WO2008007570A1

WO2008007570A1 - Lead-free glass composition

Info

Publication number: WO2008007570A1
Application number: PCT/JP2007/063159
Authority: WO
Inventors: Satoshi Kumano; Ichiro Uchiyama
Original assignee: Nihon Yamamura Glass Co., Ltd.
Priority date: 2006-07-14
Filing date: 2007-06-29
Publication date: 2008-01-17
Also published as: JP2008019145A

Abstract

The object is to reduce the amount of bismuth used and improve the light transmission rate in a lead-free glass composition having a softening point as low as 600˚C or lower. Disclosed is a lead-free glass composition having the following composition in terms of oxides (by mass): 5-30% of SiO2; 30-60% of B2O3; 1-25% of Al2O3; 5-20% of at least one member selected from Li2O, Na2O and K2O in total; 0.1-15% of at least one member selected from MgO and CaO in total; and 0.1-20% of at least one member selected from SrO and BaO in total, wherein the total amount of MgO, CaO, SrO and BaO is 0.2-25% by mass and the amount of ZnO is 0-15% by mass.

Description

Lead-free glass composition

Technical field

[0001] The present invention relates to a lead-free glass composition and a glass for a plasma display panel dielectric layer in which the lead-free glass composition is used.

Background art

[0002] In the trend of high image quality, space saving, and energy saving in recent years, instead of cathode ray tube image display devices (hereinafter also referred to as “CRT”), image display devices are flat. Panel displays are being used.

In particular, a plasma display panel (hereinafter also referred to as “PDP”) is well-colored, has a clear image, and is relatively easy to enlarge!

[0003] In this PDP, glass plates are arranged on the front side and the back side. The front side glass plate (hereinafter also referred to as "front plate") and the back side glass plate (hereinafter referred to as "back plate"). Is also formed by providing an electrode on one side of a glass substrate using, for example, soda lime glass or high strain point glass. The front plate and the rear plate are arranged on the PDP with their surfaces on which electrodes are formed facing each other.

Linear electrodes are used for the electrodes of the front plate and the back plate, and the electrode surfaces of the front plate and the back plate are formed in a stripe shape in which a large number of linear electrodes are arranged in parallel. The front plate and the rear plate are arranged with their linear electrodes orthogonal to each other so as to form a lattice when the front force of the PDP is viewed. In each of the front plate and the back plate, this electrode is further covered with a glass layer called a dielectric layer. In addition, a glass wall called a partition that partitions the electrodes is usually provided on the back plate.

In the PDP, the dielectric layer of the front plate (hereinafter also referred to as “front dielectric layer”) is separated from the dielectric layer of the back plate (hereinafter also referred to as “back dielectric layer”) by the partition of the back plate. It is supported in the state. Thus, a space is defined by the front dielectric layer, the back dielectric layer, and the barrier ribs, and a phosphor is arranged in the space to form a display cell. The phosphor of the display cell is emitted by plasma discharge between the front and back electrodes. I am making it light.

[0004] The dielectric layer and the partition are usually formed by sintering a paste or green sheet containing powdery glass on a glass substrate. For this reason, the glass used for these dielectric layers and partition walls must have a low softening temperature (softening point) that can be sintered on a glass substrate. It has a soft spot below C.

In addition, the dielectric layer, particularly the dielectric layer of the front plate, is required not only to be baked at a low temperature, but also to have a high transparency (light transmittance) as the obtained dielectric layer. .

By the way, conventionally, a glass containing a large amount of lead oxide is known as a low softening point glass having a low and softening point as described above. However, in recent years, with increasing environmental awareness, lead-free, low-soft spot glass that can suppress problems in waste disposal and the working environment is desired.

In recent years, bismuth-based lead-free glass compositions mainly composed of bismuth oxide and boron oxide have been used as glass compositions for this lead-free low soft spot glass. . (See Patent Document 1 below)

However, bismuth is a rare metal and, in recent years, bismuth is not as likely as lead, but there are concerns about adverse effects on the environment, and it is desired to reduce the use of bismuth. It ’s like that!

For these reasons, in recent years, the use of zinc borate-based lead-free glass compositions has been studied. (See Patent Documents 2 and 3 below)

However, no zinc borate-based lead-free glass composition has been found that has a sufficiently improved light transmittance.

In other words, no conventional lead-free glass composition has been found that has the excellent light transmittance required for PDP dielectric layer glass while suppressing the bismuth content.

