JP2001207152A - Sealing material and sealed glass structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass sealing material as a substitute for a low melting point glass, capable of sealing at a low temperature and nontoxic, especially the above material capable of being formed as a sheet state and wire state, and also provide a glass structure such as a PDP, etc. sealed by using the above material. SOLUTION: This sealing material contains a curable silicone-based resin and refractory filler, in which the content of the refractory filler is 10-80 mass %. The glass structure formed with a hermetically sealed inner space is obtained by applying the above material at the sealing position and curing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the sealing of a cathode ray tube panel and a funnel, and a plasma display (PD).
The present invention relates to a glass sealing material used for sealing P), a fluorescent display tube (VFD), a field emission display (FED), and the like, and a glass structure sealed using the material.

[0002]

2. Description of the Related Art Conventionally, low-melting glass has been used for sealing a panel of a CRT and a funnel, for example, PbO-B ₂ O ₃
The low melting point glass -ZnO-SiO ₂ system was sealed and maintained for about 30 to 40 minutes to a temperature of four hundred forty to four hundred fifty ° C.. The sealed panel and funnel were evacuated under heating at 300 to 380 ° C. in order to obtain a high vacuum of 10 ^-6 Torr or less. Also,
Sealing of glass substrates in PDPs, VFDs, FEDs and the like has also been performed at 440 to 500 ° C. using low melting point glass. In the case of VFD or FED, the sealed substrate is
It was evacuated and heated under heating at 250-380 ° C. to obtain a vacuum and sealed. In the case of PDP, 250-38
It was evacuated under heating at 0 ° C., and was filled with a discharge gas such as Ne, Ne-Xe, He-Xe or the like at 100 to 500 Torr.

[0003]

The conventional powdered glass for sealing contains a lead component in order to lower the melting point.
Lead has been pointed out to be harmful, and recently, a material containing no harmful components such as lead and cadmium has been required as a sealing material. Further, from the viewpoint of energy saving, a material that can be sealed at a lower temperature of less than 400 ° C. is desired.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been developed in place of low melting point glass.
This is based on the finding that a composition containing a specific heat-resistant resin and a refractory filler can bond glass at a low temperature.

[0005] That is, the present invention relates to a glass sealing material containing a curable silicone resin or a curable silicone resin comprising a modified resin thereof and a refractory filler, wherein the content of the refractory filler is entirely sealing material. 1 for
It is a sealing material characterized by being 0 to 80% by mass.

[0006] A preferred present invention is the above sealing material, wherein the curable silicone resin is a methylphenyl silicone resin.

In a preferred embodiment of the present invention, the refractory filler is silica, alumina, mullite, zircon, cordierite, β-eucryptite, β-spodumene,
-The sealing material is at least one selected from the group consisting of quartz solid solution, forsterite and bismuth titanate.

Further, a preferred invention is the glass sealing material according to any one of claims 1 to 3, which is in the form of a sheet or a wire.

A second aspect of the present invention has a portion of a glass material sealed with any one of the above glass sealing materials,
A glass structure having a sealed internal space characterized by having an internal space in a vacuum or reduced pressure state.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The material to be sealed to which the sealing material of the present invention is applied and the purpose thereof are sealing of a panel of a cathode ray tube to a funnel, sealing of PDP, VFD, FED and the like. Therefore, it is necessary not only to assemble the glass structure by bonding but also to maintain the internal space of the glass structure at a vacuum or reduced pressure. For example, in the case of PDP, it is necessary to perform a vacuum or reduced pressure treatment at a high temperature, and then seal the gas inside the structure to maintain the reduced pressure.
The characteristics required there are various, diverse and strict.

In the present invention, the term "sealing" refers to bonding that can maintain the vacuum or reduced pressure and prevent gas leakage from the outside even when the internal space of the glass structure is vacuum or reduced pressure. Further, the glass structure in the present invention, the glass material or a part or one is a glass material, the other is made of a material other than glass, for example, a metal,
By the sealing material, it is meant a structure having a sealed portion. The structure includes a cathode ray tube panel and a funnel, various electric products such as PDP, VFD, and FED, optical products, optical electric products, and the like.

These glass structures have a sealed internal space, and the internal space must be maintained at a vacuum or reduced pressure. If the sealing material is inappropriate, gas such as air enters from the material of the sealing portion itself or the interface between the sealing material and glass, and it becomes impossible to maintain vacuum or reduced pressure.

