JP2012162441A - Sealing material and paste material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase long-term reliability of an organic EL device or the like utilizing an organic EL element package by inventing a sealing material capable of being laser-sealed by a low output laser.SOLUTION: The sealing material includes at least an SnO-containing glass powder, a refractory filler and a pigment, has a ratio (average particle diameter Dof SnO-containing glass powders/average particle diameter Dof refractory fillers) of 0.6-4, and is used for the laser-sealing.

Description

  The present invention relates to a sealing material and a paste material using the same, and more specifically to a sealing material used for a sealing process using a laser (hereinafter referred to as laser sealing) and a paste material using the same.

  In recent years, organic EL displays have attracted attention as flat display panels. Since the organic EL display can be driven by a direct current voltage, the driving circuit can be simplified, and there are advantages such as a liquid crystal display that does not depend on the viewing angle, is bright because of self-emission, and has a high response speed. Currently, organic EL displays are mainly used in small portable devices such as mobile phones, but in the future, application to ultra-thin televisions is expected. Note that the organic EL display is mainly driven by disposing an active element such as a thin film transistor (TFT) in each pixel in the same manner as a liquid crystal display.

  The organic EL display is composed of two glass substrates, a negative electrode such as metal, an organic light emitting layer, a positive electrode such as ITO, and an adhesive material. Conventionally, an organic resin adhesive material such as an epoxy resin having a low temperature curability or an ultraviolet curable resin has been used as the adhesive material. However, organic resin adhesive materials cannot completely block gas intrusion. For this reason, when an organic resin adhesive material is used, the airtightness inside the organic EL display cannot be maintained, and as a result, the organic light emitting layer having low water resistance is easily deteriorated, and the organic EL display There was a problem that the display characteristics of the display deteriorated with time. In addition, the organic resin-based adhesive material has an advantage that the glass substrates can be bonded to each other at a low temperature. However, since the water resistance is low, when the organic EL display is used for a long time, the reliability of the display is likely to be lowered. .

US Pat. No. 6,416,375 JP 2006-315902 A

  The sealing material containing glass powder is excellent in water resistance as compared with the organic resin adhesive material, and is suitable for ensuring airtightness inside the organic EL display.

  However, since glass powder generally has a softening temperature of 300 ° C. or higher, it has been difficult to apply it to an organic EL display. More specifically, when sealing glass substrates with the above-mentioned sealing material, the entire organic EL display is put into an electric furnace and baked at a temperature equal to or higher than the softening temperature of the glass powder to soften and flow the glass powder. It was necessary to let them. However, since the active element used in the organic EL display has only heat resistance of about 120 to 130 ° C., sealing the glass substrates by this method damages the active element due to heat, and the organic EL display. Display characteristics will deteriorate. In addition, since the organic light emitting material also has poor heat resistance, sealing the glass substrates by this method damages the organic light emitting material due to heat and degrades the display characteristics of the organic EL display.

  In view of such circumstances, in recent years, laser sealing has been studied as a method for sealing an organic EL display. According to laser sealing, since only the portion to be sealed can be locally heated, it is possible to seal the glass substrates while preventing thermal degradation of the active element or the like.

  Patent Documents 1 and 2 describe laser sealing of glass substrates of a field emission display. However, Patent Documents 1 and 2 do not describe a specific material configuration, and it is unclear what material configuration is suitable for laser sealing. For this reason, even if the sealing material is irradiated with the laser, the sealing material cannot absorb the laser accurately, and it is difficult to efficiently convert the laser light into heat energy in the portion to be sealed. . If the output of the laser is increased, laser sealing can be performed without optimizing the material configuration. In this case, however, the active element or the like may be heated to deteriorate the display characteristics of the organic EL display. .

  Therefore, the present invention has a technical problem to improve the long-term reliability of an organic EL device using an organic EL element package by creating a sealing material that can be laser-sealed with a low-power laser. .

As a result of intensive studies, the present inventors use a sealing material containing at least a SnO-containing glass powder, a refractory filler, and a pigment, and regulate the particle size of the SnO-containing glass powder and the particle size of the refractory filler to a predetermined range. Thus, the present inventors have found that the above technical problem can be solved, and propose as the present invention. That is, the sealing material of the present invention is a sealing material containing at least a SnO-containing glass powder, a refractory filler, and a pigment, wherein (average particle diameter D ₅₀ of SnO-containing glass powder) / (average of refractory filler) The particle size D ₅₀ ) ratio is 0.6 to 4 and is used for laser sealing. Here, the “SnO-containing glass powder” refers to a glass powder containing 20 mol% or more of SnO as a glass composition. The “average particle diameter D ₅₀ ” refers to a value measured with a laser diffraction particle size distribution meter. In the volume-based cumulative particle size distribution curve when measured with a laser diffraction particle size distribution meter, the accumulated amount is the particle size. The particle size is 50% cumulative from the smallest.

