JP2008130316A - Composition for dielectric layer formation, green sheet, dielectric layer forming substrate and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for dielectric layer formation, having an inorganic constituent that does not contain lead content, and having uniform and stable dispersibility and storage stability, and to provide a green sheet, a dielectric layer formation substrate, and to provide a manufacturing method of the composition. <P>SOLUTION: This composition for dielectric layer formation contains the inorganic constituents, a thermally-degradable binder, a dispersant and a solvent. The composition for dielectric layer formation is such that the inorganic constituents do not contain lead content; the dispersant is a polycarboxylic acid-based polymer compound; and the content of the thermally-degradable binder is 55-105 pts.wt., with respect to 100 pts.wt. of the inorganic constituent by a solid content ratio. This green sheet is obtained, by molding the composition for dielectric layer formation into a film-like shape, and this dielectric layer formation substrate has a dielectric layer, formed by using the green sheet on a substrate. The manufacturing method of the composition is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dielectric layer forming composition suitable for forming a dielectric layer such as a plasma display panel, a green sheet obtained by molding this composition into a film, and a dielectric obtained from the green sheet. The present invention relates to a dielectric layer forming substrate having a body layer and a method for manufacturing 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.

  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. Display electrodes 3 and address electrodes 4 which 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 display electrode 3 and the address 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 (partition walls) 8 through a protective film 7, and a phosphor 9 is formed in each pixel.

  As a method for forming a PDP dielectric layer, a method is known in which a green sheet obtained by forming a dielectric layer forming composition into a film is bonded to a substrate, and then the green sheet is fired ( Patent Documents 1 and 2). According to this method, a high quality dielectric layer can be formed efficiently.

  Such a dielectric layer forming composition is required to have excellent dispersibility and long-term storage stability. When using a composition for forming a dielectric layer that has poor dispersibility or deteriorated during storage, a uniform coating film cannot be formed, and the formed dielectric layer has many drawbacks. Therefore, it is difficult to obtain desired characteristics as a dielectric.

In relation to the present invention, Patent Document 3 discloses a dielectric layer forming composition containing an inorganic component (glass component), a thermally decomposable binder, a dispersant, and a solvent. It has been proposed to use a polymer compound.
JP-A-9-102273 Japanese Patent Laid-Open No. 10-182919 JP 2004-2164 A

  In recent years, from the viewpoint of environmental protection and the like, it is desired to use an inorganic component that does not contain lead (lead compound) as an inorganic component used for forming a dielectric layer.

  When the present inventors applied the formulation described in Patent Document 3 to a composition for forming a dielectric layer that does not contain lead, the dispersibility and storage stability of the resulting composition for forming a dielectric layer were improved. I found it was not enough.

  Therefore, the present invention provides a dielectric layer forming composition containing an inorganic component, a thermally decomposable binder, a dispersant, and a solvent, even when the inorganic component does not contain lead. Dielectric layer forming composition, green sheet, and dielectric having uniform and stable dispersibility and storage stability, and capable of forming a uniform and high-quality dielectric layer by applying and firing. It is an object of the present invention to provide a layer forming substrate and a manufacturing method thereof.

  In order to solve the above-mentioned problems, the present inventors have intensively studied a dielectric layer forming composition containing an inorganic component not containing lead, a thermally decomposable binder, a dispersant, and a solvent. As a result, when a polycarboxylic acid polymer compound is used as a dispersant and the content of the thermally decomposable binder is 55 to 105 parts by weight with respect to 100 parts by weight of the inorganic component, it is uniform and stable. It was found that a dielectric layer-forming composition having dispersibility and storage stability was obtained, and that a high-quality dielectric layer could be obtained without using defects when a green sheet formed from this composition was used. The present invention has been completed.

Thus, according to the first aspect of the present invention, there is provided a dielectric layer forming composition containing an inorganic component, a thermally decomposable binder, a dispersant and a solvent, wherein the inorganic component does not contain lead, The dispersant is a polycarboxylic acid polymer compound, and the content of the thermally decomposable binder is 55 to 105 parts by weight with respect to 100 parts by weight of the inorganic component in the solid content ratio. A dielectric layer forming composition is provided.
In the dielectric layer forming composition of the present invention, the content of the dispersant is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the inorganic component in terms of solid content ratio.

  In the dielectric layer forming composition of the present invention, the polycarboxylic acid polymer compound comprises an α-olefin / maleic anhydride copolymer partial ester, an aliphatic polycarboxylate, and an aliphatic polycarboxylic acid. It is preferably at least one selected from the group consisting of special silicones.

In the dielectric layer forming composition of the present invention, the inorganic component preferably contains a glass component and a filler component.
The dielectric layer forming composition of the present invention is preferably a slurry having an average particle size of 0.5 to 4.0 μm.
The composition for forming a dielectric layer of the present invention is preferably used for forming a dielectric layer of a plasma display panel.

