JP5219238B2 - Glass paste composition - Google Patents

Description

  The present invention relates to a glass paste composition used for sealing parts composed of glass, ceramics, metals, and the like, and in particular, a cathode ray tube (CRT), a plasma display (PDP), a field emission display (FED), and a fluorescence. The present invention relates to a glass paste composition suitable for bonding or sealing materials having different compositions and sealing or coating an IC package or the like in the manufacture of a display tube (VFD) or the like.

For example, when manufacturing a gas discharge display panel such as a PDP, a transparent electrode, a dielectric layer, a protective layer, etc. are formed on the front substrate, and an address electrode, a barrier, a phosphor layer, etc. are formed on the rear substrate. The periphery of the substrate is joined with a sealing material to exhaust the internal space and enclose a discharge gas. Since each substrate is heated to a high temperature of several hundred degrees in the manufacturing process, a glass substrate having a thermal expansion coefficient of about 85 × 10 ⁻⁷ / ° C. is used in order to suppress thermal deformation due to thermal shrinkage and align thermal expansion with the mounted components. It is done. As the sealing material, a low melting point glass frit having a sealing temperature of 400 to 500 ° C. and a thermal expansion coefficient of about 70 to 80 × 10 ⁻⁷ / ° C. is used.

  The sealing material is prepared in a paste form, that is, a glass paste composition by dispersing a low-melting glass frit and refractory filler particles in a solvent in which a resin is dissolved. Here, many of these low-melting glass frit are mainly composed of Pb, but lead-free glass frit containing no lead has been attracting attention in recent years due to environmental considerations. The refractory filler particles are contained in the glass paste in order to reduce the coefficient of thermal expansion between the glass frit and the object to be sealed and to reduce the strain remaining in the object to be sealed after sealing.

And the above glass paste composition is applied to the periphery of the back substrate to a width of 3 to 5 mm and a thickness of about 10 to 500 μm by using a dispenser or the like, and 20 to 30 ° C. from the softening temperature of the glass frit. After pre-baking at a relatively high temperature, after firing together with the front substrate at a temperature about 20 ° C. higher than the softening temperature of the glass frit, sealing is performed while evacuating below the softening temperature of the glass frit ( (See Patent Documents 1 and 2).
JP 62-72543 A WO00 / 45411

  The above glass paste composition is heated to the softening temperature or higher and adheres to each other, that is, the above-described PDP manufacturing example, for example, bonding and sealing a front substrate and a back substrate. In the sealing operation, the glass paste composition is heated in a state where it is applied to the substrate. At this time, if the thermal conductivity of the glass paste is poor, the melting of the glass frit is deteriorated, and bubbles existing in the glass frit are present. May not be removed by calcination. If air bubbles remain inside the glass frit, the sealing performance by the glass frit may not be maintained, which may be a factor that impairs the reliability of the plasma panel after sealing.

  Therefore, an object of the present invention is to suppress bubbles that are likely to remain in the glass frit as much as possible by improving the thermal conductivity while keeping the softening temperature low in order to solve the above problems. Moreover, in that case, it exists in improving without containing lead which becomes a problem from an environment.

The present invention for achieving the above object, in an organic solvent containing a dispersing agent, in the glass paste composition containing dispersed filler particles with low melting point glass frit mainly composed of vanadium, said filler particles that thermal conductivity Using a thing whose rate is 3.7 W / m · K or more larger than the thermal conductivity of the low melting point glass frit ,
The filler particles (this usage amount is b) to the low melting point glass frit (this usage amount is a) are contained in the range of 20 to 50% by mass as {(b / a + b) × 100}. It is said.

In the above invention, the low melting point glass frit containing vanadium as a main component has a composition in terms of oxide of V ₂ O ₅ : 45 to 65% by mass, P ₂ O ₅ : 15 to 27% by mass, Sb ₂ O. _3: 5 to 25 wt%, BaO: 1 to 15 _wt%, TeO 2: 0 to 10 wt%, and a glass transition temperature _{(T g)} 300 to 380 ° C., a crystallization temperature _{(T cry)} is It is preferable that it is 480 degreeC or more (Claim 2). Further, the filler powder is a ceramic powder (for example, _Al 2 _{O 3)} and / or a high melting point glass frit (e.g., glass mainly containing SiO ₂₎ is preferably (claim 3-5).