  The sealing material of the present invention includes at least a SnO-containing glass powder, a refractory filler, and a pigment. In this way, the efficiency and reliability of laser sealing can be improved. In addition, since SnO containing glass powder has a low softening temperature, it can soften and flow at a low temperature. Since the refractory filler has a low thermal expansion coefficient, it is possible to reduce the thermal expansion coefficient of the sealing material. Since the pigment is excellent in color developability, the laser absorbability is good.

The present inventors have found that when the fired film and an object to be sealed (glass substrate or the like) are brought into close contact with each other, laser sealing can be performed with a low-power laser, and (average particle diameter D ₅₀ of SnO-containing glass powder) / When the ratio of (average particle diameter D ₅₀ of the refractory filler) is regulated to 0.6 to 4, the surface smoothness of the fired film (glaze film) is improved, and the adhesion between the fired film and the sealed object is significantly improved. I found out.

Therefore, the sealing material of the present invention can be laser-sealed with a low-power laser. As a result, since the airtightness inside the organic EL device can be properly secured, it is possible to prevent the situation where H ₂ O, O ₂ or the like that deteriorates the organic light emitting layer enters the inside of the organic EL device. Long-term reliability can be improved.

Secondly, the sealing material of the present invention preferably has an average particle diameter _{D 50} of the SnO-containing glass powder is 1.0 to 3.0 m.

Third, the sealing material of the present invention preferably has an average particle diameter D50 of the refractory filler of _0.5 to 2.0 μm.

Fourthly, in the sealing material of the present invention, the pigment is preferably amorphous carbon or graphite. Amorphous carbon or graphite has excellent color developability, so it has good laser absorption and prevents the SnO-containing glass powder from being altered during laser sealing, that is, during laser sealing. SnO in the glass composition has the effect to prevent the oxidation in SnO ₂ in.

Fifth, the sealing material of the present invention preferably has an average particle size D ₅₀ of the primary particles of the pigment is 1 to 100 nm.

  Sixth, the sealing material of the present invention preferably has a pigment content of 0.05 to 1% by mass. If the pigment content is regulated to 0.05% by mass or more, the laser light can be efficiently converted into thermal energy, so that only the portion to be sealed is easily heated locally. It becomes easy to laser seal glass substrates together while preventing thermal degradation. On the other hand, if the pigment content is regulated to 1% by mass or less, excessive heating during laser irradiation can be suppressed, and it is easy to prevent the glass from devitrifying during laser sealing.

Seventh, the sealing material of the present invention, SnO-containing glass powder, as a glass composition, in mole%, SnO 35 to _70%, preferably contains _P 2 O 5 _10~30%.

  Eighth, the sealing material of the present invention is characterized in that the SnO-containing glass powder contains 1 to 20 mol% of ZnO as a glass composition.

Ninth, the sealing material of the present invention, SnO-containing glass powder, a glass composition _preferably contains B 2 _{O 3} 1 to 20 mol%.

Tenth, the sealing material of the present invention, SnO-containing glass powder, a glass composition preferably contains _Al 2 _{O 3} 0.1 to 10 mol%.

  Eleventhly, in the sealing material of the present invention, the mixing ratio of the SnO-containing glass powder and the refractory filler is preferably 40 to 99.9%: 0.1 to 60% by volume.

Twelfth, the sealing material of the present invention, as the refractory filler, cordierite, zircon, tin oxide, niobium oxide, zirconium phosphate-based ceramic, NbZr (PO _{4) 3} from one or more selected It is preferable to contain.

  Thirteenth, the sealing material of the present invention is preferably used for sealing an organic EL device. Here, the “organic EL device” includes an organic EL display, an organic EL lighting device, and the like.

  14thly, the paste material of this invention is a paste material containing a sealing material and a vehicle, The sealing material is said sealing material.

  15thly, as for the paste material of this invention, it is preferable that a vehicle contains an aliphatic polyolefin-type carbonate. Sixteenth, in the paste material of the present invention, the vehicle further comprises N, N′-dimethylformamide, ethylene glycol, dimethyl sulfoxide, dimethyl carbonate, propylene carbonate, butyrolactone, caprolactone, N-methyl-2-pyrrolidone. It is preferable that 1 type, or 2 or more types chosen from phenyl diglycol (PhDG), dibutyl phthalate (DBP), benzyl glycol (BzG), benzyl diglycol (BzDG), and phenyl glycol (PhG) are included.

Seventeenth, the paste material of the present invention is preferably subjected to a binder removal treatment in an inert atmosphere. Here, the “inert atmosphere” includes a neutral gas atmosphere such as an N ₂ gas atmosphere and an Ar gas atmosphere, and a reduced pressure atmosphere such as a vacuum atmosphere.

  Eighteenth, the paste material of the present invention is preferably subjected to laser sealing in an inert atmosphere.

