KR101417009B1 - Lead-free borosilicate glass frit and its glass paste for forming an insulating layer - Google Patents

Abstract

An object of the present invention is to provide a glass frit for forming an insulating layer containing no PbO in a glass composition forming an insulating layer.

As a means for achieving the above _{object, SiO 2, Al 2 O 3} , B 2 O 3, Li 2 O + Na 2 O + K 2 O, MgO + CaO + SrO + BaO, ZnO, CuO, SnO 2, CeO ₂ and Gd ₂ O ₃ as a base composition, at least one inorganic oxide of Al ₂ O ₃ , SiO ₂ , ZrO, and ZnO is contained in the lead-free borosilicate glass frit and coated as a glass paste , The insulating layer formed by firing is hardly yellowed to white.

Lead-free borosilicate glass, glass paste, inorganic oxide

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lead-free borosilicate glass frit for forming an insulating layer,

The present invention relates to a lead-free borosilicate glass frit and a glass paste thereof for forming an insulating layer which is hardly yellowed (that is, sulfur-changed) into white by firing, and more particularly relates to a lead- The present invention relates to a lead-free borosilicate glass frit and a glass paste thereof for forming an insulating layer which is difficult to be formed on a silver electrode by firing, and to a silver paste formed on a silver electrode formed on a rear substrate of a plasma display panel or an electronic display of a planar discharge- Lead-free borosilicate glass frit and its glass paste for forming an insulating layer which is hardly yellowed by firing.

Conventionally, a low-melting point glass frit is used as an insulating layer of a plasma display panel, a fluorescent display tube or the like. Such a glass contains a lead component for lowering the melting point. In recent years, an environmental problem has been pointed out with respect to lead-containing glass, and glass which does not contain lead has been demanded in order to avoid problems such as working environment and waste treatment. In response to such a problem, a phosphate-based lead-free low melting point glass is known as a glass for sealing and coating (for example, Patent Document 1). The inventors of the present invention have proposed a glass for forming an insulating layer that does not contain PbO, which is a glass for sealing and coating such as a plasma display panel, a fluorescent display tube, and the like, For example, Patent Document 2). Further, it is known that the dielectric layer formed of a dielectric paste containing a low-melting glass and an oxidizing agent is prevented from yellowing to improve the luminous efficiency (for example, Patent Document 3).

[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-180972

[Patent Document 2] Japanese Patent Application No. 2005-94574

[Patent Document 3] Japanese Unexamined Patent Publication No. 2002-25341.

The present inventors have proposed a glass frit for forming an insulating layer used for covering a plasma display panel, a fluorescent display tube and the like, and a glass paste thereof without the problem of environmental pollution because Pb is not contained (Patent Document 2). The glass frit that does not contain Pb can be fired at 590 DEG C or lower, and cracking or the like does not occur in the insulating layer (acting as a dielectric layer) after firing, and the insulating performance is maintained. Furthermore, by using this glass paste as a glass paste containing black inorganic pigment, inorganic oxide, organic binder and organic solvent in the lead-free borosilicate glass frit and forming an insulating layer such as a black stripe or a fluorescent display tube of a plasma display panel, And has an effect of exerting a contrast in image display.

The paste of the glass frit for forming an insulating layer which does not contain PbO proposed in Patent Document 2 exerts excellent effects when used for forming an insulating layer such as a black stripe or a fluorescent display tube. When the insulating layer is formed by the paste, silver in the silver electrode is ionized and diffused into the white insulating layer, and the white insulating layer is yellowed. For example, there has been a problem in that the insulating layer required for a display panel such as an insulating layer of a rear substrate of a plasma display panel is white, opaque, and hardly changed in yellow.

Although it is known that the yellowing of the dielectric layer is prevented and the luminous efficiency is improved, the present invention has been disclosed in Patent Document 3. However, the present invention does not include lead so that there is no problem in working environment and waste treatment, Free borosilicate glass frit and a glass paste thereof for forming an insulating layer having a property of being opaque and also hardly changeable by sintering by firing.

The present invention (claim 1) is a glass composition in which the glass composition has a molar conversion percentage,

16 to 30 mol% of SiO ₂ ,

1 to 8 mol% of Al ₂ O ₃ ,

B ₂ O ₃ : 20 to 32 mol%

At least Li ₂ O in 0.1 mol% or more of Li ₂ O + Na ₂ O + K ₂ O, and the total of two or more species is 8 to 14 mol%

MgO + CaO + SrO + BaO, the total amount of which is 1 to 10 mol%

22 to 35 mol% of ZnO,

0.005 to 0.1 mol% of CuO,

SnO ₂ : 0.01 to 1 mol%

0.01 to 1 mol% of CeO ₂ and

Gd ₂ O ₃ : 0.1 to 2.0 mol%

Which is a lead-free borosilicate glass,

Wherein the glass having the above composition is a glass frit having an average particle size of 1 to 5 占 퐉 and a maximum particle size of less than 20 占 퐉 and having a glass transition point of 500 占 폚 or less and an average linear expansion coefficient of 65 to 80 占^10-7 / The frit is excellent in water resistance and has a performance of 0.1 mg / cm 2 or less as a water loss value under the condition that the performance is exposed to pure water at 80 ° C for 24 hours. The glass frit and Al ₂ O ₃ , SiO ₂ , ZrO and ZnO Wherein the insulating layer formed by applying and firing a glass paste containing at least one inorganic oxide on a silver electrode is hardly yellowed to white. The present invention relates to a lead-free borosilicate glass frit for forming an insulating layer by firing.

The present invention (claim 2) is characterized in that the lead-free borosilicate glass frit described in the above (claim 1), at least one inorganic oxide of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO as inorganic fillers , And a glass paste, which is a glass paste, and the insulating layer formed by applying and firing the glass paste onto a silver electrode is hardly yellowed to white, and a paste of a lead-free borosilicate glass frit to be.

In addition, the present invention (Claim 3) is characterized in that 100 parts by weight of the lead-free borosilicate glass frit described in the above (Claim 1), at least one of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO which are inorganic fillers 1 to 10 parts by weight of an inorganic oxide, 30 to 100 parts by weight of a vehicle containing ethyl cellulose or an acrylic resin and an organic solvent, and the insulating layer formed by applying the glass paste on the silver electrode and firing is white Lead-free borosilicate glass frit paste for forming an insulating layer by firing.

In the present invention (claim 4), the white light-emitting layer formed by applying the paste of the lead-free borosilicate glass frit onto the silver electrode and firing is used as lightness, red, * In the colorimetric display, the L * value is 85 or more, the a * value is -2 to 2, the b * value is 0 to 13, and the insulating layer is hardly yellowed to white Free bismuth-borate glass frit paste for forming the insulating layer according to claim 2 or claim 3 by firing.

