JP4377314B2 - Dielectric layer composition, green sheet, and dielectric layer forming substrate - Google Patents

Description

  The present invention relates to a dielectric layer composition suitable for forming a dielectric layer of a plasma display panel and a method for producing the same, a green sheet obtained by forming the composition into a film, a dielectric layer forming substrate, and a method for producing the same.

  Examples of the display device include a liquid crystal display device, an electroluminescence display device, and a plasma display panel. Among these, a plasma display panel (hereinafter also referred to as “PDP”) is attracting attention as a next-generation multimedia display. Since this PDP has a large number of layers laminated on the substrate surface, the manufacturing process is complicated. Therefore, improvement in yield and simplification of work processes are being promoted.

  FIG. 3 shows a cross-sectional view of an example of a PDP. The PDP shown in FIG. 3 is composed of a pair of glass substrates: a front plate glass substrate 1 and a back plate glass substrate 2. Transparent electrodes 3 and data electrodes 4 that are orthogonal to each other are formed on the inner surfaces of the glass substrate 1 for the front plate and the glass substrate 2 for the back plate. The transparent electrode 3 and the data electrode 4 are covered with a dielectric layer 5 (front plate dielectric layer) and 6 (back plate dielectric layer), respectively. Further, the glass substrates 1 and 2 are separated into discharge spaces (pixels) by ribs (partitions) 8 through a protective film 7, and a phosphor 9 is formed in each pixel.

  By the way, as a method of forming a dielectric layer of PDP, a dielectric layer composition comprising a glass component and a thermally decomposable binder is applied on a substrate and then fired, or a dielectric layer composition is used. A method is known in which a green sheet obtained by forming into a film is pasted on a substrate and then fired. In these methods, in order to obtain a dielectric layer having few bubbles and excellent withstand voltage characteristics, the glass component in the dielectric layer composition to be used is preferably uniformly dispersed.

  Conventionally, as a method for preparing a uniform dielectric layer composition, after premixing a glass component, a thermally decomposable binder, a dispersant, and various additives added as necessary, together with a solvent, A method of mechanically stirring and dispersing these mixtures is generally employed (Patent Document 1).

  However, in this method, it is necessary to treat with a disperser for a long time in order to make the dispersion state of glass components and the like more uniform. In other words, when preparing a composition for a dielectric layer by treating a mixture containing glass components that are easily crushed with a disperser for a long time, the surface of the glass component is crushed by the strong shearing force of the disperser and the shear heat increases. To do. As a result, there is a problem that glass components and the like are easily aggregated and it is difficult to obtain a uniform dielectric layer composition. In addition, abrasion powder is likely to be generated due to collision and friction between the media of the disperser and the glass component, and there is a possibility that foreign matter may be mixed into the obtained dielectric layer composition.

JP 2004-2164 A

  The present invention has been made in view of the actual situation of the prior art, and is a composition for a dielectric layer in which a glass component and a thermally decomposable binder are uniformly dispersed and foreign matter is less mixed, a method for producing the same, and the dielectric It is an object of the present invention to provide a green sheet obtained by forming a layer composition into a film, a dielectric layer forming substrate having a dielectric layer formed from the green sheet, and a method for producing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have made the glass component and the thermally decomposable binder uniform by radical polymerization of the (meth) acrylate compound in the presence of the glass component in a solvent. It has been found that a composition for a dielectric layer that is dispersed and contains little foreign matter can be obtained efficiently. In addition, when the obtained dielectric layer composition is used, it is possible to obtain a green sheet having a smooth surface, good film quality, a dielectric layer having less bubbles and excellent withstand voltage characteristics, and forming this dielectric layer. It was found that a plasma display panel free from pixel defects can be obtained by using the prepared substrate, and the present invention has been completed.

  Thus, according to the first aspect of the present invention, there is provided a dielectric layer composition comprising a glass component and a thermally decomposable binder, wherein the thermally decomposable binder polymerizes a polymerizable monomer in the presence of the glass component. A composition for a dielectric layer is provided which is obtained by the above.

  In the dielectric layer composition of the present invention, the thermally decomposable binder is preferably obtained by radical polymerization of an acrylic ester compound or a methacrylic ester compound in the presence of the glass component. It is preferably obtained by polymerizing a polymerizable monomer in the presence of a glass component and a dispersant.

The composition for a dielectric layer of the present invention may contain a filler component.
The composition for a dielectric layer of the present invention is preferably used for a dielectric layer of a plasma display panel.

  According to a second aspect of the present invention, there is provided a method for producing a dielectric layer composition comprising a glass component and a thermally decomposable binder by polymerizing a polymerizable monomer in a solvent in the presence of the glass component. There is provided a method for producing a dielectric layer composition comprising a step of obtaining a dispersion containing a glass component and a thermally decomposable binder.

The method for producing a dielectric layer composition of the present invention comprises a dispersion containing a glass component and a thermally decomposable binder by radical polymerization of an acrylic ester compound or a methacrylic ester compound in a solvent in the presence of the glass component. It is preferable to have the process of obtaining a liquid.
The method for producing a composition for a dielectric layer of the present invention comprises a dispersion comprising a glass component, a dispersant and a thermally decomposable binder by polymerizing a polymerizable monomer in a solvent in the presence of the glass component and a dispersant. It is preferable to have the process of obtaining a liquid.

