black layer and dried to form a tack-free white layer (conductive layer). This is overlaid with a photomask having an exposure pattern of bus electrodes and exposed. Next, a non-exposed portion is removed by development with an aqueous alkali solution and baked to form a bus electrode composed of a black layer (lower layer) electrode and a white layer (upper layer) electrode on the transparent electrode of the windshield substrate. , A black matrix is formed.
Japanese Patent Laying-Open No. 2005-8700 (Claims 1 and 4, specification [0052], FIG. 2)

  However, in the photolithography method as shown in Patent Document 1, a so-called photosensitive black paste containing a photo-curable monomer having a photo-curing property is used as a material for the black layer or the black matrix. ing. In the photolithography method, it is necessary to expose and cure the entire coating layer formed by applying a photosensitive black paste. However, when the particle size of a black powder such as a black pigment contained in the photosensitive black paste is reduced to form a black layer with a finer pattern, if the particle size is set to a certain value or less, the particles become dense. In such a situation, the light of exposure is blocked and the photocurable composition such as a photocurable monomer cannot be sufficiently cured, and a fine pattern black layer cannot be formed. . On the other hand, when the particle size of the black powder is increased to obtain sufficient curing of the photocurable composition, the gap between the particles is increased, and the effect of shielding the visible light of the black layer is sufficiently obtained. The problem of not.

  In addition, since the portions other than the exposed portions are removed in a post process in the photolithography method, the use efficiency of the paste material is extremely poor, and depending on the type of element contained in the paste material to be removed, the cost for the processing method, recycling, etc. Such a problem has also occurred.

  Furthermore, when forming a black layer or a black matrix by the photolithography method as in Patent Document 1, complicated manufacturing processes such as coating, drying, exposure, development, and baking must be performed.

  Therefore, the present invention has been made to solve the problems of such conventional techniques.

  An object of the present invention is to provide a black paste composition having a high shielding rate and capable of forming a fine pattern black film, and a method for producing a black film using the composition.

  Another object of the present invention is to provide a method for producing a black film using a black paste composition, which can improve the utilization efficiency of the paste material.

  Still another object of the present invention is to provide a method for producing a black film using a black paste composition, which can improve the complexity of a conventional production process using a photolithography method and simplify the production process. is there.

  As shown in FIG. 1, the invention according to claim 1 is a black paste composition for producing black films 16 b and 24 on a windshield substrate 11 constituting the PDP 10 by an offset printing method. The characteristic structure includes a black oxide powder having a composition of 10 to 50% by mass, a glass powder of 5 to 30% by mass, and the balance being an organic vehicle, and the composition having a viscosity of 0.5 to 30 Pa.・ It is where s.

  In the offset printing method, the viscosity of the paste is important and greatly affects the transferability when the paste is printed. If the paste viscosity is too high, the paste will not fill well to the metal intaglio with the desired pattern by offset printing, and when transferring to a blanket or windshield substrate, the pattern will be uneven or discontinuous Is likely to occur. On the other hand, if the paste viscosity is too low, the paste shape cannot be maintained and easily spread when the pattern is transferred from the intaglio by offset printing. Therefore, in the invention according to claim 1, by limiting the paste composition to a viscosity in the optimum range for offset printing, there is no line disturbance, a good paste shape is maintained, and a fine pattern black film can be formed. And

  The invention according to claim 2 is the black paste composition according to claim 1, wherein the tack value of the composition is 5-30. Here, “tack” is a value indicating the degree of adhesive strength, and is a numerical value measured by an incometer according to JIS K 5701-2000.

  In the invention according to claim 2, by setting the tack value of the black paste composition to 5 to 30, the black paste composition is made of glass without leaving the black paste composition on the blanket during transfer from the blanket to the glass substrate. Suitable for transfer onto a substrate.

  The invention according to claim 3 is the invention according to claim 1, wherein the organic vehicle has a viscosity of 0.01 to 10 Pa · s.