The sealing material of the present invention contains a curable silicone resin and a refractory filler. Since the silanol group of the curable silicone resin has an affinity with the surface of the refractory filler, the mixing of the curable silicone resin and the refractory filler can be uniformly and freely controlled. As a result, a composition capable of sufficiently exhibiting the properties of both the curable silicone resin and the refractory filler is obtained, and the composition is suitable as a heat resistant adhesive material or a sealing material, particularly a glass sealing material. In other words, it adheres to glass at low temperature, has strong adhesive strength,
It is expected to be used as a glass sealing material because it has a number of properties such as excellent adhesive workability, high mechanical heat resistance over a long period of time, good gas leak resistance, high airtight retention, good heat resistance dimensional stability, etc. You.

The curable silicone resin is excellent in heat resistance, weather resistance, moisture resistance, electric characteristics, etc.
It is also widely used as a material for precision equipment and the like, and it is also known that a reinforcing filler such as silica is compounded to improve the strength. Further, for example, a curable silicone resin denatured with an epoxy resin has excellent strength, heat resistance, moisture resistance, and mold release properties, and is further mixed with a filler such as silica to obtain fluidity and mechanical properties of a molded product. A composition having improved strength is known (JP-A-7-316398). However, it is not known to use a curable silicone resin and its modified resin as a sealing material.

[0015] The curable silicone resin or a modified resin as a starting material in the present invention is not particularly limited as long as it has heat resistance, but are not limited to, bifunctional (R ₂ -Si-
X ₂ ) -based systems are preferably mixed systems of bifunctional (R ₂ —Si—X ₂ ) and trifunctional (R—Si—X 3). Here, R is an alkyl group having 1 to 4 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and is preferably a methyl group, an ethyl group, a phenyl group or the like. X is a hydroxyl group or a hydrolyzable group, and a hydroxyl group is preferable. Specifically, a methyl phenyl silicone resin, such as a methyl silicone resin, an ethyl silicone resin, and a methyl phenyl silicone resin, which does not easily decompose and discolor even when kept at a high temperature of 250 ° C. or more for a long time, is preferable.

The denaturing resin is produced by appropriately selecting a denaturing agent in consideration of the required performance from the application of the sealing material. For example, a curable silicone resin that has been epoxy-modified to improve the mechanical strength and adhesion of the curable silicone resin has excellent heat resistance and corrosion resistance. Other examples include alkyd, polyester, acrylic, and phenol-modified resins.

Generally, the heat resistance decreases as the alkyl group bonded to Si of the curable silicone resin or its modified resin becomes longer. An aromatic hydrocarbon group represented by a phenyl group has a mechanical heat resistance equal to or higher than that of a methyl group, which is the shortest alkyl group. Becomes plastic. Therefore, the mechanical strength such as heat resistance and bending property of the resin can be adjusted by the ratio of the number of phenyl groups to the total number of R in the resin. Alkyl phenyl silicone resins in which the ratio of phenyl groups is 20 to 60%, in particular, methyl phenyl silicone resins which are short-chain alkyls are preferred.

The curable silicone resin or its modified resin has a relatively small elastic modulus, can reduce the stress applied to the glass material to be bonded, and can reduce the distortion due to the difference in the thermal expansion coefficient.

A curable silicone resin composed of a curable silicone resin or a modified resin thereof (hereinafter simply referred to as a silicone resin) is usually a solution (varnish) dissolved in a solvent.
Received transportation and storage. Sealing is a method in which the solvent of the varnish is removed before the operation, the silicone resin is heat-cured, and placed at a predetermined site of an object to be sealed such as glass.
A method of applying a varnish to a predetermined portion of an object to be sealed such as glass, evaporating and removing the solvent after the application, manufacturing a silicone resin in a sheet shape, a wire shape or the like containing no solvent, and applying the same to the predetermined It is carried out by a method of arranging at a site.

The solvent used for varnishing the silicone resin is not particularly limited, and may be any solvent that dissolves the silicone resin. For example, aromatic solvents such as xylene, toluene, and benzene may be used. Can be used. The amount of the solvent used is preferably 5 to 50% by mass. If the amount is less than 5% by mass, the dissolving action of the resin is insufficient and a uniform sealing material cannot be obtained. If the content is more than 50% by mass, coloring occurs at the time of firing and sealing. Varnishing can be achieved by simply adding a silicone resin to a solvent and stirring and mixing in a conventional manner. If necessary, heating may be performed.

The curing of the silicone resin normally proceeds only by heating, and a sealing material layer insoluble in a solvent is formed by a dehydration condensation reaction between silanol groups of the resin and crosslinking and curing.
For example, after volatilizing a solvent that is a component of a silicone resin varnish applied to an object to be sealed, the resin is heated at a temperature of 150 ° C. or more, preferably 200 ° C. to less than 400 ° C.
The resin is cross-linked and hardened only by heating for 120 minutes to make it insoluble. A curing catalyst may be used to lower the heating temperature for curing, and as a catalyst, an organic metal salt such as zinc, cobalt, tin, iron, zirconium, or a quaternary ammonium salt,
Examples include chelates such as aluminum and titanium, various amines and salts thereof.

