KR20060105443A - Glass composition and glass paste composition - Google Patents

Abstract

A glass composition which is used to form a dielectric or partition wall of a plasma display panel, a fluorescent display tube, or a field emission display and which contains no harmful substances and has a low environmental load, and by using the glass composition, the warpage of the substrate can be greatly reduced. Provided is a glass paste composition.

Specifically, a glass composition having a glass transition temperature of 430 ° C. to 540 ° C. substantially free of lead (Pb) and bismuth (Bi), which is 1 to 15 mol% of SiO ₂ in terms of oxide, and B ₂ O ₃ 10 to 50 mol%, ZnO 30 to 50 mol%, alkali metal oxide: 0 to 12 mol of R ₂ O (where R represents at least one alkali metal element selected from K, Na or Li) %, And 3 to 20 mol% of BaO is provided.

Description

Glass Composition and Glass Paste Composition {GLASS COMPOSITION AND GLASS PASTE COMPOSITION}

1 is a partially broken perspective view showing a front plate and a back plate of a typical AC PDP structure;

2 is a partially broken perspective view showing the structure of the VFD;

3 is a cross-sectional view showing the structure of the FED.

Description of the main symbols in the drawings

10a front panel 10b back panel

11 transparent electrodes 12 bus electrodes

13 address electrode 14 MgO electrode

15 dielectric membrane 16 bulkhead

17 phosphor 21 windshield

22 Glass Electrode 23 Grid Electrode

24 segment electrode 25 insulation layer

26 Filament 27 Wiring

28 terminal 31a, 31b glass substrate

32 anode 33 phosphor

34 Gate Electrode 35 spacer

36 emitter electrode 37 resistive layer

38 Cathode Electrode

B Blue G Green R Red

TECHNICAL FIELD The present invention relates to glass compositions and glass paste compositions, and more particularly, to dielectrics or barrier ribs of plasma display panels, fluorescent display panels, or field emission displays. The present invention relates to a glass composition, which is used for forming and which does not contain harmful substances such as lead (Pb) and which has a low environmental load, and which can significantly reduce warpage of a substrate by using the glass composition.

Plasma display panels (hereinafter referred to as PDPs) are spotlighted as large-sized plasma displays, which have been put into practical use as large-scale TV receivers, and are rapidly spreading. Fluorescent display tubes (hereinafter referred to as VFDs) are used as display devices for letters and symbols as display devices such as automobiles, audio equipment, and measuring instruments such as digital multimeters, and field emission displays ( Hereinafter referred to as FED, is expected as a future display device in place of the brown tube.

The PDP is a pair of glass plates that face each other at minute intervals and is sealed at the bottom to obtain a discharge space having a phosphor at the bottom. The PDP is a phosphor that stimulates and emits light by ultraviolet rays generated by discharge. Can be screened. In the PDP, the glass plate on the side where the image is displayed is called the front plate and the other is the back plate. The back plate of a general AC PDP has a structure as shown in FIG.

A stripe-shaped partition wall 16 is formed on the back plate 10b, and one electrode 13 (also referred to as an address electrode) is formed on the bottom surface of the recessed portion of the partition wall 16 in parallel with the partition wall. The dielectric layer 15 is formed on the surface of the electrode to cover the electrode. The phosphor 17 which emits light when irradiated with ultraviolet rays is applied to the wall surface or the like of these partition walls 16.

On the front plate 10a, a transparent electrode 11 formed by stripe indium tin oxide (ITO) or the like and transmitting visible light and a bus electrode 12 formed of one silver or the like provided on the transparent electrode are disposed. It is. A dielectric film 15 made of glass or the like is formed to cover the electrode, and an MgO film 14 is formed by vapor deposition to cover the dielectric film. In forming a PDP having such a structure, conventional thick film technology is used for electrodes, dielectrics, or partitions formed of silver.

On the other hand, the general VFD has a vacuum container constructed from a face glass substrate 22, as shown in FIG. 2, and the electrons emitted from the filaments 26 in the vacuum container are lattice electrodes 23. As shown in FIG. By controlling the polarization to impinge on the segment electrode 24, the fluorescent substance on the segment electrode 24 is stimulated to emit light, thereby displaying characters, symbols, and the like. The segment electrode which becomes a display part is formed in the glass substrate, and the wiring 27 which transmits a signal to this electrode, and the insulator layer 25 which insulates between the wiring 27 and the segment electrode 24 are arranged.