  In the invention which concerns on Claim 3, it becomes easy to adjust the viscosity of a black paste composition by making the viscosity of an organic vehicle into the range of 0.01-10 Pa.s. The viscosity of the black paste composition is related to the blending ratio of the black oxide powder, glass powder and organic vehicle, and the particle size and specific surface area of the black oxide powder, but the viscosity value of the organic vehicle is black paste. It most affects the viscosity of the composition.

  As shown in FIGS. 4 and 5, the invention according to claim 4 is the black film 16 b, 24 on the substrate 11 by the offset printing method using the black paste composition according to any one of claims 1 to 3. Is a method for producing a black film.

  In the invention according to claim 4, in order to form a black film having a high density and a high shielding rate, the offset printing method has a viscosity excellent in offset printability, that is, transferability when the paste is printed by an offset printing machine. By using the black paste composition, it is possible to form a black film with a fine pattern that does not disturb the line and maintains a good paste shape. In the photolithography method used in the conventional manufacturing process, since the photosensitive paste is exposed and cured, it is necessary to secure a certain gap between the particles of the black powder and allow the exposure light to pass through. Therefore, the particle size of the black powder has to be increased more than necessary, and there has been a limit in forming a black film with higher density and higher shielding rate. By making it possible to use a black powder having a small particle size, it is possible to form a black film having a higher density and a higher shielding rate.

  According to the present invention, the composition contains 10 to 50% by weight of black oxide powder, 5 to 30% by weight of glass powder, and the balance is an organic vehicle with a viscosity of 0.5 to 30 Pa · s. Since this is a black paste composition in the range, the use of this composition makes it possible to form a fine pattern black film by an offset printing method instead of the photolithography method used in the prior art. As a result, it is possible to use a black powder having a particle diameter smaller than that of the black powder used in the photolithography method, and thus it is possible to produce a black film having a higher density and a higher shielding rate. In addition, it becomes easy to adjust the viscosity of a black paste composition to the range of 0.5-30 Pa.s by making the viscosity of an organic type vehicle into the range of 0.01-10 Pa.s.

  In the photolithography method used in the conventional manufacturing process, the paste composition is applied to the entire desired surface and then exposed, and unnecessary portions are discarded and removed in a subsequent process. In the present invention, offset printing is performed. Since the black film is formed by the method, it is only necessary to apply the paste composition only to a necessary portion, so that an effect of improving the material utilization efficiency can be obtained. Further, it is not necessary to take complicated steps such as coating, exposure, and development in the photolithography method, and the manufacturing process can be simplified. Furthermore, in the offset printing method, after forming the black layer, after forming the white layer on the formed unfired black layer, the black layer and the white layer can be fired at the same time. It can be simplified.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the black paste composition of the present invention is used for producing black films 16b and 24 on a windshield substrate 11 constituting the PDP 10 by an offset printing method. The black paste composition of the present invention is configured so as to contain 10 to 50% by mass of black oxide powder, 5 to 30% by mass of glass powder, and the balance of the organic vehicle, and the viscosity of the composition is 0.5-30 Pa · s.

  In the conventional manufacturing process, the photosensitive paste is exposed and cured by a photolithography method, so that a black powder having a particle size of micron order to sub-micron order is used in order to secure a gap for passing the exposure light. Although it was necessary, since the offset printing method is used in the present invention, it is possible to use a black powder having a smaller particle diameter than that used in the prior art, and a black film having a higher density and a higher shielding rate is formed. be able to. Further, by using the black paste composition 13 of the present invention having a viscosity suitable for the offset printing method, it is possible to form a fine pattern black film having a good paste shape without line disturbance due to offset printing. it can. The black paste composition of this invention is comprised so that 10-50 mass% black oxide powder, 5-30 mass% glass powder, and the remainder may contain an organic vehicle.