According to the second aspect of the present invention, there is provided a green sheet obtained by forming the dielectric layer forming composition of the present invention into a film.
According to a third aspect of the present invention, there is provided a dielectric layer-formed substrate comprising a dielectric layer formed using the green sheet of the present invention on a substrate.
According to a fourth aspect of the present invention, there is provided a method for manufacturing a dielectric layer-formed substrate, comprising: a step of bonding the green sheet of the present invention to a substrate; and a step of forming a dielectric layer by firing the green sheet. Provided.

The composition for forming a dielectric layer of the present invention is superior from the viewpoint of environmental protection because it uses an inorganic component that does not contain lead.
Even if the composition for forming a dielectric layer of the present invention is stored or transported in a slurry state, the inorganic component does not aggregate or settle, and the dispersion is uniform and stable over a long period of time. Have a state.
When the composition for forming a dielectric layer of the present invention is used, a uniform green sheet can be formed because uniform coating is possible, and as a result, a uniform and high-quality dielectric layer without defects can be obtained. it can.

The dielectric layer forming composition and the green sheet of the present invention can be suitably used for forming a dielectric layer of a plasma display panel.
Since the dielectric layer forming substrate of the present invention has a dielectric layer formed using the green sheet of the present invention, it is uniform and of high quality.
According to the method for manufacturing a dielectric layer forming substrate of the present invention, it is possible to efficiently manufacture a uniform and high quality dielectric layer forming substrate having a dielectric layer free from pixel defects.

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

1) Dielectric layer forming composition The dielectric layer forming composition of the present invention (hereinafter sometimes simply referred to as "the composition of the present invention") comprises an inorganic component, a thermally decomposable binder, a dispersant, and a solvent. A dielectric layer-forming composition comprising: the inorganic component does not contain lead; the dispersant is a polycarboxylic acid polymer compound; and the thermally decomposable binder. It is characterized by being content of 55-105 weight part with respect to 100 weight part of inorganic components by solid content ratio.

(Inorganic component)
The inorganic component used in the composition of the present invention does not contain lead from the viewpoint of environmental protection. As an inorganic component, the glass component which does not contain lead content, or the mixture which consists of a glass component and filler component which do not contain lead content is mentioned.

  By using a mixture comprising a glass component and a filler component not containing lead as the inorganic component, a white dielectric layer forming composition having excellent reflectance can be obtained.

The glass component not containing lead is not particularly limited as long as it does not contain lead. For example, ZnO—B ₂ O ₃ —SiO ₂ (zinc oxide-boron oxide-silicon oxide) glass, ZnO -P ₂ O ₅ -SiO ₂ (zinc oxide - phosphorus - silicon oxide) based _{glass, Bi 2 O 3 -B 2 O} 3 -SiO 2 ( bismuth oxide - boron oxide - silicon oxide) based glass, _{ZnO-B 2} O ₃ -K ₂ O (zinc oxide - boron oxide - potassium oxide) based _{glass, ZnO-P 2 O 5 -TiO} 2 ( zinc oxide - phosphorus - titanium oxide) based _glass, B ₂ O 3 -SiO ₂ -Al ₂ O ₃ (boron oxide - silicon oxide - aluminum oxide) based _{glass, P 2 O 5 -B 2 O} 3 -Al 2 O 3 ternary such (phosphorus - - boron oxide aluminum oxide) based glass _{Glass; Bi 2 O 3 -B 2 O} 3 -SiO 2 -Al 2 O 3 ( bismuth oxide - boron oxide - silicon oxide - aluminum oxide) based _{glass, ZnO-B 2 O 3 -SiO} 2 -Al 2 O 3 ( zinc oxide - boron oxide - silicon oxide - aluminum oxide) based _{glass, ZnO-P 2 O 5 -SiO} 2 -Al 2 O 3 ( ZnO - phosphorus - silicon oxide - aluminum oxide) based glass, _ZnO-Bi 2 O ₃ -SiO ₂ -B ₂ O ₃ quaternary glass such as (zinc oxide - bismuth oxide - - silicon oxide boron oxide) based _{glass; ZnO-Bi 2 O 3 -SiO} 2 -Al 2 O 3 -B 2 O 3 five-component glasses such as (zinc oxide - bismuth oxide - silicon oxide - - aluminum oxide boron oxide) based _{glass; ZnO-Bi 2 O 3 -SiO} 2 -Al 2 O -B ₂ O ₃ -BaO six-component glass such as (zinc oxide - bismuth oxide - silicon oxide - aluminum oxide - - boron oxide, barium oxide) based glass; and the like.
Further, these glass _{components, CaO, Na 2 O, TiO} 2, CuO, Li 2 O, K 2 O, BaO, MgO, SrO , etc. may be added.