Such problems are not limited to lead-free glass compositions used for PDP dielectric layer glass, but also low softness that requires high light transmittance while suppressing bismuth content. This is a common problem with lead-free glass compositions.

[0006] Patent Document 1: Japanese Unexamined Patent Publication No. 2003-128430

Patent Document 2: Japanese Unexamined Patent Publication No. 2000-313635

Patent Document 3: Japanese Patent Laid-Open No. 2005-47778

Disclosure of the invention

Problems to be solved by the invention

[0007] In view of the above problems, the present invention has an object to improve light transmittance while suppressing the bismuth content in a lead-free glass composition having a low soft spot of 600 ° C or lower. .

Means for solving the problem

[0008] A lead-free glass composition, such as a zinc borate-based lead-free glass composition, which contains less bismuth, contains a relatively large amount of ZnO as a component for lowering the soft spot. It is composed. In contrast, the present inventors have found that in a lead-free glass composition in which the use of bismuth is suppressed, the light transmittance can be improved by reducing the amount of ZnO. And we are earnest about the composition of lead-free glass with B 2 O and SiO as the main components.

2 3 2

As a result of study, the present invention has been completed.

That is, the present invention solves the above problems by mass% in terms of oxide,

2

30%, B O force 30-60%, Al O force ^ -25%, Li 0, Na O and Κ Ο One or more

2 3 2 3 2 2 2 Above 5 to 20% in total, MgO and CaO at least one kind is total 0.1 to 15%, SrO and BaO at least one kind is total 0.1 to 20 The lead-free glass composition is characterized in that the total content of MgO, CaO, SrO and BaO is 0.2 to 25% and ZnO is 0 to 15%.

The invention's effect

[0009] Pb-free glass composition of the present invention, the mass ^_0/0 compositions force in terms of oxide other than ZnO, SiO force S5~30%, BO force 30 to 60%, Al O mosquitoes ^ ~ 25%, Li Any of 0, Na O and KO

2 2 3 2 3 2 2 2 Force One or more types total 5 to 20%, one or more of MgO and CaO total 0.1 to 15%, one type of SrO and BaO one or more total 0. 1-20%, and the strength is MgO, CaO, SrO And the total of BaO is 0.2-25%. This force can make the lead-free glass composition have a low soft spot while suppressing the ZnO content.

Therefore, since the lead-free glass composition of the present invention can suppress the ZnO content, the light transmittance of the glass can be improved.

That is, according to the present invention, it is possible to provide a lead-free glass composition capable of improving the light transmittance while suppressing the amount of bismuth used.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] A lead-free glass composition used for forming a dielectric layer of a front plate of a plasma display panel (PDP) according to a preferred embodiment of the present invention will be described below.

The lead-free glass composition in the present embodiment contains SiO, B 2 O, and Al 2 O.

2 2 3 2 3

. In addition, any one or more of Li 0, Na O and Κ ならびに, and any of MgO and CaO

2 2 2

Contains at least one kind of force. Furthermore, at least one of SrO and BaO is contained.

Moreover, the lead-free glass composition of this embodiment contains ZnO as an optional component.

[0011] The SiO is an essential component necessary for the stability of the glass, and the content thereof is oxide conversion.

2

The calculated mass% is 5-30%.

This SiO content is in this range when the SiO content is less than 5%.

twenty two

This is because the lead-free glass becomes unstable, and the lead-free glass that is formed crystallizes to reduce light transmission. 600 ° C or less when SiO power exceeds 30%

2

Firing is difficult, and firing on a glass substrate is difficult. In addition, the glass has too high a viscosity, and in the case where a dielectric layer is formed using powdered glass, it is difficult to remove bubbles, which may reduce light transmission.

In this respect, the SiO content is preferably 5 to 25%, more preferably.

2

Or 10-25%, more preferably 15-25%.

[0012] The B 2 O is also an essential component necessary for the stability of the glass, and the content thereof is oxide conversion.

twenty three

The calculated mass% is 30-60%.

This B 2 O content is in this range when the B 2 O content is less than 30%.

2 3 2 3

The lead-free glass becomes unstable, and the lead-free glass that is formed crystallizes to reduce light transmission. It is for letting you lower. 600 ° C or less when BO force exceeds 60%

twenty three

Firing is difficult, and firing on a glass substrate is difficult. The strength of the glass may also reduce the chemical durability of the glass.

In this respect, the B 2 O content is preferably 33 to 60%.

twenty three

More preferably, the power is 35-57% and 40-55%!