The present invention (claim 5) is characterized in that the insulating layer formed by firing the paste of the glass frit is formed on a silver electrode formed on the rear glass substrate of the plasma display panel. 4] is a paste of a lead-free borosilicate glass frit for firing an insulating layer according to any one of [1] to [4].

In the present invention (claim 6), it is preferable that the insulating layer formed by firing the paste of the glass frit is formed on the silver electrode of the electronic display of the planar discharge light emission method Is a paste of a lead-free borosilicate glass frit for forming an insulating layer according to any one of < 1 >

The lead-free borosilicate glass frit and its glass paste for forming the insulating layer of the present invention do not contain lead as a component of the glass, so there is no problem of environmental pollution caused by lead. In addition, the lead-free borosilicate glass frit of the present invention has a glass composition of 16 to 30 mol% SiO ₂ , 1 to 8 mol% of Al ₂ O ₃ , 20 to 32 mol% of B ₂ O _3, , contains Li ₂ O + Na ₂ O + K ₂ O of at least Li ₂ O 0.1 containing more than mole% and the sum of two or more from 8 to 14 mol%, MgO + CaO + SrO + BaO of at least one of , SnO ₂ : 0.01 to 1 mol%, CeO ₂ : 0.01 to 1 mol%, and Gd ₂ O _{3 in a} total amount of 1 to 10 mol%, ZnO: 22 to 35 mol%, CuO: 0.005 to 0.1 mol% : 0.1 to 2.0 mol% based on the total weight of the lead-free borosilicate glass. This lead-free borosilicate glass has no problem of environmental pollution because it does not contain lead and has a glass transition temperature of 500 캜 or lower, the coefficient of 65 to 80 × 10 ^-7 / ℃, when exposed for 24 hours in water resistance is 80 ℃ pure, that the domestic loss value with the performance of more than 0.1 ㎎ / ㎠ will excellent water resistance after firing It does not cause cracks in the yeoncheung.

When manufacturing a plasma display panel or an electronic display of a flat discharge light emission type, an insulating layer formed by attaching a silver electrode on a substrate and applying and firing a glass paste thereon is silver ionized into a silver electrode Layer. However, the glass paste containing the lead-free borosilicate glass frit for forming the insulating layer of the present invention does not cause yellowing of the white insulating layer.

That is, in manufacturing a plasma display panel or an electronic display of a flat discharge light emission type, the insulating layer which is a dielectric layer is formed by coating and firing a glass paste. Silver used for the electrode material diffuses to yellow the insulating layer There is a thing to do. If the rear glass substrate of the plasma display panel or the insulating layer of the electronic display of the planar discharge light emission system is yellowed, the reflectance of the light is lowered, the emission rate of the display is lowered and the color displayed on the display is deteriorated There was a problem.

Particularly, in order to use an insulating layer formed by applying and firing a glass paste as a dielectric layer on the rear glass substrate side of a plasma display panel, it is possible to perform firing at 590 DEG C or lower, And is also required to be white. There is a problem in that when the image is emitted from the plasma display panel, the luminance of light emission does not rise and the address electrode is reflected, which results in poor image quality and color.

(L * a *), a red color (a *), and a yellow color (b *) of the white insulating layer are formed by a glass paste containing a lead-free borosilicate glass frit of the present invention is white. b * color system, the L * value is 85 or more, the a * value is -2 to 2, the b * value is in the range of 0 to 13, and no yellowing is caused. And the plasma display panel or the flat panel discharge light emitting type electronic display can obtain a sufficient reflectance and a high emission ratio and a good color. Further, since the white insulating layer does not yellow, the plasma display panel or the flat discharge light emission The electronic display of the present invention does not lower the reflectance of the light and does not lower the light emission rate and does not deteriorate the color. Insulating layer is formed on a rear glass substrate of a plasma display panel is superior as being formed on the electrode. In addition, the electronic display of the planar light-emitting discharge method is superior as being formed on the electrode.

The present invention relates to a lead-free borosilicate glass frit for forming an insulating layer, and at least one or more inorganic oxides, such as Al ₂ O ₃ , SiO ₂ , ZrO and ZnO, inorganic fillers such as ethylcellulose or acrylic resin And a vehicle containing an organic solvent, and the insulating layer formed by applying and firing the glass paste is hardly yellowed to white.

The glass paste containing the lead-free borosilicate glass frit of the present invention is applied to a substrate such as a rear substrate of a plasma display panel, an electronic display of a planar discharge light emission type, and the like to form an insulating layer. Background Art Soda lime glass is generally used as a back substrate of a plasma display panel and a substrate of an electronic display of a flat discharge light emission type. Therefore, the borosilicate glass frit according to the present invention assumes that firing is performed on soda-lime glass which is a plate glass as a substrate, and the glass plate has a softening temperature of 730 to 740 ° C, a strain point of 495 to 505 ° C, a thermal expansion coefficient 87 to 91 x 10 < ^-7 > / [deg.] C, the glass frit can be baked at a temperature of 590 [deg.] C or lower and the difference in coefficient of linear expansion between the glass and the substrate is made small, So that cracks do not occur in the insulating layer formed by firing when applied and baked as a glass paste. It is also possible to perform firing at a temperature of 590 DEG C or less even in a high-point aluminum silicate glass having a softening temperature of about 870 DEG C and a melting point of about 570 DEG C, which is used for a substrate, I do not want to do anything.

First, the glass composition of the lead-free borosilicate glass frit of the present invention will be described.

SiO ₂ is a network former, which is effective in stabilizing glass. When the content is less than 16 mol%, the effect of stabilizing glass is not sufficient. When the content is more than 30 mol%, the softening point becomes excessively high. Therefore, the content of SiO ₂ is 16 to 30 mol%, preferably 17 to 25 mol%.

Al ₂ O ₃ is effective for stabilizing glass and has an effect of increasing chemical durability. When the content is less than 1 mol%, the effect is not sufficient, the adhesion with the glass substrate is poor, and the water resistance is also poor. On the other hand, if it exceeds 8 mol%, the softening temperature rises and it becomes difficult to fuse at 590 캜 or lower. Therefore, the content of Al ₂ O ₃ is preferably 1 to 8 mol%, and the content of Al ₂ O ₃ is preferably more than 4.0 to 7.5 mol%, because the content of Al ₂ O ₃ is more than 1/4 of the content of SiO ₂ , to be.

