JP2009269808A - Method for forming layer of inorganic matter and plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a layer of inorganic matter enabling to sufficiently suppress deterioration of electrical or optical characteristics of the layer of inorganic matter when forming the layer of the inorganic matter by using a composition including an organic compound and inorganic fine particles. <P>SOLUTION: This method for forming the layer of inorganic matter comprises a first step of providing a coating layer by applying on a substrate an inorganic fine particle-containing composition containing an organic compound (A) and inorganic fine particles (B), and a second step of heating the coating layer at a temperature of 150°C or higher and 350°C or lower under an atmosphere of ≤10 vol.% oxygen concentration. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for forming an inorganic layer and a plasma display panel.

  As a method of forming an inorganic layer on a substrate, there is a method of using an inorganic fine particle-containing resin composition containing inorganic fine particles and an organic compound such as an organic solvent or a binder polymer. This method generally includes (1) a coating process in which the resin composition is coated on a substrate to form a coating layer, and (2) a relatively low boiling point organic compound (for example, an organic solvent) is evaporated from the coating layer. A drying process for curing the coating layer, and (3) a baking process for decomposing and removing the remaining organic compound (for example, binder polymer) by baking to leave only inorganic fine particles.

  In the above method, it is easy to control the thickness of the inorganic layer to be formed, and by adjusting the viscosity of the resin composition, it can be handled like a liquid during transportation, and the scattering of inorganic fine particles is suppressed during coating. Since it has the advantage that the cleanliness of the work space can be improved by being applied, it is widely applied as a method for forming an inorganic layer.

  As the binder polymer, a cellulose derivative using a natural polymer as a raw material is preferably used, and an artificial polymer such as an acrylic resin may also be used. However, these binder polymers may remain in the inorganic layer as a small amount of carbon component after the firing step, and may adversely affect the properties of the inorganic layer, particularly electrical and optical performance. In addition, although the method of making the residual component derived from the organic compound in an inorganic layer sufficiently small by baking at high temperature of 400 degreeC or more in a baking process is also performed, in this case, the heat history concerning the base material to be used is large. Therefore, distortion and the like are likely to occur, and at the same time, there are disadvantages such as production costs increase due to heating at a high temperature.

Recently, for the purpose of not using or reducing the binder polymer, a vanishing binder composition containing a C _{10 to} C ₁₆ bridged cyclic bicyclic hydrocarbon compound or a derivative thereof has been proposed (for example, Patent Documents). 1).
JP 2007-217603 A

  However, the present inventor has found that even the vanishing binder composition described in Patent Document 1 may adversely affect the properties of the formed inorganic layer. Specifically, the inventors have found that coloring or discoloration occurs when a phosphor layer of a plasma display panel (PDP) is formed.

  Recently, the level of demand for plasma display performance has increased, and it has excellent characteristics for dielectric layers and phosphor layers of plasma display panels in order to achieve high image quality and low power consumption. It is required to be. Therefore, there is room for further improvement in the above-described conventional technology.

  The present invention has been made in view of the above circumstances. When an inorganic layer is formed using a composition containing an organic compound and inorganic fine particles, the electrical or optical performance of the inorganic layer is sufficiently reduced. An object of the present invention is to provide a method of forming an inorganic layer that can be suppressed and a plasma display panel including a phosphor layer formed by the method.

  In order to achieve the above object, the present invention provides a first step of applying an inorganic fine particle-containing composition containing (A) an organic compound and (B) inorganic fine particles on a substrate to provide an application layer; And a second step of heating the layer at a temperature of 150 ° C. or higher and 350 ° C. or lower in an atmosphere having an oxygen concentration of 10% by volume or lower.

  According to the method for forming an inorganic layer of the present invention, by having the above configuration, it is possible to form an inorganic layer in which a decrease in electrical or optical performance is sufficiently suppressed. When the coating layer is heated in the above temperature range in an atmosphere where the oxygen concentration exceeds 10% by volume, it is difficult to sufficiently suppress the deterioration of the performance of the inorganic layer. The inventor presumes the reason as follows. That is, organic compounds often have the property of decomposing at 150 ° C. or higher, and the decomposition reaction further proceeds when heated at around 300 ° C. This decomposition reaction has a concerted relationship with evaporation, and it is considered that the component that has undergone the decomposition reaction faster than evaporation tends to remain on the substrate surface as a tar-like residue in an atmosphere where the oxygen concentration exceeds 10% by volume. It is done. The present inventor believes that the residual component derived from the organic compound causes coloring or discoloration of the inorganic layer or a decrease in electrical characteristics. When the heating temperature is lower than 150 ° C., the removal of the organic compound is insufficient, and when the heating temperature exceeds 350 ° C., the heat history to the base material and the increase in production cost become problems. In the method for forming an inorganic layer according to the present invention, the present invention includes the second step, whereby the organic compound can be sufficiently removed while sufficiently preventing the generation of residual components derived from the organic compound. Thinks.

