JP4692918B2 - Sealing material - Google Patents

Description

  The present invention relates to a sealing material, specifically a sealing paste and a sealing tablet, which can make the interval between the sealing materials constant.

  The sealing material is used after being uniformly mixed with a glass powder mainly composed of a low-melting glass and a filler powder and then processed into a sealing paste or a sealing tablet in order to improve workability.

  The sealing paste is produced by adding and kneading a vehicle mainly composed of a resin and a solvent to uniformly mixed glass powder and filler powder. The paste thus prepared is applied between the sealed material and the sealed material by screen printing, a dispenser, or the like, and the sealed material and the sealed material are sealed by heat treatment.

  The tablet for sealing is added to a glass powder and filler powder that are uniformly mixed, and a granule is formed by adding a vehicle mainly composed of a resin and a solvent. It is produced by volatilizing, burning, and decomposing.

  Incidentally, in recent years, flat panel displays (FPD) such as plasma display panels (PDP), liquid crystal panel displays (LCD), and organic EL displays are becoming popular as information display media. These FPDs have a hollow structure in which two substrates are bonded to each other at a certain interval in the periphery of a glass substrate.

In particular, in the PDP, since the display screen is large and there are many heat treatment processes, it is difficult to keep the distance between the two substrates constant. Therefore, a method has been proposed in which glass beads (granular material) having the same size as the desired interval are added to the sealing material (see, for example, Patent Documents 1 to 3).
JP 2001-236896 A JP 2003-36794 A JP 2003-217464 A

  The PDP produced by the methods described in Patent Documents 1 to 3 certainly had less variation in the distance between the two substrates than when no glass beads were used. However, the stress concentrates on some glass beads, so that there is a possibility that the substrate may be cracked, and the sealing part may leak because the glass beads are close to each other.

  An object of the present invention is to provide a sealing material that can reduce variations in the distance between substrates and that does not cause cracks in the substrate or leakage at the sealing part.

The sealing material of the present invention is a sealing material containing glass powder and beads, wherein 0.01 to 7 parts by mass of beads are added to 100 parts by mass of glass powder , and the particle size of the beads is 30. a ～200Myuemu, with a maximum particle size and minimum particle size of the beads is within ± 20% of the average particle diameter, wherein the ratio der Rukoto less 200ppm beads minor axis / major axis is 0.6 or less And

  The sealing material of the present invention can reduce the variation in the distance between the sealed object and the sealed object by means of beads, and can suppress the occurrence of cracks and leaks at the sealed part.

In the sealing material of the present invention, the bead is less than 0.01 part by weight of the glass powder 100 parts by weight, since the stress applied to a single bead is increased, possibly sealing kimono or article to be sealed is damaged is there.

  On the other hand, if the number of beads is more than 7 parts by mass, the beads are likely to be adjacent to each other, so that there is a risk of leakage from the cavity between them.

In the sealing material of the present invention, the beads are preferably 0.03 to 6 parts by mass, more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the glass powder.

  The sealing material of the present invention is preferable from the viewpoint of the environment if it does not substantially contain lead.

  The beads must be a material that does not soften and deform when sealed, and is made of alumina, zinc silicate, cordierite, zirconia, zircon, niobium phosphate, borosilicate glass, soda lime glass, and aluminoborosilicate glass. One kind selected from the above or a mixture of two or more kinds can be used.

  In particular, alumina and zirconia have high strength, and borosilicate glass, soda lime glass, and aluminoborosilicate glass are preferable because they have a thermal expansion coefficient close to that of the sealing material.

As the glass powder, Sn-P-based glass, Bi-B-based glass, Pb-B-based glass, Pb-Si-based glass, B-Si-based glass, and the like can be used. In particular, Sn-P-based glass, Bi-- B-based glass is preferred as a sealing material due to its low melting point.

