JP2008069033A - Lead-free low melting point glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead-free low melting point glass showing restrained yellowing in the silver mirror reaction and having high visible light transmissivity required in the development of a substrate as an electronic material represented by a plasma display panel. <P>SOLUTION: This glass is a B<SB>2</SB>O<SB>3</SB>/ZnO/Bi<SB>2</SB>O<SB>3</SB>lead-free low melting point glass containing 0-7 SiO<SB>2</SB>, 10-20 B<SB>2</SB>O<SB>3</SB>, 7-20 ZnO, 60-78 Bi<SB>2</SB>O<SB>3</SB>, 0-10 BaO, 0-10 R<SB>2</SB>O(Li<SB>2</SB>O+Na<SB>2</SB>O+K<SB>2</SB>O), 0-10 RO(MgO+CaO+SrO), 0-8 Al<SB>2</SB>O<SB>3</SB>, 0-2 CuO, 0-3 La<SB>2</SB>O<SB>3</SB>, 0-2 CeO<SB>2</SB>, 0-1 CoO, 0-1 MnO<SB>2</SB>, and 0-5 TiO<SB>2</SB>by wt.%. It has also a coefficient of thermal expansion at 30-300°C of (65-100)×10<SP>-7</SP>/°C and a softening point of not lower than 450°C but not higher than 550°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is an insulating coating material for an electronic material substrate typified by a plasma display panel, a liquid crystal display panel, an electroluminescence panel, a fluorescent display panel, an electrochromic display panel, a light emitting diode display panel, a gas discharge display panel, etc. The present invention relates to a low-melting glass used.

  With the recent development of electronic components, many types of display panels such as plasma display panels, liquid crystal display panels, electroluminescence panels, fluorescent display panels, electrochromic display panels, light emitting diode display panels, and gas discharge display panels have been developed. Has been. Among them, a plasma display panel (hereinafter abbreviated as PDP) is attracting attention as a thin and large flat color display device. In a PDP, a large number of cells are provided between a front substrate and a rear substrate used as a display surface, and an image is formed by performing plasma discharge in the cells. This cell is partitioned by partition walls, and an electrode is formed for each pixel unit in order to control the display state of each pixel forming an image.

  An electrode for discharging plasma is formed on the front glass plate of the plasma display panel, and thin linear silver is often used as the electrode. Around the electrode, an insulating coating material having high transparency is disposed. This insulating coating material is excellent in plasma durability and is preferably transparent. For this reason, dielectric glass is often used as the insulating coating material. The dielectric glass is naturally required to have a melting point lower than that of the glass plate serving as the substrate in the process, and therefore low-melting glass is used.

  However, with conventional low melting point dielectric glass, firing at a low temperature of 450 to 600 ° C. causes a phenomenon that the dielectric glass reacts with the silver of the bus electrode and the dielectric glass is colored yellow (yellowing), resulting in high transmission. There was a big problem that the rate could not be obtained.

Regarding this yellowing, there are various known techniques to be solved by adjusting the glass component. A material for plasma display which contains SiO ₂ , Al ₂ O _3, etc. as essential components, for example, limits the contents of PbO and CuO and prevents silver diffusion by Cu (for example, see Patent Document 1), and CuO In addition to the above, the same effect can be obtained by further adding SrO, and a material for plasma display in which the content of BaO + SrO + MgO is limited (see, for example, Patent Document 2), and a material for plasma display in which the content of BaO + CaO + Bi ₂ O ₃ is limited ( For example, see Patent Document 3).
JP 2001-52621 A JP 2001-80934 A JP 2001-48577 A

  In conventional low-melting-point dielectric glass, which is an insulating coating material, a phenomenon occurs in which the dielectric layer (glass) is colored yellow (yellowing) due to the reaction between the glass and the silver electrode, and the visible light transmittance is reduced. There's a problem. It is difficult to respond to this yellowing phenomenon, and it has not yet been able to respond to the level desired by the market.

  Conventionally, lead glass has been adopted as the low melting point glass. Although the lead component is an important component for making the glass have a low melting point, it has a great detrimental effect on the human body and the environment. In recent years, there is a tendency to avoid its use. Yes.

  That is, Japanese Patent Application Laid-Open Nos. 2001-52621, 2001-80934, and 2001-48577 show a considerable improvement against yellowing, but basically contain lead. There is a problem.