  Since the formation method of the inorganic layer of this invention is equipped with the said process heated at the temperature of 150 to 350 degreeC, a baking process can be skipped. In this case, it is possible to reduce the heat history of the base material and simplify the inorganic layer forming process and reduce the cost.

  In the method for forming an inorganic layer of the present invention, the organic compound (A) preferably contains a terpene compound from the viewpoint of further improving the coating property on the substrate and the dispersibility of the inorganic fine particles. Moreover, since the terpene compound can be removed at a relatively low temperature, the residue derived from the organic compound after the second step can be further reduced.

The terpene compound is preferably a compound represented by the following general formula (1).

  The present invention provides a method for forming an inorganic layer, wherein the substrate is a substrate for plasma display, the inorganic fine particles (B) are phosphor fine particles, and the phosphor layer for plasma display is formed as an inorganic layer. it can. In this case, the phosphor layer for a plasma display can be formed while sufficiently suppressing a decrease in electrical or optical performance, in particular, a decrease in optical performance such as discoloration or coloring.

  The present invention also provides a plasma display panel comprising a phosphor layer for plasma display formed by the above-described inorganic layer forming method. Since the plasma display panel of the present invention includes the phosphor layer for plasma display formed by the above-described inorganic layer forming method, performance degradation such as electrical and optical performance can be sufficiently suppressed. In the plasma display panel of the present invention, the manufacturing cost for forming the phosphor layer and the thermal history of the substrate can be reduced as compared with the conventional case.

  ADVANTAGE OF THE INVENTION According to this invention, when forming an inorganic layer using the composition containing an organic compound and inorganic fine particles, formation of the inorganic layer which can fully suppress the electrical or optical performance fall of an inorganic layer. Methods and plasma display panels comprising phosphor layers formed by such methods can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  The method for forming an inorganic layer of the present invention includes a first step of applying an inorganic fine particle-containing composition containing (A) an organic compound and (B) inorganic fine particles on a substrate to provide a coating layer; And a second step of heating at a temperature of 150 ° C. to 350 ° C. in an atmosphere having an oxygen concentration of 10% by volume or less.

  First, the inorganic fine particle-containing composition according to the present invention will be described.

  The organic compound (A) contained in the inorganic fine particle-containing composition according to the present invention is not particularly limited as long as the inorganic fine particles can be dispersed and the inorganic fine particle-containing composition can be applied. What the heating residue when heating for 1 minute is 1 mass% or less is preferable. The heating residue at 300 ° C. in the air means the ratio of the weight of the organic compound after heating to the weight of the organic compound before heating when the organic compound is heated at 300 ° C. for 10 minutes in the air. To do.

  (A) The organic compound preferably contains a terpene compound. Since the terpene compound can be removed at a relatively low temperature, the residue derived from the organic compound after the second step can be further reduced.

  (A) The organic compound more preferably contains (a-1) isobornylcyclohexanol represented by the following formula (1) as a terpene compound.

  As for isobornylcyclohexanol represented by the above formula (1), “Telsolve MTPH” (trade name, manufactured by Nippon Terpene Chemical Co., Ltd.) is commercially available.

  By including the isobornylcyclohexanol represented by the above formula (1) in the inorganic fine particle-containing composition according to the present invention, the adverse effect caused by the organic compound can be further reduced in the formed inorganic layer.

  In the composition containing inorganic fine particles according to the present invention, the content of (a-1) isobornylcyclohexanol represented by the above formula (1) is preferably 30 to 100% by mass, based on the total amount of the organic compound, and 50 to 95. % By mass is more preferable, and 70 to 90% by mass is particularly preferable. By making content of the isobornyl cyclohexanol represented by the said Formula (1) into the said range, it becomes easy to acquire the effect that it becomes easy to form a uniform coating film compared with the case outside the said range. According to the method for forming an inorganic layer of the present invention, even if the content of isobornylcyclohexanol is within the above range, it is possible to sufficiently suppress a decrease in the electrical or optical performance of the inorganic layer. it can.

  Further, the content of isobornylcyclohexanol represented by the above formula (1) is 30 to 70 on the basis of the total amount of the inorganic fine particle-containing composition from the viewpoint of improving the coating property of the inorganic fine particle-containing composition. % By mass is preferable, and 40 to 60% by mass is more preferable. According to the method for forming an inorganic layer of the present invention, even if the content of isobornylcyclohexanol is within the above range, it is possible to sufficiently suppress a decrease in the electrical or optical performance of the inorganic layer. it can.

  Moreover, the inorganic fine particle containing composition which concerns on this invention contains the organic solvent which has (a-2) boiling point in the range of 150-250 degreeC as (A) organic compound from a viewpoint of the flatness of a coating layer. preferable. In the present specification, the boiling point of the organic solvent refers to a value under atmospheric pressure.