[0013] AlO is also an essential component necessary for the stability of glass, and its content is determined by oxide conversion.

twenty three

The calculated mass% is 1-25%.

The Al O content is in this range when the Al O content is less than 1%.

2 3 2 3

This is because the lead-free glass becomes unstable, and the lead-free glass that is formed crystallizes to lower the light transmittance. If it contains more than 25% Al O force, 600 ° C or more

twenty three

Firing below becomes difficult, and firing on a glass substrate becomes difficult.

In this respect, the content of Al 2 O is preferably 3 to 23%, more preferably.

twenty three

Alternatively, it is 5 to 20%, and more preferably 7 to 15%.

[0014] The Li 0, Na 2 O and Κ Ο are effective components for reducing the melting of glass, and these Li 0,

2 2 2 2

It is essential that the lead-free glass composition contains at least one of Na O and Κ Ο

twenty two

. Moreover, the content is 5 to 20% in total in terms of mass% in terms of acid chloride. Li 0, Na O and

The total content power of one or more of 2 2 and K 力 Such a range is that the total content is 5%

2

If it is less than 1, the soft spot of the lead-free glass composition exceeds 600 ° C., and firing on the glass substrate becomes difficult.

On the other hand, when one or more of Li 0, Na O and Κ Ο is contained in excess of 20% in total

2 2 2

The thermal expansion coefficient becomes too large, warping during firing, causing cracks and making firing itself difficult. In addition, when the dielectric layer is formed, there is a high possibility that coloring (yellowing) due to reaction with the electrode occurs.

In this respect, the content of one or more of Li 0, Na O and 及び Ο

2 2 2

More preferably, it is 7 to 18%, more preferably 9 to 16%, and further preferably 10 to 15%.

[0015] Shishika also has an oxide-based mass% of LiO content of X, NaO content of X, and KO.

2 When Li 2 Na 2 content is X, these Li 0, Na O and Κ Ο are (X +)) / Χ ≤ 1 When it is contained in a lead-free glass composition at a composition ratio that satisfies the relationship, the above yellowing can be more reliably suppressed, and the lead-free glass composition is suitable for forming a dielectric layer of a PDP. Can be.

[0016] The MgO and CaO are effective components for suppressing the crystallization of glass and improving the light transmittance, and any one or more of these MgO and CaO is contained in the lead-free glass composition. It is essential. Moreover, the content is 0.1 to 15% in total in terms of mass% in terms of oxide. The total content of one or more of MgO and CaO is within this range because when the total content is less than 0.1%, the lead-free glass becomes unstable and the lead-free glass formed This is because crystallization causes a decrease in light transmittance.

On the other hand, when one or more of MgO and CaO is contained exceeding 15% in total force, firing at 600 ° C. or less becomes difficult, and firing on a glass substrate becomes difficult.

In such a point, the content of one or more of MgO and CaO is preferably 0.1 to 10% in total, more preferably 0.2 to 8%, and 0.2 to 0.2%. It is more preferably 5%.

[0017] The SrO and BaO are effective components for suppressing crystallization of glass and improving the light transmittance, and any one or more of these SrO and BaO are contained in the lead-free glass composition. It is essential. Moreover, the content is 0.1 to 20% in total in the mass% of oxide conversion. The total content of one or more of SrO and BaO is in this range. If the total content is less than 0.1%, the lead-free glass becomes unstable and lead-free formed. This is because the glass crystallizes to reduce the light transmission.

On the other hand, if one or more of SrO and BaO is contained exceeding 20% in total strength, the thermal expansion coefficient becomes too large, warping during firing, causing cracks and making firing itself difficult. .

In such a point, the content of one or more of SrO and BaO is preferably 0.1 to 15% in total, more preferably 0.2 to 10%, and 0.3 to 0.3%. ~ 8% Power S More preferred.

[0018] Note that one or more of MgO and CaO and one or more of SrO and BaO are the sum of them, that is, the total of MgO, CaO, SrO, and BaO. The calculated mass% should be 0.2 to 25%.

Outside these ranges, lead-free balance in properties such as glass stability, soft spot below 600 ° C, high light transmission, optimization of thermal expansion coefficient, and chemical durability. This is because it cannot be made of glass.

The total amount of MgO, CaO, SrO, and BaO is 0.2% to 23% in terms of oxide in terms that the above characteristics can be balanced in a range suitable for the formation of a PDP dielectric layer. Power S is preferable, more preferably 0.4 to 20%, and still more preferably 0.6 to 15%.