Among these, the use of ZnO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ (zinc oxide-boron oxide—silicon oxide—aluminum oxide) glass is preferable, and ZnO—Bi ₂ O ₃ —SiO ₂ —Al ₂ The use of O ₃ —B ₂ O ₃ —BaO (zinc oxide-bismuth oxide-silicon oxide-aluminum oxide-boron oxide-barium oxide) glass is more preferred.

Examples of the filler component include TiO ₂ (titanium oxide), Al ₂ O ₃ (alumina), SiO ₂ (silica), and ZrO ₂ (zirconia). Among these, TiO ₂ and Al ₂ O ₃ are preferable.

  When the inorganic component is a mixture composed of a glass component and a filler component, the blending ratio of the glass component and the filler component is usually glass component: filler component = 50: 50 to 99: 1 (weight ratio), preferably 70:30. ~ 95: 5.

  For the inorganic component, a powdery glass component and optionally a powdery filler component are mixed, or the glass component is melted, then cooled and ground to form a frit, and this is mixed with the powdery filler component as desired. Can be obtained.

  The average particle size of the inorganic component used is preferably 3 μm or less, more preferably 0.5 to 3.0 μm. By using an inorganic component having an average particle diameter in such a range, it becomes easy to obtain a dielectric layer forming composition having a uniform and stable dispersion state.

The maximum particle size of the inorganic component is preferably 20 μm or less from the viewpoint of obtaining a uniform and transparent dielectric layer. If the maximum particle size of the inorganic component exceeds 20 μm, defects such as pinholes are likely to occur on the surface of the obtained dielectric layer, making it difficult to obtain the desired withstand voltage characteristics.
The average particle size and the maximum particle size of the inorganic component can be measured by, for example, a laser diffraction / scattering particle size distribution measuring apparatus.

(Dispersant)
The composition of the present invention uses a polycarboxylic acid polymer compound as a dispersant.
The polycarboxylic acid-based polymer compound used in the present invention means a polymer compound having a plurality of carboxylic acid groups in the molecule. Such polycarboxylic acid polymer compounds can disperse particles with high specific gravity, such as glass frit, better than known dispersants such as silane coupling agents and general surfactants. It is.

  By using a polycarboxylic acid polymer compound as a dispersant, the dispersibility of the glass frit in the dielectric layer composition can be improved, and the composition can be kept in a good dispersion state. That is, it is suppressed that the glass frit aggregates and forms secondary particles. As a result, it is possible to improve the variation in dielectric characteristics in the dielectric layer and further improve the withstand voltage of the dielectric layer.

  As the polycarboxylic acid polymer compound, at least one selected from the group consisting of α-olefin / maleic anhydride copolymer partial ester, aliphatic polycarboxylate, and aliphatic polycarboxylic acid special silicone is used. Is preferred. Especially, the partial ester of an α-olefin / maleic anhydride copolymer exhibits an excellent dispersion effect. The molecular weight of the partial ester of the α-olefin / maleic anhydride copolymer is not particularly limited, but is preferably 10,000 to 50,000.

  The blending amount of the dispersant is preferably 0.01 to 5 parts by weight, more preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the inorganic component in terms of solid content ratio. If the blending amount of the dispersing agent is less than this range, the dispersion state of the obtained dielectric layer forming composition becomes non-uniform, and the inorganic component may be easily precipitated or aggregated. On the other hand, if the amount is larger than this range, the dispersant remains in the dielectric layer even after the firing step, causing a decrease in withstand voltage and transparency.

(Pyrolytic binder)
The composition of the present invention contains a thermally decomposable binder in addition to the inorganic component and the dispersant.
The content of the thermally decomposable binder in the composition of the present invention is 55 to 105 parts by weight, preferably 65 to 95 parts by weight, based on 100 parts by weight of the inorganic component, as a solid content ratio. By setting the heat decomposable binder in such a range, a composition for forming a dielectric layer having a uniform and stable dispersion state and excellent in dispersibility and storage stability can be obtained.

The thermally decomposable binder has a function as a binder that can be decomposed and easily removed by firing.
Although it does not restrict | limit especially as a thermally decomposable binder used for this invention, it has the function as a binder, the role as an outstanding binder and glass as an organic polymer which decomposes | disassembles by baking and can be removed easily. The use of an acrylic resin that serves as a pressure sensitive adhesive with the substrate is preferred.

  Examples of the acrylic resin include a homopolymer of a (meth) acrylate compound, a copolymer obtained from two or more types of (meth) acrylate compounds, and a (meth) acrylate compound and other copolymerizable monomers. A copolymer etc. are mentioned. Among these, a copolymer obtained from two or more of (meth) acrylate compounds is preferable. Here, (meth) acrylate represents either acrylate or methacrylate (the same applies hereinafter).