  (A-2) Examples of the organic solvent having a boiling point in the range of 150 to 250 ° C. include ketones such as holon (boiling point: 198 ° C.), cyclohexanone (boiling point: 155 ° C.), and methylcyclohexanone (boiling point: 170 ° C.). Solvents, methyl phenyl ether (boiling point: 153 ° C.), ethyl phenyl ether (172 ° C.), methoxytoluene (boiling point: 172 ° C.), benzyl ethyl ether (boiling point: 189 ° C.), diethylene glycol dimethyl ether (boiling point: 160 ° C.), diethylene glycol Diethyl ether (boiling point: 188 ° C), diethylene glycol monomethyl ether (boiling point: 194 ° C), diethylene glycol monobutyl ether (boiling point: 231 ° C), diethylene glycol monobutyl ether acetate (boiling point: 247 ° C), ethylene glycol mono Ether solvents such as chill ether (boiling point: 171 ° C), ethylene glycol monoisoamyl ether (boiling point: 181 ° C), 1-hexanol (boiling point: 157 ° C), 1-heptanol (boiling point: 176 ° C), 2-heptanol (boiling point) : 160 ° C), 3-heptanol (boiling point: 156 ° C), 1-octanol (boiling point: 195 ° C), 2-octanol (boiling point: 179 ° C), 2-ethyl-1-hexanol (boiling point: 184 ° C), cyclo Hexanol (boiling point: 161 ° C), 1-methylcyclohexanol (boiling point: 155 ° C), 2-methylcyclohexanol (boiling point: 165 ° C), 3-methylcyclohexanol (boiling point: 173 ° C), 4-methylcyclohexanol ( Boiling point: 174 ° C), furfuryl alcohol (boiling point: 170 ° C), ethylene glycol ( Point: 198 ° C, propylene glycol (boiling point: 187 ° C), 1,2-butylene glycol (boiling point: 191 ° C), hexylene glycol (boiling point: 197 ° C), 3-methyl-3-methoxybutanol (boiling point: 174) Alcohol) such as 3-methoxy-3-methyl-1-butyl acetate (boiling point: 188 ° C.), ethylene glycol monoacetate (boiling point: 182 ° C.), diethylene glycol monobutyl ether acetate (boiling point: 247 ° C.), etc. Acetate solvents, cyclic carbonate solvents such as propylene carbonate (boiling point: 241 ° C), lactone solvents such as γ-butyrolactone (boiling point: 204 ° C), pyrrolidones such as N-methyl-2-pyrrolidone (boiling point: 202 ° C) Solvent, α-pinene (boiling point: 156 ° C), β-pinene (boiling point: 161 ° C) ), Limonene (boiling point: 177 ° C.), terpineol (boiling point: 217 ° C.), dihydroterpineol (boiling point: 207 ° C.), dihydroterpinyl acetate (boiling point: 220 ° C.), and the like, dimethylformamide (boiling point: 153) ° C), dimethyl sulfoxide (boiling point: 189 ° C), and the like. These can be used alone or in combination of two or more.

  Among these, it is more preferable to contain a terpene solvent such as terpene alcohol or terpene ester such as terpineol, dihydroterpineol and dihydroterpinyl acetate. As a result, when the inorganic fine particle-containing composition according to the present invention applied on the substrate is heat-dried, unevenness such as film thickness variation caused by the temperature distribution on the substrate surface is more reliably reduced. can do.

  Turpineol is an isomer mixture of α-, β-, and γ-terpineol derived from gum turpentine oil and represented by the following formula, and “Terpineol C” (trade name, manufactured by Nippon Terpene Chemical Co., Ltd.) is commercially available. Is possible.

  Dihydroterpineol is a compound obtained by hydrogenating terpineol derived from gum turpentine oil represented by the following formula, and is commercially available from Nippon Terpene Chemical.

  Dihydroterpinyl acetate is a compound obtained by hydrogenation and esterification of terpineol derived from gum turpentine oil represented by the following formula, and is commercially available from Nippon Terpene Chemical.

  From the viewpoint of preventing unevenness in the coating layer after heat drying, the content of the organic solvent (a-2) having a boiling point in the range of 150 to 250 ° C. in the inorganic fine particle-containing composition according to the present invention is: It is preferably 0 to 50% by mass, more preferably 2 to 40% by mass, and particularly preferably 5 to 30% by mass based on the total amount of organic compounds contained in the composition.

  In addition, in the inorganic fine particle-containing composition according to the present invention, from the viewpoint of further shortening the drying time of the coating layer while preventing unevenness in the coating layer after heat drying, the boiling point (a-2) In addition to the organic solvent which exists in the range of 150-250 degreeC, the organic solvent (a-3) whose boiling point is less than 150 degreeC can be used together as an organic compound (A).