B ₂ O ₃ has the effect of stabilizing the glass and increasing the flowability. When the content is less than 20 mol%, the effect is not sufficient and the coefficient of linear expansion is increased. If it exceeds 32 mol%, the effect on the stabilization and flowability of the glass tends to be weakened, and the water-proofing performance is lowered. Therefore, the content of B ₂ O ₃ is 20 to 32 mol%, preferably 25 to 30 mol%.

Li ₂ O, Na ₂ O and K ₂ O contain at least 0.1 mol% of Li ₂ O among these, and the total of two or more species is 8 to 14 mol%. This is because Li ₂ O, Na ₂ O and K ₂ O have the effect of lowering the softening temperature of the glass and also have an effect of increasing the fluidity. In the present invention, Li ₂ O is contained in an amount of 0.1 mol% or more. If the total content thereof is less than 8 mol%, the effect can not be sufficiently obtained. That is, the effect of lowering the softening temperature of the glass was not sufficient, and the yield point was 550 DEG C or higher. Also, the viscosity of the glass increases and the fluidity decreases. On the other hand, when the content exceeds 14 mol%, adverse effects such as a decrease in chemical durability, a decrease in electrical insulation, and an excessively large expansion coefficient may occur. Therefore, the total amount of Li ₂ O + Na ₂ O + K ₂ O is preferably 8 to 14 mol %, Preferably 9 to 12.5 mol%.

In addition, Li ₂ O, Na ₂ O and K ₂ O contain at least 0.1 mol% of Li ₂ O among them, which means that at least one of the glass frit and Al ₂ O ₃ , SiO ₂ , ZrO and ZnO of the present invention It is necessary that the insulating layer formed by applying and firing a glass paste containing at least one inorganic oxide is sufficiently white. In addition, in the case of Li ₂ O, Na ₂ O and K ₂ O, it is preferable that at least Li ₂ O in the Li ₂ O, Na ₂ O and K ₂ O is contained in an amount of 0.1 mol% or more and contains two or more kinds thereof. And it is necessary to make the glass transition point of the lead-free borosilicate glass frit to 500 ° C or less.

Li ₂ O, Na ₂ O and K ₂ O in the total amount of 8 to 14 mol%. However, as for each ratio, 4 parts of Li ₂ O, 6 parts of Na ₂ O and 2 parts of K ₂ O are preferable .

MgO, CaO, SrO, and BaO are effective in stabilizing glass. When the total content is less than 1 mol%, devitrification of the glass tends to occur, and crystallization during firing can not be suppressed. When the content exceeds 10 mol%, the softening temperature becomes high and firing becomes difficult. On the other hand, when the content exceeds 10 mol%, the coefficient of linear expansion more than 80 × 10 ^-7 / ° C. often occurs, so that the glass substrate is fired and cracked when the film is formed, and a coating film having sufficient insulating effect can not be obtained.

ZnO is effective for stabilization of glass and lowers the softening temperature and is a component for suppressing the release. When the content is less than 22 mol%, the effect is not sufficient. When the content is more than 35 mol%, crystallization is apt to occur and stable glass can not be obtained.

In the composition having the same composition as the borosilicate glass containing no Pb of the present invention, the content of CuO is preferably 0.005 to 0.1 mol%, preferably 0.01 to 0.05 mol%, SnO ₂ : 0.01 to 1.0 mol%, more preferably 0.1 to 0.8 mol% By containing Gd ₂ O _{3 at} 0.1 to 2.0 mol%, preferably at 0.3 to 1.0 mol%, at a temperature of 590 ° C. or lower by containing 0.01 to 1.0 mol% of CeO ₂ , 0.01 to 1.0 mol%, preferably 0.1 to 0.5 mol% And the average coefficient of thermal expansion at 40 to 300 캜 was 65 to 80 × 10 ^-7 / ° C. Further, the insulating layer formed by coating and firing on the silver electrode does not cause the sulfur change of the white insulating layer, which is generated by silver ionization in the silver electrode and diffusion into the white insulating layer.

Generally, the low melting point glass frit contains lead as a main component for lowering the melting point. Bismuth or phosphoric acid is contained as a main component in the case of not using lead. In the present invention, since it contains CuO, SnO ₂ , CeO ₂ and Gd ₂ O ₃ as a borosilicate glass based on boric acid or silicic acid, which does not contain lead and does not contain bismuth or phosphoric acid, And an insulating layer formed by firing is not ionized into silver in the silver electrode and diffused into the white insulating layer to prevent the sulfur change of the white insulating layer from occurring .

As described above for ZnO and B ₂ O ₃ , the composition ratio of B ₂ O ₃ and ZnO is ZnO / B ₂ O ₃ = 0.69 to 1.75. By setting ZnO / B ₂ O ₃ = 0.69 to 1.75, the crystallization ratio can be lowered. Specifically, the crystallization ratio can be 20% or less. In the lead-free borosilicate glass not containing PbO, crystallization tends to occur. The surface of the insulating film obtained by baking the glass paste with a glass paste containing a high glass powder having a crystallization ratio equal to or higher than 20% is not smooth with irregularities. It may also cause a short circuit of the insulating coating. Thus, the crystallization ratio is lowered. Further, when ZnO / B ₂ O ₃ is 0.69 or less, the water resistance performance is lowered. The decrease in the water-resisting performance is a cause of the water absorption of the glass in the milling process for obtaining the fine particles, which causes the deterioration of the properties of the glass frit. Preferably, ZnO / B ₂ O ₃ = 0.83 to 1.28.

The glass frit according to the present invention is characterized in that the glass composition contains 16 to 30 mol% of SiO ₂ , 1 to 8 mol% of Al ₂ O ₃ , 20 to 32 mol% of B ₂ O ₃ , Li ₂ O ₃ At least one of Na ₂ O and K ₂ O is contained in an amount of 0.1 mol% or more and Li ₂ O is contained in an amount of 0.1 to 10 mol%, MgO, CaO, SrO, and BaO in total, ZnO: 0.005 to 0.1 mol%, CuO: 0.005 to 0.1 mol%, SnO ₂ : 0.01 to 1 mol%, CeO ₂ : 0.01 to 1 mol%, and Gd ₂ O ₃ : 0.1 to 2.0 mol% And a glass frit is made of a lead-free borosilicate glass having a basic composition of B ₂ O ₃ and ZnO with a ZnO / B ₂ O ₃ ratio of 0.69 to 1.75.