  Specific examples of the (meth) acrylate compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and 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, Decyl (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;
Alkoxyalkyl such as 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-methoxybutyl (meth) acrylate, etc. ) 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, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, bornyl (meth) acrylate, isobornyl ( Cycloalkyl (meth) acrylates such as (meth) acrylate and tricyclodecanyl (meth) acrylate;
Examples include benzyl (meth) acrylate and tetrahydrofurfuryl (meth) acrylate.

  The other copolymerizable monomer is not particularly limited as long as it is a compound copolymerizable with the (meth) acrylate compound. For example, unsaturated carboxylic acids such as (meth) acrylic acid, vinyl benzoic acid, maleic acid, vinyl phthalic acid; vinyl group-containing radical polymerization such as vinyl benzyl methyl ether, vinyl glycidyl ether, styrene, α-methyl styrene, butadiene, isoprene, etc. And the like.

  In the present invention, as the thermally decomposable binder, those produced by a known production method or those obtained as a commercial product can be used.

  The method for producing the thermally decomposable vanider is not particularly limited, and a known method can be adopted. For example, the acrylic resin can be produced by (co) polymerizing the (meth) acrylate compound and optionally another copolymerizable monomer. The polymerization method is not particularly limited, and examples thereof include a radical polymerization method using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).

  The weight average molecular weight of the thermally decomposable binder used in the present invention is not particularly limited, but is usually 15,000 to 400,000, preferably 50,000 to 300,000. The molecular weight can be measured by gel permeation chromatography (GPC).

  The glass transition temperature (Tg) of the thermally decomposable binder used in the present invention is not particularly limited, but is usually -15 ° C to + 40 ° C.

  In the present invention, as the thermally decomposable binder, an emulsion of a thermally decomposable binder obtained by dispersing the thermally decomposable binder in the aqueous phase in the form of fine particles can also be used.

(solvent)
The composition of the present invention contains a solvent in addition to the inorganic component, the dispersant, and the thermally decomposable binder. The solvent imparts appropriate fluidity or plasticity and good film forming properties to the composition.

Examples of the solvent used in the present invention include water; ethers such as diethyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane; methyl acetate, ethyl acetate, propyl acetate, butyl acetate, Esters such as methyl lactate; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, and cyclohexanone: N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylphosphate phosphoramide, N-methylpyrrolidone Amides such as ε; Lactams such as ε-caprolactam; Lactones such as γ-lactone and δ-lactone; Sulphoxides such as dimethyl sulfoxide and diethyl sulfoxide; Pentane, hexane, heptane, octane, nonane, decane Aliphatic hydrocarbons; Cyclopentane, cyclohexane, cyclooctane and other alicyclic hydrocarbons; benzene, toluene, xylene and other aromatic hydrocarbons; dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene Halogenated hydrocarbons such as; and a mixed solvent composed of two or more of these; Among these, from the viewpoint of efficiently obtaining a dielectric layer forming composition having a uniform and stable dispersion state, an ester, a ketone, an aromatic hydrocarbon, or a mixed solvent composed of two or more of these is used. Use is preferred.
Although the usage-amount of a solvent is not specifically limited, It is 1 to 55 weight% normally with respect to the whole composition.

(Other additives)
If necessary, other additives such as a plasticizer, a tackifier, a storage stabilizer, an antifoaming agent, a thermal decomposition accelerator, and an antioxidant may be added to the composition of the present invention.
For example, a plasticizer is added to improve processability. Examples of the plasticizer to be used include an adipate ester plasticizer, a phthalate ester plasticizer, and a glycol ester plasticizer. The usage-amount of a plasticizer is 0-10 weight part with respect to 100 weight part of inorganic components.

(Preparation of composition)
The composition of the present invention can be prepared by premixing raw materials such as the above-described thermally decomposable binder, inorganic component, dispersant and solvent, and then mechanically dispersing the mixture using a disperser.

  The disperser used for dispersion is not particularly limited, and examples thereof include known dispersers such as a media mill such as a ball mill and a bead mill; various homogenizers such as an ultrasonic type and a stirring type; a jet mill; and a roll mill.

After the dispersion, the average particle size of the slurry of the composition (the average particle size of the total inorganic components after preparing the composition) is 0.5 to 4.0 μm, preferably 1 to 3.5 μm. .
The average particle diameter of the slurry is measured by, for example, diluting the slurry with methyl isobutyl ketone so as to have a concentration of 0.05% by weight, and measuring with a laser diffraction / scattering type particle size distribution analyzer in accordance with JISZ8825-1. be able to.

  The composition of the present invention obtained as described above is excellent from the viewpoint of environmental protection because it does not contain lead.