  Nineteenth, the method for producing a fired film of the present invention is a method for producing a fired film by firing a paste material, and the surface roughness Ra of the fired film is 0.6 μm or less, The paste material is baked so that the roughness RMS is 1.0 μm or less. Here, “surface roughness Ra” refers to a value measured by a method based on JIS B0601: 2001. “Surface roughness RMS” refers to a value measured by a method based on JIS B0601: 2001.

  20thly, the laser sealing method of this invention is characterized by performing laser sealing by irradiating said baking film with a laser.

It is a schematic diagram which shows the softening temperature of the sealing material when it measures with a macro type | mold DTA apparatus. It is data which shows the influence which phenylglycol (PhG) has on the drying rate of a paste material.

In the sealing material of the present invention, the ratio (average particle diameter _{D 50} of the refractory filler) / (average particle diameter _D 50 of the SnO-containing glass powder) is 0.6 to 4, preferably from 0.8 to 3. (Average particle diameter _D 50 of the SnO-containing glass powder) / a ratio (average particle diameter _{D 50} of the refractory filler) is less than 0.6, the specific surface area of the refractory filler is too large relative to the SnO-containing glass powder As a result, the SnO-containing glass powder tends to be devitrified, and as a result, the softening flow of the sealing material may be hindered, and unevenness tends to remain on the surface of the fired film due to devitrification. On the other hand, (the average particle diameter D ₅₀ of the SnO-containing glass _{powder) /} (average particle diameter D ₅₀ of the refractory _filler) ratio granularity of the refractory filler is increased relative to 4 larger than the particle size of SnO-containing glass powder Moreover, since the refractory filler powder itself does not soften and flow, irregularities easily remain on the surface of the fired film. In addition, when the unevenness | corrugation of a baked film is large, the surface smoothness of a baked film will be impaired, and it will become difficult to adhere | attach objects to be sealed (for example, glass substrates) uniformly before laser sealing, As a result, it becomes difficult to perform laser sealing with a low-power laser.

  The sealing material of the present invention is used for laser sealing. As described above, according to laser sealing, only the portion to be sealed can be locally heated, so that the glass substrates can be sealed together while preventing thermal degradation of the active element or the like.

Various lasers can be used for laser sealing. In particular, a semiconductor laser, a YAG laser, a CO ₂ laser, an excimer laser, an infrared laser, and the like are preferable in terms of easy handling.

In the sealing material of the present invention, the average particle diameter _{D 50} of the SnO-containing glass powder 1.0 to 3.0 m, particularly 1.5~2.5μm is preferred. The average particle diameter D ₅₀ of the SnO-containing glass powder is 1.0μm less than the glass tends to devitrify during firing, there is a possibility that the softening flow of the sealing material is inhibited. Further, the glass powder tends to aggregate during pulverization and classification, and remains as an aggregate after kneading the paste material, which may cause clogging of the screen mesh during screen printing. On the other hand, the average particle diameter D ₅₀ of the SnO-containing glass powder is larger than 3.0 [mu] m, the unevenness of the printing surface when the screen printing becomes too large, it becomes difficult to improve the surface smoothness of the fired film. Further, since the sealing material is softened and hardly flows during firing, it is necessary to raise the firing temperature. In this case, thermal damage to the sealed object is likely to increase, which may contribute to high cost.

In the sealing material of the present invention, the average particle diameter _{D 50} of the refractory filler is 0.5 to 2.0 [mu] m, particularly 0.5~1.8μm is preferred. The average particle diameter D ₅₀ and 0.5μm less than the refractory filler, refractory filler is easily dissolves in the glass during firing, there is a possibility that the softening flow of the sealing material is inhibited. In addition, the refractory filler easily aggregates during pulverization and classification, and remains as an aggregate after kneading the paste material, which may cause clogging of the screen mesh during screen printing. On the other hand, the average particle a diameter D ₅₀ of greater than 2.0μm of refractory filler, uneven printing surface when the screen printing becomes too large, it becomes difficult to improve the surface smoothness of the fired film.

In the sealing material of the present invention, the 90% particle size D ₉₀ of the SnO-containing glass powder is preferably 7.0 μm or less, and the 90% particle size D ₉₀ of the refractory filler is preferably 5.0 μm or less. In this way, it becomes easy to narrow the gap between both glass substrates, in this case, the time required for laser sealing is shortened, and even if there is a difference in the thermal expansion coefficient between the glass substrate and the sealing material, Cracks and the like are less likely to occur in the glass substrate and the sealed portion. Here, “90% particle size D ₉₀ ” refers to a value measured with a laser diffraction particle size distribution meter, and in the volume-based cumulative particle size distribution curve when measured with a laser diffraction particle size distribution meter, the integrated amount is The particle size is 90% cumulative from the smaller particle.