  In the offset printing method, as shown in FIG. 2A, first, a black paste composition 31 is filled into a metal intaglio plate having a groove 30 a, called a plate 30. Next, as shown in FIG. 2B, the image is once transferred to a cylinder called a blanket 32. Then, as shown in FIG. 2C, the black paste composition 31 once transferred to the blanket 32 is transferred to the substrate 33 to form a black film 34 made of the black paste composition 31. The reason why the viscosity of the black paste composition of the present invention is in the range of 0.5 to 30 Pa · s is that when the upper limit of the viscosity of the composition exceeds 30 Pa · s in the step of FIG. When the black paste composition 31 is not satisfactorily filled in the groove 30a of the substrate 30, the pattern is transferred to the blanket 32 in the step of FIG. 2B or to the substrate 33 in the step of FIG. Cause spots or discontinuities in the skin. Conversely, when the viscosity of the composition is less than the lower limit of 0.5 Pa · s, the black paste composition in the step shown in FIG. 2C is transferred from the blanket 32 to the substrate 33 and then pasted on the substrate 33. This is because the film spreads without being maintained, and a good paste shape cannot be maintained. Among these, the viscosity of the composition is preferably 1 to 20 Pa · s.

  In the present invention, the tack value of the black paste composition is preferably 5-30. Specifically, the black paste composition is configured such that the tack value measured by an incometer according to JIS K 5701-2000 exhibits tackiness that falls within the above range. The larger the tack value, the stronger the adhesive strength. Conversely, when the tack value is small, the adhesive strength is weak. When the tack value of the black paste composition in the present invention is less than the lower limit value, the adhesiveness becomes poor and it becomes difficult to perform good offset printing. Specifically, it becomes difficult to transfer the entire shape during printing. On the contrary, if the tack value of the black paste composition in the present invention exceeds the upper limit value, the tackiness is very strongly expressed, so it is possible to transfer the entire shape at the time of printing. Since it adheres strongly, the shape after printing on the windshield substrate tends to be disturbed. Specifically, corners are formed in the shape during printing, and as shown in FIGS. 3A and 3B, the shape of the composition 15 formed on the substrate 11 becomes a mountain shape or the like. It is easy to cause pattern defects. Among these, a particularly preferable tack value is 10-25.

  The organic vehicle is used to give the black paste composition an adhesive suitable for the printing process of the offset printing method shown in FIG. The alkali-soluble resin is dissolved in an organic solvent, and a dispersant for improving the dispersibility of the black oxide powder and the glass powder, a viscosity modifier for adjusting the paste viscosity, and the like are added as necessary. When adjusting the viscosity of the black paste composition, the mixing ratio of the black oxide powder, the glass powder and the organic vehicle, the particle size of the black oxide powder, the specific surface area, etc. are related, but the viscosity of the organic vehicle is It is most relevant in determining the final paste viscosity. Of these, the viscosity of the organic vehicle is preferably in the range of 0.01 to 10 Pa · s because it is easy to adjust the viscosity of the black paste composition, and among these, 0.05 to 5 Pa · s is particularly preferable.

The black oxide powder is desirably a metal oxide containing one or more metal elements selected from the group consisting of Co, Cr, Cu, Mn, Fe, and Ni, or a composite oxide thereof. Among these, Co ₃ O ₄ , Fe, Mn, Cu composite oxide, and Cu, Cr, Mn composite oxide are particularly preferable. The average particle size of the black oxide powder is preferably in the range of 0.05 to 0.3 μm. If it is less than 0.05 μm, the specific surface area of the black oxide powder becomes large, and even if the black paste composition is adjusted to an optimum viscosity, thixotropic properties are exhibited. Therefore, the black paste composition has poor fluidity and tends to have corners in the shape after printing. If the particle diameter exceeds 0.3 μm, the black oxide powder has a large particle size. Therefore, when a black film having a desired film thickness is produced, the black oxide powder is not collected densely, and the shielding ratio of the formed black film is low. It tends to be low. If the black oxide powder has an average particle size in the above range, it can be used as a paste composition suitable for the offset printing method and for producing a black film having a high density and a high shielding rate.