Thick film techniques are frequently used for forming electrodes and insulators on glass substrates, and wiring to segment electrodes is often formed by thick film silver paste, and the insulator covering the dielectric is formed by thick film glass paste. The segment electrode is formed of a thick film paste containing graphite as a main component. In addition, in order to secure electrical connection between the segment electrode and the wiring, the insulating layer is printed so that a through hole is formed.

In contrast, the FED shown in FIG. 3 forms an emitter electrode 36 which emits electrons on one glass substrate 31b of a vacuum vessel composed of two opposing glass substrates 31, and emits the emitted electrons. The impinging light emission is caused by colliding with the phosphor 33 of the other glass substrate 31a.

The glass substrate 31b having the emitter electrode 36 formed thereon has a cathode electrode 38 which sends a signal to the emitter electrode 36, a resistance layer 37 covering the cathode electrode 38, and a spacer. A gate electrode 34 provided on the 35 is formed. The emitter electrode 36 is provided in each place where the spacer 35 is not provided. In addition, in order to increase the mechanical strength of the VFD vacuum vessel formed in the glass substrate, etc., although not shown in the drawings, a strut-like structure formed of a dielectric material or the like may be provided between the two glass substrates. Each component of the FED is formed using many thin film technologies, but a dielectric is formed by a thick film technique.

These PDPs, VFDs, and FEDs are fired in order to use high strain point glass (eg, PD-2000 manufactured by ASAHI GLASS CO.) Or soda lime glass as the substrate. The temperature is limited to a maximum of 600 ° C or less. Therefore, a dense baked film cannot be obtained unless the softening point of glass is below this temperature. Conventional glass realizes this softening point by containing lead (Pb) and bismuth (Bi) which are harmful substances. Patent documents 1 and 2 disclose glass containing lead, and patent document 3 discloses glass containing bismuth.

These harmful substances contained in the glass are released to the global environment as waste not only when the display device is disposed, but also when the display device is manufactured, causing environmental problems such as pollution of soil, ground water, rivers, and pollution.

About such a problem, although the glass containing phosphorus (P) is disclosed by patent documents 4 and 5, phosphorus containing glass has a problem in water resistance, and is not practical. B-Si-Zn type glass composition is disclosed by patent document 3 and patent documents 6-10. Although the deformation | transformation of the board | substrate by baking temperature is disclosed in this in patent document 10, in these documents, no consideration was given about the curvature of the board | substrate by baking of a glass composition.

If conventional glass containing lead is used, the dielectric of the obtained thick film glass paste will not bend the substrate by firing. However, if glass containing no lead is used, the resulting dielectric of the thick film glass paste may be largely warped when fired. In particular, in a dielectric having a glass film formed on one surface of the substrate, warpage of the substrate becomes remarkable. If the substrate is warped, the device cannot be sealed in the sealing process, in particular, the vacuum container cannot be obtained, and as a result, a defect in which the device cannot be obtained or defects in terms of ensuring accuracy can occur.

Under such circumstances, even if a thick film glass paste dielectric is produced using glass that does not contain harmful substances such as lead or bismuth, there is a demand for a glass composition capable of assembling a device having a high accuracy without causing a large bending of the substrate in the firing process. It is becoming.

[Patent Document 1] Japanese Patent Laid-Open No. 8-119725

[Patent Document 2] Japanese Patent Laid-Open No. 11-60273

[Patent Document 3] Japanese Patent Laid-Open No. 9-283035

[Patent Document 4] Japanese Patent Laid-Open No. 8-301631

[Patent Document 5] JP 2000-128567

[Patent Document 6] Japanese Patent Laid-Open No. 9-278482

[Patent Document 7] JP 2000-226231

[Patent Document 8] Japanese Patent Laid-Open No. 2000-226232

[Patent Document 9] Japanese Patent Laid-Open No. 2000-313635

[Patent Document 10] JP 2000-327370

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a dielectric composition or partition wall of a plasma display panel, a fluorescent display tube, or a field emission display, and a glass composition containing no harmful substances and having a low environmental load. The present invention provides a glass paste composition capable of significantly reducing warpage of a substrate by using a glass composition.