  Examples of the solvent having a boiling point of less than 150 ° C. include alcohol organic solvents (methanol, ethanol, isopropyl alcohol, n-butyl alcohol, etc.), aromatic organic solvents (benzene, toluene, xylene, etc.), ketone solvents (acetone). , Methyl ethyl ketone, methyl isobutyl ketone, etc.), ether solvents (tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether), ethyl acetate, methylpropyl diglycol, hexyl carbitol, butylpropylene diglycol, benzyl alcohol, butyl Examples include carbitol, DBE thinner (DuPont Co., Ltd .: trade name), cyclohexane, methylcyclohexane, cyclohexanone, and the like.

  In the inorganic fine particle-containing composition of the present embodiment, (a-3) the content of the organic solvent having a boiling point of less than 150 ° C. is not particularly limited, but when mixed with isobornylcyclohexanol represented by the above formula (1) It is preferable to set so that the viscosity of the mixture at 25 ° C. is 500 to 50000 mPa · s. Furthermore, it is preferable to set the viscosity of the inorganic fine particle-containing composition to be in a range described later.

  In addition, the inorganic fine particle-containing composition according to the present invention may further contain (a-4) a binder polymer as the organic compound (A) for the purpose of improving the dispersibility of the inorganic fine particles.

  (A-4) Although it does not restrict | limit especially as a binder polymer, It is preferable that it is excellent in compatibility with the other component in an inorganic fine particle containing composition, such as the said organic solvent and the additive added as needed. Specifically, for example, (meth) acrylic resin, hydroxystyrene resin, novolak resin, polyester resin and the like can be suitably used. Among these, (meth) acrylic resins having a low thermal decomposition temperature are preferable. Here, in this specification, “(meth) acryl” means methacryl or acrylic, and “(meth) acrylic resin” means a monomer unit derived from a monomer having a methacryl group or an acrylic group. Means a polymer mainly composed of

  Examples of the (meth) acrylic resin used as the resin include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, (meth) What polymerized (meth) acrylic acid ester, such as (2-ethyl) hexyl acrylate, lauryl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, dicyclopentanyl (meth) acrylate, etc. Can be mentioned. These monomers may be polymerized singly or in combination of two or more.

  In addition to monomers such as the above (meth) acrylates, aromatic vinyl monomers such as styrene and α-methylstyrene, conjugated dienes such as butadiene and isoprene, polystyrene, poly (meth) acrylate methyl , Macromonomers having a polymerizable unsaturated group such as a (meth) acryloyl group at one end of a polymer chain such as poly (meth) ethyl acrylate and poly (meth) acrylate benzyl, o-hydroxystyrene, m- Examples thereof include polymers obtained by polymerizing monomers such as phenolic hydroxyl group-containing monomers such as hydroxystyrene and p-hydroxystyrene, alone or in combination.

  (A-4) The binder polymer preferably has a weight average molecular weight of 40,000 to 2,000,000, more preferably 50,000 to 300,000, and 100,000 to 200,000. It is particularly preferred that In the present specification, the weight average molecular weight of the binder polymer is a weight average molecular weight (Mw) estimated by a GPC (gel permeation chromatography) method based on a calibration curve created using a polystyrene standard substance.

  The content of the (a-4) binder polymer in the inorganic fine particle-containing composition of the present embodiment is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, based on the total amount of the organic compound, and 0 to 1% by mass. Is particularly preferred. However, since the organic compound contained in the inorganic fine particle-containing composition preferably has a heating residue of 1% by mass or less when heated at 300 ° C. for 10 minutes, it does not contain (a-4) a binder polymer. Is most preferred.

  In the inorganic fine particle-containing composition according to the present invention, for example, a dye, a color former, a plasticizer, a pigment, a polymerization inhibitor, a surface modifier, a stabilizer, an adhesion promoter, a thermosetting agent, etc. Can be added. These additives are preferably blended so that the heating residue when the organic compound contained in the inorganic fine particle-containing composition is heated at 300 ° C. for 10 minutes is 1% by mass or less.

  The inorganic fine particle-containing composition according to the present invention preferably has a viscosity at 25 ° C. of 1000 to 100,000 mPa · s. When the viscosity of the inorganic fine particle-containing composition is less than 1000 mPa · s, the inorganic fine particles are likely to settle during storage of the inorganic fine particle-containing composition. On the other hand, when the viscosity is higher than 100,000 mPa · s, the coating layer is flat. Tends to decrease.

  (B) The inorganic fine particles may be appropriately selected according to the use of the inorganic layer to be formed. Examples thereof include metal particles, metal oxide particles, glass particles, and phosphor fine particles. Examples of the metal particles include gold powder and silver powder. Moreover, you may add the glass particle mentioned later as a binder to these particle | grains. Examples of the metal oxide particles include ruthenium oxide, copper oxide, tin oxide, ITO, and the like, and glass particles described later as a binder may be added to these particles.

  0.01-20 micrometers is preferable and, as for the average particle diameter of a metal particle and a metal oxide particle, 0.1-10 micrometers is more preferable.