Filler powder is added to adjust the thermal expansion coefficient of the sealing material and to adjust the viscosity of the sealing material at the time of sealing, cordierite, willemite, alumina, zircon, tin oxide, β-eucryptite, Lead titanate, KZr ₂ (PO ₄ ) ₃ , NbZr (PO ₄ ) ₃ , Na _0.5 Nb _0.5 Zr _1.5 (PO ₄ ) ₃ , K _0.5 Nb _0.5 Zr _1.5 (PO ₄ ) ₃ , Ca _0.5 Zr ₂ (PO ₄ ) ₃ and WO ₄ Zr ₂ (PO ₄ ) ₂ may be used alone or in combination of two or more selected from the group consisting of WO ₄ Zr ₂ (PO ₄ ) ₂ .

In particular, lead titanate is preferable because it has a low thermal expansion coefficient, and phosphoric acid compounds such as cordierite and NbZr (PO ₄ ) ₃ do not contain lead.

  The mixing ratio of the glass powder and the filler powder is preferably expressed by mass%, and is 40 to 70 mass% of the glass powder and 30 to 60 mass% of the filler powder.

Sealing material of the present invention, the maximum particle size and minimum particle size of the beads is within ± 20% of the average particle diameter, Ru can reduce variations in the distance between the sealing kimono and the article to be sealed in the sealing portion. More preferably, it is within ± 15%, and further preferably within ± 10%.

  In addition, the average particle diameter of beads is an average value obtained by measuring 100 arbitrary particles by a photography method, and the particle diameter of beads indicates each measured value.

  In the sealing material of the present invention, it is preferable that the ratio of beads having a minor axis / major axis of 0.6 or less is 200 ppm or less, because variations in the distance between the sealed article and the sealed article in the sealed part can be reduced. That is, the closer the bead is to a true sphere, the smaller the influence of the bead orientation. Preferably it is 100 ppm or less, More preferably, it is 20 ppm or less.

  In addition, the short diameter and long diameter of a bead refer to the shortest diameter and longest diameter in the same bead when the bead is assumed to be an elliptical sphere.

Because the spacing between the sealing kimono and the article to be sealed is about 30 to 200 [mu] m, the particle size of the beads Ru 30 to 200 [mu] m der.

  When the form of the sealing material of this invention is a sealing paste, it produces as follows.

  First, a mixed powder is produced in which glass powder and filler powder are uniformly mixed with 40 to 70 mass% glass powder and 30 to 60 mass% filler powder in terms of mass%.

  Next, a vehicle composed of a resin and a solvent as main components is added to the mixed powder and kneaded using a roll mill or the like to prepare a sealing paste precursor.

  In addition, when the addition amount of the vehicle with respect to 100 mass parts of mixed powder is 7-80 mass parts, the viscosity of the sealing paste precursor tends to become 200-1500 poise, and it is preferable when performing screen printing etc.

  Finally, 0.01 to 7 parts by mass of beads with respect to 100 parts by mass of the glass powder is added to the sealing paste precursor, and the beads are uniformly diffused to produce a sealing paste.

  The resin is a component that adjusts the viscosity of the vehicle. As the resin, ethyl cellulose, polyethylene glycol derivatives, nitrocellulose, polymethylstyrene, polyethylene carbonate, methacrylic acid ester, and the like can be used.

  Solvents include N, N′-dimethylformamide (DMF), terpineol, γ-butyrolactone, tetralin, butyl carbitol acetate, ethyl acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, benzyl alcohol, toluene, 3-methoxy -3-methylbutanol, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, propylene carbonate, dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone or the like can be used.

  When the form of the sealing material of this invention is a sealing tablet, it produces as follows.

  First, a mixed powder is produced in which glass powder and filler powder are uniformly mixed with 40 to 70 mass% glass powder and 30 to 60 mass% filler powder in terms of mass%.

  Next, a vehicle composed of a resin and a solvent as main components is added to the mixed powder to produce granules having a particle size of about 1 mm.

  In addition, since 3-10 mass parts of vehicles are added with respect to 100 mass parts of mixed powder, since mixed powder tends to become a granular form, it is preferable.

  Subsequently, 0.01 to 7 parts by mass of beads are added to the granules with respect to 100 parts by mass of the glass powder, and press molding is performed to produce a sealing tablet precursor.

  Finally, the vehicle is burned, volatilized or decomposed by temporary baking at 350 to 400 ° C. for 10 to 30 minutes to produce a sealing tablet.