In the present invention of claim 1, as a glass paste composition, the main component and the difference in thermal conductivity of the filler powder of more than 3.7 W / m · K than the low melting glass frit vanadium, the low melting point glass frit ( By containing this usage amount in the range of 20 to 50% by mass as the blending amount {(b / a + b) × 100} of the filler particles with respect to a) (this usage amount is b) , heat is applied in the sealing operation. Air bubbles remaining in the sealing portion can be reduced by being transmitted quickly and uniformly to the whole. As a result, the present invention can improve the reliability of sealing with glass frit. Moreover, since the glass frit is lead-free glass, environmental problems can be eliminated.

  In the case of Claim 2, the composition of suitable vanadium containing glass, glass characteristic temperature, etc. are specified. In the case of Claims 3-5, all can have the above-mentioned advantage, using cheap and easily available filler powder.

  Hereinafter, as an example of the glass paste composition according to the present invention, the glass frit configuration, the filler configuration, the combination configuration of the glass frit and filler, and the blending configuration will be described in this order, and then the usefulness thereof will be clarified by giving examples. .

The (glass frit configuration) low-melting glass frit, vanadium as a main component, in the composition of oxides in _terms, V ₂ O 5: _{45~65 wt%, P} 2 O 5: _15~27 wt%, Sb ₂ O ₃ : 5 to 25% by mass, BaO: 1 to 15% by mass, TeO ₂ : 0 to 10% by mass, glass transition temperature (T _g ) of 300 to 380 ° C., crystallization temperature (T _cry ) Is preferably 480 ° C. or higher. Next, the reason for limiting the composition range will be described.

V ₂ O ₅ is a useful material for suppressing expansion of glass with a lower melting point. This content is preferably in the range of 45 to 65 mass%. This is because when the content of V ₂ O ₅ is less than 45% by mass, the melting point becomes high and the sealing temperature rises, so that sealing of display tubes and ICs with a sealing temperature of 400 to 500 ° C. This is because it is not suitable for sealing or covering a package or the like, and conversely, if the content of V ₂ O ₅ exceeds 65% by mass, the weather resistance as a glass frit is lowered, and as a sealing material for glass. This is because the reliability of the device is impaired.

P ₂ O ₅ is a useful material as a glass forming oxide. This content is preferably in the range of 15 to 27% by mass. This is because when the content of P ₂ O ₅ is less than 15% by mass, the glass frit is easily crystallized, and the glass sealing portion becomes brittle. Conversely, the content of P ₂ O ₅ is 27% by mass. If it exceeds 50%, the melting point of the glass frit becomes high and the sealing temperature rises as in the case of V ₂ O ₅ , so it is not suitable for sealing display tubes and IC packages. is there.

Sb ₂ O ₃ is a material useful for improving the weather resistance of glass. This content is preferably in the range of 5 to 25% by mass. This is because, when the content of Sb ₂ O ₃ is less than 5% by mass, the weather resistance is lowered and the reliability as a glass sealing material is lacking. Conversely, the content of Sb ₂ O ₃ If the amount exceeds 25% by mass, the softening behavior deteriorates, and film formation as a sealing film becomes difficult.

  BaO is a material useful for improving chemical stability. This content is preferably in the range of 1 to 15% by mass. This is because the effect cannot be obtained if the content of BaO is less than 1% by mass. Conversely, if the content of BaO exceeds 15% by mass, the melting point of the glass frit increases and the sealing temperature increases. Because it invites.

TeO ₂ is a material useful for improving the melting temperature and chemical stability. This content is preferably in the range of 0 to 10% by mass. This is because when the content of TeO ₂ exceeds 10% by mass, the stability is adversely affected.

The above composition range was confirmed from the test, and in the low melting point glass frit having the composition range, the thermal conductivity is about 0.7 to 0.8 W / m · K. As the glass temperature characteristic, glass transition temperature _{(T g)} 300 to 380 ° C., a crystallization temperature _{(T cry)} is 480 ° C. or higher.

(Filler composition) The filler particles used together with the above low melting glass frit are ceramic powder and / or high melting glass frit. In this case, Al ₂ O ₃ is preferably used as the filler powder in the case of ceramic powder. In the case of a high melting point glass frit, glass mainly composed of SiO ₂ is preferable. The thermal conductivity of these filler powders is about 4.5 to 7.0 W / m · K, which is higher than the thermal conductivity of the low melting point glass frit described above of 0.7 to 0.8 W / m · K. .