  The glass particles preferably have a low melting point, and preferably have a softening point in the range of 300 to 600 ° C. When the softening point of the glass particles is less than 300 ° C., the glass particles are melted at a stage where (A) the organic compound is not completely removed, whereby organic matter remains, and problems such as coloring tend to occur. On the other hand, when the softening point exceeds 600 ° C., distortion or the like tends to occur in a base material such as a glass substrate.

As the glass particles, for example, lead oxide, boron oxide, silicon oxide _{(PbO-B 2 O 3 -SiO} 2 system), lead oxide, boron oxide, silicon oxide, aluminum oxide-based _(PbO-B 2 O 3 -SiO _2- Al ₂ O ₃ system), zinc oxide, boron oxide, silicon oxide system (ZnO—B ₂ O ₃ —SiO ₂ system), zinc oxide, boron oxide, silicon oxide, aluminum oxide system (ZnO—B ₂ O ₃₎ -SiO ₂ -Al ₂ O ₃ system), lead oxide, zinc oxide, boron oxide, silicon oxide _{(PbO-ZnO-B 2 O} 3 -SiO 2 system), lead oxide, zinc oxide, boron oxide, silicon oxide, based on aluminum oxide _{(PbO-ZnO-B 2 O} 3 -SiO 2 -Al 2 O 3 system), bismuth oxide, boron oxide, silicon oxide _{(Bi 2 O 3 -B 2 O} 3 -SiO 2 system), acid Bismuth, boron oxide, silicon oxide, aluminum oxide-based _{(Bi 2 O 3 -B 2 O} 3 -SiO 2 -Al 2 O 3 system), bismuth oxide, zinc oxide, boron oxide, silicon oxide _(Bi 2 _{O 3} - ZnO—B ₂ O ₃ —SiO ₂ system), bismuth oxide, zinc oxide, boron oxide, silicon oxide, aluminum oxide system (Bi ₂ O ₃ —ZnO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ system), etc. Glass particles. These may be used alone or in combination of two or more.

  The average particle size of the glass particles is preferably from 0.01 to 20 μm, more preferably from 0.1 to 10 μm.

Examples of the phosphor fine particles include phosphors mainly composed of metal oxides. Examples of red-colored phosphors include Y ₂ O ₂ S: Eu, Zn ₃ (PO ₄ ) ₂ : Mn, Y ₂ O. ₃ : Eu, YVO ₄ : Eu, (Y, Gd) BO ₃ : Eu, and the like. Examples of blue-colored phosphors include ZnS: Ag, ZnS: Ag, Al, ZnS: Ag, Ga, Al, ZnS: Ag, Cu, Ga, Cl, ZnS: Ag ⁺ In ₂ O ₃ , and Ca ₂ B. ₅ O ₉ Cl: Eu ²⁺ , (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , BaMgAl ₁₄ O ₂₃ : Eu ²⁺ , BaMgAl ₁₆ O ₂₆ : Eu ^{2+ and the} like. Examples of green phosphors include ZnS: Cu, Zn ₂ SiO ₄ : Mn, ZnS: Cu ⁺ Zn ₂ SiO ₄ : Mn, Gd ₂ O ₂ S: Tb, Y ₃ Al ₅ O ₁₂ : Ce, ZnS. ^{_{: Cu, Al, Y 2 O}} 2 S: Tb, ZnO: Zn, ZnS: Cu, Al + In 2 O 3, LaPO 4: Ce, Tb, BaO · 6Al 2 O 3: Mn , and the like.

  The average particle size of the phosphor fine particles is preferably 0.01 to 20 μm, and more preferably 0.1 to 10 μm.

  When the inorganic fine particle-containing composition according to the present invention contains metal particles or metal oxide particles as inorganic particles, the inorganic fine particle-containing composition is suitable for forming an electrode. In addition, when the inorganic fine particle-containing composition according to the present invention includes glass particles, the inorganic fine particle-containing composition is suitable for forming a dielectric layer. In addition, when the inorganic fine particle-containing composition according to the present invention includes phosphor fine particles, the inorganic fine particle-containing composition is suitable for forming a phosphor layer.

  The content of inorganic fine particles in the inorganic fine particle-containing composition according to the present invention is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, based on the total amount of the composition, from the viewpoint of ensuring applicability. 60 mass% is especially preferable and 30-50 mass% is the most preferable.

  Next, things other than the inorganic fine particle containing composition according to the present invention will be described.

  As a substrate on which the inorganic fine particle-containing composition according to the present invention is applied, for example, on a glass plate, a transparent electrode such as ITO (indium tin oxide) and a metal electrode made of silver, copper, aluminum, etc. Examples thereof include a glass substrate with an electrode formed into a desired shape as required.

  Examples of the coating method include screen printing, knife coating method, roll coating method, spray coating method, gravure coating method, bar coating method, die coating method, curtain coating method, dispenser coating method, and the like.

