JP2006117440A - Lead-free glass having low melting point - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide lead-free glass having a low melting point, which is prevented from yellowing due to silver reaction and has high visible light transmittance, and which is required in the development of an electronic material substrate represented by a plasma display panel. <P>SOLUTION: The lead-free low melting point glass is SiO<SB>2</SB>-B<SB>2</SB>O<SB>3</SB>-R<SB>2</SB>O-CuO-based glass which contains, by weight, 20-38% SiO<SB>2</SB>, 45-65% B<SB>2</SB>O<SB>3</SB>, 0-5% ZnO, 8-20% R<SB>2</SB>O (Li<SB>2</SB>O+Na<SB>2</SB>O+K<SB>2</SB>O), 0.1-2% CuO, 0-2% MnO<SB>2</SB>, and 0-20% RO(MgO+CaO+SrO+BaO); and which is characterized in that the coefficient of thermal expansion within a temperature range of 30-300°C is (65-95)×10<SP>-7</SP>/°C and the softening point is within a range of 500-600°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to 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, and the like. The present invention relates to a low melting point glass used as a sealing material.

  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. A highly transparent insulating material is disposed around the electrode. This insulating material is preferably excellent in plasma durability and transparent. For this reason, dielectric glass is often used as an insulating 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), and materials for plasma display (see, for example, Patent Document 4) with limited contents of SiO ₂ , B ₂ O ₃ , ZnO, Bi ₂ O ₃ , BaO, and Al ₂ O ₃ are disclosed. Has been.
JP 2001-52621 A JP 2001-80934 A JP 2001-48577 A JP 2003-226549 A

  In the conventional dielectric material (insulating material), there is a problem that the visible light transmittance is lowered due to a phenomenon that the dielectric layer is colored yellow (yellowing) by the reaction between the glass and the silver electrode. 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-based glass has been employed for low-melting glass, for example, low-melting glass for substrate coating. 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 the basics that lead is contained. There is a problem. Furthermore, JP 2003-226549 A does not contain lead, and a considerable improvement against yellowing is recognized, but as well as lead, it contains bismuth that tends to be avoided from an environmental standpoint. Yes.

The present invention provides a transparent insulating lead-free low-melting-point glass, SiO ₂ and 20 to 38 _weight%, B 2 _{O 3} 45 to 65, 0-5 and _{ZnO, R 2 O (Li 2} O + Na 2 O + K 2 O ) 8 to 20, a _{SiO 2 -B 2 O 3 -R 2} O-CuO system lead-free low-melting glass, which comprises a CuO 0.1 to 2.

Further, in weight%, which is above the lead-free low-melting glass, characterized in that it comprises a MnO ₂ 0 to 2.

Moreover, it is said lead-free low melting glass whose thermal expansion coefficient in 30 degreeC-300 degreeC is (65-95) x10 < ^-7 > / degreeC, and a softening point is 500 degreeC or more and 600 degrees C or less.

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

  Still further, the present invention is a PDP panel using the above lead-free low melting point glass.

  The present invention relates to 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, and the like. In the low melting point glass used as the sealing material, it is possible to suppress a phenomenon in which the dielectric layer is colored yellow (yellowing) due to a reaction between the glass and the silver electrode.

The present invention provides a transparent insulating lead-free low-melting-point glass, SiO ₂ and 20 to 38 _weight%, B 2 _{O 3} 45 to 65, 0-5 and _{ZnO, R 2 O (Li 2} O + Na 2 O + K 2 O ) 8 to 20, a _{SiO 2 -B 2 O 3 -R 2} O-CuO system lead-free low-melting glass, which comprises a CuO 0.1 to 2.

SiO ₂ is a glass-forming component, and can form a stable glass by coexisting with another glass-forming component B ₂ O _3, and 20% (weight%, the same applies to the following) ) The above is contained. If it exceeds 40%, the softening point of the glass will increase, making the formability and workability difficult. More preferably, it is 30 to 36% 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 make it contain in glass at 45 to 65%. If it is less than 45%, the fluidity of the glass becomes insufficient and the sinterability is impaired. On the other hand, if it exceeds 65%, the stability of the glass is lowered. More preferably, it is 47 to 60% of range.