[0019] ZnO is an optional component, and can reduce the glass melting while suppressing the change in the thermal expansion coefficient of the glass. However, this ZnO may cause the lead-free glass to become unstable, lead to crystallization of the lead-free glass that is formed, and may reduce light transmission. Therefore, the content is 0 to 15% in terms of mass% in terms of oxide, more preferably 13% or less, and further preferably 10% or less.

[0020] In addition, the lead-free glass composition of the present embodiment can contain other components than those described above as long as the effects of the present invention are not impaired.

Examples of the other components include components such as CuO and impurity components that suppress yellowing due to reaction with the electrode when forming a PDP dielectric layer. When this CuO is contained in a lead-free glass composition, it is preferably 0.1 to 1% in terms of mass% in terms of oxide.

[0021] By setting the lead-free glass composition of the present invention to the composition as described above, the content of BiO is reduced.

twenty three

For example, while suppressing to 5% or less by mass% in terms of acid hydrate, further, the content of BiO

The lead-free glass composition has a low softness of 600 ° C or less while keeping 2 3 substantially 0% (composition not containing Bi 2 O).

twenty three

It can be excellent in light transmittance at the conversion point.

[0022] When lead-free glass is formed using these lead-free glass compositions, all raw materials are mixed and melted at a temperature of, for example, 1000 to 1300 ° C to produce a uniform glass, and the glass is then ball milled. A glass having a uniform property can be obtained by making the powder by a pulverizing means such as.

In addition, the powder produced as described above, general binder resin and solvent, etc. It is possible to form a glass film having a uniform thickness by applying paste onto the glass substrate by screen printing or the like, drying and sintering.

In addition, a glass sheet having a uniform thickness can be formed by producing a green sheet using the powder glass produced as described above, pressing the glass sheet onto a glass substrate, and sintering the green sheet.

In the present embodiment, the case where the PDP front plate is used as a lead-free glass for a dielectric layer has been described as an example.

Lead-free glass for the dielectric layer of the PDP front plate is strongly demanded to be lead-free and to have a low softening point that can be sintered on a glass substrate. In addition, there is a strong demand for improved light transmission. Therefore, the effect can be remarkably exhibited by using the lead-free glass composition of the present invention.

However, the use of the lead-free glass composition of the present invention is not limited to the dielectric layer of the PDP front plate. For example, the lead-free glass composition of the present invention can also be used for the dielectric layer of the PDP rear plate and the partition.

The strength and appearance of the PDP back plate can be adjusted by, for example, mixing a lead-free glass composition and an oxide ceramics filler for the dielectric layer and partition walls.

As this oxide ceramic filler, a single or mixed mixture of silica, alumina, titania, zircoure, etc. can be used.

In the present invention, the lead-free glass composition is not limited to the PDP application as illustrated above but can be used for applications other than the PDP.

Example

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Examples 1 to 15, Comparative Example 1 to: LO)

The compounding materials used to produce the lead-free glass compositions of the examples and comparative examples are as follows.

Compounding material: SiO ,: H BO, Al O, ZnO, MgCO, CaCO, SrCO, BaCO, Li C O, Na CO, K CO, CuO

3 2 3 2 3

The above compounding materials were prepared so as to have the compositions shown in Tables 1 and 2, and after mixing, they were melted at a temperature of about 1000 to 1300 ° C for 1 to 2 hours using a platinum crucible. The molten glass was quenched with a stainless steel cooling roll to produce glass flakes.

Next, the glass flakes were pulverized, and powder glass having an average particle size of 1 to 3 m was prepared by air classification.

The powder glass was used as a sample for differential thermal analysis (DTA).

Further, after the above powder glass was press-molded and fired, a cylindrical sample having a diameter of 5 mm X a length of 15 mm was prepared and used as a sample for measuring a thermal expansion coefficient.

Further, a glass paste was prepared from the powdered glass and a vehicle mainly composed of ethylcellulose and tervineol.

The obtained glass paste was screen-printed on a glass substrate (trade name “PD-200” manufactured by Asahi Glass Co., Ltd.) to a thickness of 30 m after sintering. A light transmittance measurement sample having a thickness of 30 μm was fired at a temperature 5 ° C. higher than the soft spot of the lead-free glass composition for 30 minutes.

Furthermore, the glass paste used for the preparation of the light transmittance measurement sample was used as an observation sample for the reaction (yellowing) with the electrode.