  Although it does not restrict | limit especially as a heating means in a 2nd process, Usually, heating apparatuses, such as a hot air dryer and an electric furnace, can be used. In that case, the oxygen concentration in the heating atmosphere needs to be 10% by volume or less, more preferably 0 to 5% by volume, and particularly preferably 0 to 3% by volume. By setting the oxygen concentration in the heating atmosphere to 10% by volume or less, it is possible to reduce organic compound residues and to suppress discoloration of the inorganic layer.

  Although heating temperature is 150-350 degreeC, 170-300 degreeC is preferable and 200-280 degreeC is more preferable. The heating time is preferably 1 to 120 minutes, more preferably 5 to 100 minutes, and particularly preferably 10 to 90 minutes. When the heating temperature and time are outside this range, the flatness of the inorganic layer formed tends to be poor.

  The oxygen concentration in the heating device is about 20% by volume equivalent to the oxygen concentration in the air in the natural state. Examples of means for reducing the oxygen concentration to 10% by volume or less include replacing the inside of the heating device with an inert gas such as nitrogen or argon, helium, or neon, using a vacuum pump, and the like. A value as low as possible is preferred. The measurement of the oxygen concentration can be easily performed with an oxygen concentration meter, and examples of a commercially available oxygen concentration meter include an oxygen concentration meter LC-750L (manufactured by Toray Engineering Co., Ltd.).

  Usually, the heating and drying step for removing the organic compound is generally performed in the atmosphere. However, when the temperature required for the drying is set to 150 ° C. or higher, the chemistry such as reduction in the strength, discoloration, and modification of the organic compound is performed. May cause change. Therefore, for example, when a binder polymer is used as the organic compound, polyethylene has a deflection temperature under load of 130 ° C. or less (high density polyethylene), a glass transition point of polyethylene terephthalate is about 80 ° C., and is a general (meth) acrylic resin glass. There are limited materials that are organic compounds that are inexpensive and stably available, such as having a transition point of about −50 to 190 ° C., and that do not change when heated to 150 ° C. or higher. In addition, when heating at 150 ° C. or higher, there is a high possibility that denaturation of the organic compound itself by heat (chemical reaction by heat, etc.) proceeds in parallel with the evaporation of the organic compound. When evaporation and thermal reaction occur in a concerted manner in this way, in the drying process, the thermal reaction product of the organic compound remains in the inorganic layer after drying, and the organic component in the finally obtained inorganic layer In some cases, the inorganic layer cannot achieve desired characteristics (for example, insulating properties). The present inventor considers that the influence of oxygen in the atmosphere is large as the main cause of the reaction of the organic compound by such heating.

  On the other hand, the method for forming an inorganic layer according to the present invention includes the second step, so that the selection range of the organic compound can be expanded and generation of organic component residues can be sufficiently suppressed. Become.

  In the method for forming an inorganic layer of the present invention, firing can be further performed as necessary after the second step.

  Examples of the firing method include a method of heating in an electric furnace. The firing temperature is preferably 300 to 1500 ° C, more preferably 350 to 700 ° C, and further preferably 400 to 600 ° C. This step is preferably performed in the atmosphere. The firing time is preferably about 5 minutes to 2 hours.

  In the present embodiment, the organic compound is preferably removed in an amount of 90% by mass or more in the second step, more preferably 95% by mass or more, and particularly preferably 99% by mass or more. preferable.

  In addition, the method for forming an inorganic layer according to the present invention can remove almost all of the organic compound by the second step, and therefore does not require a firing step, and the method for forming an inorganic layer is simplified. Useful as.

  The method for forming the inorganic layer of the present invention includes, for example, applying the inorganic fine particle-containing composition according to the present invention on a substrate by a known method, heat drying under the above-mentioned specific conditions, and then firing as necessary. Thus, an electrode, a dielectric layer, a phosphor layer and the like for a plasma display panel can be formed. Similarly, in the case of forming an insulator layer, a dielectric layer, etc., in an electronic component manufacturing process such as a chip capacitor, the inorganic fine particle-containing composition according to the present invention is applied onto a substrate by a known method, The electronic component can be obtained by heating and drying under the specified conditions, followed by firing.

  The method for forming an inorganic material layer of the present invention is particularly useful as a method for forming a phosphor layer for a plasma display panel because it can also suppress discoloration of phosphor particles when heated to 150 ° C. or higher.

  Next, a method for forming a phosphor layer for a plasma display panel will be described as an embodiment of the method for forming an inorganic layer of the present invention.

  FIG. 1 is a schematic cross-sectional view for explaining an embodiment of a method for forming an inorganic layer of the present invention. FIG. 1A shows a cross section of a substrate on which an inorganic layer is provided, FIG. 1B shows a cross section of a substrate provided with a coating layer provided in the first step, and FIG. The cross section of a board | substrate provided with the inorganic substance layer formed through two processes is shown. Hereinafter, the method for forming the phosphor layer will be described in detail with reference to this drawing.