According to the third aspect of the present invention, there is provided a green sheet obtained by molding the dielectric layer composition of the present invention into a film shape.
According to a fourth aspect of the present invention, there is provided a dielectric layer forming substrate comprising a dielectric layer formed from the dielectric layer composition of the present invention.
According to a fifth aspect of the present invention, there is provided a method for manufacturing a dielectric layer-formed substrate, comprising the steps of applying the green sheet of the present invention and firing the green sheet.

In the dielectric layer composition of the present invention, the glass component and the thermally decomposable binder are uniformly dispersed, and foreign matter is less mixed.
According to the production method of the present invention, a polymerizable monomer having good wettability with a glass component is selected, and the polymerizable monomer is polymerized in the presence of the glass component. A composition for a dielectric layer that can be dispersed and has excellent dispersibility can be prepared.
The green sheet of the present invention is obtained by forming the dielectric layer composition of the present invention into a film, and has a smooth surface and uniform film quality.
The dielectric layer-formed substrate of the present invention is obtained by applying the green sheet of the present invention on a substrate and firing it, and has a dielectric layer that is free from bubbles and has excellent withstand voltage characteristics. Therefore, a plasma display panel having no pixel defects can be obtained by using the dielectric layer forming substrate of the present invention.

  Hereinafter, the present invention will be described in detail by dividing into 1) a composition for a dielectric layer and a method for producing the same, 2) a green sheet, and 3) a substrate for forming a dielectric layer and a method for producing the same.

1) Dielectric layer composition and method for producing the same The dielectric layer composition of the present invention comprises a glass component and a thermally decomposable binder, and the thermally decomposable binder comprises the glass component. It is obtained by polymerizing a polymerizable monomer in the presence of.

(1) As the glass component contained in the dielectric layer composition of the glass component present invention, for example, _PbO-B 2 _{O 3} (lead oxide - boron oxide) based _{glass, PbO-B 2 O 3 -SiO} 2 ( Lead oxide-boron oxide-silicon oxide) glass, PbO-B ₂ O ₃ —SiO ₂ —A1 ₂ O ₃ (lead oxide—boron oxide—silicon oxide—aluminum oxide) glass, PbO—BaO—SiO ₂ —A1 ₂ O ₃ (lead oxide - barium oxide - silicon oxide - aluminum oxide) based _{glass, ZnO-B 2 O 3 -SiO} 2 ( zinc oxide - boron oxide - silicon oxide) based _{glass, PbO-ZnO-B 2 O} 3 - SiO ₂ (lead oxide - zinc oxide - boron oxide - silicon oxide) based _{glass, Na 2 O-B 2 O} 3 -SiO 2 ( sodium oxide - boron oxide - silicon oxide) based glass BaO-CaO-SiO ₂ (barium oxide - calcium oxide - silicon oxide) based glass. Among these, it is preferable to use PbO—B ₂ O ₃ —SiO ₂ glass, PbO—B ₂ O ₃ —SiO ₂ —A1 ₂ O ₃ glass, PbO—BaO—SiO ₂ —A1 ₂ O ₃ glass. .

  In the present invention, these glasses are used in powder form. The average particle size of the glass component is 0.1 to 5 μm, and the maximum particle size of the glass component is preferably 20 μm or less. By setting the particle size of the glass component in this way, it is possible to form a dielectric layer having excellent withstand voltage characteristics.

Moreover, when using the composition for dielectric layers of this invention as a composition for backplate dielectric layers, in order to obtain a white dielectric layer, it is preferable that the said glass component contains a filler component further. Examples of the filler component used include TiO ₂ (titanium oxide), Al ₂ O ₃ (alumina), SiO ₂ (silica), and ZrO ₂ (zirconia). Among these, the use of TiO ₂ and _Al 2 _{O 3} is preferred. The average particle size of the filler component is 0.1 to 5 μm, and the maximum particle size is preferably 10 μm or less.

  The mixing ratio of the glass powder and the filler component in the glass component is usually 50:50 to 100: 0, but when used as a back plate dielectric layer composition, it is 50:50 to 95: 5, When used as a front plate dielectric layer composition, it is preferably 90:10 to 100: 0.

  In the present invention, the glass component can also be used as a glass frit. The glass frit can be obtained by mixing a glass component and, if desired, a filler component in a predetermined ratio, melting the obtained mixture, and then cooling. The obtained glass frit is pulverized and used as a powder.

  The addition amount of a glass component is 40 to 80 weight% normally with respect to the composition for dielectric layers. By adding the glass component within this range, a dielectric layer composition in which the glass component is uniformly dispersed can be obtained.

(2) Thermally decomposable binder The thermally decomposable binder contained in the dielectric layer composition of the present invention has a function as a binder and can be easily removed by being decomposed by firing. If it is, it will not be restrict | limited in particular. Further, the thermally decomposable binder may be a homopolymer obtained by polymerizing only one type of polymerizable monomer, or a copolymer obtained by polymerizing a plurality of types of polymerizable monomers. May be. The type of copolymer is not particularly limited, and may be in any form such as a random copolymer or a block copolymer.

  The thermally decomposable binder contained in the dielectric layer composition of the present invention is obtained by polymerizing a polymerizable monomer in the presence of a glass component. By selecting a polymerizable monomer that has good wettability with the glass component, and by polymerizing the polymerizable monomer in the presence of the glass component, it is possible to disperse under low temperature and low shear force. An excellent dielectric layer composition can be prepared.

  Specifically, the thermally decomposable binder can be obtained by dissolving or dispersing the glass component and the polymerizable monomer in an appropriate solvent and polymerizing the polymerizable monomer.