MEANS TO SOLVE THE PROBLEM As a result of extensive research in order to solve the said subject, the present inventors selected glass which does not contain lead and bismuth, optimizes the kind and compounding quantity of various components containing alkali metal oxide, and specifies the glass transition temperature. By setting it as the range, when an inorganic oxide and a vehicle were mix | blended with this glass, it discovered that the glass composition which does not bend a board | substrate in the process of baking a PDP board | substrate etc. was obtained, and completed this invention.

That is, according to the first invention of the present invention, a glass composition having a glass transition temperature of 430 ° C. to 540 ° C. substantially free of lead (Pb) and bismuth (Bi), which is converted into an oxide, contains SiO ₂ from 1 to 1. 15 mol%, B ₂ O ₃ 10 to 50 mol%, ZnO 30 to 50 mole%, an oxide of an alkali metal: R ₂ O (wherein, R is, K, alkali of at least one member selected from Na or Li It provides a glass composition, characterized in that it contains 0 to 12 mol%, and 3 to 20 mol% BaO.

Moreover, according to the 2nd invention of this invention, 1-35 mol% of either CaO or SrO is further converted into oxide in the 1st invention, The glass composition provided is characterized by the above-mentioned.

Moreover, according to the 3rd invention of this invention, in 1st or 2nd invention, the thermal expansion coefficient is 70-81x10 <^-7> / degreeC, The glass composition is provided.

Further, according to the fourth invention of the present invention, in any one of the first to third inventions, at least one paper inorganic selected from alumina, silica, forsterite, zirconia, zircon, titania, or heat-resistant inorganic pigment A glass composition is provided, which contains 5 to 20% by weight of the oxide powder with respect to the total amount of the composition.

On the other hand, according to the 5th invention of this invention, the glass paste composition which mix | blended resin and a solvent with the glass composition in any one of 1st-4th invention is provided.

The glass composition of the present invention does not contain harmful substances such as lead or bismuth, contains a small amount of alkali metal oxide and has a specific glass transition temperature. Thus, when used as a raw material of the glass paste composition, the glass substrate for display panel can be used. When baking at predetermined temperature, the curvature of a board | substrate can be suppressed and the value of the same grade as the glass composition containing lead and bismuth is possible. Therefore, it is very useful as a material for forming dielectrics, partition walls, etc. constituting PDP, VFD, FED and the like, and has high industrial value.

Hereinafter, the glass composition and glass paste composition of this invention are demonstrated in detail.

One. Glass composition

The glass composition of the present invention, that is substantially free of Pb and Bi, and a glass transition glass composition temperature of 430 ℃ ~ 540 ℃, in terms of oxide, 1 to 15 mol% of SiO _2, the B ₂ O ₃ 10 to 50 mol%, ZnO to 30 to 50 mol%, alkali metal oxide: R ₂ O (wherein R represents at least one alkali metal element selected from K, Na or Li) 0 to 12 It is characterized by containing 3-20 mol% of mol% and BaO.

Of glass SiO ₂ is an essential component of a component that forms the network of the glass. The content in the glass is 1 to 15 mol% in terms of oxide, and when the content is less than 1 mol%, the water resistance and chemical resistance of the glass are inferior, and when the content exceeds 15 mol%, an alkali metal oxide R described later to obtain a desired softening point. ₂ O component increases, and curvature generate | occur | produces in the board | substrate after baking. Preferable content is 3-13 mol%.

B ₂ O ₃ in the glass is an essential component, which lowers the softening point, increases fluidity and stabilizes the glass. The content in the glass is 10 to 50 mol% in terms of oxide. If the content is 10 mol% or less, the softening point is not high and the desired dimension cannot be realized. If the content exceeds 50 mol%, the softening point cannot be lowered. Not to be realized, of course, results in poor water resistance and chemical resistance of the glass. More preferable content is 45 mol% or less.

ZnO in glass is an essential component and is a component that lowers the softening point and appropriately adjusts the coefficient of thermal expansion. Content in glass is 30-50 mol%. If content in glass is less than 30 mol%, a desired softening point cannot be implement | achieved, and if it exceeds 50 mol%, vitrification is difficult. More preferable content is 30 to 45 mol%.