The glass frit having the composition of the present invention is a finely pulverized powder having an average particle diameter of 1 to 5 占 퐉 and a maximum particle diameter of 20 占 퐉 or less which is easily fused and easily made into a glass paste, , And a better insulating film can be obtained by firing. However, when the glass is pulverized with a fine powder, the surface area becomes large, so that it is generally easy to adsorb moisture in the air. However, by adjusting the glass frit of the present invention to such a particle size, It is possible to obtain a water-reducing property value of 0.1 mg / cm < 2 > or less and excellent water resistance in a condition of exposing to pure water for 24 hours. The insulating film obtained by firing has a water resistance reduction value of not more than 0.1 mg / cm 2 under the condition that the water resistance is exposed to pure water at 80 캜 for 24 hours, It does not happen.

The glass frit of the present invention has a glass transition point of 500 캜 or lower. A glass used for forming a dense insulation coating at 590 캜 or below on a substrate such as a rear glass substrate of a plasma display panel and a glass substrate of an electronic display of a planar discharge light emission type is required to have a glass transition point of 500 캜 or lower . Since the glass frit of the present invention is finely pulverized by adjusting the composition and the particle size as described above, the glass transition point can be set to 500 占 폚 or less, specifically 450 占 폚 to 500 占 폚.

When the glass paste is applied and baked, if the baking temperature is high, the electrical characteristics of the electric circuit on the glass substrate deteriorate or the glass substrate is deformed. Therefore, the baking temperature is required to be baked at 590 캜 or lower.

Further, the glass frit of the present invention has an average linear expansion coefficient of 65 to 80 占 10 ^-7 / 占 폚. BACKGROUND ART [0002] Glasses of soda lime glass are used for substrates such as a rear glass substrate of a plasma display panel and an electronic display of a planar discharge light emitting system. The glass frit of the present invention has the above-described composition on the assumption that the insulating layer is fired on the glass substrate of soda lime finishing, and the glass frit of the present invention has an average linear expansion coefficient of from 65 to 80 x 10 ^-7 / 占 폚.

In general, the coefficient of linear expansion of the glass of the soda-lime-based is 87 to 91 × 10 ^-7 / ℃, is the consideration that the average linear expansion coefficient of 65 to 80 × 10 ^-7 / ℃ is desirable. This is because the difference from the average linear expansion coefficient of the glass frit of the present invention is small so that cracks do not occur in the insulating layer formed by firing when applied as glass paste and fired. In addition, the insulating layer may be deteriorated in insulating performance due to cracking, so that cracks do not occur.

Further, when a glass substrate, for example, a back glass substrate of a plasma display panel is coated with glass paste and fired to form a white insulating layer, the glass substrate must be prevented from being deformed at the firing temperature. When the glass of soda lime finishing has a softening temperature of 730 to 740 캜 and a transition temperature of 495 to 505 캜 and it is assumed that it is possible to sinter the insulating layer on the glass substrate of soda lime finishing, It is necessary that the glass transition point be 500 占 폚 or less in order to prevent the electric characteristics of the electric circuit of the plasma display panel from deteriorating and the glass frit of the present invention can meet such a demand.

The glass paste of the present invention contains at least one or more inorganic oxide powders of a lead-free borosilicate glass frit, inorganic fillers Al ₂ O ₃ , SiO ₂ , ZrO and ZnO, and a vehicle. The layer is opaque to white and is also difficult to change to yellow.

Specifically, it is preferable that 100 parts by weight of the lead-free borosilicate glass frit of the present invention, 1 to 10 parts by weight, preferably 2 to 10 parts by weight, of at least one inorganic oxide powder of inorganic fillers Al ₂ O ₃ , SiO ₂ , ZrO and ZnO, 8 parts by weight, ethyl cellulose or 30-100 parts by weight of a vehicle containing an acrylic resin and an organic solvent.

Al ₂ O ₃ , SiO ₂ , ZrO, and ZnO, which are inorganic fillers, serve to make the insulating layer formed white when applied and baked as a glass paste. If the amount is less than 1 part by weight, the insulating layer can not be made sufficiently white. If the amount is more than 10 parts by weight, the surface of the insulating layer (coating) becomes uneven and uneven. Therefore, at least one inorganic oxide powder among Al ₂ O ₃ , SiO ₂ , ZrO and ZnO as inorganic fillers is 1 to 10 parts by weight. Preferably 2 to 8 parts by weight.

In addition, when it is used as an insulating layer (dielectric layer) on the rear glass substrate side of a plasma display panel or as an insulating layer (dielectric layer) of an electronic display of a planar discharge luminescence type, it is sometimes required to be opaque.

The insulating layer formed by baking the glass paste of the present invention is opaque, so that the address electrode does not enter the mirror, and the reflectance and the light emission luminance are not lowered. As the amount of the inorganic filler powder Al ₂ O ₃₃ , SiO ₂ , ZrO and ZnO contained in the glass paste is larger, the insulating layer formed becomes more opaque.

When the glass paste of the present invention contains at least one or more inorganic oxides of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO, which are inorganic fillers, in the lead-free borosilicate glass frit of the present invention, the formed insulating layer becomes white The white insulating layer has a lightness L * value of 85 or more, a red a * value of -2 to 2, and a yellow b * value of 0 to 13, which are expressed by an L * a * b * It is not. Thus, an image projected onto a plasma display or an electronic display of a planar discharge light emission type is excellent as a back glass substrate of a plasma display panel, without a sufficient light emission luminance being obtained and being irradiated with an address electrode, And is excellent in that it is formed on the silver electrode of the electronic display of the light emission type.

In the present invention, the glass paste specified in the composition or the like is obtained by mixing fine powder of glass frit which is finely powdered and fine powder of inorganic oxide of at least one of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO as inorganic fillers, Kneaded with a vehicle to form a glass paste. The glass paste containing the glass frit of the present invention is applied to a predetermined site by a screen printing method, sufficiently dried at 120 占 폚 and then baked at 590 占 폚 or lower. As the vehicle, ethyl cellulose or an acrylic resin and an organic solvent, or a resin and an organic solvent, which is obtained by dissolving ethyl cellulose as a resin component in a solvent, such as butyl carbitol acetate or terpineol, is used.

Specifically, the present invention relates to a non-burnable borosilicate glass frit comprising 100 parts by weight of at least one inorganic oxide selected from the group consisting of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO, It is preferable to use 30 to 100 parts by weight of a vehicle containing an organic solvent as an insulating layer opaque to white, to be hardly changed to yellow, to have a lightness L * value of 85 or more as expressed by a L * a * b * The red group a * value is preferably -2 to 2, and the yellow group b * value is preferably 0 to 13. [

As described above, according to the glass paste containing the glass frit of the present invention, an insulating layer formed by forming a dense coating and applying and firing on the silver electrode by adjusting the composition of the glass, the grain size, Which is opaque to white and is hardly changed in sulfur, is formed on the rear glass substrate of the plasma display panel and is also formed as an electronic display of a flat discharge light emission type, and a sufficient reflectance and light emission rate can be obtained as an insulating layer of the display panel It is also good in color.