  The glass powder, filler powder, beads, resin, and solvent described above can be used, but are not limited to those materials.

  Hereinafter, it demonstrates in detail based on the Example of this invention.

  Table 1 shows bead samples A to E, and Tables 2 and 3 show sealing material samples 1 to 8.

In Samples A to E, beads having low sphericity were observed from each commercially available bead using an optical microscope (magnification: 50 times), and the beads were removed and used for the preparation of Samples 1 to 8 .

  Samples A to E were measured for average particle size, maximum particle size, minimum particle size, sphericity and softening point.

  The average particle diameter is an average value obtained by measuring 100 arbitrary particles by a photography method.

  The maximum particle size and the minimum particle size indicate the maximum and minimum measured values when the average particle size is measured.

  The sphericity was measured by measuring 100,000 beads using an optical microscope (magnification: 150 times), counting the number of beads having a minor axis / major axis of 0.6 or less, and calculating the ratio.

  The softening point was measured by a macro type differential thermal analysis (DTA) apparatus (manufactured by Rigaku).

  Samples 1 to 8 were produced as follows.

  First, a glass powder (average particle size: 5 μm) and filler powder (average particle size: 5 μm) shown in the table were mixed at a ratio described in the table to prepare a mixed powder.

  Next, 50 parts by mass of an acetate ester containing 1% by mass of nitrocellulose as a vehicle was added to 100 parts by mass of the mixed powder, and kneaded using a roll mill to prepare a sealing paste precursor.

  Finally, the beads described in the table (samples A to E) were added to the sealing paste precursor in the ratio described in the table, and the beads were uniformly diffused to prepare the sealing paste (samples 1 to 8). .

  Samples 1 to 8 were evaluated for sealing thickness, substrate cracking and leakage as follows.

  First, two substrates (30 × 40 mm) made of the materials shown in the table were prepared, and each sample was applied to one central portion with an area of 20 × 20 and dried at 100 ° C. for 15 minutes.

  Next, the vehicle component was removed by baking for 10 minutes at a temperature 10 ° C. lower than the softening point of the glass powder described in the table.

Subsequently, another substrate was placed on the fired sample, and the substrate was held between the substrates so that the pressure was 2 kgf / cm ² .

  Finally, the holding time described in the table was held at the sealing temperature described in the table.

  The sealing thickness was determined by measuring the distance between the substrates using an optical microscope (magnification: 100 times).

  Substrate cracking was visually evaluated as “X” when the substrate was cracked or cracked, and “◯” when the substrate was not cracked or cracked.

  Leakage was visually evaluated as “X” when a gap was generated between adjacent beads (samples A to E), and “◯” when no gap was generated.

  As is clear from Table 2, Samples 1 to 5 were not cracked or cracked in the substrate and did not leak.

  On the other hand, as apparent from Table 3, the samples 6 and 8 were leaked, and the samples 7 and 8 were cracked or cracked in the substrate.

  Since the sealing material of the present invention can be sealed at equal intervals without leaks and cracks, it is suitable for sealing FDPs such as PDP and FED, and glass or ceramic packages on which various components are mounted. It can be used.

Claims (6)

A sealing material containing glass powder and beads, wherein 0.01 to 7 parts by mass of beads are added to 100 parts by mass of glass powder , and the bead particle size is 30 to 200 μm. particle size and with the minimum particle size is within ± 20% of the average particle diameter, the sealing material the proportion of beads minor axis / major axis is 0.6 or less, characterized in der Rukoto below 200 ppm. The beads are one or more selected from the group consisting of alumina, zinc silicate, cordierite, zirconia, zircon, niobium phosphate, borosilicate glass, soda lime glass, and aluminoborosilicate glass. The sealing material according to claim 1. The sealing material according to claim 1 or 2, wherein the glass powder is Sn-P glass or Bi-B glass . The sealing material according to any one of claims 1 to 3, further comprising filler powder. The sealing material according to any one of claims 1 to 4, which is substantially free of lead. The sealing material according to claim 1, wherein the sealing material is used for sealing a PDP substrate.