  ZnO lowers the softening point of the glass and adjusts the thermal expansion coefficient to an appropriate range, but it is a component that induces yellowing and is preferably contained in the range of 0 to 5%. If it exceeds 5%, the occurrence of yellowing becomes remarkable. More preferably, it is 0 to 3% 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 8 to 20%. It is preferable to contain. If it is less than 8%, the above effect cannot be exhibited, and if it exceeds 20%, the thermal expansion coefficient is excessively increased. More preferably, it is 11 to 17% of range.

  CuO has the effect of relieving 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). It is preferable to make it contain in 2% of range. If it is less than 0.1%, the above effect cannot be exhibited, and if it exceeds 2%, the glass is colored and the transparency is lowered. More preferably, it is 0.1 to 1% of range.

MnO ₂ has the effect of mitigating 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 to cause the color of silver colloid (yellowing). It is preferable to make it contain in the range of%. If it exceeds 2%, the glass is colored and the transparency is lowered. More preferably, it is 0 to 1% of range.
RO (MgO + CaO + SrO + BaO) imparts moderate fluidity to glass and adjusts the thermal expansion coefficient to an appropriate range, and is contained in the range of 0 to 20%. If it exceeds 20%, the thermal expansion coefficient excessively increases. More preferably, it is 0 to 10% of range.

In addition, In ₂ O ₃ , TiO ₂ , SnO ₂ , TeO 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 lead-free low melting point glass having a thermal expansion coefficient of (65 to 95) × 10 ⁻⁷ / ° C. and a softening point of 500 to 600 ° C. at 30 to 300 ° C. When the thermal expansion coefficient is outside (65 to 95) × 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 (75 to 85) × 10 ⁻⁷ / ° C. If the softening point exceeds 600 ° C., problems such as softening deformation of the substrate occur. Preferably, it is 500 degreeC or more and 590 degrees C or less. Furthermore, it is a substrate for electronic materials using the low melting point glass. 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 above-mentioned low melting point glass. 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.

  The lead-free low-melting glass of the present invention can be used, for example, on the front plate or the back plate of PDP glass. When used as a back plate, it is used as a sealing material or a covering material, and is often used after being powdered. This powdered glass is mixed with a low expansion ceramic filler represented by mullite or alumina, a heat-resistant pigment, etc. at a ratio of 0.6 {glass / (glass + filler) weight ratio} or more, and then organically. Generally, it is kneaded with oil to form a paste.

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

  Hereinafter, a description will be given based on examples.

(Production of low melting point glass mixed paste)
The fine silica sand as a SiO _{2 source,} a boric acid as a B 2 _{O 3} source, a zinc oxide as a ZnO source, lithium carbonate as Li ₂ O source, sodium carbonate as Na ₂ O source, potassium carbonate as _{K 2} O source Further, cupric oxide was required as the CuO source, manganese dioxide as the MnO ₂ source, magnesium carbonate as the MgO source, calcium carbonate as the CaO source, strontium carbonate as the SrO source, and barium carbonate as the BaO source. After preparing these as a desired low melting-point glass composition, it puts into a platinum crucible and heat-melts in 1000-1300 degreeC and 1-2 hours in an electric heating furnace, Examples 1-5 of Table 1, Table 1 The glass of the composition shown in 2 comparative examples 1-5 was obtained.

  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 made into flakes 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 600 ° 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 to the conventional case.

  On the other hand, Comparative Examples 1 to 5 in Table 2 outside the compositional range of the present invention show remarkable yellowing as in the prior art, or do not show preferable physical properties, and low melting point glass for substrate coating such as PDP. As inapplicable.

Claims (5)

The transparent insulating lead-free low-melting-point glass, SiO ₂ and 20 to 38 _weight%, B 2 _{O 3} 45 to 65, 0-5 and _ZnO, R 2 O and _{(Li 2 O + Na 2 O} + K 2 O) 8~ 20. A SiO ₂ —B ₂ O ₃ —R ₂ O—CuO-based lead-free low-melting glass characterized by containing 0 to 20 RO (MgO + CaO + SrO + BaO) and 0.1 to ₂ CuO. The lead-free low-melting-point glass according to claim 1, wherein the lead-free low-melting glass contains 0 to 2 MnO ₂ by weight. The coefficient of thermal expansion at 30 ° C to 300 ° C is (65 to 95) × 10 ^-7 / ° C, and the softening point is 500 ° C or higher and 600 ° C or lower. Melting point glass. A lead-free low-melting glass according to any one of claims 1 to 3 is used. 4. A PDP panel using the lead-free low melting point glass according to claim 1.