  First, the rear glass substrate 41 provided with the address electrodes 54 is prepared. Next, the back dielectric layer 72 is formed on the side of the back glass substrate 41 where the electrodes 54 are provided. Barrier ribs 80 are formed on the formed dielectric layer 72 (see FIG. 1A).

  Next, an inorganic fine particle-containing composition according to the present invention containing phosphor particles as inorganic fine particles is applied to the gaps between adjacent barrier ribs 80 to form a coating layer 1 (see FIG. 1B).

  Examples of the coating method include screen printing, knife coating method, roll coating method, spray coating method, gravure coating method, bar coating method, die coating method, curtain coating method, dispenser coating method, and the like.

  Next, the coating layer 1 is dried by heating at a temperature of 150 ° C. or more and 350 ° C. or less in an atmosphere having an oxygen concentration of 10% by volume or less to form a phosphor layer 90 as an inorganic layer (FIG. 1 ( see c)).

  In this embodiment, it is preferable to heat in an inert gas atmosphere. The heating temperature is preferably about 150 to 300 ° C., and the heating time is preferably about 1 minute to 1 hour. Specific conditions include, for example, a condition of heating at 250 ° C. for 30 minutes.

  In the present embodiment, the phosphor layer 90 may be formed by further baking the coating layer after the above heating.

  Examples of the firing method include a method in which a laminated body in which the coating layer is provided on a substrate is accommodated in an electric furnace and heated, a method in which the laminated body is placed on a hot plate and heated. It is done.

  The firing temperature is not particularly limited as long as the coating layer composed of the inorganic fine particle-containing composition is sufficiently sintered, but the maximum temperature is preferably 350 to 700 ° C, more preferably 400 to 600 ° C. preferable. The firing time is preferably about 5 minutes to 2 hours. Moreover, it is preferable that baking is implemented in air | atmosphere.

  According to the method for forming the phosphor layer 90 of the present embodiment, impurities derived from the organic compound contained in the coating layer during firing can be reduced as compared with the prior art. Can be suppressed.

  The laminate 200 provided with the phosphor layer on the substrate thus obtained can be suitably used as a PDP rear substrate (PDP substrate).

  FIG. 2 is a cross-sectional view showing the main part of an embodiment of the plasma display panel according to the present invention. A PDP 300 shown in FIG. 2 is mainly composed of a PDP front substrate 100 and a PDP rear substrate 200. The front substrate 100 for PDP is composed of the laminate 3 and a protective layer 71 provided so as to cover the surface of the front dielectric layer 70 in the laminate 3. The laminate 3 is configured by laminating a front glass substrate 40, a strip-shaped display electrode 52, and a front dielectric layer 70 in order. The PDP rear substrate 200 includes a rear glass substrate 41, a strip-shaped address electrode 54 provided on the rear glass substrate 41, a rear dielectric layer 72 provided on the rear glass substrate 41 and the address electrode 54, and a rear surface. The barrier rib 80 provided on the dielectric layer 72 and a phosphor layer 90 formed so as to cover the wall surface of the barrier rib 80 and the surface of the back dielectric layer 72 are mainly configured. The phosphor layer 90 is obtained by the inorganic layer forming method of the present invention. The PDP front substrate 100 and the PDP rear substrate 200 are bonded together so that the protective layer 71 and the barrier rib 80 are in close contact with each other, thereby forming a discharge space 76 surrounded by the phosphor layer 90 and the protective layer 71. Has been. In the PDP 300, the constituent members such as the glass substrates 40 and 41, the protective layer 71, the back dielectric layer 72, the barrier rib 80, the electrodes 52 and 54, and the phosphor film 90 are formed by a conventionally known material and method. Can do. The electrodes 52 and 54, the front dielectric layer 70, and the back dielectric layer 72 may be formed by the inorganic layer forming method of the present invention, and the barrier rib 80 is also uniform by the inorganic layer forming method of the present invention. After forming the layer, it may be formed by, for example, sandblasting.

  The PDP 300 including the phosphor layer 90 formed by the inorganic layer forming method of the present invention can be manufactured with lower energy than conventional methods because the firing step can be omitted in forming the phosphor layer. It can also be excellent in terms.

  In addition, when the electrode and / or dielectric layer in the PDP 300 is formed by the method for forming an inorganic layer of the present invention, the PDP 300 can be manufactured with lower energy than the conventional one, and the manufacturing cost and environment are excellent. Can be.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Reference Example 1)
1.3074 g of isobornylcyclohexanol (manufactured by Nippon Terpene Chemical Co., Ltd., trade name: Tersolve MTPH) was weighed on a watch glass having a diameter of 45 mm and a wall thickness of 2 mm and preheated to 250 ° C. The sample was dried for 1 hour in a dryer under a nitrogen atmosphere (oxygen concentration of about 1% by volume). After drying, the state of the residue was visually observed and the weight was measured. However, no obvious residue was visually observed, and as shown in Table 1, the residue could not be confirmed by weight measurement.