The glass powder contains one or more oxides selected from the group consisting of lead oxide, bismuth oxide, zinc oxide, boron oxide, silicon oxide, aluminum oxide, phosphorus oxide, calcium oxide and titanium oxide, 400 to 400 A frit glass having a softening point of 550 ° C. is preferable. The reason why the softening point is within the above range is that in the frit glass having a softening point less than the lower limit, the glass powder hinders binder removal of the binder resin constituting the organic vehicle in the paste composition, and this black paste composition This is because a black film produced using an object tends to have an increased resistance value. Moreover, in the frit glass whose softening point exceeds the upper limit value, it is difficult for the glass powder to provide a sufficient anchor between the glass substrate. Among these, the softening point of frit glass is particularly preferably 450 to 550 ° C. Moreover, it is preferable that the average particle diameter of glass powder is 0.05-1.0 micrometer. If it is less than 0.05 μm, the specific surface area of the glass powder becomes large, and even if the black paste composition is adjusted to an optimum viscosity, thixotropic properties are exhibited. Therefore, the black paste composition has poor fluidity and tends to have corners in the shape after printing. On the other hand, when the thickness exceeds 1.0 μm, when the glass powder is softened after firing and spreads in a matrix form as a glass frit, a black film is formed that does not spread uniformly over the entire black film to be formed and has unevenness in shielding. Easy to be. Specifically, PbO—B ₂ O ₃ —SiO ₂ , ZnO—B ₂ O ₃ —SiO ₂ , PbO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ , PbO—ZnO—B ₂ O ₃ —SiO ₂ , PbO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ —ZnO, PbO—B ₂ O ₃ —SiO ₂ —CaO, B ₂ O ₃ —ZnO—Bi ₂ O ₃ , B ₂ O ₃ —Bi ₂ O ₃ , B ₂ O ₃ —ZnO, Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ , ZnO—P ₂ O ₅ —SiO ₂ , P ₂ O ₅ —B ₂ O ₃ —Al ₂ O ₃ , ZnO— Combinations such as P ₂ O ₅ —TiO ₂ can be mentioned.

  The method for producing a black film of the present invention is characterized in that a black film is produced on a substrate by the offset printing method using the black paste composition. In the conventional manufacturing process, the photosensitive paste is exposed and cured by a photolithography method, so that the particle size of the black powder is larger than necessary in order to secure a gap for passing the exposure light. Although it was necessary, since the offset printing method is used in the present invention, it is possible to use a black powder having a smaller particle diameter than that used in the prior art, and a black film having a higher density and a higher shielding rate is formed. be able to. Further, by using the black paste composition of the present invention suitable for the offset printing method, it is possible to form a fine pattern black film having a good paste shape without any line disturbance due to offset printing. Further, in the photolithography method used in the conventional manufacturing process, the paste composition is applied to the entire desired surface and then exposed, and unnecessary portions are discarded and removed in a subsequent process. Since the black film is formed by the offset printing method, it is only necessary to apply the paste composition only to a necessary portion, so that an effect of improving the material utilization efficiency can be obtained. Further, it is not necessary to go through complicated steps such as coating, exposure, and development in the photolithography method. Furthermore, in the offset printing method, after forming the black layer, after forming the white layer on the formed unfired black layer, it is possible to simultaneously fire the two layers of the black layer and the white layer. It can be simplified.

  Next, a method for producing a front substrate for PDP using the method for producing a black film of the present invention will be described.

First, a windshield substrate 11 as shown in FIG. 4A is prepared, and a transparent electrode 23 is formed on the windshield substrate 11 as shown in FIG. The transparent electrode 23 formed here is formed of a transparent material that is necessary for plasma discharge and does not hinder light emission. Specifically, the transparent electrode 23 uses an oxide film such as ITO (Indium Tin Oxide) or SnO _2, and is formed by a vacuum film forming method such as sputtering or vapor deposition or a CVD (Chemical Vapor Deposition) method.

  Next, as shown in FIG. 4C, the black layer 16b is formed on the formed transparent electrode 23 by applying and baking the black paste composition of the present invention by an offset printing method. In the method of the present invention, since the coating film is formed by the offset printing method, a black powder having a smaller particle size can be used, and a black film having a high density and a high shielding rate can be formed. Subsequently, as shown in FIG. 4D, a highly conductive white conductive paste containing conductive powder such as Ag, Au, Pt, or Pd is applied and fired on the formed black layer 16b. Thereby, the white layer 16a is formed. Thereby, the bus electrode 16 composed of the black layer 16b and the white layer 16a is formed.