  The polymerizable monomer to be used is not particularly limited, and an appropriate one can be used according to the type of the thermally decomposable binder and the polymerization method.

  In the present invention, (i) excellent wettability with the glass component, a dispersion in which the glass component and the thermally decomposable binder are uniformly dispersed is obtained, (ii) while serving as an excellent binder, Acrylic acid ester compound or methacrylic acid ester compound (hereinafter referred to as “(meth) acrylic acid ester compound”) because it is possible to obtain a thermally decomposable binder that also serves as a pressure sensitive adhesive with a glass substrate. Is preferred).

  Specific examples of the (meth) acrylic acid ester compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t -Butyl (meth) acrylate, pentyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate DOO, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, alkyl (meth) acrylates such as isostearyl (meth) acrylate;

  2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl ( Hydroxyalkyl (meth) acrylates such as meth) acrylate; phenoxyalkyl (meth) acrylates such as phenoxyethyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate; 2-methoxyethyl (meth) acrylate, 2 -Alkoxyalkyl (meta) such as ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate and 2-methoxybutyl (meth) acrylate Acrylate;

  Polyethylene glycol mono (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxypolypropylene Polyalkylene glycol (meth) acrylates such as glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, nonylphenoxypolypropylene glycol (meth) acrylate; cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, dicyclopenta Nyl (meth) acrylate, dicyclopen Cycloalkyl (meth) acrylates such as nyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate; benzyl (meth) acrylate And tetrahydrofurfuryl (meth) acrylate.

  By polymerizing the (meth) acrylic acid ester compound, a (meth) acrylic resin is obtained. (Meth) acrylic resins include homopolymers of (meth) acrylic ester compounds, copolymers of two or more of (meth) acrylic ester compounds, (meth) acrylic ester compounds and other copolymerizable monomers. And a copolymer with a monomer.

  The other copolymerizable monomer is not particularly limited as long as it is a compound copolymerizable with the (meth) acrylic acid ester compound. For example, (meth) acrylic acid such as acrylic acid and methacrylic acid; aromatic vinyl compounds such as vinylbenzoic acid, styrene, and α-methylstyrene; unsaturated carboxylic acids such as maleic acid and vinylphthalic acid; vinylbenzyl methyl ether, vinyl And vinyl ether compounds such as glycidyl ether; conjugated diene compounds such as butadiene and isoprene. The weight ratio of the (meth) acrylic acid ester compound to the other monomer is usually 100: 0 to 80:20, preferably 99.5: 0.5 to 90:10.

  The usage-amount of a polymerizable monomer is 10-100 weight part by the total weight of the polymerizable monomer to be used with respect to 100 weight part of glass components by solid content ratio. By using a polymerizable monomer in such a range, a dispersion liquid in which a glass component and a thermally decomposable binder are uniformly dispersed in a solvent can be obtained.

  The solvent used when polymerizing the polymerizable monomer in the presence of the glass component is not particularly limited as long as it does not inhibit the polymerization reaction. For example, water; ethers such as diethyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and methyl lactate Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, and cyclohexanone: amides such as N, N′-dimethylformamide, N, N′-dimethylacetamide, hexamethylphosphate phosphoramide, and N-methylpyrrolidone Lactams such as ε-caprolactam; lactones such as γ-lactone and δ-lactone; sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide; aliphatic hydrocarbons such as pentane, hexane, heptane, octane, nonane and decane; Alicyclic hydrocarbons such as cyclopentane, cyclohexane and cyclooctane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated carbonization such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane and chlorobenzene Hydrogen; and a mixed solvent composed of two or more of these; and the like. Among these, it is preferable to use esters, ketones, aromatic hydrocarbons, or a mixed solvent composed of two or more thereof.

  The amount of the solvent used is usually in the range of 5 to 70% by weight based on the total weight of the dielectric layer composition.

  In the present invention, it is preferable to add a dispersant to the reaction system when polymerizing the polymerizable monomer in the presence of the glass component. By adding a dispersant, a dispersion liquid in which the glass component and the thermally decomposable binder are more uniformly dispersed can be obtained.

Examples of the dispersant used include a surfactant and a silane coupling agent.
Surfactants include anions such as alkylbenzene sulfonate, alkyl naphthalene sulfonate sodium salt, alkyl sulfosuccinate sodium salt, alkyl diphenyl ether disulfonate sodium salt, formalin condensate sodium salt, and aromatic sulfonic acid formalin condensate sodium salt. Cationic surfactants such as alkylamine salts and quaternary ammonium salts; polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monooleate, diethanolamine laurate Nonionic surfactants such as decyl glucoside and lauryl glucoside; α-olefin / maleic anhydride copolymer partial ester, aliphatic polycarboxylate Polycarboxylic acid type high molecular surfactants such as aliphatic polycarboxylic acid special silicones; polyether ester acids such as polyether polyester acid and polyether polyol polyester acid, and high molecular weight obtained from organic amines such as high molecular polyamines Polyether ester amine salts of molecular dispersants (specifically, Disparon DA-234 (trade name, manufactured by Enomoto Kasei Co., Ltd.)) and the like.

  As silane coupling agents, vinyltrimethoxysilane, vinyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyl Trimethoxysilane / hydrochloride, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltri Methoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, aminosilane Emissions, vinyl triacetoxy silane, .gamma. anilino trimethoxysilane, octadecyl dimethyl (3- (trimethoxysilyl) propyl) ammonium chloride, .gamma.-ureidopropyltriethoxysilane and the like.