Alkali metal oxide R ₂ O is an essential component of glass, which is at least one of K ₂ O, Na ₂ O, or Li ₂ O. These are components which lower the softening point and raise the coefficient of thermal expansion.

The R ₂ O content in the glass is 0 to 12 mol% in terms of oxide. When this content exceeds 12 mol%, the board | substrate after baking will be largely bent.

Generally, when the thermal expansion of a glass composition is larger than the thermal expansion of a board | substrate, when a glass composition is apply | coated to a board | substrate and it bakes, it is known that a board | substrate bends. This is because the glass composition on the substrate shrinks as the temperature is lowered in the process of lowering the temperature from heating at the time of firing. That is, the substrate also shrinks naturally, but shrinks in proportion to the coefficient of thermal expansion. Therefore, if the shrinkage of the glass composition is greater than that of the substrate (if the coefficient of thermal expansion of the glass composition is larger than that of the substrate), the glass composition of the substrate is glass. It will shrink more than the free side.

That is, the substrate is bent due to the difference in shrinkage caused by the surface of the substrate. On the contrary, if the shrinkage of the substrate is greater than the shrinkage of the glass composition, the glass composition is compressed by the substrate and the substrate is not bent, but warpage occurs in the substrate even when the thermal expansion of the glass composition is smaller than the thermal expansion of the substrate. have.

The present applicant has confirmed that the composition of glass greatly influences the warpage phenomenon of the substrate. The warpage of the substrate after firing for glass containing a temperature of 500 ° C. and containing no more than 12 mol% of R ₂ O containing no lead and glass containing only less than 12 mol% of R ₂ O. When irradiated, the glass containing much R ₂ O is larger. In addition, R ₂ O in addition to SiO _2, it can be seen that due to the composition balance (valance) with ZnO. This is because glass containing a large amount of R ₂ O agglomerates and sinters the glass powders at temperatures near the softening point to form a glass film. On the other hand, glass with less R ₂ O obtains fluidity at temperatures above the softening point, and the adjacent glass This is because excessive shrinkage does not occur by melting with particles to form a glass film.

The glass which does not contain lead has the characteristic that it contains many R <_2> O compared with the glass containing lead of the same softening point in order to become a desired softening point. It is for this reason that the board | substrate using glass which does not contain lead may be bent, although the glass containing lead does not bend after baking.

R ₂ O conducts as R ⁺ ions in glass and adversely affects electrical insulation. From this point of view, the R ₂ O content is regulated.

In addition, BaO, an oxide of an alkali metal, has an effect of lowering the softening point of glass and may be added up to 35 mol%. BaO has the effect | action which raises a coefficient of thermal expansion, and from such a viewpoint, said addition amount is preferable. Content in glass is 10-20 mol% in conversion to oxide.

CaO and SrO can be added suitably to the glass composition of this invention. Although CaO and SrO are not an essential component in glass, it is effective in stabilizing glass by containing them. However, these have the effect of raising the coefficient of thermal expansion, and when included excessively, the coefficient of thermal expansion becomes large, which is inappropriate to use soda-lime glass or the like as a substrate. The CaO and SrO content in the glass is preferably 35 mol% or less in terms of oxide. In particular, the content of CaO is preferably 1 to 5 mol% in terms of oxide.

In addition, ZrO ₂ can be appropriately added to the glass composition of the present invention. ZrO ₂ is not an essential component of glass, but has an effect of improving water resistance and chemical resistance. However, when content in glass becomes 15 mol% or more in conversion of oxide, the softening point of glass will be raised and a desired value cannot be implement | achieved.

Al ₂ O ₃ is not an essential component of glass, but has an effect of improving water resistance and chemical resistance. However, when content in glass becomes 15 mol% or more in conversion of oxide, a softening point becomes high and a desired value cannot be implement | achieved.