  The black paste composition of the present invention is applied by the offset printing method to form the black layer 16b, and then the white conductive paste is applied by the offset printing method to form the white layer 16a on the black layer 16b. After the formation, the bus electrode 16 composed of the black layer 16b and the white layer 16a can be formed by simultaneously firing the black layer 16b and the white layer 16a. In such a method, the two layers of the coated film are simultaneously fired, so that the process can be shortened.

  Next, as shown in FIG. 4E, a transparent dielectric layer 21 is formed on the entire surface of the windshield substrate 11 so as to cover the transparent electrode 23 and the bus electrode 16. The transparent dielectric layer 21 is formed in order to provide a memory function by forming wall charges on the surface of the dielectric layer during electrode protection and discharging. The transparent dielectric layer 21 is formed on the bus electrode 16 so as to have a thickness of 20 to 40 μm.

  Next, as shown in FIG. 5A, a black stripe 24 is formed on the formed transparent dielectric layer 21 by applying and baking the black paste composition of the present invention by an offset printing method. By forming the black stripe 24, the external light reflectance is reduced and the contrast is improved. In the method of the present invention, since the coating film is formed by the offset printing method, a black powder having a smaller particle size can be used, and a black film having a high density and a high shielding rate can be formed.

Next, as shown in FIG. 5B, the color filter 22 is formed on the transparent dielectric layer 21 so as to have the same height as the black stripe 24. Subsequently, as shown in FIG. 5C, the transparent dielectric layer 21 is formed on the color filter 22 and the black stripe 24. Further, as shown in FIG. 5D, a protective film 19 is formed on the transparent dielectric layer 21.
The protective film 19 is formed when the dielectric layer is damaged by ion bombardment due to discharge and the panel life is shortened, and the efficiency of secondary electron emission necessary for plasma discharge is low, and the discharge voltage becomes high. This is to prevent this. The protective film 19 is made of MgO and can be formed by electron beam evaporation, ion plating, or sputtering.

  As described above, the front substrate for PDP is obtained through the steps shown in FIGS. 4 (a) to 5 (d).

  Next, examples of the present invention will be described in detail together with comparative examples.

<Examples 1-6 and Comparative Examples 1-4>
Prepare the black oxide powder, glass powder and organic vehicle shown in the following Table 1 and Table 2, and add the black oxide powder and glass powder to the organic vehicle so as to have the content shown in the following Table 1 and Table 2. Were mixed to prepare a black paste composition.

  The organic vehicle was prepared by dissolving an alkali-soluble resin in an organic solvent. Depending on the black paste composition to be produced, additives such as a dispersant and a viscosity modifier are added to the organic vehicle as appropriate. The dispersant was appropriately added to improve the dispersibility of the black oxide powder and the glass powder, and the viscosity modifier was appropriately added to adjust the viscosity of the paste.

  The viscosity was measured twice using a rheometer (TA Instruments), using a 40 mm Al cone, only with an organic vehicle, and after producing a black paste composition.

＜比較試験＞
実施例１〜６及び比較例１〜４で得られた黒色ペースト組成物を用いて、以下のオフセット印刷性、最小線幅、保存安定性についての評価を行った。その結果を次の表３,表４に示す。

<Comparison test>
Using the black paste compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 4, the following offset printability, minimum line width, and storage stability were evaluated. The results are shown in Tables 3 and 4 below.

  (1) Offset printability: The transferability when the black paste composition was printed on a glass substrate with an offset printer (manufactured by JEOL Ltd.) was evaluated as offset printability. When the black paste composition is transferred from the blanket to the glass substrate, the line shape is not disturbed and transferred 100%, and there is no residual paste on the blanket. In some cases, bleeding and disturbance are confirmed in part of the line shape, but when there is no residual paste composition on the blanket and 100% transfer can be performed, An evaluation of “impossible” was made when a defective portion or the like was confirmed or a paste that could not be transferred on the blanket remained.

