JPH0458422B2 - - Google Patents

Description

[Detailed description of the invention]

[Object of the Invention] (Industrial Application Field) The present invention relates to a sealing glass composition, and particularly to a sealing glass composition suitable for sealing a lighting glass member. (Prior Art) Generally, low melting point sealing glass compositions are used for bonding or coating glass ceramics or metals, and are PbO-B ₂ O _3- based, PbO-B ₂ O ₃ -
ZnO-based glass powder or a powder composition prepared by adding metal oxide powder called a suitable filler to this powder is used. Among these, sealing glass compositions that are applied to seal soda-lime glass or potash-soda-lead glass commonly used for lighting have an average linear expansion coefficient (hereinafter referred to as α) of 88 to 88. 100×10 ^-7 /℃, and it is required to be able to fuse at 450℃ or higher so that glass members such as tubes do not deform during fusion, and in particular, the fused portion of lighting tube members must be transparent. is desirable. As a sealing glass composition that can be consistently fused with soda lime glass, for example,
There are those disclosed in Publication No. 7977 and Japanese Patent Application Laid-open No. 17607/1983. (Problems to be Solved by the Invention) The sealing glass described in Japanese Patent Publication No. 56-7977 contains copper oxide, and therefore has the drawback that the fused portion is colored black, which is unfavorable in terms of appearance. Furthermore, the crystalline solder glass described in JP-A-53-17607 is difficult to process after fusion and takes a long time to crystallize, making it unfavorable in terms of workability. In general, if you try to lower the melting point of a low-melting point glass composition, α tends to increase, and if the difference in α between the mating material and the material to be fused becomes large to some extent, the amount of shrinkage of both materials will increase while the temperature drops after welding. Cracks occur in the fused portion due to the difference in Therefore, when developing this type of glass composition, the problem was how to lower the melting point without increasing α.
Various low-melting point glass compositions have been proposed, such as those described in Japanese Patent Publication No. 7977 and Japanese Patent Application Laid-open No. 17607/1982, but the most suitable for sealing glass members mainly used for lighting as mentioned above. A sealing glass composition with a low melting point has not been put into practical use. The object of the present invention is to be able to fuse at a temperature of 450°C or less,
The object of the present invention is to provide a transparent sealing glass composition having α in the range of 88 to 100×10 ⁻⁷ /°C. [Structure of the invention] (Means and effects for solving the problems) In order to achieve the above object, the present invention
It is made by mixing B ₂ O ₃ type low melting point glass with low expansion refractory filler powder, and these components are: low melting point glass powder 70~95% refractory filler powder 5~30% by weight. This is a sealing glass composition characterized by being within the range of The low melting point glass powder used in the present invention has a content of PbO 75-85%, _B2O3 5-20%, _{SiO2 0.5%} by weight.
~5%, _{Al2O3 0.5-3} %, _Li2O , _Na2O , _K2O
The composition has a composition consisting of 0.1 to 2% of at least one of F and F, and the reasons for limiting the values of each component are as follows. When PbO is less than 75%, fluidity is poor, and the glass does not wet the surface to be sealed during sealing, resulting in loss of strength and airtightness of the sealed portion. Moreover, if it exceeds 85%, α becomes too large. B ₂ O ₃ has poor meltability when it is less than 5%, and fluidity deteriorates when it exceeds 20%. SiO ₂ and Al ₂ O ₃ are effective in improving weather resistance, but if each is below a limited range, there is no effect in improving weather resistance, and if they exceed the limited range, the softening temperature becomes high. It is desirable to add at least one of Na ₂ O, K ₂ O, Li ₂ O, and F to promote melting, but if it is less than 0.1%, there is no effect;
When it exceeds α, α increases. Glass with the above composition has a softening point of 370℃ or less, but α of this glass is 110 to 130×
10 ^-7 /℃, and the objective α of the present invention is 88~
Not suitable for sealing with materials of around 100×10 ^-7 /℃.
Therefore, in the present invention, a low-expansion refractory filler powder is mixed with the low-melting point glass powder to adjust α. As a low expansion refractory filler powder,
It is sufficient that α is smaller than that of soft glass and that α does not change significantly after heat treatment at 450°C for 30 minutes.There are many types of materials that have such characteristics, but lead titanate and zirconium silicate are among them. It can be effectively used for adjusting α after sealing of the sealing glass composition of the present invention. Note that lead titanate and zirconium silicate may be added individually or both may be added together within the limited range of the present invention. The reason why the mixing ratio of the low melting point glass powder and the refractory filler powder is limited is as follows. When the low melting point glass powder is less than 70%, the fluidity is poor, and when it exceeds 95%, α becomes large and cracks occur in the sealed part. When the refractory filler powder is less than 5%, α becomes too large, and when it exceeds 30%, the fluidity deteriorates.
Sealing becomes difficult at temperatures below 450%. (Example) Next, an example of the present invention will be described. No. in the table
Glass compositions No. 1 to 4 are examples of the present invention, and glass composition No. 5 is a reference example. In addition, the composition in the table is shown in weight%.

【table】

[Table] After weighing and mixing each raw material so that it has the composition shown in Table 1, it is placed in a platinum crucible and heated in an electric furnace.
The mixture was heated to 1000°C to 1100°C and melted with stirring for 1 to 2 hours. Next, the molten glass is formed into flakes, cooled, and then placed in a ball mill with an average particle size of 10~
It was ground to 15μ. Lead titanate or zirconium silicate having the same particle size was mixed with the obtained glass powder in the amount shown in the table to obtain a glass composition for sealing. The obtained sample powder was processed into a paste and applied on a soda lime glass plate. A plate glass of the same composition was placed on top of it, dried and solidified, and then heated at 450℃.
After heating for 30 minutes and cooling, the sealed state was observed. The sealed state and the measured values of α and softening point of each sample were
Shown in the table.

[Table] In Table 2, samples Nos. 1 to 4 according to the present invention have good wettability, even though α is relatively small at 90 to ⁹⁵ A sealed portion with sufficiently good adhesive strength was formed by connecting the two.
Furthermore, there was no devitrification or discoloration in the sealed area, and no cracks were observed. On the other hand, in the sample No. 5 of Reference Example, although α was a sufficiently small value, the two sheets of glass could not be sealed under the above sealing conditions, and the glass sheets were easily peeled off. The above has described fusion with soda-lime glass, but there are also other types of fusion bonding with potash, soda, and lead-based glass, metals, and ceramics, etc., which have an α that is almost the same as soda-lime glass. Needless to say, it can be applied. (Effects of the Invention) Since the sealing glass composition of the present invention can be fused at a temperature of 450°C or lower, it is particularly suitable for sealing glass members such as tubes when used for sealing glass used in lighting. The glass composition for sealing is extremely suitable for sealing glass members for lighting because it can be sealed without deformation, and the sealed portion does not devitrify or color, so it does not impair the brightness or aesthetics of lighting.

Claims (1)

[Claims] 1% by weight: PbO 75-85%, B ₂ O ₃ 5-20%,
_SiO2 0.5-5%, _{Al2O3 0.5-3} %, _Li2O ,
0.1 of at least one of Na ₂ O, K ₂ O and F
It consists of a low melting point glass powder having a composition of ~2% and a low expansion refractory filler powder,
A sealing glass composition characterized in that these components are in the range of 70 to 95% low melting point glass powder, 5 to 30% fire resistant filler powder, in terms of weight percent. 2 Lead titanate as the refractory filler powder,
The sealing glass composition according to claim 1, which contains one or both of zirconium silicate.