Among these, polycarboxylic acid type polymer surfactants and polyether ester amine salts are preferred because of their excellent dispersibility.
The amount of the dispersant added is usually 0 to 10% by weight, preferably 0 to 5% by weight, and more preferably 0 to 3% by weight with respect to the dielectric layer composition.

  A method for polymerizing the polymerizable monomer is not particularly limited, and examples thereof include an anionic polymerization method, a cationic polymerization method, and a radical polymerization method. Of these, the radical polymerization method is preferred because the desired thermally decomposable binder can be obtained in a high yield by a simple operation.

When the radical polymerization method is employed, a radical polymerizable monomer is used as the polymerizable monomer.
As a specific method for obtaining a target thermally decomposable binder by polymerizing a radical polymerizable monomer by a radical polymerization method, (a) adding a glass component, a solvent and, if desired, a dispersing agent to a polymerization reactor. Then, one or two or more kinds of polymerizable monomers and a radical polymerization initiator are added to the resulting mixture, and further mixed and stirred, followed by solution polymerization, (b) glass component, polymerizable monomer Body, water and, if necessary, a dispersing agent into a polymerization reactor and mixing and stirring, adding a radical polymerization initiator to the resulting mixture, further mixing and stirring, and emulsion polymerization, (c) glass component and water Are added to a polymerization reactor and mixed and stirred, and one or more polymerizable monomers and a radical polymerization initiator are added to the resulting mixture and further mixed and stirred, followed by suspension polymerization. It is done.

The radical polymerization initiator used is not particularly limited. For example, hydrogen peroxide, isobutyl peroxide, t-butyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, potassium persulfate, Peroxides such as ammonium sulfate and sodium persulfate; azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpro) Azo compounds such as pionitrile), 2,2′-azobis (2-methylpropionitrile), 2,2′-azobis (2-methylbutyronitrile); hydrogen peroxide-ascorbic acid, hydrogen peroxide-salt And redox initiators such as ferrous iron and persulfate-sodium hydrogen sulfite;
The addition amount of the radical polymerization initiator is usually 0.0005 to 0.01 part by weight, preferably 0.002 to 0.007 part by weight, based on 1 part by weight of the polymerizable monomer to be used.

  In addition, a plasticizer may be used to improve processability. Examples of the plasticizer used include adipic acid ester plasticizers and phthalic acid ester plasticizers. The usage-amount of a plasticizer is 0-10 weight part with respect to 100 weight part of glass components.

The polymerization temperature depends on the type of polymerizable monomer used and the like, but is usually 50 to 180 ° C, preferably 60 to 90 ° C.
The polymerization reaction is stopped when the polymerization reaction proceeds until the obtained polymer (thermally decomposable bander) has a desired molecular weight. The completion of the polymerization reaction can be confirmed, for example, by sampling the reaction product and measuring the viscosity.
Although the polymerization time depends on the reaction scale, it is usually several minutes to several hours.

  The obtained heat decomposable binder has a weight average molecular weight of usually 15,000 to 400,000, preferably 100,000 to 250,000.

As described above, it is possible to obtain a dispersion liquid in which a glass component, a thermally decomposable binder, and, if desired, a dispersant are uniformly dispersed in a solvent.
In the present invention, this can be used as a dielectric layer composition as it is, but if necessary, a tackifier, a storage stabilizer, an antifoaming agent, a thermal decomposition accelerator, an antioxidant, and Additives such as wetting agents can also be included. These additives are not particularly limited, and those commonly used in this field can be appropriately selected.

  The composition for a dielectric layer of the present invention is obtained by polymerizing a glass component and a polymerizable monomer having good wettability in the presence of a glass component. Dispersible and has excellent dispersibility. In addition, since dispersion is possible under low temperature and low shear force, there is no generation of abrasion powder due to collision or friction between the media of the disperser and the glass component, and there is little contamination with foreign matter.

2) Green sheet The green sheet of the present invention is obtained by molding the dielectric layer composition of the present invention into a film.
Specifically, the green sheet of the present invention can be produced by coating the dielectric layer composition of the present invention on a carrier film and then drying to form a film.

An example of producing the green sheet of the present invention is shown in FIG.
In FIG. 1, 13 is a carrier film, 14 is a coating apparatus for applying the dielectric layer composition of the present invention, and 18 is a drying apparatus for drying the coating film of the dielectric layer composition (removing the solvent). , 20a and 20b are laminating rolls for laminating a protective film on a green sheet.
Hereinafter, the manufacturing method of the green sheet of this invention is demonstrated, referring FIG.

  First, the carrier film 13 wound up in a roll shape is sent to the coating apparatus 14. The carrier film 13 is not particularly limited as long as it has excellent peelability from the coating film of the dielectric layer composition. For example, a plastic film such as a polyethylene terephthalate film, a polyethylene naphthalate film, a polyethylene film, or a polypropylene film can be used. Moreover, it is preferable to use what applied peeling agents, such as a silicone resin, an alkyd resin, a fluororesin, and a long-chain alkyl resin, to the single side | surface of the said plastic film. Further, a resin having peelability on the plastic film, for example, a polyolefin resin extruded on a polyethylene terephthalate film may be used. The thickness of the carrier film is usually 10 to 200 μm.