In the sealing material of the present invention, the maximum particle diameter D ₉₉ of the SnO-containing glass powder is preferably 15 μm or less, and the maximum particle diameter D ₉₉ of the refractory filler is preferably 10 μm or less. In this way, it becomes easy to narrow the gap between both glass substrates, in this case, the time required for laser sealing is shortened, and even if there is a difference in the thermal expansion coefficient between the glass substrate and the sealing material, Cracks and the like are less likely to occur in the glass substrate and the sealed portion. Here, the “maximum particle size D ₉₉ ” refers to a value measured by a laser diffraction particle size distribution meter, and in the volume-based cumulative particle size distribution curve measured by the laser diffraction particle size distribution meter, the accumulated amount is a particle size. The particle size is 99% cumulative from the smaller of the two.

In the sealing material of the present invention, the pigment is preferably an inorganic pigment, and carbon, Co ₃ O ₄ , CuO, Cr ₂ O ₃ , Fe ₂ O ₃ , MnO ₂ , SnO, and Ti _n O _2n-1 (n is an integer) 1 type or 2 types or more selected from the above are more preferable, and carbon is particularly preferable. These pigments have excellent color developability and good laser absorptivity. As carbon, amorphous carbon or griffite is preferable. These carbon has a property of easily processing the average particle diameter _{D 50} of the primary particles in the 1 to 100 nm.

In the sealing material of the present invention, the average particle diameter D50 of the primary particles of the pigment is preferably 1 to 100 nm, 3 to 70 nm, 5 to 60 nm, and particularly preferably 10 to ₅₀ nm. When the average particle diameter D ₅₀ of the primary particles of the pigment is too small, the pigment each other tend to aggregate, pigment becomes difficult to uniformly disperse, sealing material during the laser sealing is not locally softened flow There is a fear. On the other hand, too large an average particle diameter D ₅₀ of the primary particles of the pigment, the pigment is difficult to uniformly disperse, sealing material during the laser sealing there is a possibility not to locally soften flow.

  In the sealing material of the present invention, the pigment content is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.5% by mass. When there is too little content of a pigment, it will become difficult to convert the light of a laser into heat energy. On the other hand, if the content of the pigment is too large, the sealing material becomes difficult to soften and flow during laser sealing, and it becomes difficult to increase the sealing strength.

  The pigment preferably contains substantially no Cr-based oxide from the environmental viewpoint. Here, “substantially free of Cr-based oxide” refers to a case where the content of Cr-based oxide in the pigment is 1000 ppm (mass) or less.

In the sealing material of the present invention, the SnO-containing glass powder preferably contains SnO 35 to 70% and P ₂ O ₅ 10 to 30% as a glass composition in terms of the following oxide equivalent mol%. The reason for limiting the glass composition range as described above will be described below. In addition, in description of the content range of each component,% display points out mol% except the case where there is particular notice.

  SnO is a component that lowers the melting point of glass and is an essential component. The content is preferably 35 to 70%, 40 to 70%, particularly preferably 50 to 68%. If the SnO content is 50% or more, the glass tends to soften and flow during laser sealing. When the content of SnO is less than 35%, the viscosity of the glass becomes too high, and it becomes difficult to perform laser sealing with a desired laser output. On the other hand, if the SnO content is more than 70%, vitrification becomes difficult.

P ₂ O ₅ is a glass-forming oxide and is a component that increases the thermal stability of glass. The content is preferably 10 to 30%, 15 to 27%, particularly preferably 15 to 25%. When the content of P ₂ O ₅ is less than 10%, the thermal stability of the glass tends to be lowered. On the other hand, when the content of P ₂ O ₅ is more than 30%, reduces the weather resistance of the glass, it becomes difficult to ensure long-term reliability of the organic EL device or the like.

  In addition to the above components, for example, the following components may be added.

  ZnO is an intermediate oxide and a component that stabilizes the glass. The content is preferably 0 to 30%, 1 to 20%, particularly preferably 1 to 15%. When there is more content of ZnO than 30%, the thermal stability of glass will fall easily.

B ₂ O ₃ is a glass-forming oxide and a component that stabilizes the glass. _Further, B 2 _{O 3} is a component for enhancing the weather resistance of the glass. The content is preferably 0 to 20%, 1 to 20%, particularly preferably 2 to 15%. If the content of B ₂ O ₃ is more than 20%, the viscosity of the glass becomes too high, and it becomes difficult to perform laser sealing with a desired laser output.

Al ₂ O ₃ is an intermediate oxide and a component that stabilizes the glass. Al ₂ O ₃ is a component that lowers the thermal expansion coefficient of glass. The content is preferably 0 to 10%, 0.1 to 10%, particularly preferably 0.5 to 5%. When the content of Al ₂ O ₃ is more than 10%, the softening temperature of the glass powder is unduly increased, and it becomes difficult to perform laser sealing with a desired laser output.

SiO ₂ is a glass-forming oxide and is a component that stabilizes the glass. The content is preferably 0 to 15%, particularly preferably 0 to 5%. When the content of SiO ₂ is more than 15%, the softening temperature of the glass powder rises unreasonably and it becomes difficult to perform laser sealing with a desired laser output.