(Combination structure) The low melting point glass frit and the filler powder are combined so that the difference in thermal conductivity between them is 3.7 W / m · K or more. This is because the difference in thermal conductivity between the low melting point glass frit and the filler powder is 3.7 W / m · K or more, thereby improving the thermal conductivity characteristics, so that heat can be quickly transferred to the entire paste in the sealing operation. This is because it can be transmitted uniformly. In other words, in the conventional configuration, since the difference in thermal conductivity did not reach 3.7 W / m · K, the effect of containing filler powder having high thermal conductivity was hardly exhibited. For this reason, it is necessary to contain a large amount of filler powder, but if an excessive amount of filler powder is contained, the strain on the bonding surface increases. This is an example in which the above-mentioned substrates are bonded to each other. When the strain between the seal frit and the substrate increases, the bonding surface becomes brittle against external stress and impact, and the bonding surface is destroyed to provide a sealing function. It means becoming easy to lose. The present invention eliminates such problems.

(Blended configuration) or as the content of the filler powder to the low-melting glass frit (amount), the difference of both the thermal conductivity of about 3.7 W / m · K (this value is, for example, of SiO ₂ based high In the case of a melting point glass frit of about 4.5 W / m · K), it is 20 to 50% by mass, preferably 30 to 40% by mass. When the difference in thermal conductivity between the two is about 6.5 W / m · K (this value is about 7.2 W / m · K for Al ₂ O ₃ ceramic powder, for example), preferably 5 to 30% by mass, Is 10 to 20% by mass. Therefore, in the present invention, the content (blending amount) of the filler powder (this usage amount b) with respect to the low melting point glass frit (this usage amount a ) , that is, {(b / a + b) × 100} is 20 to 50. It was set as mass%.

  In such a relationship between the difference in thermal conductivity and the blending amount, when the thermal conductivity difference is small, it is necessary to contain a large amount of filler powder. Conversely, when it is necessary to reduce the filler powder, the object of the present invention can be achieved by adopting a filler having a large difference in thermal conductivity. The thermal conductivity of the sealed portion by the glass paste composition can be improved by including a filler powder having a higher thermal conductivity than the low melting point glass frit, but if the change rate of the thermal conductivity is small, the sealed portion. There is no change in the number (or degree) of bubbles remaining inside.

  In addition, it becomes possible to obtain a temperature distribution integrated with the glass substrate by making the rate of change of thermal conductivity almost the same or higher than that of general glass, and heating and cooling during sealing This makes it easier to remove distortion.

  This example is an example when a glass paste composition in which the filler composition and the compounding composition are changed to the glass frit structure considering the above thermal conductivity is prepared and actually evaluated through a sealing operation.

In Example (Preparation of glass frit), a glass raw material _formulation, the V 2 _{O 5} and 55 _g, the P 2 _{O 5} 20 g, a TeO ₂ 5 g, a BaO 5 g, and 10g of _Sb 2 _{O 3,} the entire amount 100g As above, using a platinum crucible, the oxide was dissolved by maintaining at 900 ° C. for 30 minutes in the atmosphere, and then cooled to vitrify.

  The obtained glass was coarsely pulverized in a mortar, and further pulverized using a ball mill (processing time: about 30 minutes) to obtain a glass frit having an average particle diameter of 10 μm. The average particle size of the glass frit was measured using a laser optical particle size distribution analyzer SALD-2000 (manufactured by Shimadzu Corporation). The produced low melting point glass frit was measured for thermal conductivity by a laser flash method using a thermal constant measuring device TC-3000 type (manufactured by Vacuum Riko). This thermal conductivity was 0.701 W / m · K.

(Specification of filler) As filler powder, alumina particles (Al ₂ O ₃ , indicated as alumina ceramics in the table) and silica particles (SiO ₂ , indicated as silica in the table) are used as ceramic powders. Further, SiO ₂ —B ₂ O ₃ —Na ₂ O glass frit (in the table, referred to as “high melting point glass frit”) was used as the high melting point glass frit. Similar to the low melting point glass frit, the thermal conductivity was measured by a laser flash method. The respective thermal conductivities were 7.22 W / m · K for alumina particles, 1.47 W / m · K for silica particles, and 4.72 W / m · K for high melting point glass frit.