The glass transition temperature of the glass composition of this invention must be 430-540 degreeC. The glass transition temperature can be measured by TG-DTA or TMA. Preferred glass transition temperatures range from 480 ° C to 510 ° C. Generally, it is possible to obtain stable glass at a desired softening point. However, since warpage of the substrate occurs due to the mixing relationship with SiO ₂ or alkali metal oxide, the composition so that the glass transition temperature of the glass composition falls within this range. It is important to

As mentioned above, PDP, VFD, and FED need to bake the glass paste composition apply | coated on a glass substrate at the temperature of 600 degrees C or less. For that purpose, it is necessary to suppress the softening point of a glass composition to 600 degrees C or less. The glass transition temperature of the glass composition with a softening point of 600 degreeC is 540 degreeC.

On the other hand, these display devices adhere | attach and seal two glass substrates etc., and form a vacuum container. The glass transition temperature is closely related to the heating conditions of the sealing process of the display device. The sealing process is carried out by softening and firing the sealing material at 430 ° C. However, when the glass transition temperature of the glass composition of the present invention is lower than this temperature, the partition walls and the dielectric formed by the sealing process are softened to ensure the dimensional accuracy of the display device. It becomes impossible to do it. Therefore, by making the sealing temperature 430 degrees C or less, the glass transition temperature of a glass composition can also be lowered with it.

Powder particle size of the glass composition is less than 10 ㎛ preferably from D _50, and more preferably not more than 5 ㎛. If the particle size is larger than 10 mu m, it is impossible to obtain dense partitions and dielectrics. In order to obtain a powder having a desired particle size, it can be pulverized using a known means such as a ball mill, a jet mill, or the like.

To prepare a glass composition, a single glass composition may be used, or a plurality of glass compositions may be prepared and mixed. The glass composition which has the warpage shape of a board | substrate and is not practical also can improve the warpage of a board | substrate by mixing the glass composition of this invention.

In order to form partitions and dielectrics, such as a PDP, an inorganic oxide can be mixed and used for the glass composition of this invention. Examples of the inorganic oxides include alumina, silica, forsterite, zirconia, zircon, titania, and heat-resistant inorganic pigments. At least one inorganic oxide selected from these may be added to the glass composition. Transparency may be impaired by adding an inorganic oxide, but an inorganic oxide can be added to the transparent dielectric of PDP in the range which can ensure the transmittance | permeability of a glass film, and, thereby, the mechanical strength of a glass film can be improved.

As a heat resistant inorganic pigment, Fe-Co-Cr complex oxide, Cu-Cr-Mn complex oxide, Cu-Cr-Fe complex oxide, Ni-Mn-Fe-Co complex oxide, Fe-Mn complex oxide, Fe-Cu- The black pigment of Mn type complex oxide, the green pigment of Cr oxide, etc. can be used.

The particle size D ₅₀ of the inorganic oxide is preferably 10 μm or less, more preferably 5 μm or less. If it is larger than this, it is impossible to obtain dense partitions and dielectrics.

The coefficient of thermal expansion of the glass ceramic material is determined by the glass composition and the inorganic oxide, and can be adjusted by changing the combination thereof. The coefficient of thermal expansion is preferably in the range of 50 to 87 × 10 ⁻⁷ / ° C. The thermal expansion coefficient of substrates, such as soda-lime glass, is 83-87x10 <^-7> / degreeC, and when it becomes a value below this, it will cause the device to bend when baking.

The thermal expansion coefficient of silica is 140x10 <^-7> / degreeC, and the thermal expansion coefficient of fosterite is 95x10 <^-7> / degreeC, By combining these in a glass composition, the effect of raising a thermal expansion coefficient is acquired. It is known that silica (quartz) has a phase potential, and when the phase potential is cristobalite or the like, the coefficient of thermal expansion changes rapidly. Cracks may occur in the barrier ribs or the dielectric due to the change in the coefficient of thermal expansion. Quartz glass powder can be used to prevent such a situation. The quartz glass has a coefficient of thermal expansion of 55 × 10 ⁻⁷ / ° C., and by blending it in the glass composition, the effect of lowering the coefficient of thermal expansion is obtained.

Although one type of inorganic oxide may be selected, it is not limited to it, It can also combine multiple types. TiO ₂ can be added to make the barrier or dielectric white. It is also effective to add TiO ₂ to increase the dielectric constant.