The present invention is a transparent insulating lead-free low-melting glass, in which the SiO ₂ is 0 to 7, the B ₂ O ₃ is 10 to 20, the ZnO is 7 to 20, the Bi ₂ O ₃ is 60 to 78, and the BaO is by weight%. _{0~10, R 2 O (Li 2} O + Na 2 O + K 2 O) of 0~10, RO (MgO + CaO + SrO) of 0, _Al 2 _{O 3} 0-8, 0-2 and CuO, the La ₂ O ₃ 0 to 3, CeO ₂ 0 to 2, CoO 0 to 1, MnO ₂ 0 to 1, TiO ₂ 0 to 5 B ₂ O ₃ —ZnO—Bi ₂ O ₃ based lead-free low It is a melting point glass.

Moreover, it is said lead-free low melting glass whose thermal expansion coefficient in 30 degreeC-300 degreeC is (65-100) x10 < ^-7 > / degreeC, and a softening point is 450 degreeC or more and 550 degrees C or less.

  Furthermore, it is an electronic material substrate using the above lead-free low-melting glass as an insulating coating material.

  Furthermore, the PDP panel uses the above lead-free low-melting glass as an insulating coating material.

  It is possible to obtain a glass in which a phenomenon in which the glass and the silver electrode are reacted and the glass is colored yellow (yellowing), which has been a problem with the low melting point dielectric glass which is a conventional insulating coating material, is reduced.

The present invention is a transparent insulating lead-free low-melting glass, in which the SiO ₂ is 0 to 7, the B ₂ O ₃ is 10 to 20, the ZnO is 7 to 20, the Bi ₂ O ₃ is 60 to 78, and the BaO is by weight%. _{0~10, R 2 O (Li 2} O + Na 2 O + K 2 O) of 0~10, RO (MgO + CaO + SrO) of 0, _Al 2 _{O 3} 0-8, 0-2 and CuO, the La ₂ O ₃ 0 to 3, CeO ₂ 0 to 2, CoO 0 to 1, MnO ₂ 0 to 1, TiO ₂ 0 to 5 B ₂ O ₃ —ZnO—Bi ₂ O ₃ based lead-free low It is a melting point glass.

SiO ₂ is a glass forming component and can form a stable glass, and is contained in an amount of 0 to 7% (% by weight, the same applies hereinafter). If it exceeds 7%, the softening point of the glass will increase, making the formability and workability difficult. More preferably, it is 2 to 5% of range.

B ₂ O ₃ is a glass-forming component similar to SiO ₂ , facilitates glass melting, suppresses an excessive increase in the thermal expansion coefficient of the glass, and imparts moderate fluidity to the glass during baking, together with SiO ₂ It decreases the dielectric constant. It is preferable to contain 10 to 20% in glass. If it is less than 10%, the fluidity of the glass becomes insufficient and the sinterability is impaired. On the other hand, if it exceeds 20%, the softening point of the glass increases. More preferably, it is 10 to 18% of range.

  ZnO lowers the softening point of the glass and adjusts the thermal expansion coefficient to an appropriate range. However, ZnO is a component that deteriorates the stability, and is preferably contained in the glass in a range of 7 to 20%. If it is less than 7%, the effect cannot be exhibited, and if it exceeds 20%, the stability deteriorates. More preferably, it is 9 to 18% of range.

Bi ₂ O ₃ is a glass forming component, facilitates glass melting, and lowers the softening point of glass. It is preferable to make it contain in glass at 60 to 78%. If it is less than 60%, the glass softening point is not sufficiently lowered, and the sinterability is impaired. On the other hand, if it exceeds 78%, the thermal expansion coefficient of the glass becomes too high. More preferably, it is 62 to 75% of range.

R ₂ O (Li ₂ O, Na ₂ O, K ₂ O) lowers the softening point of glass, imparts moderate fluidity, and adjusts the thermal expansion coefficient to an appropriate range, and is in the range of 0 to 10%. It is preferable to contain. If it exceeds 10%, the thermal expansion coefficient is excessively increased. More preferably, it is 0 to 7% of range.

  BaO lowers the softening point of the glass and improves the sinterability. It is preferable to make it contain in glass at 0 to 10%. If it exceeds 10%, the thermal expansion coefficient of the glass becomes too high. More preferably, it is 0 to 7% of range.