(Evaluation)

1) Softening point

Powder glass samples using the lead-free powder glass of each Example and Comparative Example were used for 20 ° CZ min in an atmospheric environment using DTA (model name “Cho 0-8120”) manufactured by Rigaku Corporation. Differential thermal analysis measurement was performed at the rate of temperature increase, and the point at which the endothermic peak during softening was completed was determined by the tangential method and was defined as the softening point. The results are shown in Tables 1 and 2.

2) Thermal expansion coefficient

Using a rod-shaped sample made of lead-free powder glass of each example and comparative example and a standard sample made of quartz glass, a thermomechanical analyzer manufactured by Rigaku Corporation (trade name `` TMA8 310 ") and the coefficient of thermal expansion was measured. In the measurement, the thermal expansion curve was measured by raising the temperature from room temperature at 10 ° C Zmin, and the values of thermal expansion coefficients observed from 50 ° C to 350 ° C were averaged for each example and comparative example. The coefficient of thermal expansion of the lead-free powder glass. The results are also shown in Tables 1 and 2. (Normally, the thermal expansion coefficient is within a range of 60~85 X 10- ⁷ Z ° C, sintering time of cracks and fissures, problems such as warping can sufficiently reduce the possibility of occurrence.)

3) Light transmittance

Using a spectrophotometer manufactured by Hitachi High-Technologies Corporation (model name Γυ-3010 (without integrating sphere)), a test piece on which a glass film having a thickness of 30 m was formed in each example and comparative example. The light transmittance was determined. The results are shown in Tables 1 and 2.

4) Yellowing

A silver electrode is formed on a glass substrate (trade name “PD-200” manufactured by Asahi Glass Co., Ltd.), and a glass paste is screen-printed on this glass substrate, which is 5 ° C higher than the soft spot. After firing at temperature for 30 minutes, the occurrence of yellowing in the silver electrode portion was visually observed.

As a result of the observation, a force with no yellowing was judged as “◯”, a slight yellowing was observed as “Δ”, and a clear yellowing was judged as “X”. The results are shown in Tables 1 and 2.

[table 1]

[0027] [Table 2]

[0028] From this table, the mass ^_0/0 terms of oxides, SiO force ~ 30%, BO is 30 to 60%, Al O

2 2 3 2 3 Force Sl ~ 25%, Li 0, Na O and KO any one or more total 5 ~ 20%, MgO and C Any one or more of aO is a total of 0.1 to 15%, and one or more of SrO and BaO is a total of 0.1 to 20%, and the total force of MgO, CaO, SrO and BaO is 0.2. A lead-free glass composition characterized by having a composition of ˜25% and ZnO of 0˜15% has a low softness of 600 ° C. or less while suppressing (or without using) bismuth. It can be seen that at the saddle point, the force is excellent in light transmittance.

Furthermore, when the Li O content is X, the Na O content is X, and the K 2 O content is X,

2 Li 2 Na 2 K

, Li 2 O, Na 2 O and K 2 O are in a composition ratio satisfying (X + X) ZX ≤ 1

2 2 2 Li Na K

It can also be seen that yellowing (reaction with the electrode) can be more reliably suppressed, and that the lead-free glass composition can be made suitable for forming a dielectric layer of DP.

Claims

The scope of the claims

[1] in a weight ^_0/0 terms of oxides, SiO force ~ 30%, BO force 0 to 60%, Al O force ^ ~ 25%

2 2 3 2 3

, Li 0, Na O, and 力何れ Any one or more total 5 to 20%, MgO or CaO

2 2 2

Force 1 or more types total 0.1 to 15%, SrO and BaO any one or more types total 0.1 to 20%, force also MgO, CaO, SrO and BaO total 0.2 to 25% A lead-free glass composition having a composition in which ZnO is 0 to 15%.

[2] Oxygen equivalent mass%, Li O content X, Na O content X, K O content

2 Li 2 Na 2

When the amount is X, Li 0, Na O and Κ Repulsive force

Κ 2 2 2

The lead-free glass composition according to claim 1.

(X + Χ) / Χ ≤ 1

Li Na K

[3] The lead-free glass composition according to [1] or [2], wherein the composition further contains 0.1 to 1% of CuO in mass% in terms of acid oxide.

[4] A lead-free glass for a dielectric layer of a plasma display panel used for forming a dielectric layer of a plasma display panel, wherein the lead-free glass composition according to any one of claims 1 to 3 is used. Lead-free glass for dielectric layers of plasma display panels.

5. The lead-free glass for a dielectric layer of a plasma display panel according to claim 4, which is used for forming a dielectric layer of a front plate of the plasma display panel.