In ₂ O ₃ is a component that enhances the thermal stability of the glass, and its content is preferably 0 to 5%. When the content of In ₂ O ₃ is more than 5%, the batch cost increases.

Ta ₂ O ₅ is a component that enhances the thermal stability of the glass, and its content is preferably 0 to 5%. When the content of Ta ₂ O ₅ is more than 5%, the softening temperature of the glass powder is unduly increased, and it becomes difficult to perform laser sealing with a desired laser output.

La ₂ O ₃ is a component that enhances the thermal stability of the glass and is a component that enhances the weather resistance of the glass. The content is preferably 0 to 15%, 0 to 10%, particularly preferably 0 to 5%. When the content of La ₂ O ₃ is more than 15%, batch cost soars.

MoO ₃ is a component that enhances the thermal stability of the glass, and its content is preferably 0 to 5%. When the content of MoO ₃ is more than 5%, the softening temperature of the glass powder rises unreasonably and it becomes difficult to perform laser sealing with a desired laser output.

WO ₃ is a component that enhances the thermal stability of the glass, and its content is preferably 0 to 5%. When the content of WO ₃ is more than 5%, the softening temperature of the glass powder is unduly increased, and it becomes difficult to perform laser sealing with a desired laser output.

Li ₂ O is a component that lowers the melting point of glass, and its content is preferably 0 to 5%. The content of Li 2 _O is more than 5%, the thermal stability of the glass tends to decrease.

Na ₂ O is a component that lowers the melting point of glass, and its content is preferably 0 to 10%, particularly preferably 0 to 5%. When the content of Na 2 _O is greater than 10%, thermal stability of the glass tends to decrease.

K ₂ O is a component that lowers the melting point of glass, and its content is preferably 0 to 5%. When the content of K 2 _O is more than 5%, the thermal stability of the glass tends to decrease.

  MgO is a component that enhances the thermal stability of the glass, and its content is preferably 0 to 15%. When the content of MgO is more than 15%, the softening temperature of the glass powder rises unreasonably, making it difficult to perform laser sealing with a desired laser output.

  BaO is a component that enhances the thermal stability of the glass, and its content is preferably 0 to 10%. When the content of BaO is more than 10%, the component balance of the glass composition is impaired, and conversely, the glass is easily devitrified.

F ₂ is a component to lower the melting point of the glass, the content thereof is preferably 0 to 5%. When the content of F ₂ is greater than 5%, the thermal stability of the glass tends to decrease.

In consideration of thermal stability and low melting point characteristics, In ₂ O ₃ , Ta ₂ O ₅ , La ₂ O ₃ , MoO ₃ , WO ₃ , Li ₂ O, Na ₂ O, K ₂ O, MgO, BaO, The total amount of F ₂ is preferably 10% or less.

  In addition to the above components, other components (CaO, SrO, etc.) can be added, for example, up to 10%.

  It is preferable that the SnO-containing glass powder according to the present invention does not substantially contain a transition metal oxide. If it does in this way, it will become easy to prevent the situation where the thermal stability of glass falls. Here, “substantially no transition metal oxide” refers to the case where the content of the transition metal oxide in the glass composition is 3000 ppm (mass) or less, preferably 1000 ppm (mass) or less.

  In addition, it is preferable that the SnO containing glass powder which concerns on this invention does not contain PbO substantially from an environmental viewpoint. Here, “substantially no PbO” refers to the case where the content of PbO in the glass composition is 1000 ppm (mass) or less.

  The sealing material of the present invention includes a refractory filler. In this way, the thermal expansion coefficient of the sealing material can be reduced, and the mechanical strength of the sealing material can be increased. The mixing ratio of SnO-containing glass powder and refractory filler is 40-99.9% by volume%: 0.1-60%, 45-90%: 10-55%, 50-80%: 20-50%, 50 to 70%: 30 to 50%, particularly 50 to 65%: 35 to 50% is preferable. When there is too little content of a refractory filler, it will become difficult to receive the effect by a refractory filler. On the other hand, when there is too much content of a refractory filler, the ratio of SnO containing glass powder will become relatively small, and the efficiency of laser sealing will fall easily.

Zircon, zirconia, tin oxide, quartz, β-spodumene, cordierite, mullite, quartz glass, β-eucryptite, β-quartz, zirconium phosphate, zirconium phosphate tungstate, zirconium tungstate as refractory filler NbZr (PO ₄ ) _{3 and} other compounds having a basic structure of [AB ₂ (MO ₄ ) ₃ ],
A: Li, Na, K, Mg, Ca, Sr, Ba, Zn, Cu, Ni, Mn etc. B: Zr, Ti, Sn, Nb, Al, Sc, Y etc. M: P, Si, W, Mo etc. Alternatively, these solid solutions can be used.