  (2) Minimum line width: The line width capable of offset printing is represented by four line widths of 50 μm, 70 μm, 100 μm, and 150 μm, and this line width is defined as the minimum line width.

  (3) Storage stability: Store the black paste composition in a low-temperature storage kept at 15 ° C, and set the time until the black paste composition is altered or precipitated to be stored. The number of days was used as an index of storage stability.

  Next, the black paste compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were applied on a glass substrate by a screen printing method, and this coating film was baked at 580 ° C. for 30 minutes to form a black film. did. About the formed black film, the following blackness and adhesiveness were evaluated. The results are shown in Table 3 below.

  (4) Blackness: The blackness of the formed black film was measured using a color computer (manufactured by Suga Test Instruments Co., Ltd.). Specifically, a Y value representing blackness when an XYZ color difference was measured was obtained. In addition, it means that blackness is so high that Y value is small.

  (5) Adhesion: For the formed black film, the adhesion of the black film was evaluated by a cross-cut tape test method based on JIS-K5400. The specific evaluation of the adhesion is a “good” evaluation when the black film on the tape side is not transferred and the black film adheres to 100% on the glass substrate when the grid tape tape test is performed. When the black film adheres to both the tape and the glass substrate due to internal destruction, it was evaluated as “Yes”. Many black films adhered to the tape side, and the glass substrate was observed at the interface after thinning. The evaluation was “impossible”.

表３は、黒色ペースト組成物の粘度の違いによる評価結果を表したものである。表３より明らかなように、黒色ペースト組成物の粘度が高い比較例１では、保存安定性においては実施例３，４よりも優れた値を示し、黒色度についても実施例２，３と同程度の高い黒色度が得られたものの、粘度が高すぎるために、黒色ペースト組成物がブランケットに良好に転写せず、基板上に印刷されたペースト組成物には途切れや斑が生じてしまい最小線幅を確認できなかった。黒色ペースト組成物の粘度が低い比較例２では、黒色度については、ラインの膜厚に斑が出て、部分的に遮蔽率が不十分な箇所が発生したため、実施例１〜４に比べてＹ値が若干高い値を示し、黒色度は下がった。また、密着性は実施例３と同等の結果が得られた。しかし、比較例２における黒色ペースト組成物は、粘度が低すぎるために、転写した後にペースト形状が保てず線と線の間が、広がったペーストによってふさがってしまったため最小線幅を確認できなかった。一方、実施例１〜４では、最小線幅を確認でき、オフセット印刷性においても比較例１，２よりも優れた結果が得られた。

Table 3 shows the evaluation results based on the difference in viscosity of the black paste composition. As is clear from Table 3, Comparative Example 1 in which the viscosity of the black paste composition is high shows a value superior to Examples 3 and 4 in terms of storage stability, and the blackness is also the same as in Examples 2 and 3. Although a high degree of blackness was obtained, the viscosity was too high, so the black paste composition did not transfer well to the blanket, and the paste composition printed on the substrate produced discontinuities and spots. The line width could not be confirmed. In Comparative Example 2 in which the viscosity of the black paste composition is low, the blackness is uneven in the film thickness of the line, and a part with insufficient shielding ratio is partially generated, so compared with Examples 1 to 4. The Y value showed a slightly high value, and the blackness decreased. Moreover, the result equivalent to Example 3 was obtained for adhesiveness. However, since the viscosity of the black paste composition in Comparative Example 2 is too low, the paste shape cannot be maintained after transfer, and the gap between the lines is blocked by the spread paste, so the minimum line width cannot be confirmed. It was. On the other hand, in Examples 1 to 4, the minimum line width could be confirmed, and the results superior to Comparative Examples 1 and 2 were also obtained in the offset printability.