  Next, the dielectric layer composition is applied onto the carrier film 13 by the coating device 14. The coating device 14 includes a storage unit 15 and a coating unit 16. The storage unit 15 stores the slurry-like composition for a dielectric layer of the present invention, and sends the composition for the dielectric layer of the present invention to the coating unit 16 by a certain amount. Since the dielectric layer composition of the present invention is excellent in dispersibility and storage stability, the glass component and the like are uniformly dispersed in the storage unit 15 without settling. Further, the coating part 16 is not particularly limited. For example, a known coater such as a knife coater or a die coater can be used.

  The coating amount of the dielectric layer composition of the present invention can be appropriately set according to the thickness of the coating film 17a of the dielectric layer composition to be formed. Since the dielectric layer composition of the present invention is excellent in dispersibility and storage stability, the dielectric layer composition coating film 17a having a uniform film quality can be formed.

  Next, the carrier film 13 having the coating layer 17a of the dielectric layer composition formed on the surface is fed into the drying device 18. The coating film 17a of the dielectric layer composition is dried in this drying device 18 (that is, volatile components such as a solvent are removed), so that the dried coating film of the dielectric layer composition, that is, the green sheet 17 is obtained. Can be obtained by laminating on the carrier film 13.

The method for drying the coating film 17a of the dielectric layer composition is not particularly limited. For example, (a) a method in which the carrier film on which the coating film is formed is heated to a predetermined temperature, and (b) on the coating film surface. Examples thereof include a method of sending dry air or hot air, (c) a method of combining (a) and (b) above, and the like.
The temperature during drying is not particularly limited as long as the carrier film does not cause thermal deformation, and is usually room temperature to 150 ° C., preferably 60 to 130 ° C., and the drying time is 1 to 10 minutes. is there.
The thickness of the coating film 17a after drying is usually 10 to 200 μm, preferably 20 to 120 μm.

Next, a protective film 19 is laminated on the green sheet 17.
In FIG. 1, the protective film 19 is a long film wound up in a roll shape. As the protective film to be used, the same film as the carrier film can be used. The thickness of the protective film is usually 10 to 200 μm.

  In order to laminate the protective film 19 on the green sheet 17, the green sheet 17 and the protective film 19 are passed between the two laminating rolls 20a and 20b in FIG. In this case, both or one of the laminated rolls 20a and 20b, for example, the roll 20b on the protective film surface side may be heated.

As described above, the laminated film 21 composed of the three layers of the carrier film 13 -the green sheet 17 -the protective film 19 can be obtained.
The obtained laminated film 21 can be rolled up, collected, stored, and transported.

Since the green sheet of the present invention is obtained by molding the dielectric layer composition of the present invention into a film shape, the surface is smooth, foreign matter is less mixed, and the film quality is uniform.
As described below, the green sheet of the present invention is useful as a raw material for producing a dielectric layer forming substrate.

3) Dielectric Layer Forming Substrate and Manufacturing Method Thereof The dielectric layer forming substrate of the present invention has a dielectric layer formed on the substrate surface from the dielectric layer composition of the present invention.
The dielectric layer-formed substrate of the present invention was obtained by (A) a method of applying the composition for a dielectric layer of the present invention on a substrate by a screen printing method, followed by firing, and (B) as described above. After peeling the protective film from the green sheet, it can be obtained by laminating on the front plate substrate or the back plate substrate, then peeling the carrier film, and then firing the green sheet. This method is preferable.

  Examples of the substrate used here include a glass substrate and a ceramic substrate, and a glass substrate is preferable. Further, the glass substrate is not particularly limited as long as an electrode is formed on the surface, and a known substrate can be used. For example, the glass substrate for front plates in which the transparent electrode was formed on the surface, and the glass substrate for back plates in which the data electrode was formed on the surface can be mentioned. The thickness of the substrate is not particularly limited, but is usually about 1 to 10 mm.

  An example of manufacturing the dielectric layer-formed substrate of the present invention by the method (B) is shown in FIG. Hereinafter, a method of forming the dielectric layer forming substrate of the present invention will be described with reference to FIG. 2 shows an example in which the transparent dielectric layer 5 is formed on the glass substrate 1 for front plate in FIG.

First, as shown in FIG. 2A, the protective film 19 on one side of the laminated film 21 is peeled and removed.
Next, as shown in FIG.2 (b), the green sheet 17 is thermocompression-bonded on the glass substrate 1 for front plates in which the transparent electrode 3 was formed in the surface (the side in which the transparent electrode 3 is formed). Thermocompression bonding can be performed, for example, using a heating roller under conditions of a heating temperature of 70 to 130 ° C. and a pressure of 0.05 to 1.0 MPa. Since the thermally decomposable binder in the dielectric layer composition of the present invention is not only a binder but also a pressure-sensitive adhesive, the green sheet 17 can be uniformly attached to the glass substrate 1 by a simple operation. .

  Next, as shown in FIG. 2C, the carrier film 13 is peeled and removed from the green sheet 17, and the glass substrate 1 on which the green sheet 17 is thermocompression bonded is fired. In this process, the thermally decomposable binder in the dielectric layer composition is thermally decomposed, and the organic components are completely removed.

  Examples of the method for firing the glass substrate on which the green sheet 17 is thermocompression bonded include a method in which the glass substrate on which the green sheet 17 is thermocompression bonded is placed in a heating furnace and the whole is heated. The heating temperature and heating time are such that the glass substrate is not deformed by heat, the thermally decomposable binder is thermally decomposed, the organic components are completely removed, and the inorganic components (glass components, etc.) are in a uniform molten state. There is no particular limitation as long as the temperature and time allow the components to melt and become uniform. The heating temperature is usually 500 to 700 ° C., and the heating time is usually several minutes to several hours.