  In the sealing material of the present invention, the softening temperature is preferably 450 ° C. or lower, 420 ° C. or lower, and particularly preferably 400 ° C. or lower. When the softening temperature is higher than 450 ° C., the efficiency of laser sealing tends to decrease. The lower limit of the softening temperature is not particularly limited, but it is preferable to limit the softening temperature to 300 ° C. or higher in consideration of the thermal stability of the SnO-containing glass. Here, the “softening temperature” refers to a value measured with a macro-type differential thermal analysis (DTA) apparatus in a nitrogen atmosphere, DTA starts measurement from room temperature, and the rate of temperature rise is 10 ° C./min. . In addition, the softening temperature measured with the macro type | mold DTA apparatus points out the temperature (Ts) of the 4th bending point shown in FIG.

Currently, an active matrix drive in which an active element such as a TFT is arranged and driven in each pixel is adopted as an organic EL display as a drive method. In this case, non-alkali glass (for example, OA-10G manufactured by Nippon Electric Glass Co., Ltd.) is used for the glass substrate for organic EL display. The thermal expansion coefficient of the alkali-free glass is usually 40 × 10 ⁻⁷ / ° C. or less. On the other hand, the thermal expansion coefficient of the conventional sealing material is usually 76 to 83 × 10 ⁻⁷ / ° C. For this reason, it has been difficult to strictly match the thermal expansion coefficient of the sealing material with that of the alkali-free glass. However, the SnO-containing glass powder according to the present invention has good compatibility with a low expansion refractory filler, particularly NbZr (PO ₄ ) ₃ and zirconium phosphate. Therefore, when the SnO-containing glass powder according to the present invention is used, the thermal expansion coefficient of the sealing material can be significantly reduced. In the sealing material of the present invention, the thermal expansion coefficient is preferably 75 × 10 ⁻⁷ / ° C. or less, 65 × 10 ⁻⁷ / ° C. or less, 55 × 10 ⁻⁷ / ° C. or less, particularly 49 × 10 ⁻⁷ / ° C. or less. . By doing so, since the stress applied to the sealed portion is reduced, it becomes easy to prevent stress destruction of the sealed portion. Here, the “thermal expansion coefficient” refers to an average value measured in a temperature range of 30 to 300 ° C. by a push rod type thermal expansion coefficient measurement (TMA) apparatus.

  The sealing material of the present invention and a vehicle are preferably kneaded and processed into a paste material. If it does in this way, workability | operativity etc. can be improved. Note that the vehicle usually includes a resin binder and a solvent.

  In the paste material of the present invention, the resin binder is preferably an aliphatic polyolefin carbonate, particularly polyethylene carbonate or polypropylene carbonate. These resin binders have the characteristic that it is difficult to alter the SnO-containing glass powder during binder removal or laser sealing.

  In the paste material of the present invention, N, N′-dimethylformamide, ethylene glycol, dimethyl sulfoxide, dimethyl carbonate, propylene carbonate, butyrolactone, caprolactone, N-methyl-2-pyrrolidone, phenyl diglycol (PhDG) , One or more selected from dibutyl phthalate (DBP), benzyl glycol (BzG), benzyl diglycol (BzDG), and phenyl glycol (PhG) are preferred. These solvents have the characteristic that it is difficult to alter the SnO-containing glass powder during binder removal or laser sealing. In particular, among these solvents, one or two selected from propylene carbonate, phenyl diglycol (PhDG), dibutyl phthalate (DBP), benzyl glycol (BzG), benzyl diglycol (BzDG), and phenyl glycol (PhG). The above is preferable. These solvents have a boiling point of 240 ° C. or higher. For this reason, when these solvents are used, it becomes easy to suppress the volatilization of the solvent during the application work such as screen printing, and as a result, the paste material can be used stably over a long period of time. Furthermore, phenyl diglycol (PhDG), dibutyl phthalate (DBP), benzyl glycol (BzG), benzyl diglycol (BzDG), and phenyl glycol (PhG) have high affinity with pigments. For this reason, even if the addition amount of these solvents is small, the situation where a pigment separates in the paste material can be suppressed.

  As described above, propylene carbonate, phenyl diglycol (PhDG), dibutyl phthalate (DBP), benzyl glycol (BzG), benzyl diglycol (BzDG), and phenyl glycol (PhG) suppress the volatilization of the solvent and paste It has the effect of increasing the long-term stability of the material. Taking phenyldiglycol (PhDG) as an example, this effect will be specifically described. First, as shown in FIG. 2, phenyldiglycol (PhDG) was extrapolated to propylene carbonate to prepare various solvents. Next, after a certain amount of this solvent was dropped onto a glass substrate (OA-10G manufactured by Nippon Electric Glass Co., Ltd.), the glass substrate was left as shown in FIG. Finally, the influence of phenyl diglycol (PhDG) on the drying rate of the paste material was evaluated by measuring the weight loss rate of the solvent. The result is shown in FIG. According to FIG. 2, as the content of phenyldiglycol (PhDG) increases, the solvent weight loss rate decreases. Therefore, it can be seen that if phenyldiglycol (PhDG) is added, the drying speed of the paste material is decreased, and as a result, the long-term stability of the paste material is improved.