The glass frit of the present invention can be obtained by mixing silica glass, alumina, anhydrous boric acid, boric acid, potassium nitrate, lithium carbonate, magnesium oxide, barium carbonate, calcium carbonate, zincation, copper compound or silver compound as a raw material in a molar ratio SiO ₂ : 16 to 30 mol%, Al ₂ O ₃ : 1 to 8 mol%, B ₂ O ₃ : 20 to 32 mol%, at least Li ₂ O in 0.1 mol of Li ₂ O + Na ₂ O + K ₂ O At least one selected from the group consisting of MgO, CaO, SrO and BaO in an amount of 1 to 10 mol%, ZnO: 22 to 35 mol%, CuO: 0.005 to 0.1 mol%, SnO ₂ : 0.01 to 1.0 mol%, CeO ₂ : 0.01 to 1.0 mol%, and Gd ₂ O ₃ : 0.1 to 2.0 mol% are blended and melted so as to be a lead-free borosilicate glass as a base composition .

Melting is performed in an atmospheric environment using a platinum crucible. Fritization is obtained by blowing molten glass out of two rolls (twin rolls) or steel plates cooling the molten glass into water by being poured into water or in water, drying and finely pulverizing it by a ball mill.

More specifically, it is vitrified at 1240 to 1300 占 폚 for 20 minutes in a platinum crucible, and air-cooled. In the pulverization and frying, the glass is pulverized to adjust the particle size to an average particle diameter of 1 to 5 μm and a maximum particle diameter of 20 μm or less.

Further, in the glass paste containing the glass frit of the present invention,

100 parts by weight of the lead-free borosilicate glass frit of the present invention;

Inorganic fillers _{(Al 2 O 3, SiO 2} , ZrO, ZnO) 1 to 10 parts by weight;

The vehicle (containing ethyl cellulose or an acrylic resin and an organic solvent)

30 to 100 parts by weight

to be.

Figs. 1 to 3 show embodiments of a plasma display panel in which an insulating layer is formed with a paste of a lead-free borosilicate glass frit of the present invention.

1 is a perspective view of a plasma display panel in which a front glass substrate 10 and a back glass substrate 1 are shown apart from each other. 2 and 3 show a front glass substrate 10 and a rear glass substrate 1 joined together. Fig. 2 is a sectional view taken along the line A-A in Fig. 1, and Fig. 3 is a sectional view taken along line B-B in Fig.

As shown in Figs. 1 to 3, the rear glass substrate 1 is covered with an insulating layer (dielectric layer) 3 by disposing an address electrode 2 thereon. The address electrode 2, which is called a silver electrode, is formed by screen printing with a paste composed of a silver powder and an organic binder. For example, the silver paste is composed of 65 to 90% of silver powder, 1 to 10% of low melting point glass frit and an organic solvent containing a resin, and an electrode is formed on the glass substrate by firing at 500 to 600 캜 . Ribs (separation walls) 4 are formed in the longitudinal direction of Fig. 1, and ribs (separation walls) 6, 7 are formed in the lateral direction of Fig. Phosphors R, G and B are formed between ribs 4 and 6 and 7, respectively.

A transparent electrode 12, a black stripe 14, a bus electrode 13, a dielectric layer 11 and a protective film (MgO) 15 are formed on the front glass substrate 10.

The black stripe 14 of the front glass substrate 10 is superimposed on the ribs (separation walls) 6 and 7 of the rear glass substrate 1.

The front glass substrate 10 and the rear glass substrate 1 are bonded to each other to form a vacuum in which the periphery is hermetically sealed, and then a gas such as Ne-Xe is sealed.

The glass frit paste of the present invention is lead-free borosilicate glass frit is 100 parts by weight of Al ₂ O _3, SiO _2, ZrO, and the inorganic oxide of ZnO 1 to 10 parts by weight, the vehicle 30 which contains ethyl-cellulose or acrylic resin with an organic solvent (Silver electrode) of the rear glass substrate 1, as in the case of the insulating layer (dielectric layer) 3 shown in Fig. 1. (Dielectric layer) 3 is coated by a clean printing method so as to cover the address electrode (silver electrode) on the rear glass substrate 1 and sufficiently dried, and then fired at 580 캜.

(Silver electrode) 2 is formed on the back glass substrate 1 of the plasma display panel and the insulating layer (dielectric layer) 3 (silver electrode) is formed so as to cover the silver electrode 2, ). The insulating layer (dielectric layer) 3 formed of the back glass substrate 1 and the paste of the lead-free borosilicate glass frit of the present invention have almost the same average coefficient of linear thermal expansion, and the generation of cracks in the insulating layer (dielectric layer) There was no.

The insulating layer (dielectric layer) 3 of the present invention is white and the insulating layer 3 has a lightness (L * value) of 85 or more, a red color (a * value) of 12 to 2, Value) range of 0 to 13, a sufficient reflectance and a high light emission rate were obtained, and the color was good. In addition, the insulating layer of white did not yellow. Further, the insulating layer (dielectric layer) 3 is white, and sufficient light emission luminance can be obtained when the image is projected on the plasma display panel, and the color of the image in which the address electrode 2 is irradiated or emitted is poor There was no such thing as doing. Further, no change in sulfur occurred in the insulating layer (dielectric layer) 3 on the address electrode (silver electrode) 2. That is, even if the silver in the silver electrode 2 is ionized and diffused, the white insulating layer is not yellowed.