Although content of an inorganic oxide differs also according to a use, although less is preferable than glass, it is 5 to 20 weight%. In the case of PDP, when the content is less than 5% by weight, a dense dielectric film can be formed, but the white PDP partition wall or dielectric cannot be realized. Moreover, when using this as a PDP partition material, the function as an aggregate is too weak, and a problem arises that a PDP partition melts and collapses after baking. On the other hand, if it exceeds 20% by weight, there is a problem that a dense dielectric material cannot be realized.

2. Glass paste composition

The glass paste composition of this invention mix | blends resin and a solvent as an essential component to the said glass composition, and can add an appropriate inorganic oxide, a dispersing agent, etc.

The resin according to the present invention is a component that retains the viscosity of the paint, maintains the shape after application and drying, and improves chemical resistance of the dried film. The resin must be decomposed or burned in the firing process and removed completely below the softening point of the glass composition. This is because a resin that burns at a temperature above the softening point is trapped in the softened glass film to generate a large number of voids and the like.

As preferable resin from this viewpoint, ethyl cellulose, an acryl, a polyvinyl phthalate, and methyl styrene are mentioned. Acryl also includes methacryl resin. These resins may be used independently and may mix multiple types.

Although the compounding quantity of resin in a glass paste composition depends also on the use, it is made into 0.5 to 10 weight% with respect to 100 weight% of inorganic components. An inorganic component is comprised from a glass composition and the inorganic oxide added as needed here. When the amount of the resin is less than 0.5% by weight, the glass ceramic composition powder in the paste is precipitated, which degrades the shelf life of the paste. Moreover, when there are more resins than 10 weight%, a viscosity will become high and a viscosity suitable for application | coating cannot be made unless a large amount of solvent is added.

In addition, when the formation of the PDP barrier ribs is carried out by a sand blast method, a mask is masked with a resist where it is desired to be left, and the resist developing step is generally performed in an aqueous alkali solution such as Na ₂ CO ₃ . . At this time, when there are few resins, the problem of peeling a dry film at the time of image development in aqueous alkali solution arises, On the contrary, when there are many resins, the grinding speed of a sandblast will become slow.

Solvent is an indispensable component to improve the flowability of the paste. In addition, it must not only be able to dissolve the resin, but also must be volatilized in the drying process. However, if a solvent which does not focus on volatility but has a boiling point of less than 150 ° C. is used, the paste dries in the coating step, causing deterioration of workability.

It is preferable that the boiling point of a solvent is 150 degreeC or more from such a viewpoint, and terpinol, dihydro terpinol, butylcarbitolacetate, and butyl carbitol ( butyl carbitol), 2,2,4-trimethyl-1,3-pentanediol monobutyrate (2,2,4-trimethyl-1,3-pentadiol monobutyrate) and the like are selected.

Although the compounding quantity of a solvent varies with the kind, it shall be 20 to 45 weight% with respect to 100 weight% of inorganic components. If the blending amount is less than 20% by weight, it is difficult to form a paste, and if it exceeds 45% by weight, the film shrinkage during drying becomes large and cracks are likely to occur in the dry film. In addition, when the solvent is large, not only the energy consumption at the time of drying is high, but also the shrinkage at the time of drying is increased, and the drying temperature is deflected, which may cause cracks in the dry film.

The additive known in thick film glass pastes, such as an antifoamer, a dispersing agent, and a plasticizer, can be added to the glass paste composition of this invention.

( Example )

Although the Example and comparative example of this invention are shown below, this invention is not limited at all by these Examples.

(Evaluation of the warpage of the board)

The curvature of the board | substrate which arises after application | coating to a glass substrate and baking was evaluated by the following method. In order to make it easier to detect the warpage of the substrate after firing, the glass paste was screen printed on one side of a soda-lime glass substrate having a thickness of 0.5 mm in a 50 mm × 50 mm square, and then dried at 120 ° C. × 5 minutes, and peak conditions 580 The board | substrate for evaluation was obtained by baking in the belt type kiln of (degreeC) * 5 minutes, and printing the glass film of 20 micrometers of fired film thicknesses. The surface where the glass paste of this board | substrate was not printed was traced by 40 mm with the surface roughness meter (made by TOKYO SEIMITSU CO., Surfcom E-MD-S39A type), and the curvature of the glass substrate was confirmed. Moreover, the thermal expansion coefficient of a board | substrate is 86x10 <^-7> / ^degreeC .