  In this invention, this baking is a temporary baking process in which heating is performed at a temperature of 300 to 450 ° C. for 10 to 60 minutes, and then a main baking process of further performing main baking at a temperature of 500 to 700 ° C. for 20 to 120 minutes. It is preferable to divide into two because it is possible to obtain a dielectric layer having more uniform film quality and thickness and excellent in transparency or reflectivity and surface smoothness.

  After firing, by cooling, a glass substrate 1 on which a transparent dielectric layer 5 having a thickness of 5 to 100 μm, preferably 5 to 90 μm, is laminated as shown in FIG. 2D can be obtained.

The transparent dielectric layer 5 obtained as described above has a high total light transmittance, a low haze value, and is excellent in transparency.
The total light transmittance of the transparent dielectric layer 5 is preferably 75% or more. The total light transmittance of the transparent dielectric layer can be measured using, for example, a HAZEMETER measuring apparatus.
The haze of the transparent dielectric layer is preferably 15% or less, more preferably 13% or less. The haze of the transparent dielectric layer can be measured using, for example, a HAZEMETER measuring apparatus.

In the present embodiment, the case where the transparent dielectric layer 5 used for the front plate glass substrate 1 of the PDP is formed has been described. However, the transparent dielectric layer 5 is formed on the white dielectric layer 6 or the ceramic substrate for the rear plate glass substrate 2. A dielectric layer or the like can be formed in the same manner. The reflectance of the obtained white dielectric layer 6 is preferably 25 to 100%.
The reflectance of the white dielectric layer 6 can be measured using, for example, a spectrophotometer.

  The dielectric layer according to the present invention is obtained from the composition for a dielectric layer according to the present invention, in which the glass component and the thermally decomposable binder are uniformly dispersed, and the amount of foreign matter is less mixed. Excellent, with few bubbles and uniform dielectric properties.

  Moreover, the smaller the average particle size of the slurry containing the glass component and the thermally decomposable binder, the better the dispersibility and the better the dielectric properties obtained. The average particle diameter can be measured by, for example, a laser diffraction / scattering particle size distribution measuring apparatus.

  The surface roughness of the obtained dielectric layer surface is preferably 0.2 μm or less, more preferably 0.1 μm or less. In the case of a white dielectric layer, 0.05 to 0.15 μm is preferable. The surface roughness can be measured using, for example, a contact surface roughness meter.

When the number of bubbles per unit area of the dielectric layer of the present invention is visually observed using an optical microscope, the number of bubbles having a diameter of 50 μm or more per 100 cm ² is preferably 20 or less, More preferably, it is 10 or less.

  As described above, the dielectric layer of the present invention has excellent surface flatness and few bubbles, and thus has uniform dielectric characteristics and excellent withstand voltage characteristics. The dielectric layer must have a withstand voltage of 1.5 kV or more for the front plate and 0.5 kV or more for the back plate. The withstand voltage can be measured, for example, by forming an evaluation electrode on a dielectric layer to produce a withstand voltage measuring sample and using a withstand voltage measuring machine.

  In the present invention, when a glass substrate is used as the substrate, a dielectric layer-formed glass substrate can be produced. By using this dielectric layer-formed glass substrate, it is possible to manufacture a high-quality PDP that can withstand the plasma discharge voltage when the plasma display is turned on and has few pixel defects.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to the following Example.

Example 1
The glass component, the dispersant and the solvent were put into a polymerization tank and mixed and stirred. Next, a polymerizable monomer and a radical polymerization initiator were added to the mixture in the polymerization tank, and further mixed and stirred, and the temperature was set to 70 ° C. to initiate polymerization. The reaction solution was sampled every hour, and the viscosity was measured with a viscometer (VISCOMETER, Tokimec Co., Ltd.). When the viscosity of the reaction solution reached 2000 mPa · S, the temperature was lowered to 25 ° C. to stop the reaction. A plasticizer was added to the product obtained after the reaction was stopped, and the mixture was stirred and mixed with a stirring and mixing device (TK Homodisper, Special Machine Industries Co., Ltd.) to obtain a slurry of the dielectric layer composition. .

The following were used for the glass component, dispersant, solvent, polymerizable monomer, polymerization initiator, and plasticizer.
Glass component:
100 parts by weight of glass component A-1 (PbO, B ₂ O ₃ , SiO ₂ are main components, average particle size is 1 μm) was used.
Dispersant:
0.5 parts by weight of an amine salt of polyetherester acid (Disparon DA-234, Enomoto Kasei Co., Ltd.) was used.
solvent:
70 parts by weight of a mixed solvent of methyl isobutyl ketone: toluene: ethyl acetate = 1: 1: 5 (weight ratio) was used.
Polymerizable monomer:
A total weight of 30 parts by weight of 2-ethylhexyl methacrylate and acrylic acid (weight ratio = 99: 1) was used.
Radical polymerization initiator:
0.1 part by weight of azoisobutyronitrile was used.
Plasticizer:
5 parts by weight of di-2-ethylhexyl adipate was used.
The weight average molecular weight of the polymerized binder polymer (thermally decomposable binder) was 210,000.