As an embodiment of the present invention, for the black stripe 14 formed on the front glass substrate 10 of the plasma display panel shown in Figs. 1 to 3, a glass paste for forming the insulating layer by firing SiO ₂ : 16 to 32 mol%, Al ₂ O ₃ : 4 to 8 mol%, B ₂ O ₃ : 20 to 35 mol%, Li ₂ O + Na ₂ O + K ₂ O, the total amount is 8 to 14 mol%, at least 3 mol% of BaO among MgO + CaO + BaO + SrO is contained, and the total amount of at least one of them is 3 to 16 mol% : 6 to 33 mol%, Cu ₂ O: 0.01 to 3 mol%, Ag ₂ O: 0.01 to 1 mol%, and the composition ratio of B ₂ O ₃ and ZnO is ZnO / B ₂ O ₃ = Wherein the glass of the above composition is a glass frit having an average particle diameter of 1 to 5 占 퐉 and a maximum particle diameter of not more than 20 占 퐉 and having a glass transition point of 500 占 폚 or less, And has a water resistance value of 0.1 mg / cm 2 or less as a water-reducing weight value under the condition that the coefficient is 65 to 80 x 10 < ^-7 > / deg. C and the water resistance performance is in a pure water of 80 deg. C for 24 hours. The unleaded borosilicate glass It is preferable to use a glass paste composed of an inorganic black pigment, an inorganic filler, and an organic solvent in the frit. The black stripe 14 formed on the front glass substrate 10 is combined with the insulating layer 3 on the silver electrode 2 of the rear glass substrate 1 to have a composition of the present invention, It is preferable to use those which are hardly yellowed.

The glass frit specified in the composition of the present invention and the glass frit have a performance of 0.1 mg / cm 2 or less as the water-reducing amount value under the condition that the water resistance is exposed to pure water at 80 캜 for 24 hours.

With respect to the water resistance performance, the water resistance test and the acid resistance test will be described. 4 is shown in the flowchart of FIG. The glass was pulverized and subjected to a water resistance test and an acid resistance test in the state that the glass frit was sintered in a powdered glass frit in which the particle size was adjusted to 1 to 5 탆 in average particle size and 20 탆 or less in the maximum applied particle size, Performance.

As shown in the flowchart of Fig. 4, the glass frit is put into a plaster mold as in step (31) and sintered in a lump shape. Subsequently, it is processed into a cylindrical shape as in the step (32), and a specimen having a diameter of 5 mm and a length of 20 mm is used.

In step (33), a cylindrical glass sample having a diameter of 5 mm and a length of 20 mm is put in 50 ml of pure water in a capped poly container. This was kept in a thermostatic chamber set at 80 DEG C in step (35) for 24 hours. It was taken out in the step (37) to calculate a small amount of weight. A small amount of weight per non-surface area of the cylindrical glass sample was calculated. This was regarded as the water-reducing value indicating the water-resistance performance.

Step 34 is an acid-resistance test, and a cylindrical glass sample having a diameter of 5 mm and a length of 20 mm is placed in 50 ml of a 1N sulfuric acid aqueous solution in a capped poly container. This was kept for 24 hours in a thermostatic chamber set at 50 DEG C as in step (36). In step (37), it was taken out to calculate a small amount of weight. A small amount of weight per unit surface area of the cylindrical glass sample was calculated. This shows the acid resistance performance. Then, the glass samples are compared and evaluated in step (38).

In the present invention, it is specified that the water resistance is very excellent so that the water resistance performance is 0.1 mg / cm < 2 > or less as the water loss weight value under the condition that the water resistance performance is exposed to pure water at 80 DEG C for 24 hours. This indicates that the lead-free borosilicate glass frit specifying the composition of the present invention is excellent in long-term reliability, and is superior to the insulating layer formed of the paste of the conventional lead oxide-containing glass frit, (3) formed on the silver electrode (2) formed on the substrate (1).

[ Example ]

Examples 1 to 7 are shown in Tables 1 and 2, and Comparative Examples 1 to 6 are shown in Tables 3 and 4 for the present invention. 5 (a) and 5 (b) show test specimens. 6 shows a dielectric strength test of the insulating layer. Figs. 7 to 10 show L * value, a * value and b * value according to the display of the L * a * b * color system.

The test pieces of Examples 1 to 7 and Comparative Examples 1 to 6 and Figures 5 (a) and 5 (b) were made of a lead-free borosilicate-based material having an average particle size of 1 to 5 탆 and a maximum particle size of 20 탆 or less A glass paste containing at least one of frit of glass and at least one of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO which is an inorganic filler is applied, sufficiently dried, and then fired at 580 ° C to form an insulating layer.

In Table 1-4, the composition is in terms of mole percent, the glass transition point of the glass composition in mole% is ℃, the linear expansion coefficient α is 10 ^-7 / ℃ to a value ranging from 0 to 300 ℃, the water resistance is 24Hr × 80 ℃ (Mg / cm < 2 >). In addition, the glass composition of Tables 1 to 4 has a total of more than 100% of the components, but it is due to other components such as impurities.

As shown in Figs. 5A and 5B, a test piece is formed by screen printing a paste composed of an organic solvent containing a silver powder, a low melting point glass frit and a resin on a glass substrate 41, The electrode 42 is formed on the glass substrate by firing at 500 deg. C to 600 deg. The glass frit paste is applied and fired to form the insulating layer 43 so as to cover the glass substrate 41 and the silver electrode 42 thereon.

Fig. 6 shows a dielectric strength test of the insulating layer. A silver paste composed of an organic solvent containing a silver powder, a low melting point glass frit and a resin is applied on the glass substrate 50 by screen printing to the silver electrode 51a. 51b, 51c, and 51d, and silver electrodes 51a to 51d are formed on the glass substrate by firing at 500 to 600 占 폚. The glass frit paste is applied and fired to form the insulating layer 52 so as to cover the silver electrodes 51a to 51d. In the dielectric strength test of the insulating layer 52, the thickness of the insulating layer 52 of the test sample was set to 14 占 퐉.

The electrodes 51a to 51d are connected to the voltmeter V by the wirings 53a to 53c and 54d and the wiring 54 and the copper foil 56 is formed on the insulating layer 52 A voltage of 600 V was applied to the silver electrodes 51a to 51d connected by the copper foil 56 and the wiring 54. However, There was no destruction. In addition, a voltage of 700 V was applied, but this also did not destroy the insulation.

Figs. 7 to 10 show L * value, a * value and b * value according to the display of the L * a * b * color system. The values of the L * a * b * color system are in accordance with JIS Z8729.

Fig. 7 is a diagram showing an L * a * b * colorimetric system in three dimensions.

L * a * b * In the colorimetric system, the brightness (brightness) is represented by L *, and the chromaticity representing the hue and color is represented by a * and b *. a * and b * indicate the direction of the color, + a * is the red direction, and -a * is the green direction. + b * is the yellow direction, and -b * is the blue direction. As the absolute value becomes larger, the color becomes clearer, and as it goes toward the center, it becomes a subtle color.

FIG. 8 shows directions of a *, b * colors in FIG. 7 showing a stereoscopic image, in which the horizontal axis is + a * red and -a * green, and the vertical axis is + b * yellow and -b * blue . Fig. 9 is an enlarged view of the area of Fig. 8 (C). Fig. 10 shows the brightness (brightness) of Fig. 7 showing the stereoscopic image as L *, where L * is 100 to white and L * is 0 to black.