The refractory filler used in the present invention is not particularly limited as long as it is a heat-resistant inorganic filler used for refractories. Specific examples include silica, alumina, mullite, zircon, cordierite, β-eucryptite, β-spodumene, β-quartz solid solution, forsterite, bismuth titanate, and the like. Preferred are silica and alumina. Two or more kinds can be used in combination.

The average particle size of the refractory filler is 0.5 to 10
0 μm is preferred. If it is less than 0.5 μm, agglomeration of the powder occurs and the powder is not homogeneously dispersed in the silicone resin. 100
If it exceeds μm, after the silicone resin is cured, cracks occur at the interface between the refractory filler and the silicone resin,
There is a possibility that the gas leaks into the internal space of the glass structure and the vacuum cannot be maintained. Particularly preferred are 1 to 8
0 μm.

The amount of the refractory filler is 1 to the total amount of the sealing material.
0 to 80% by mass is mixed. When the amount is less than 10% by mass, sufficient heat resistance cannot be exhibited, and it is difficult to secure a thickness of several tens μm or more necessary for sealing. If the content exceeds 80% by mass, dispersibility and affinity with the silicone resin are deteriorated, and as a result, cracks are generated in the sealing material layer, gas leaks into the internal space of the glass structure, and vacuum cannot be maintained. . In addition, the strength of the sealing portion is reduced due to the occurrence of cracks. Preferred is 15-70% by weight.

In the sealing material of the present invention, the viscosity of the sealing material can be adjusted to a desired viscosity by adjusting the mixing ratio of the silicone resin and the refractory filler and performing an appropriate pretreatment. For example, a silicone resin having a ratio of 50 to 70% by mass, heated in a vacuum furnace at 100 ° C. for 2 hours, and kept at room temperature for 48 hours becomes clay-like. 60 ℃
Since the aging treatment increases the workability, it can be processed into various desired forms such as a sheet shape, a wire shape, and the like using a mold previously made of a fluororesin or the like.
The obtained sealing material in the form of a sheet or a wire is applied as it is to the sealing of the article to be sealed. For example, it is used by sandwiching a sheet-like sealing material between objects to be sealed. Also,
When a certain degree of viscosity is developed, there are advantages that the sealing material can be thickly applied, and that gas can be released from the sealing material at the time of sealing by pretreatment.

The sealing material of the present invention can be applied to a material to be sealed and cured by heating, as in the case of conventional low-melting glass. The application is performed using a brush, a spray, a dispenser or the like.

In the sealing material of the present invention, in addition to the silicone resin and the refractory filler, if necessary, a curing agent such as an amine curing agent is mixed in an amount of 5% by mass or less for the purpose of adjusting heat resistance. Is also good. A pigment or the like may be mixed in an amount of 5% by mass or less for the purpose of further increasing the mechanical heat resistance of the sealing layer and for the purpose of coloring. Furthermore, the pot life of the sealing material is improved,
For the purpose of improving the dispersibility of the pigment and the silicone resin and the adhesion between the glass structure and the sealing layer, pine resin, rosin, and a rosin derivative may be mixed in an amount of 0 to 5% by mass.

The glass material to be sealed to which the sealing material of the present invention is applied is a combination of a CRT panel and a funnel, an electric product material such as PDP, VFD, FED, an optical product material, an optical electric product material, and the like. It is. These are sealed and assembled into a glass product, that is, a glass structure,
The internal space of the structure is maintained at a vacuum or reduced pressure.

[0029]

EXAMPLES (Examples 1 to 5) In a container equipped with a stirrer, varnishes of silicone resin, refractory fillers and other components shown in Table 1 were added at the ratios shown in Table 1, and mixed by stirring. Was prepared. The obtained sealing material was previously polished with an abrasive “Carborundum” # 1000 on one surface (2.8 × 5 × 5 mm) of a soda lime glass substrate (2.8 × 5 × 5 mm).
mm), another soda-lime glass substrate was placed thereon, and heat-treated at 150 ° C. for 30 minutes. afterwards,
It was baked at 300 ° C. for 30 minutes to be cured. The test piece composed of the obtained laminate was subjected to a heat treatment at 350 ° C. for 30 minutes, and the color tone and the state of occurrence of cracks were observed. Table 1 shows the results together with the state of the sealing material before firing. Further, a shear stress was applied to the test piece using a peeling test apparatus, and the load at the time of breaking was measured. The results are shown in Table 1.