The composition of the present invention is excellent in dispersibility, has no secondary aggregation or sedimentation even after long-term storage or transportation, and can maintain a good dispersion state immediately after preparation of the composition over a long period of time. .
Therefore, even after storing the composition for forming a dielectric layer of the present invention after long-term storage over a long period of time, by using this composition, a uniform green sheet can be obtained just after preparation. Furthermore, a uniform and high-quality dielectric layer free from defects can be obtained.

  The storage stability of the composition for forming a dielectric layer can be determined, for example, by placing the composition for forming a dielectric layer immediately after preparation in a sealed container, and allowing the container to stand at room temperature for a predetermined period of time, and then visually observing the glass component and It can be evaluated by examining the presence or absence of phase separation of the components.

  Moreover, the storage stability of the composition for forming a dielectric layer includes the height H of the liquid level immediately after being put in the sealed container and the height Ha of the phase separation boundary line between the glass component and the organic component after a predetermined period. It is also possible to measure and evaluate the sedimentation rate (%) by the following formula.

  The sedimentation rate after leaving the composition of the present invention at room temperature for 4 weeks is preferably 20% or less, more preferably 15% or less, and the composition of the present invention is excellent in storage stability.

The composition of the present invention can be suitably used for forming a dielectric layer of a flat panel display, particularly a PDP dielectric layer.
Moreover, the composition of this invention is useful also as a manufacturing raw material of the green sheet of this invention mentioned later.

2) Green sheet The green sheet of the present invention is obtained by molding the composition of the present invention into a film. Specifically, the composition of the present invention can be produced by coating 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 forming composition of the present invention, and 18 is for drying the coating film of the dielectric layer forming composition (removing the solvent). The drying devices 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 is excellent in peelability from the coating film of the dielectric layer forming 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 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, and sends the composition to the coating unit 16 by a certain amount. 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 composition of the present invention can be appropriately set according to the thickness of the coating film 17a of the composition to be formed.

  Next, the carrier film 13 on the surface of which the coating film 17a of the composition is formed is fed into the drying device 18. By drying the coating film 17a of the composition in the drying device 18 (that is, removing volatile components such as a solvent), the dried coating film of the composition, that is, the green sheet 17 is laminated on the carrier film 13. A laminate can be obtained.

The method for drying the coating film 17a of the 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) dry air or Examples thereof include a method of sending hot air, (c) a method of combining (a) and (b) above, and the like.
The temperature for drying is not particularly limited as long as it is not higher than the temperature at which the carrier film is not thermally deformed, and is usually from room temperature to 150 ° C, preferably 60 to 130 ° C, and the drying time is 1 to 10 minutes.
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. Lamination may be performed by heating both or one of the laminated rolls 20a and 20b, for example, the roll 20b on the protective film surface side.

  Since the green sheet of the present invention is excellent in dispersibility of the composition, not only the surface in contact with the carrier film surface but also the exposed surface becomes smooth. For this reason, the green sheet of this invention is excellent in the bonding ease with a carrier film and a protective film, and can laminate smoothly (it is excellent in lamination suitability). Lamination suitability can be evaluated by observing the laminated film (carrier film-green sheet-protective film) with the naked eye and whether the three layers are properly bonded. Since the green sheet of the present invention is in such a laminated state, the dielectric layer obtained by firing does not have a pinhole defect and can form a smooth surface.

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 obtained as described above is obtained by molding the composition of the present invention into a film, a uniform and high-quality dielectric layer can be formed.

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 using the green sheet of the present invention.

  The dielectric layer forming substrate of the present invention includes, for example, a step of bonding a green sheet to the substrate and a step of forming a dielectric layer by firing the green sheet. It can be obtained by a manufacturing method. Specifically, after the protective film is peeled off from the green sheet, it is laminated on the substrate, and then the carrier film is peeled off, and then the green sheet is fired. According to this method, a uniform and high-quality dielectric layer forming substrate can be manufactured even in a large area.

  Examples of the substrate used here include a glass substrate and a ceramic substrate, and a glass substrate is preferable. As a glass substrate, the glass substrate for front plates with which the display electrode was formed on the surface etc. are mentioned, for example. The thickness of the substrate is not particularly limited, but is usually about 1 to 10 mm.

  An example of producing a transparent dielectric layer used for a glass substrate for a front panel of a PDP as a dielectric layer forming substrate of the present invention is shown in 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. 2B, the green sheet 17 is thermocompression bonded onto the front plate glass substrate 1 on which the display electrode 3 is formed (the side on which the display electrode 3 is formed). Thermocompression bonding can be performed, for example, using a heating roller under the conditions of a heating temperature of 50 ° C. to 130 ° C. and a pressure of 0.05 MPa to 2.0 MPa. Since the thermally decomposable binder in the composition of the present invention is a binder and can have a function as a pressure-sensitive adhesive, the green sheet 17 is uniformly adhered to the glass substrate 1 by a simple operation. be able to.