As for the curvature of the board | substrate, what curved the concave side of the glass paste was made to "bend forward", and the opposite (when the paste is applied convexly curved) was made to "bend back". The obtained result was represented by absolute value. If the curvature of a board | substrate exists in the range of 0-50 micrometers, there is no problem in actual use.

(Examples 1 to 4)

The glass did not contain Pb and Bi, and the composition shown in Table 1 was used so that 0-12 mol% of alkali metal oxides might be contained. This glass composition was melted and quenched at 1300 ° C. and ground in a ball mill. The particle size of the obtained glass powder was measured by microtrack, and the glass transition temperature and softening point were measured by TG-DTA (type TG / DTA320 manufactured by SEIKO ELECTRONIC CORP.). The particle diameter, glass transition temperature, and softening point of the obtained glass powder are shown in Table 1. In addition, content of each component of Table 1 is mol% conversion equivalent.

The glass powder was press-molded into a rod shape and fired at 580 ° C for 30 minutes to obtain a sample having a diameter of 4 mm and a length of 10 mm. The thermal expansion coefficient of this sample was measured by TMA (Type TMA320 by SEIKO ELECTRONIC CORP.).

To 90% by weight of the glass powder, 10% by weight of the Cu-Cr-Mn composite oxide powder was blended, and then 40% by weight of the vehicle was added to 100% by weight of the mixture of the glass powder and the Cu-Cr-Mn composite oxide powder and the roll mill ( roll mill) to obtain a glass paste composition. The vehicle was mixed with 10% by weight of ethyl cellulose (molecular weight: 80,000) and 90% by weight of terpinol with a solvent, and heated at 60 ° C to obtain a vehicle. Next, the curvature of the board | substrate was evaluated based on said method using this glass paste composition.

(Comparative Examples 1 to 3)

As glass, the glass composition shown in Table 1 was prepared like Example except having contained Pb or using content exceeding 12 mol% of alkali metal oxide. The glass transition temperature, softening point, thermal expansion coefficient, and particle size were measured. Next, the curvature of the board | substrate was evaluated by the method similar to an Example.

[evaluation]

The coefficient of thermal expansion of each glass composition produced by the said Example and the comparative example is a value smaller than that of a board | substrate. However, the curvature of a board | substrate is large and the glass compositions of Comparative Examples 1 and 2 exceed the practical level. On the other hand, in the glass composition of Examples 1-4, the curvature of a board | substrate exists in the range of practical level, and is about the same as the glass containing the conventional lead shown by the comparative example 3. From this, it turns out that the glass composition of this invention is useful as a material for display devices, such as PDP.

Since the glass composition of this invention does not contain harmful substances, such as lead and bismuth, contains a small amount of alkali metal oxide and has a specific glass transition temperature, when using this as a raw material of a glass paste composition, it is a glass substrate for display panels When baking at the predetermined temperature, the curvature of a board | substrate can be suppressed and the value of the same grade as the glass composition containing lead and bismuth is possible. Therefore, it is very useful as a material for forming dielectrics, partition walls, etc. constituting PDP, VFD, FED and the like, and has high industrial value.

Claims (5)

A glass composition having a glass transition temperature of 430 ° C. to 540 ° C. that is substantially free of lead (Pb) and bismuth (Bi), which is converted into an oxide to contain 1 to 15 mol% of SiO ₂ and 10 to 10 of B ₂ O ₃ . 50 mol%, 30 to 50 mol% of ZnO, an oxide of alkali metal: R ₂ O (wherein, R is, K, represents at least the alkali metal element of one member selected from Na, or Li) from 0 to 12 mol% , And BaO at 3 to 20 mol%. The glass composition according to claim 1, which further contains 1 to 35 mol% of CaO or SrO in terms of oxide. The glass composition according to claim 1 or 2, wherein the coefficient of thermal expansion is 70 to 81 × 10 ⁻⁷ / ° C. ⁴ . The method according to any one of claims 1 to 3, wherein at least one species of inorganic oxide powder selected from alumina, silica, forsterite, zirconia, zircon, titania, or heat-resistant inorganic pigments is based on the total amount of the composition. A glass composition comprising 5 to 20% by weight. The glass paste composition which mix | blended resin and a solvent with the glass composition of any one of Claims 1-4.

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