(Reference Example 2)
A hot air convection system in which 1.2835 g of isobornyl cyclohexanol (manufactured by Nippon Terpene Chemical Co., Ltd., trade name: Tersolve MTPH) was weighed on a watch glass having a diameter of 45 mm and a wall thickness of 2 mm made of soda glass and preheated to 250 ° C. It was dried in the air (oxygen concentration about 20% by volume) with a dryer for 1 hour. As a result of measuring the weight of the residue after drying, 0.0003 g (0.02 mass%) of the residue was generated as shown in Table 1.

Example 1
52 parts by mass of isobornylcyclohexanol (manufactured by Nippon Terpene Chemical Co., Ltd., trade name: Tersolve MTPH), 15 parts by mass of terpineol C (isomer mixture), and 33 parts by mass of phosphor fine particles (Zn ₂ SiO ₄ : Mn) are mixed. Then, they were mixed and dispersed for 15 minutes using a bead mill, and further filtered through a filter cloth having a 30 μm square opening to prepare a phosphor fine particle-containing composition solution.

  About 1.3 g of the obtained phosphor fine particle-containing composition solution was weighed on a watch glass made of soda glass, diameter 45 mm, wall thickness 2 mm, and preheated to 170 ° C. in a nitrogen atmosphere using a hot air convection dryer. Under heating (oxygen concentration of about 1% by volume), the mixture was heated and dried for 1 hour to form an inorganic layer. As a result of visually observing the obtained inorganic layer, coloring was not seen.

(Example 2)
An inorganic layer was formed in the same manner as in Example 1 except that the heating temperature of 170 ° C. in Example 1 was changed to 250 ° C. As a result of visually observing the obtained inorganic substance layer, coloring was not seen but the fluorescent substance layer comprised only by fluorescent substance fine particles was obtained.

(Comparative Example 1)
About 1.3 g of a phosphor powder-containing resin composition solution produced in the same manner as in Example 1 was weighed on a soda glass, diameter 45 mm, wall thickness 2 mm watch glass and preheated to 250 ° C. An inorganic layer was formed by heating and drying in air (oxygen concentration of about 20% by volume) for 1 hour using a dryer. As a result of visual observation of the obtained inorganic layer, coloring was particularly observed at the edge. Moreover, it was confirmed that the residue derived from an organic compound or the organic compound mix | blended initially exists in an inorganic layer.

(Comparative Example 2)
An inorganic layer was formed in the same manner as Comparative Example 1 except that the heating temperature 250 ° C. in Comparative Example 1 was changed to 170 ° C. As a result of visually observing the obtained inorganic layer, some coloring was observed. Moreover, it was confirmed that the residue derived from an organic compound or the organic compound mix | blended initially exists in an inorganic layer.

(Comparative Example 3)
An inorganic layer was formed in the same manner as in Example 1 except that the heating temperature of 170 ° C. in Example 1 was changed to 100 ° C. However, in the obtained inorganic layer, the organic compound remained in an amount of 50% by mass or more compared with the initial amount, and the drying was insufficient.

  As described above, according to the method for forming an inorganic layer of the present invention, when an inorganic layer is formed using a composition containing an organic compound and inorganic fine particles, generation of residual components derived from the organic compound is sufficiently prevented. An organic compound can be sufficiently removed, and a decrease in electrical or optical performance can be sufficiently suppressed, and an inorganic layer having desired characteristics can be formed.

It is a schematic cross section for demonstrating one Embodiment of the formation method of the inorganic substance layer of this invention. It is principal part sectional drawing which shows one Embodiment of the plasma display panel of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coating layer, 40, 41 ... Substrate, 52, 54 ... Electrode, 70 ... Front dielectric layer, 71 ... Protective layer, 72 ... Back dielectric layer, 76 ... Discharge space, 80 ... Barrier rib, 90 ... Phosphor layer , 100: Front substrate for plasma display panel, 200: Back substrate for plasma display panel, 300: Plasma display panel.

Claims (5)

A first step of applying an inorganic fine particle-containing composition containing (A) an organic compound and (B) inorganic fine particles on a substrate to provide a coating layer;
A second step of heating the coating layer at a temperature of 150 ° C. or higher and 350 ° C. or lower in an atmosphere having an oxygen concentration of 10% by volume or lower;
A method for forming an inorganic layer.   The method for forming an inorganic layer according to claim 1, wherein the organic compound (A) includes a terpene compound. The method for forming an inorganic layer according to claim 2, wherein the terpene compound is a compound represented by the following general formula (1).

The substrate is a substrate for plasma display;
The (B) inorganic fine particles are phosphor fine particles,
The formation method of the inorganic substance layer as described in any one of Claims 1-3 which forms the fluorescent substance layer for plasma displays as the said inorganic substance layer. A plasma display panel comprising the phosphor layer for plasma display formed by the method for forming an inorganic layer according to claim 4.

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