  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 composition is thermally decomposed and the organic components are completely removed.

  Examples of the method for firing the glass substrate to which the green sheet 17 is thermocompression bonded include a method in which the glass substrate to which the green sheet 17 is thermocompression bonded is placed in a firing furnace and the whole is heated.

The firing temperature is a temperature at which the thermally decomposable binder is thermally decomposed, the organic component is completely removed, and the inorganic component is melted and homogenized in a uniform molten state. This firing temperature is generally considered to be a temperature near the softening point of the inorganic component in the green sheet. Specifically, it is 500-650 degreeC normally, Preferably it is 520-620 degreeC.
The firing time is usually 1 minute to 3 hours, preferably 5 minutes to 120 minutes.

  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 is uniform and high quality without pinhole defects, and is excellent in transparency.
The surface roughness Ra (μm) of the dielectric layer is usually 0.2 or less. The surface roughness Ra (μm) can be measured using, for example, a contact-type surface roughness meter.

  In the present embodiment, the case where the transparent dielectric layer 5 used for the glass substrate 1 for the front plate of the PDP is formed has been described. However, the white dielectric layer 6 for the glass substrate 2 for the rear plate, the ceramic substrate, A dielectric layer or the like on the circuit board can be formed in the same manner.

  By using the dielectric layer forming substrate of the present invention, a high quality flat panel display can be manufactured. Examples of the flat panel display include a PDP, a field emission display (FED), a liquid crystal display device, an electroluminescence display device, and the like, and the PDP is particularly preferable.

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

The following were used for the inorganic component, the thermally decomposable binder, the dispersant, the solvent and the plasticizer.
1) Inorganic component ZnO—Bi ₂ O ₃ —SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ —BaO glass (80 wt%), TiO ₂ , SiO ₂ (TiO ₂ / SiO ₂ = 75/25 (weight) %)) As a main component and a glass frit having an average particle diameter of 1.4 μm comprising a filler component (20% by weight)

2) Thermally decomposable binder Using 0.5 parts by weight of azobisisobutyronitrile as a radical polymerization initiator, 100 parts by weight of 2-ethylhexyl methacrylate and 1 part by weight of acrylic acid are polymerized in toluene at 70 ° C. for 16 hours. A 50% by weight solution of the copolymer (weight average molecular weight (Mw) = 170,000, glass transition temperature (Tg) = − 11 ° C.) obtained by

3) Dispersant (1) Dispersant A: Polycarboxylic acid polymer compound (α-olefin / maleic anhydride copolymer partial ester, trade name: Floren G700, manufactured by Kyoeisha Chemical Co., Ltd.), concentration 100%
(2) Dispersant B: polyether-based dispersant (trade name: Floren NC-500, manufactured by Kyoeisha Chemical Co., Ltd.), concentration 50%
(3) Dispersant C: Nonionic non-silicone compound (trade name: Polyflow KL505, manufactured by Kyoeisha Chemical Co., Ltd.), concentration 100%

4) Solvent Toluene 5) Plasticizer Dibutyl adipate

Moreover, the evaluation method regarding the dispersion state of the composition prepared by each Example and the comparative example and the characteristic of a dielectric material layer is as follows.
(I) Measurement of average particle diameter and maximum particle diameter The average particle diameter (μm) and maximum particle diameter of the slurry were diluted with methyl isobutyl ketone so that the concentration of the slurry was 0.05% by weight. In conformity, the measurement was performed with a laser diffraction / scattering particle size distribution analyzer (model: LA-920, manufactured by Horiba, Ltd.).

(Ii) Measurement of sedimentation rate The composition for forming a dielectric layer immediately after preparation was placed in a container, the container was sealed, and the height H of the liquid level was measured. The container was allowed to stand at room temperature for a predetermined period, and then visually observed to examine the presence or absence of phase separation between the glass component and the organic component. When the glass component and the organic component were phase separated, the height Ha of the phase separation boundary line was measured. The sedimentation rate (%) was calculated by the following formula.

(Iii) Laminate suitability The laminate suitability was evaluated by visually observing the obtained laminated film (PET film-green sheet-PET film) and determining whether the three layers were properly bonded. The case where it was bonded together was evaluated as ◯, and the case where it was not bonded properly due to the presence of aggregates was evaluated as x.

(Iv) Film thickness The film thickness was measured with a surface roughness measuring machine (model: SVP-3000S4, manufactured by Mitutoyo Corporation).

(V) Pinhole defect The presence or absence of pinholes on the dielectric layer (95 mm × 95 mm) was observed with a microscope. The case where there was no pinhole defect was evaluated as ◯, and the case where there was even one pinhole defect was evaluated as x.