Al ₂ O ₃ is a component that improves the stability of the glass and is preferably contained in the range of 0 to 8%. If it exceeds 8%, the softening point becomes too high. More preferably, it is 0 to 6% of range.

  CuO has the effect of relaxing the silver electrode used as the bus electrode wire and the dielectric layer reacting to diffuse silver in the dielectric layer and causing silver colloid coloration (yellowing). It is preferable to make it contain in the range. If it exceeds 2%, the glass is colored and the transparency is lowered. More preferably, it is 0 to 1% of range.

La ₂ O ₃ has the effect of mitigating silver colloid coloration (yellowing) caused by the reaction between the silver electrode used as the bus electrode line and the dielectric layer, and the diffusion of silver into the dielectric layer. It is preferable to make it contain in the range of% or less. If it exceeds 3%, the glass becomes unstable. More preferably, it is 0 to 1% of range.

CeO ₂ has the effect of mitigating silver colloid coloration (yellowing) due to the reaction between the silver electrode used as the bus electrode wire and the dielectric layer, and the diffusion of silver into the dielectric layer, which is less than 2% It is preferable to contain in the range. If it exceeds 2%, the glass is colored and the transparency is lowered. More preferably, it is 0 to 1% of range.

  CoO has the effect of relaxing the silver electrode used as the bus electrode wire and the dielectric layer reacting to diffuse silver into the dielectric layer and causing silver colloid coloration (yellowing), and is less than 1%. It is preferable to make it contain in the range. If it exceeds 1%, the glass is colored and the transparency is lowered. More preferably, it is 0 to 0.7% of range.

MnO ₂ has the effect of mitigating silver colloid coloration (yellowing) due to the reaction between the silver electrode used as the bus electrode wire and the dielectric layer, and the diffusion of silver into the dielectric layer. It is preferable to contain in the range. If it exceeds 1%, the glass is colored and the transparency is lowered. More preferably, it is 0 to 0.8% of range.

TiO ₂ has the effect of reducing the silver colloid coloration (yellowing) caused by the reaction between the silver electrode used as the bus electrode wire and the dielectric layer, and the diffusion of silver into the dielectric layer, resulting in 5% or less. It is preferable to contain in the range. If it exceeds 5%, crystals are precipitated and the transparency is lowered. More preferably, it is 0 to 4% of range.

CuO, La ₂ O _3, CeO _2, CoO, MnO ₂ , TiO ₂ These have the same effect, so there is also a reasonable range for the sum, which is 0.2-4.0

  RO (MgO + CaO + SrO) imparts moderate fluidity to glass and adjusts the thermal expansion coefficient to an appropriate range, and is contained in the range of 0 to 10%. If it exceeds 10%, the thermal expansion coefficient excessively increases. More preferably, it is 0 to 7% of range.

In addition, In ₂ O ₃ , SnO ₂ , TeO ₂ , Fe ₂ O ₃ , ZrO ₂ or the like represented by a general oxide may be added.

  By substantially not containing PbO, it is possible to eliminate the influence on the human body and the environment. Here, “substantially free of PbO” means an amount of PbO mixed as an impurity in the glass raw material. For example, if it is in the range of 0.3 wt% or less in the low-melting glass, there is almost no influence on the adverse effects described above, that is, the influence on the human body and the environment, the insulation characteristics, etc., and it is not substantially affected by PbO. Become.

The above lead-free low melting point glass having a thermal expansion coefficient of (65 to 100) × 10 ⁻⁷ / ° C. at 30 ° C. to 300 ° C. and a softening point of 450 ° C. or higher and 550 ° C. or lower. When the thermal expansion coefficient is outside (65 to 100) × 10 ⁻⁷ / ° C., problems such as peeling of the coating film and warping of the substrate occur when the thick film is formed. Preferably, it is in the range of (70 to 85) × 10 ⁻⁷ / ° C. Further, by setting the softening point to 550 ° C. or less, not only high strain point glass conventionally used in PDP but also soda lime glass having a strain point of 600 ° C. or less can be used. Preferably, it is 450 degreeC or more and 540 degrees C or less.

  Furthermore, the present invention is an electronic material substrate using the above-described low-melting glass as an insulating coating material. By using the low-melting glass described above, a substrate for electronic material in which yellowing is suppressed can be obtained.