  As a carrier film, a long polyethylene terephthalate (PET) film having a thickness of 38 μm, one side of which was peeled with a silicone resin to a thickness of 0.1 μm, was prepared. The slurry obtained above was applied onto the surface of the film that had been subjected to a release treatment using a knife coater. Subsequently, it was dried at 100 ° C. for 2 minutes to obtain a green sheet 1 having a thickness of 70 μm on the PET film.

  Next, on the green sheet 1 obtained above, the peel-treated surface of the protective PET film having the same length as that of the PET film and having one surface peel-treated with a silicone resin at a thickness of 0.1 μm is pressure-bonded between rolls. Thus, a laminated film in which three layers of PET film-green sheet-PET film were laminated was obtained.

  Next, the protective PET film on the green sheet 1 obtained above is peeled and removed, and the green sheet surface of the laminated film is overlaid on the surface of a glass substrate (50 mm × 50 mm) having a thickness of 3 mm on which a transparent electrode is formed. These were thermocompression-bonded (100 ° C., 0.2 MPa) using a heating roller.

  Thereafter, the carrier film (PET film) is peeled and removed, placed in a heating furnace, heated to 420 ° C. at a heating rate of 10 ° C./min, heated at 420 ° C. for 10 minutes, and the resin in the green sheet 1 is removed. Pyrolysis removed. Furthermore, the temperature was raised to 590 ° C. and baked at the same temperature for 60 minutes to obtain a dielectric layer-formed glass substrate 1 on which a dielectric layer having a thickness of 40 μm was formed.

(Example 2)
As a glass component, 100 parts by weight of glass component A-2 (PbO, BaO, SiO ₂ , Al ₂ O ₃ is a main component, average particle size 2 μm) is used, and 2-ethylhexyl methacrylate is used as a polymerizable monomer. Except for using 35 parts by weight of 2-hydroxyethyl methacrylate (weight ratio = 95: 5) in the same manner as in Example 1, the dielectric layer composition, the green sheet 2 and the dielectric layer forming glass substrate 2 were obtained. Obtained. The weight average molecular weight of the polymerized binder polymer (thermally decomposable binder) was 200,000.

(Example 3)
Example of dielectric layer for back plate Glass component (PbO, B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ is the main component, average particle size 1.0 μm) 65 parts by weight of filler component (Al ₂ O ₃ 100 parts by weight of glass component B-1 added with 35 parts by weight of TiO ₂ , average particle size 1.0 μm), and 2-ethylhexyl methacrylate and acrylic acid (weight ratio = 99: A dielectric layer composition, a green sheet 3 and a dielectric layer-formed glass substrate 3 were obtained in the same manner as in Example 1 except that 1) was used in a total weight of 50 parts by weight. The weight average molecular weight of the polymerized binder polymer (thermally decomposable binder) was 190,000.

(Comparative Example 1)
A glass component, a thermally decomposable binder, a dispersant, a plasticizer and a solvent were put into a tank and mixed and stirred to obtain a mixture. The mixture was put into a circulation tank of a bead mill disperser and dispersed for 2.0 hours to obtain a slurry of the dielectric layer composition.

The following were used as the glass component, thermally decomposable binder, dispersant, plasticizer and solvent.
Glass component:
100 parts by weight of glass component A-1 was used.
Thermally decomposable binder:
30 parts by weight of (meth) acrylate resin obtained by copolymerizing 2-ethylhexyl methacrylate and acrylic acid at a weight ratio of 99: 1 and having a weight average molecular weight of 210,000 was used.
Dispersant:
0.5 parts by weight of an amine salt of polyetherester acid was used.
Plasticizer:
5 parts by weight of di-2-ethylhexyl adipate was used.
solvent:
70 parts by weight of a mixed solvent of methyl isobutyl ketone: toluene: ethyl acetate = 1: 1: 5 (weight ratio) was used.

  Next, a dielectric layer composition, a green sheet 4 and a dielectric layer-formed glass substrate 4 were obtained in the same manner as in Example 1.

(Comparative Example 2)
Example of back plate dielectric layer 100 parts by weight of glass component B-1 is used as the glass component, and 2-ethylhexyl methacrylate and acrylic acid are copolymerized at a weight ratio of 99: 1 as the polymerizable monomer. The composition for dielectric layer, green sheet 5 and dielectric layer formation were carried out in the same manner as in Comparative Example 1 except that 50 parts by weight of the (meth) acrylate resin having a weight average molecular weight of 210,000 obtained was used. A glass substrate 5 was obtained.

The kind of glass component used in Examples 1 to 3 and Comparative Examples 1 and 2, the amount of the thermally decomposable binder (parts by weight) relative to the weight of the glass component, the weight of the thermally decomposable binder obtained in Examples 1 to 3 Table 1 summarizes the average molecular weight (Mw), the weight average molecular weight (Mw) of the thermally decomposable binder used in Comparative Examples 1 and 2, and the average particle size (μm) of the slurry.
In addition, the weight average molecular weight (Mw) of the thermally decomposable binder was measured with a gel permeation chromatography (GPC) measuring device (HLC-8020, manufactured by Tosoh Corporation). The average particle size of the slurry was measured with a laser diffraction / scattering particle size distribution analyzer (LA-920, manufactured by Horiba, Ltd.).

(Green sheet surface properties)
The surface properties of the green sheets 1 to 5 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were visually observed and evaluated. The case where the surface was smooth was marked with ◯ and the case where the surface was not smooth was marked with ×. The evaluation results are shown in Table 2.