(Vi) Surface roughness (Ra)
About the dielectric layer formed by sticking the green sheet obtained from the composition for dielectric layers on the glass substrate with an electrode on the glass substrate and then firing, the surface of the dielectric layer is surface-roughened. It evaluated by measuring using a measuring machine (model: SVP-3000S4, Mitutoyo Corporation).

(Example 1)
100 parts by weight of the inorganic component, 160 parts by weight of a thermally decomposable binder (80 parts by weight in solid content with respect to 100 parts by weight of inorganic component), 1 part by weight of dispersant A (solid content ratio with respect to 100 parts by weight of inorganic component) 1 part by weight), 25 parts by weight of solvent, and 1 part by weight of a plasticizer are dispersed using a bead mill-based disperser to form a dielectric layer forming composition 1 of Example 1 (hereinafter referred to as “slurry 1”). ) Was prepared.
The average particle size (μm), the maximum particle size (μm) of the slurry 1 and the sedimentation rate (%) after 4 days, 2 weeks and 4 weeks of the slurry 1 were measured. The measurement results are shown in Table 1.

  As a carrier film, a long polyethylene terephthalate (PET) film having a thickness of 50 μm, one side of which was peeled off with a silicone resin to a thickness of 0.1 μm, was prepared. The slurry 1 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 35 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. At this time, the suitability for lamination was evaluated by the above method. The evaluation results are shown in Table 1.

The protective PET film on the green sheet 1 was peeled off. The surface of the obtained carrier film (PET film) -green sheet laminated film (95 mm × 95 mm) with the display electrode formed on the surface with the green sheet surface facing down (100 mm × 100 mm × 2.8 mm) surface And thermocompression-bonded (80 ° C., 0.5 MPa) using a heating roller.
Next, the carrier film is peeled and removed, placed in a baking furnace, heated from room temperature to 400 ° C. at 10 ° C./min, maintained at 400 ° C. for 20 minutes, and further heated to 575 ° C. at 10 ° C./min. The resin of the green sheet 1 was baked under the condition of maintaining at 575 ° C. for 20 minutes to thermally decompose and obtain a dielectric layer forming substrate 1 on which a dielectric layer having a thickness of 10 μm was formed.
The presence or absence of pinhole defects in the dielectric layer on the obtained dielectric layer forming substrate 1 was observed with a microscope, and the surface roughness Ra (μm) was measured. The measurement results are shown in Table 1.

(Example 2)
In Example 1, except that the amount of the thermally decomposable binder used was changed from 160 parts by weight to 140 parts by weight (based on 100 parts by weight of the inorganic component, the solid content ratio was 70 parts by weight). A dielectric layer forming composition 2 (hereinafter referred to as “slurry 2”) of Example 2 was obtained. Further, the green sheet 2 and the dielectric layer forming substrate 2 were prepared so that the thickness of the fired dielectric layer was 10 μm.
Average particle size (μm), maximum particle size (μm) of slurry 2, sedimentation rate (%) after 4 days, 2 weeks and 4 weeks of slurry 2, laminating suitability of green sheet 2, dielectric layer forming substrate 2 Table 1 shows the presence or absence of pinhole defects in the upper dielectric layer and the surface roughness Ra (μm).

(Comparative Example 1)
In Example 1, instead of 1 part by weight of the dispersant A, 2 parts by weight of the dispersant B (1 part by weight in solid content ratio with respect to 100 parts by weight of the inorganic component) was used in the same manner as in Example 1. Thus, a dielectric layer forming composition 3 (hereinafter referred to as “slurry 3”) was obtained. Furthermore, the green sheet 3 and the dielectric layer forming substrate 3 were prepared so that the thickness of the fired dielectric layer was 10 μm.
Average particle diameter (μm), maximum particle diameter (μm) of slurry 3, sedimentation rate (%) after 4 days, 2 weeks and 4 weeks of slurry 3, laminating suitability of green sheet 3, dielectric layer forming substrate 3 Table 1 shows the presence or absence of pinhole defects in the upper dielectric layer and the surface roughness Ra (μm).

(Comparative Example 2)
In Example 1, in place of 1 part by weight of the dispersant A, 3.3 parts by weight of the dispersant C (1 part by weight in solid content ratio with respect to 100 parts by weight of the inorganic component) was used. Thus, a dielectric layer forming composition 4 (hereinafter referred to as “slurry 4”) was obtained. Further, the green sheet 4 and the dielectric layer forming substrate 4 were produced so that the thickness of the fired dielectric layer was 10 μm. Average particle size (μm), maximum particle size (μm) of slurry 4, sedimentation rate (%) after 4 days, 2 weeks and 4 weeks of slurry 4, suitability for lamination of green sheet 4, dielectric layer forming substrate 4 Table 1 shows the presence or absence of pinhole defects in the upper dielectric layer and the surface roughness Ra (μm).