The lead-free borosilicate glass frit of Examples 1, 2 and 3 is the composition shown in Table 1 and is ZnO / B ₂ O ₃ : 0.93. The glass transition point is 474.4 ℃, yield point is 506.7 ℃ (Tables 1, 2 in the base material is omitted), the linear expansion coefficient α (0 to ^{300 ℃) 76.9 × 10 -7 /} ℃, water resistance (24Hr × 80 ℃ mass when the 2, and 3 are the same as those of the lead-free borosilicate glass frit, and Al ₂ O ₃ , SiO ₂ , ZrO, and ZnO contained in the glass paste were used in Examples 1, ₂ , Or the amount thereof is changed with respect to 100 parts by weight of the glass frit.

In Example 1, an insulating layer is formed with glass paste containing 1.4 parts by weight of Al ₂ O ₃ as an inorganic filler and 3.2 parts by weight of ZnO in 100 parts by weight of lead-free borosilicate glass frit. The L * value of this insulating layer was 85.05 as shown in Table 2 and Fig. 10, and the a * value was -0.58 and the b * value was 11.08 as shown in Table 2 and Fig. In Example 2, as shown in Table 2 and Figs. 9 and 10, 87.00, the a * value was -0.70, and the b * value was 9.90. In Example 3, as shown in Table 2 and Figs. 9 and 10, 85.86, the a * value was -1.17, and the b * value was 11.46.

The fleece of the lead-free borosilicate glass of Example 4 had a composition (ZnO / B ₂ O ₃ : 0.93), glass transition point, coefficient of linear expansion? (0 to 300 ° C) and water resistance (24Hr x 80 ° C Cm 2) of the lead-free borosilicate glass frit. An insulating layer is formed with glass paste containing 1.4 parts by weight of Al ₂ O _{3 and} 3.2 parts by weight of ZnO in 100 parts by weight of the lead-free borosilicate glass frit. Was 86.22 as shown in Table 2 and Fig. 10, and the a * value was -0.81 and the b * value was 10.82 as shown in Table 2 and Fig.

The frit of the lead-free borosilicate glass of Examples 5, 6 and 7 had the composition shown in Table 1 (ZnO / B ₂ O ₃ : 0.75 in Example 5, 1.13 in Example 6, 0.98 in Example 7) 1.4 parts by weight of Al ₂ O _3, 1.4 parts by weight of ZnO (weight average molecular weight of _20,000 ), and a glass transition temperature of 30 ° C. were added to 100 parts by weight of the lead- : 3.2 parts by weight The glass transition temperature of the insulating layer was measured using a glass paste containing L * value, a * value and b * value of the insulating layer, as shown in Table 2 and Figures 9 and 10, * Value was 86.07, the a * value was -0.61 and the b * value was 11.45, the L * value of Example 6 was 87.93, the a * value was -1.08 and the b * value was 9.66, Was 86.51, the a * value was -0.69, and the b * value was 10.04.

From these data, it can be seen that the insulating layer formed in Examples 1 to 7 has an L * value of 85 or more and an a * value of -2 to 2, the b * value is in the range of 0 to 13, the reflectance of the light is not lowered to white and the light emission rate is not lowered.

On the contrary, the lead-free borosilicate glass frit of Comparative Examples 1 to 5 is the composition shown in Table 3, and is outside the range of the specific composition in the present invention.

Comparative Example 1 with respect to the present invention, "Li ₂ O + Na ₂ O + K ₂ O of at least Li ₂ O and 0.1 mol% or more containing and 2, the sum or more species from 8 to 14% by mole", which specified in, Li ₂ O of 13.00 mol%, but does not contain two or more species. An insulating layer was formed with 100 parts by weight of the lead-free borosilicate glass frit using glass paste containing 1.4 parts by weight of Al ₂ O ₃ as an inorganic filler and 3.2 parts by weight of ZnO. The L * value, the a * value, and the b * value of the insulating layer are shown in Table 4 and in Figures 8 and 10, respectively, with L * value of 38.55, a * value of 14.05, and b * value of 19.60. The L * value of the insulating layer is out of the range of 85 or more, the a * value is in the range of -2 to 2, and the b * value is in the range of 0 to 13, which is the range in which the decrease in the reflectance and the light emission rate are decreased.

Comparative Example 2 does not contain CeO ₂ with respect to "CeO ₂ : 0.01 to 1 mol%" specified in the present invention. An insulating layer was formed with 100 parts by weight of the lead-free borosilicate glass frit using glass paste containing 1.4 parts by weight of Al ₂ O ₃ as an inorganic filler and 3.2 parts by weight of ZnO. The L * value, the a * value, and the b * value of this insulating layer are shown in Table 4 and in Figures 8 and 10, the L * value is 84.30, the a * value is -5.75 and the b * value is 34.85 , The L * value of the insulating layer is 85 or more, the a * value is in the range of -2 to 2, and the b * value is in the range of 0 to 13, which means that the light reflectance is lowered and the light emission rate is lowered.

In Comparative Example 3, "Gd ₂ O ₃ : 0.1 to 2.0 mol%" specified in the present invention does not contain Gd ₂ O ₃ . An insulating layer was formed with 100 parts by weight of the lead-free borosilicate glass frit using glass paste containing 1.4 parts by weight of Al ₂ O ₃ as an inorganic filler and 3.2 parts by weight of ZnO. The L * value, the a * value, and the b * value of this insulating layer have an L * value of 79.73, an a * value of -0.47 and a b * value of 11.37, as shown in Table 4 and Figs. 8 and 10, The L * value of the insulating layer was outside the range of 85 or more, and the range was such that the decrease of the reflectance of light and the light emission rate were lowered. Gd ₂ O ₃ has an effect on the white insulating layer.

Example 1 and Comparative Example 3 differ in whether or not they contain Gd ₂ O ₃ . The L * value of Example 1 containing Gd ₂ O ₃ is 85.05 as shown in Table 2 and FIG. 10, and the L * value of Comparative Example 3 containing no Gd ₂ O ₃ is shown in Tables 4 and 10 As shown, the content of 79.73 and the content of Gd ₂ O ₃ : 0.1 to 2.0 mol% indicates that the white color is effective.