(Preparation of Glass Paste) A paste sample was prepared using the glass frit having an average particle diameter of 10 μm and the filler powder (in the table, high melting point glass frit, alumina ceramic, silica). That is, here, according to the combination of glass frit and filler described in Table 1, 60 g of the glass frit is filled with fillers according to paste samples (sample numbers 1 to 6, 11 to 16, 21 and 22 in total). The powder (corresponding to the type-amount in the filler column in 1) was blended in 40 g of a vehicle prepared in advance, mixed using a mortar, and then kneaded with a three-roll mill to obtain a glass paste sample. Here, the vehicle is obtained by dissolving ethyl cellulose (dispersing agent) in butyl carbitol (organic solvent). The content of ethyl cellulose is 30% by mass.

(Evaluation sample preparation and evaluation method) Using each glass paste sample (14 samples in total in Table 1) prepared as described above, a glass substrate (PD200 manufactured by Asahi Glass Co., Ltd.) having a length of 50 mm, a width of 50 mm, and a thickness of 2 mm. The outer edge portion of) was applied with a dispenser with a width of about 3 mm and a thickness of about 1 mm for sealing. After the application, the paste coating film was leveled by standing at room temperature for 10 minutes, and then heated at 150 ° C. for 10 minutes to volatilize the organic solvent in the paste coating film to some extent. Then, temporary baking was performed under the conditions of a heating temperature of 440 ° C. and a heating time of 30 minutes. After the preliminary firing, bubbles present on the bonding surface between the glass frit and the glass plate were observed, and the area ratio of the bubbles to the glass frit was evaluated. In addition, when the area ratio of the bubbles to the glass frit exceeds 5%, a connected hole may be formed, which causes a slow leak. In the evaluation results shown in Table 1, when the area ratio of the bubbles exceeded 5%, the evaluation was x, and when the ratio was 5% or less, the evaluation was ○.

(Table 1)

(Results) In Table 1, sample No. 1 having a blending ratio of about 14.3% by mass among sample Nos. 1 to 6 to which a high melting point glass frit having a thermal conductivity of 4.72 W / m · K is added. The area ratio of the bubbles was 8.2%, but in the samples Nos. 2 to 6 having a higher blending ratio, the area ratio of the bubbles was less than 5% (the average value of the bubble area ratio was 4.2%). It was.

  On the other hand, in the samples Nos. 11 to 16 to which alumina ceramics having a thermal conductivity of 7.22 W / m · K were added, in the sample No. 11 having a blending ratio of about 3% by mass, the area ratio of the bubbles was large 6.7%. Met. However, in the sample No. 12 and the sample (Sample Nos. 13 to 16) in which the blending amount is about 5% by mass, the bubble area ratio was 4.8% or less. Sample numbers 21 and 22 to which a high melting point glass frit and a mixed filler of alumina ceramics, or a mixed filler of alumina and silica between ceramics were added had a bubble area ratio of 4% or less, and the remaining bubbles were reduced. I was able to.

Claims (5)

In a glass paste composition in which filler particles are dispersed together with a low melting point glass frit mainly composed of vanadium in an organic solvent containing a dispersant,
The filler particles have a thermal conductivity of 3.7 W / m · K or more larger than the thermal conductivity of the low-melting glass frit ,
The filler particles (this usage amount is b) to the low melting point glass frit (this usage amount is a) are contained in the range of 20 to 50% by mass as {(b / a + b) × 100}. Glass paste composition.
The low melting point glass frit containing vanadium as a main component has a composition in terms of oxide of V ₂ O ₅ : 45 to 65% by mass, P ₂ O ₅ : 15 to 27% by mass, Sb ₂ O ₃ : 5 to 25. % By mass, BaO: 1 to 15% by mass, TeO ₂ : 0 to 10% by mass, a glass transition temperature (T _g ) of 300 to 380 ° C., and a crystallization temperature (T _cry ) of 480 ° C. or more. The glass paste composition according to claim 1.   The glass paste composition according to claim 1, wherein the filler powder is a ceramic powder or / and a high melting point glass frit. The glass paste composition according to claim ₃ , wherein the ceramic powder is Al ₂ O ₃ . The glass paste composition according to claim 3, wherein the high melting point glass frit is a glass containing SiO ₂ as a main component.