(Comparative Example 3)
In Example 1, instead of using 160 parts by weight (solid content ratio; 80 parts by weight) of the thermally decomposable binder, 100 parts by weight (solid content ratio; 50 parts by weight) was used, and the dielectric was conducted in the same manner as in Example 1. A body layer forming composition 5 (hereinafter referred to as “slurry 5”) was obtained. Furthermore, the green sheet 5 and the dielectric layer forming substrate 5 were produced so that the thickness of the fired dielectric layer was 10 μm.
Average particle size (μm), maximum particle size (μm) of slurry 5, settling rate (%) after 4 days, 2 weeks and 4 weeks of slurry 5, suitability for lamination of green sheet 5, dielectric layer forming substrate 5 Table 1 shows the presence or absence of pinhole defects in the upper dielectric layer and the surface roughness Ra (μm).

(Comparative Example 4)
In Example 1, instead of using 160 parts by weight (solid content ratio; 80 parts by weight) of the thermally decomposable binder, 220 parts by weight (solid content ratio; 110 parts by weight) was used in the same manner as in Example 1 to obtain a dielectric. A layer forming composition 6 (hereinafter referred to as “slurry 6”) was obtained. Further, the green sheet 6 and the dielectric layer forming substrate 6 were prepared so that the thickness of the fired dielectric layer was 10 μm.
Average particle diameter (μm), maximum particle diameter (μm) of slurry 6, settling rate (%) after 4 days, 2 weeks and 4 weeks of slurry 6, suitability for lamination of green sheet 6, dielectric layer forming substrate 6 Table 1 shows the presence or absence of pinhole defects in the upper dielectric layer and the surface roughness Ra (μm).

  From Table 1, the dielectric layer forming compositions (slurries) 1 and 2 of Examples 1 and 2 have stable dispersibility over a long period of time (excellent storage stability), and the green obtained from this composition It can be seen that the sheets 1 and 2 have excellent laminating properties and can be formed by firing to form a uniform dielectric layer having a small surface roughness Ra and no pinhole defects.

  On the other hand, the dielectric layer forming compositions (slurries) 3 and 4 of Comparative Examples 1 and 2 obtained by using dispersants B and C other than the polycarboxylic acid polymer compound are inferior in storage stability. The dielectric layer obtained by coating and firing had a pinhole defect, and the surface roughness Ra was inferior.

  The dielectric layer forming composition (slurry) 5 of Comparative Example 3 using a thermally decomposable binder having a solid content ratio of 55 parts by weight or less with respect to 100 parts by weight of the inorganic component is Compared with storage stability, it was inferior. Moreover, the green sheet 5 obtained from this composition was inferior in laminating suitability, the dielectric layer obtained by firing had a pinhole defect, and the surface roughness Ra was inferior.

  Further, in Comparative Example 4 using a thermally decomposable binder having a solid content ratio of 105 parts by weight or more with respect to 100 parts by weight of the inorganic component, pinhole defects were observed in the obtained dielectric layer forming substrate 6.

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 ... Display electrode, 4 ... Address 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 part, 16 ... Coating part, 17a ... Composition for forming a dielectric layer 17 ... Green sheet, 18 ... Drying device, 19 ... Protective film, 20a, 20b ... Laminated roll, 21 ... Laminated film

Claims (9)

  A dielectric layer forming composition containing an inorganic component, a thermally decomposable binder, a dispersant and a solvent, wherein the inorganic component does not contain lead, and the dispersant is a polycarboxylic acid polymer compound And the content of the thermally decomposable binder is 55 to 105 parts by weight with respect to 100 parts by weight of the inorganic component as a solid content ratio.   2. The dielectric layer forming composition according to claim 1, wherein the content of the dispersant is 0.01 to 5 parts by weight with respect to 100 parts by weight of the inorganic component in solid content ratio.   The polycarboxylic acid polymer compound is at least one selected from the group consisting of a partial ester of an α-olefin / maleic anhydride copolymer, an aliphatic polycarboxylic acid salt, and an aliphatic polycarboxylic acid special silicone. The composition for forming a dielectric layer according to claim 1 or 2.   The said inorganic component contains a glass component and a filler component, The composition for dielectric material layer formation in any one of Claims 1-3.   The composition for forming a dielectric layer according to any one of claims 1 to 4, which is a slurry having an average particle size of 0.5 to 4.0 µm.   The composition for forming a dielectric layer according to claim 1, which is used for forming a dielectric layer of a plasma display panel.   A green sheet obtained by forming the dielectric layer forming composition according to claim 1 into a film shape.   A dielectric layer forming substrate comprising a dielectric layer formed on the substrate using the green sheet according to claim 7.   A method for producing a dielectric layer-formed substrate, comprising: a step of bonding the green sheet according to claim 8 and a substrate; and a step of forming a dielectric layer by firing the green sheet.

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