Comparative Example 4 is ZnO / B ₂ O ₃ : 2.93, which is out of the range of 22 to 35 mol% of ZnO specified for "ZnO: 22 to 35 mol%" specified in the present invention. To 100 parts by weight of this lead-free borosilicate glass frit, an insulating layer was formed with a glass paste containing 1.4 parts by weight of Al ₂ O ₃ as an inorganic filler and 3.2 parts by weight of ZnO. The L * value, the a * value, and the b * value of this insulating layer are as shown in Table 4 and Figures 8 and 10, respectively, with an L * value of 65.51, an a * value of -0.98 and a b * value of 8.69. The L * value of the insulating layer was outside the range of 85 or more, and the range was such that the reflectance of light and the light emission rate were lowered.

In Comparative Example 5, "ZnO: 22 to 35 mol%" specified in the present invention is out of the range of 22 to 35 mol% of ZnO specified and ZrO / B ₂ O ₃ : 0.45. An insulating layer was formed with 100 parts by weight of the lead-free borosilicate glass frit using glass paste containing 1.4 parts by weight of Al ₂ O ₃ as an inorganic filler and 3.2 parts by weight of ZnO. As shown in Table 4 and FIGS. 8 and 10, the L * value, the a * value, and the b * value of the insulating layer were 62.67, 0.86, and 9.74, respectively, Is not within the range where the L * value is 85 or more, and the range is such that the reflectance of light and the light emission rate are lowered.

In Comparative Example 6, the lead-free borosilicate glass frit has a composition as shown in Table 3. An insulating layer is formed with glass paste containing 3.0 parts by weight of Al ₂ O _{3 and} 2.0 parts by weight of TiO ₂ in 100 parts by weight of the lead-free borosilicate glass frit. The L * value of this insulating layer is 72.38 as shown in Table 4 and Fig. 10, and the a * value is -7.89 and the b * value is 37.92 as shown in Table 4 and Fig. 9, Value is not less than 85, the a * value is in the range of -2 to 2, and the b * value is out of the range of 0 to 13, which means that the reflectance of light and the light emission rate are lowered. Further, Comparative Example 6 from the inorganic oxide of the TiO ₂ is not obtained the desired effect, the invention of "the glass frit and the Al ₂ O _3, SiO _2, ZrO, and an inorganic oxide at least one or more of ZnO, which is specified in the , A predetermined effect can be obtained with at least one or more inorganic oxides of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO.

1 is a diagram showing an embodiment of the present invention;

2 is a diagram showing an embodiment of the present invention;

3 is a diagram showing an embodiment of the present invention;

4 is a view for explaining a water resistance test and an acid resistance test of the present invention;

5 is a view showing a test piece of an embodiment of the present invention;

6 is a view showing an insulation test of an embodiment of the present invention;

7 is a view for explaining L *, a * and b * of the present invention;

8 is a view for explaining a *, b * in the embodiment of the present invention;

9 is a view for explaining a *, b * in the embodiment of the present invention;

10 is a diagram for explaining L * in the embodiment of the present invention.

Description of the Related Art

1: back glass substrate 2: address electrode (silver electrode)

3: insulating layer (dielectric layer) 4, 6, 7: rib (separating wall)

10: front glass substrate 11: dielectric layer

12: transparent electrode 13: bus electrode

14: Black stripe 15: Shield

41: glass substrate 42: silver electrode

43: insulating layer 50: glass substrate

51a to 51d: silver electrode 52: insulating layer

Claims (8)

The molar percentage of the glass composition 16 to 30 mol% of SiO ₂ , 1 to 8 mol% of Al ₂ O ₃ , B ₂ O ₃ : 20 to 32 mol% At least Li ₂ O in 0.1 mol% or more of Li ₂ O + Na ₂ O + K ₂ O, and the total of two or more species is 8 to 14 mol% MgO + CaO + SrO + BaO, the total amount of which is 1 to 10 mol% 22 to 35 mol% of ZnO, 0.005 to 0.1 mol% of CuO, SnO ₂ : 0.01 to 1 mol% 0.01 to 1 mol% of CeO ₂ and Gd ₂ O ₃ : 0.1 to 2.0 mol% Which is a lead-free borosilicate glass, Wherein the glass having the above composition is a glass frit having an average particle size of 1 to 5 占 퐉 and a maximum particle size of 20 占 퐉 or less and having a glass transition point of 500 占 폚 or less and an average linear expansion coefficient of 65 to 80 占^10-7 / The frit is excellent in water resistance and has a performance of 0.1 mg / cm 2 or less as a water loss value under the condition that the performance is exposed to pure water at 80 ° C for 24 hours. The glass frit and Al ₂ O ₃ , SiO ₂ , ZrO and ZnO Wherein the insulating layer formed by applying and firing a glass paste containing at least one or more inorganic oxides on a silver electrode is hardly yellowed to white. 5. A lead-free borosilicate glass frit for forming an insulating layer by firing. A glass paste comprising the lead-free borosilicate glass frit according to claim 1, at least one or more inorganic oxides of Al ₂ O ₃ , SiO ₂ , ZrO and ZnO as fillers, and a vehicle, A lead-free borosilicate glass frit paste for forming an insulating layer by firing, characterized in that the insulating layer formed by firing is hardly yellowed to white. A process for producing a semiconductor device, which comprises: mixing 100 parts by weight of the lead-free borosilicate glass frit according to claim 1, 1 to 10 parts by weight of at least one inorganic oxide selected from Al ₂ O ₃ , SiO ₂ , ZrO and ZnO as inorganic fillers, Wherein the insulating layer formed by applying and firing the glass paste on the silver electrode is hardly yellowed to white, and a lead-free layer for forming the insulating layer by firing Borosilicate glass frit paste. The white insulating layer formed by applying the paste of the lead-free borosilicate glass frit onto the silver electrode and firing the paste of the lead-free borosilicate glass frit according to any one of claims 2 and 3 is characterized in that the lightness, redness, Wherein the insulating layer is formed by firing and has an L * value of 85 or more, an a * value of -2 to 2, and a b * value of 0 to 13, Paste of lead-free borosilicate glass frit. The plasma display panel according to claim 2 or 3, wherein the insulating layer formed by firing the glass frit paste is formed on a silver electrode formed on a rear glass substrate of a plasma display panel. Borosilicate glass frit paste. The method according to claim 2 or 3, wherein the insulating layer formed by firing the paste of the glass frit is formed on a silver electrode of an electronic display of a planar discharge light emitting system. Silicate glass frit paste. 5. The plasma display panel according to claim 4, wherein the insulating layer formed by firing the paste of the glass frit is formed on a silver electrode formed on a rear glass substrate of the plasma display panel. Of paste. The lead-free borosilicate glass frit according to claim 4, wherein the insulating layer formed by firing the paste of the glass frit is formed on the silver electrode of the planar discharge light emitting electronic display. Paste.

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