The paste material of the present invention is preferably subjected to a binder removal treatment in an inert atmosphere, and particularly preferably subjected to a binder removal treatment in an N ₂ atmosphere. If it does in this way, it will become easy to prevent the situation which SnO containing glass powder changes in the case of binder removal.

The paste material of the present invention is preferably used for laser sealing in an inert atmosphere, and particularly preferably used for laser sealing in an N ₂ atmosphere. If it does in this way, it will become easy to prevent the situation which SnO containing glass powder changes in the case of laser sealing.

  The fired film firing method of the present invention is a fired film production method for firing a paste material to produce a fired film, wherein the fired film has a surface roughness Ra of 0.6 μm or less and a surface roughness RMS of 1. The paste material is fired so as to have a thickness of 0.0 μm or less.

  The surface roughness Ra of the fired film is preferably 0.6 μm or less, 0.5 μm or less, and particularly preferably 0.4 μm or less. In this way, it becomes easy to ensure a strong sealing strength after laser sealing.

  The surface roughness RMS of the fired film is preferably 1.0 μm or less, 0.8 μm or less, and particularly preferably 0.7 μm or less. In this way, it becomes easy to ensure a strong sealing strength after laser sealing.

  The laser sealing method of the present invention is characterized in that laser sealing is performed by irradiating the fired film with a laser. If it does in this way, it will become easy to prevent peeling of a sealing part over a long period of time.

  The present invention will be described in detail based on examples. However, the following examples are merely illustrative. The present invention is not limited to the following examples.

  Table 1 shows Examples (Sample Nos. 1 to 5) and Comparative Examples (Sample Nos. 6 and 7) of the present invention.

Each SnO containing glass powder was prepared as follows. First, after preparing the raw materials so as to have a predetermined glass composition (mol%, SnO 59%, P ₂ O ₅ 20%, ZnO 5%, B ₂ O ₃ 15%, Al ₂ O ₃ 1%), This prepared raw material was put in an alumina crucible and melted at 900 ° C. for 1 to 2 hours under a nitrogen atmosphere. Next, the obtained molten glass was formed into a film shape with a water-cooled roller. Subsequently, the glass film was pulverized by a ball mill and classified to obtain SnO-containing glass powder having the particle size described in the table.

  Zirconium phosphate powder was used as a refractory filler. By adjusting the pulverization and classification conditions of zirconium phosphate, a refractory filler having the particle size described in the table was obtained.

Ketjen black (graphite) was used as the pigment. The average particle diameter _{D 50} of the primary particles of the pigment was 20 nm.

  The particle sizes of the SnO-containing glass powder, the refractory filler, and the pigment are values measured with a laser diffraction particle size distribution meter.

  99.75% by mass of inorganic powder (SnO-containing glass powder 60% by volume, refractory filler 40% by volume) prepared as described above and 0.25% by mass of pigment were mixed to prepare a sealing material.

  With respect to the obtained sealing material, the softening temperature and the thermal expansion coefficient in the temperature range of 30 to 300 ° C. were measured.

  The softening temperature is a value measured with a DTA apparatus. The measurement was performed at a heating rate of 10 ° C./min in a nitrogen atmosphere, and the measurement was started from room temperature.

  The thermal expansion coefficient in the temperature range of 30 to 300 ° C. is a value measured with a TMA apparatus. In addition, what sealed each sealing material closely was used as a measurement sample.

  A paste material was produced as follows. First, the sealing material and the vehicle were kneaded so as to have a viscosity of about 100 Pa · s (25 ° C., Shear rate: 4), and then kneaded with a three-roll mill until uniform, thereby forming a paste. Polyethylene carbonate resin (MW: 129000) was used as the resin component of the vehicle, and propylene carbonate was used as the solvent component. A vehicle in which 20% by mass of polyethylene carbonate (PEC, molecular weight: 200000) was dissolved in propylene carbonate was used. Next, the thickness of the paste material is about 30 μm and the width is about 0.6 mm on the periphery of a 40 mm long × 50 mm wide × 0.5 mm thick glass substrate (OA-10G manufactured by Nippon Electric Glass Co., Ltd.). As described above, after printing with a screen printing machine, after drying at 120 ° C. for 30 minutes in an air atmosphere, firing at 480 ° C. for 10 minutes in a nitrogen atmosphere to incinerate the resin components in the paste ( The binder film was removed and the sealing material was fixed to obtain a fired film having the average film thickness and surface roughness (Ra, RMS) shown in the table.

  The film thickness of the fired film is a value measured with a non-contact type laser film thickness meter.

  The surface roughness (Ra, RMS) of the fired film is a value measured with a surface roughness meter.