表４は、黒色ペースト組成物に含まれる黒色酸化物粉末とガラス粉末の含有割合の違いによる評価結果を表したものである。表４より明らかなように、黒色酸化物粉末の含有量が下限値である１０質量％を満たさず、ガラス粉末が上限値である３０質量％を越える比較例３では、良好な密着性は得られたものの、黒色度については、Ｙ値が最も高い値を示し十分な黒色度が得られなかった。黒色酸化物粉末の割合に比べ、ガラス粉末の割合が多いため、黒色度は最も悪くなり、良好な密着性は得られるものの、遮蔽としての十分な効果が得られない黒色膜となった。また、黒色酸化物粉末の含有割合が上限値である５０質量％を越え、ガラス粉末が下限値である５質量％に満たない比較例４では、遮蔽効果として十分な黒色度は得られたものの、密着性が不可となった。黒色酸化物粉末の含有割合に対し、ガラス粉末の含有割合が低すぎるため、ガラス粉末が、軟化した後、形成される黒色膜全体に広がらず、密着性の悪い黒色膜となった。一方、黒色酸化物粉末が１０質量％で、ガラス粉末が３０質量％である実施例５では、密着性は高く、遮蔽として十分な黒色度を示した。また、黒色酸化物粉末が５０質量％で、ガラス粉末が５質量％である実施例６では、黒色度については、Ｙ値が最も低い値を示し遮蔽に十分な黒色度が得られ、また密着性についても十分な結果が得られた。黒色酸化物粉末、ガラス粉末の上限値又は下限値いずれをも満たす実施例５，６においては、これらを満たさない比較例３，４よりもオフセット印刷に適した黒色ペースト組成物が得られる結果となった。

Table 4 shows the evaluation results based on the difference in the content ratio between the black oxide powder and the glass powder contained in the black paste composition. As is clear from Table 4, in Comparative Example 3 in which the content of the black oxide powder does not satisfy the lower limit of 10% by mass and the glass powder exceeds the upper limit of 30% by mass, good adhesion is obtained. However, as for the blackness, the Y value was the highest, and sufficient blackness was not obtained. Since the ratio of the glass powder is larger than the ratio of the black oxide powder, the blackness is the worst and good adhesion can be obtained, but a black film that does not have a sufficient effect as a shield is obtained. Further, in Comparative Example 4 in which the content ratio of the black oxide powder exceeds the upper limit of 50% by mass and the glass powder is less than the lower limit of 5% by mass, sufficient blackness as a shielding effect was obtained. , Adhesion became impossible. Since the content ratio of the glass powder was too low with respect to the content ratio of the black oxide powder, the glass powder did not spread over the entire black film formed after being softened, resulting in a black film with poor adhesion. On the other hand, in Example 5 in which the black oxide powder was 10% by mass and the glass powder was 30% by mass, the adhesion was high and the blackness was sufficient for shielding. Further, in Example 6 in which the black oxide powder is 50% by mass and the glass powder is 5% by mass, the blackness is the lowest Y value and sufficient blackness for shielding is obtained. Sufficient results were obtained for sex. In Examples 5 and 6 that satisfy both the upper limit value and the lower limit value of the black oxide powder and the glass powder, a result that a black paste composition that is more suitable for offset printing than Comparative Examples 3 and 4 that do not satisfy these is obtained. became.

The figure which shows the discharge cell of PDP. The figure which shows the printing process to the windshield board | substrate by an offset printing method. Paste shape after printing when the viscosity is too high. The figure which shows the front | former stage of the manufacturing process of the front substrate for PDP. The figure which shows the back | latter stage of the manufacturing process of the front substrate for PDP.

Explanation of symbols

10 PDP
11 Front glass substrate 16b Black film (black layer of bus electrode)
24 Black film (black stripe)

Claims (4)

A black paste composition for producing a black film by an offset printing method on a windshield substrate constituting a plasma display panel,
The composition contains 10 to 50% by weight of black oxide powder, 5 to 30% by weight of glass powder, and the balance includes an organic vehicle,
A black paste composition, wherein the composition has a viscosity of 0.5 to 30 Pa · s.   The black paste composition according to claim 1, wherein the tack value of the composition is 5 to 30.   The black paste composition according to claim 1, wherein the organic vehicle has a viscosity of 0.01 to 10 Pa · s.   A method for producing a black film, comprising producing a black film on a substrate by an offset printing method using the black paste composition according to any one of claims 1 to 3.

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