  From Table 2, the green sheets of Examples 1 to 3 had a smooth surface. In comparison, the green sheets of Comparative Examples 1 and 2 had a poor surface condition, and the surface after firing also had a bad result.

(Measurement of haze of dielectric layer)
The haze of the dielectric layer-formed glass substrates 1, 2 and 4 obtained in Examples 1 and 2 and Comparative Example 1 was measured with a HAZEMETER measuring device (HAZE METER NDH2000, Nippon Denshoku Industries Co., Ltd.). The measurement results are shown in Table 3.

(Measurement of total light transmittance and reflectance)
The total light transmittance of the dielectric layer-formed glass substrates 1, 2 and 4 obtained in Examples 1 and 2 and Comparative Example 1 was measured with a HAZEMETER measuring device (HAZE METER NDH2000, Nippon Denshoku Industries Co., Ltd.). did. Further, the reflectance of the dielectric layer-formed glass substrates 3 and 5 obtained in Example 3 and Comparative Example 2 was measured at a measurement wavelength of 560 nm using a spectrophotometer (MPC-3100, Shimadzu Corporation). did. The measurement results are shown in Table 3.

(Measurement of surface roughness and dielectric layer thickness)
The surface roughness of the dielectric layer-formed glass substrates 1 to 5 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 and the thickness of the dielectric layer were measured using a contact surface roughness meter (SV3000, Mitutoyo Corporation). ). The measurement results are shown in Table 3.

(Evaluation test for presence of bubbles in dielectric layer)
The dielectric layers of the dielectric layer-formed glass substrates 1 to 5 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were observed with an optical microscope (Digital Microscope VHX-100, Keyence Corporation), and 100 cm ^2. The number of bubbles having a diameter of 50 μm or more that was confirmed was counted. The evaluation results are shown in Table 3.

(Measurement of dielectric strength of dielectric layers)
The withstand voltage of the dielectric layers of the dielectric layer-formed glass substrates 1 to 5 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was measured with a withstand voltage measuring device (TOS9201, Kikusui Electronics Co., Ltd.). . The measurement results are shown in Table 3.

From Table 3, the dielectric layers of Examples 1 and 2 were superior to the dielectric layer of Comparative Example 1 in transparency, smooth surface, few bubbles, and excellent withstand voltage characteristics. Therefore, the dielectric layer-formed glass substrate of Examples 1 and 2 is suitable as a glass substrate for a front plate with a dielectric layer of PDP.
In addition, the dielectric layer of Example 3 had higher reflectivity than the dielectric layer of Comparative Example 2, had a smooth surface, and had excellent withstand voltage characteristics. Therefore, the dielectric layer-formed glass substrate of Example 3 is suitable as a glass substrate for a back plate with a dielectric layer of PDP.

It is process schematic which manufactures the green sheet of this invention. It is process sectional drawing which shows the formation method of the dielectric material layer formation board | substrate of this invention. It is structure sectional drawing of an example of a plasma display panel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass substrate for front plates, 2 ... Glass substrate for back plates, 3 ... Transparent electrode, 4 ... Data electrode, 5 ... Dielectric layer (front plate dielectric layer), 6 ... Dielectric layer (back plate dielectric layer) ), 7 ... Protective film, 8 ... Rib (partition), 9 ... Phosphor, 13 ... Carrier film, 14 ... Coating device, 15 ... Storage unit, 16 ... Coating unit, 17a ... Dielectric layer composition Coating film, 17 ... Green sheet, 18 ... Drying device, 19 ... Protective film, 20a, 20b ... Laminated roll, 21 ... Laminated film

Claims (11)

  A dielectric layer composition comprising a glass component and a thermally decomposable binder, wherein the thermally decomposable binder is obtained by polymerizing a polymerizable monomer in the presence of a glass component. A composition for a dielectric layer.   The composition for a dielectric layer according to claim 1, wherein the thermally decomposable binder is obtained by radical polymerization of an acrylic ester compound or a methacrylic ester compound in the presence of the glass component.   The composition for a dielectric layer according to claim 1, wherein the thermally decomposable binder is obtained by polymerizing a polymerizable monomer in the presence of a glass component and a dispersant.   The dielectric layer composition according to any one of claims 1 to 3, further comprising a filler component.   The composition for a dielectric layer according to any one of claims 1 to 4, which is used for a dielectric layer of a plasma display panel.   A method for producing a composition for a dielectric layer comprising a glass component and a thermally decomposable binder, comprising polymerizing a polymerizable monomer in a solvent in the presence of the glass component to The manufacturing method of the composition for dielectric layers which has the process of obtaining the dispersion liquid containing.   The dielectric according to claim 6, wherein the step of obtaining a dispersion containing the glass component and the thermally decomposable binder is a method in which an acrylic ester compound or a methacrylic ester compound is radically polymerized in a solvent in the presence of the glass component. A method for producing a body composition.   7. A step of obtaining a dispersion containing a glass component, a dispersant, and a thermally decomposable binder by polymerizing a polymerizable monomer in a solvent in the presence of the glass component and the dispersant. The manufacturing method of the composition for dielectric material layers of description.   The green sheet obtained by shape | molding the composition for dielectric layers in any one of Claims 1-5 in a film form.   A dielectric layer forming substrate comprising a dielectric layer formed from the dielectric layer composition according to claim 1. A method for producing a dielectric layer-formed substrate, comprising: a step of attaching the green sheet according to claim 9 on a substrate; and a step of firing the green sheet.

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