  Subsequently, after placing a glass substrate (OA-10G manufactured by Nippon Electric Glass Co., Ltd.) having a length of 50 mm × width 50 mm × thickness 0.5 mm on the fired film in a nitrogen atmosphere, the glass substrate side on which the fired film was formed By irradiating a laser having a wavelength of 808 nm along the fired film, the fired film was softened and fluidized, and the glass substrates were hermetically sealed. The laser irradiation conditions (output and irradiation speed) were adjusted according to the average film thickness of the fired film.

  High-temperature, high-humidity and high-pressure test: The sealing property after laser sealing was evaluated by observing the presence or absence of peeling at the sealing portion after the HAST test (Highly Accelerated Temperature and Humidity Stress test). The conditions of the HAST test are 121 ° C., humidity 100%, 2 atm, 24 hours.

  As is clear from Table 1, sample No. In Nos. 1 to 5, the sealed portion was not peeled off after the HAST test, and the strong sealing property was maintained. Sample No. Nos. 1 to 5 had a surface roughness Ra of the fired film of 0.3 to 0.5 μm and a surface roughness RMS of 0.5 to 0.8 μm, and had good surface smoothness. On the other hand, Sample No. As for Nos. 6 and 7, peeling was observed in all the sealing portions after the HAST test. Sample No. Nos. 6 and 7 had a surface roughness Ra of 1.1 to 1.2 μm and a surface roughness RMS of 1.4 to 1.6 μm, and were inferior in surface smoothness.

  In addition to organic EL devices such as organic EL displays and organic EL lighting devices, the sealing material of the present invention includes laser sealing of solar cells such as dye-sensitized solar cells, laser sealing of lithium ion secondary batteries, It is also suitable for laser sealing of MEMS packages.

Claims (20)

A sealing material comprising at least SnO-containing glass powder, a refractory filler, and a pigment,
(SnO-containing glass average particle diameter _D 50 of the powder) / a ratio (average particle diameter _{D 50} of the refractory filler) is 0.6 to 4, and the sealing material, which comprises using a laser sealing. The sealing material according to claim 1, wherein the SnO-containing glass powder has an average particle diameter D ₅₀ of 1.0 to 3.0 μm. Sealing material according to claim 1 or 2 average particle diameter _{D 50} of the refractory filler is characterized in that it is a 0.5 to 2.0 [mu] m.   The sealing material according to any one of claims 1 to 3, wherein the pigment is amorphous carbon or graphite. Sealing material according to claim 1, wherein an average particle diameter D ₅₀ of the primary particles of the pigment is 1 to 100 nm.   The sealing material according to any one of claims 1 to 5, wherein the pigment content is 0.05 to 1% by mass. SnO-containing glass powder, as a glass composition, in mole%, SnO 35 to _70%, sealing according to any one of claims 1 to 6, characterized in that it contains _P 2 O 5 _10~30% Landing material.   The sealing material according to any one of claims 1 to 7, wherein the SnO-containing glass powder contains 1 to 20 mol% of ZnO as a glass composition. SnO-containing glass powder, as a glass _composition, a sealing material according to any one of claims 1-8, characterized in that it comprises a B 2 _{O 3} 1 to 20 mol%. SnO-containing glass powder, as a glass composition, a sealing material according to any one of claims 1-9, characterized in that it comprises _Al 2 _{O 3} 0.1 to 10 mol%.   The mixing ratio of SnO containing glass powder and a refractory filler is 40-99.9% by volume%: 0.1-60%, The sealing as described in any one of Claims 1-10 characterized by the above-mentioned. Landing material. The refractory filler includes one or more selected from cordierite, zircon, tin oxide, niobium oxide, zirconium phosphate ceramic, and NbZr (PO ₄ ) ₃ . The sealing material as described in any one of Claims.   The sealing material according to any one of claims 1 to 12, which is used for sealing an organic EL device. In paste materials including sealing materials and vehicles,
A paste material, wherein the sealing material is the sealing material according to any one of claims 1 to 13.   The paste material according to claim 14, wherein the vehicle includes an aliphatic polyolefin carbonate.   The vehicle further comprises N, N′-dimethylformamide, ethylene glycol, dimethyl sulfoxide, dimethyl carbonate, propylene carbonate, butyrolactone, caprolactone, N-methyl-2-pyrrolidone, phenyl diglycol (PhDG), dibutyl phthalate ( The paste material according to claim 14 or 15, comprising one or more selected from DBP), benzyl glycol (BzG), benzyl diglycol (BzDG), and phenyl glycol (PhG).   The paste material according to any one of claims 14 to 16, which is subjected to a binder removal treatment in an inert atmosphere.   The paste material according to any one of claims 14 to 17, which is used for laser sealing in an inert atmosphere. A method for producing a fired film by firing a paste material to produce a fired film,
The paste material according to any one of claims 14 to 18 is fired so that the surface roughness Ra of the fired film is 0.6 μm or less and the surface roughness RMS is 1.0 μm or less. A method for producing a fired film.   20. A laser sealing method comprising performing laser sealing by irradiating the fired film according to claim 19 with a laser.