  Furthermore, the present invention is a PDP panel using the low melting point glass as an insulating coating material. By using the low melting point glass described above, a PDP panel in which yellowing is suppressed can be obtained.

  The present invention is a disclosure of a low-melting glass corresponding to the yellowing phenomenon caused by reaction with silver, and the object is not limited to a silver electrode.

  As the glass substrate, a transparent glass substrate, particularly soda-lime-silica glass, glass similar to the glass (high strain point glass), or alumino-lime borosilicate glass with little (or almost no) alkali is often used. Yes.

  Hereinafter, a description will be given based on examples.

(Production of low melting point glass mixed paste)
As shown in the table, after preparing each component to have a desired low melting point glass composition, it is put into a platinum crucible and heated and melted in an electric heating furnace at 1000 to 1300 ° C. for 1 to 2 hours. The glass of the composition shown in Examples 1-5 and Comparative Examples 1-3 of Table 2 was obtained.

ガラスの一部は型に流し込み、ブロック状にして熱物性(熱膨張係数、軟化点)測定用に供した。残余のガラスは急冷双ロール成形機にてフレーク状とし、粉砕装置で平均粒径１〜４μｍ、最大粒径１０μｍ未満の粉末状に整粒した。

A part of the glass was poured into a mold, made into a block shape, and used for measurement of thermal properties (thermal expansion coefficient, softening point). The remaining glass was flaked with a rapid cooling twin roll molding machine and sized with a pulverizer into a powder having an average particle size of 1 to 4 μm and a maximum particle size of less than 10 μm.

  Next, paste oil composed of α-terpineol and butyl carbitol acetate was mixed with ethyl cellulose as a binder and the above glass powder to prepare a paste having a viscosity of about 300 ± 50 poise.

(Formation of insulating coating)
The paste was applied using an applicator to a soda-lime glass substrate having a thickness of 2 to 3 mm and a size of 100 mm square so that the film thickness after baking was about 20 μm, thereby forming an application layer. Next, after drying, a clear dielectric layer was formed by firing at 550 ° C. or lower for 10 to 60 minutes.

  The obtained sample was observed with the naked eye and a microscope, and it was judged that the yellowing phenomenon was markedly suppressed as compared with the conventional sample, and the others were marked with x.

The softening point was the temperature when the viscosity coefficient η = 10 ^7.6 was reached using a Littleton viscometer. Moreover, the thermal expansion coefficient was calculated | required from the amount of elongation at 30-300 degreeC when it heated up at 5 degree-C / min using the thermal dilatometer.

(result)
The low melting point glass composition and various test results are shown in the table.

  As shown in Examples 1 to 5 in Table 1, within the composition range of the present invention, the occurrence of yellowing was significantly suppressed as compared with the conventional one.

  On the other hand, Comparative Examples 1 to 3 in Table 2 outside the composition range of the present invention, as in the prior art, show significant yellowing, or do not show preferred physical properties, and have a low melting point glass for substrate coating such as PDP. As inapplicable.

Claims (4)

The transparent insulating lead-free low-melting-point glass, a SiO ₂ 0 to 7 _weight%, B 2 _{O 3} 10 to 20, the ZnO 7~20, Bi ₂ O ₃ and 60 to 78, 0 to BaO, R ₂ O (Li ₂ O + Na ₂ O + K ₂ O) 0-10, RO (MgO + CaO + SrO) 0-10, Al ₂ O ₃ 0-8, CuO 0-2, La ₂ O ₃ 0-3 the CeO ₂ 0 to 2, 0-1 and CoO, MnO ₂ 0 to 1, the TiO _2, characterized in that it comprises _{0~5 B 2 O 3 -ZnO-Bi} 2 O 3 based lead-free low-melting-point glass. 2. The lead-free low-melting glass according to claim 1, wherein the coefficient of thermal expansion at 30 ° C. to 300 ° C. is (65 to 100) × 10 ⁻⁷ / ° C. and the softening point is 450 ° C. or higher and 550 ° C. or lower. 3. A substrate for electronic materials, wherein the lead-free low melting point glass according to claim 1 is used as an insulating coating material. A PDP panel, wherein the lead-free low melting point glass according to claim 1 is used as an insulating coating material.