Further, as shown in FIG. 1, a soda lime glass substrate (100.times.100.times.5 mm) has an upper plate 2 in which a circle 3 having a diameter of 5 mm is perforated at the center, and a center of the other one. A middle plate 4 was prepared by hollowing out a rectangle 5 of 70 × 70 × 5 mm in the portion. The upper plate 2 and the middle plate 4 are connected to the lower plate 1 of the glass substrate.
As shown in FIG. 2, a substrate provided with a rectangle was placed in the middle, and the entire bonding interface between the glass substrates was coated with a sealing material 6 and sealed. Then, it heat-processed at 150 degreeC for 30 minutes, and heat-baked at 300 degreeC for 30 minutes, and was hardened. Degas using a vacuum pump from the hole 3 in the center of the upper plate,
After evacuating the internal space 5 to 10 ^-10 Torr, the presence or absence of a leak was examined. Table 1 shows the results.

(Examples 6 and 7) In the same manner as in Example 1, a sealing material containing the components shown in Table 1 was prepared. This was heat-treated at 100 ° C. for 2 hours in a vacuum furnace, and then cooled and cooled to room temperature.
It was left for 8 hours to obtain a clay-like material. This was heated to 60 ° C. to form a sheet, and a soda lime glass substrate (2.8)
× 5 × 5 mm), and another soda-lime glass substrate was placed thereon, and baked at 350 ° C. for 30 minutes to be cured. Table 1 shows the results together with the state of the sealing material before firing. Further, a shear force was applied to a test piece composed of a laminate obtained using a peeling test apparatus, and a load at the time of breaking was measured. The results are shown in Table 1. Example 1
A laminated plate composed of three glass substrates was obtained in the same manner as in Example 1, and the presence or absence of leak after vacuuming was examined in the same manner as in Example 1. The results are shown in Table 1.

(Examples 8 to 10) For comparison, the production and measurement of a laminate were performed in the same manner as in Example 6 for the case where no inorganic filler was contained (Example 8) and for the case where the amount of inorganic filler was excessive (Example 9). Done. In addition, commercially available powdered glass for sealing (PbO-
Using a B ₂ O ₃ -ZnO system), a laminate was manufactured and measured by a conventional method (Example 10). The results are shown in Table 1. As can be seen from the appearance, breaking load and leak in Table 1, when the sealing material of the present invention was used, it did not discolor or carbonize at 350 ° C. and was as strong as or more than a commercially available glass frit. Has excellent properties to adhere to glass.

[0033]

[Table 1]

[0034]

According to the present invention, sealing can be performed in a low temperature range of less than 400 ° C., which is difficult to realize with a low melting point glass.
Good low-temperature adhesion to glass, good adhesive strength, excellent bonding processability, high mechanical heat resistance for a long time,
It is possible to provide a sealing material having characteristics of good airtightness. Further, the glass structure sealed with this material is not only inferior to the glass structure sealed with the conventional low-melting glass, but is excellent. Moreover, since it does not contain any harmful substances such as lead and cadmium, it has an environmentally-friendly advantage.

[Brief description of the drawings]

FIG. 1 is a plan view of three test glass substrates.

FIG. 2 is a cross-sectional view of a test glass substrate after sealing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper plate 2 Circular hole 3 Middle plate 4 Lower plate 5 Rectangular hole 6 Sealing material

Continued on the front page (72) Inventor Hiroshi Kumai 1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Asahi Glass Co., Ltd. (72) Inventor Hiroshi Usui 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Asahi Glass Co., Ltd. (72) Invention Person Yasuko Dotani 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Asahi Glass Co., Ltd. HA306 HA356 JA08 JB02 KA36 KA42 LA05 LA06 LA07 LA08 LA11 MA05 NA19

Claims (5)

[Claims] 1. A sealing material comprising a curable silicone resin or a curable silicone resin comprising a modified resin thereof and a refractory filler, wherein the content of the refractory filler is 10 to 10% with respect to all the sealing materials. A glass sealing material characterized by being 80% by mass. 2. The glass sealing material according to claim 1, wherein the curable silicone resin comprises a methylphenyl silicone resin. 3. The refractory filler is at least selected from the group consisting of silica, alumina, mullite, zircon, cordierite, β-eucryptite, β-spodumene, β-quartz solid solution, forsterite and bismuth titanate. The glass sealing material according to claim 1, which is one kind. 4. A sheet-like or wire-like form.
4. The glass sealing material according to any one of 3. 5. A sealed structure having a portion of a glass material sealed with the glass sealing material according to any one of claims 1 to 4, and having an internal space in a vacuum or reduced pressure state. Glass structure with internal space.