JPH0656461A - Glass paste composition - Google Patents

Abstract

PURPOSE:To obtain a coating film of glass having denseness, a few defects of foams, excellent surface smoothness and excellent durability of chemical adaptability by using glass paste prepared by blending specific glass powder with amorphous silica powder in a specific ratio. CONSTITUTION:100 pts.wt. glass powder having 350-600 deg.C softening point (e.g. PbO-B2O3-SiO2 based, PbO-B2O3-SiO2-Al2O3 based or PbO-B2O3-SiO2-ZnO-based glass) is blended with 0.02-0.5 pt.wt. amorphous silica powder (e.g. amorphous silicic acid or silicic acid gel). The blend is further mixed with a vehicle (ethyl cellulose) and optionally 0.5-15 pts.wt. based on 100 pts.wt. glass powder of inorganic pigment. These raw materials are weighed, kneaded and viscosity characteristics are adjusted to give glass paste.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass paste composition for obtaining a glass film having few bubbles.

[0002]

2. Description of the Related Art Glass paste has a softening point of 350 to 6
It is made by using glass powder at 00 ° C. and an organic vehicle as main components, and adding an inorganic pigment if necessary. The glass powder is borosilicate glass containing ZnO, TiO2, etc., Z
PbO-SiO2-Al2O3 containing nO, TiO2, etc.
A system glass or the like is used. These glass pastes are used for forming a protective film that shields an electronic circuit such as a thick film resistor, a thick film conductor, and a thermal head from the outside air, or forming an insulating layer at an intersection of conductors.

However, there is a problem that air between glass frits and bubbles due to a large amount of pyrolysis gas of the organic vehicle remain in the glass film during firing. If many air bubbles remain in the fired coating, chemical resistance such as water resistance, alkali resistance, and acid resistance deteriorates, so that not only the ability of circuit protection but also the insulation is deteriorated.

In order to solve the above problems, it has been attempted to add alumina powder, but it is necessary to add a considerable amount of alumina to prevent bubbles, and it is possible to reduce the residual amount of bubbles. Even if it is possible, the baked glass film lacks the denseness and the surface roughness becomes rough. When a film having a rough surface is formed, the appearance is of course deteriorated, but in the case of laminating multiple layers, a film having a uniform thickness cannot be formed on the glass surface.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a glass paste composition having few bubbles and having a high surface smoothness, which makes it possible to obtain a dense fired film having excellent chemical durability. It is in.

[0006]

To achieve the above object, the composition of the present invention comprises 0.02 amorphous silica powder per 100 parts by weight of glass powder having a softening point of 350 to 600 ° C.
It is characterized by the addition of 0.5 parts by weight.

[0007]

[Function] Glass powder has a softening point of 350 to 600 ° C.
There is no particular limitation so long as it is one of PbO-B2O.
3-SiO2 system, PbO-B2 O3-SiO2-Al2
O3 type, PbO-B2 O3 -SiO2 -ZnO type glass or the like can be used. Also, these glasses have C
You may add components, such as dO, ZnO, and TiO.

[0008] Amorphous silica refers to silica that does not have a crystal arrangement formed by an aqueous solution reaction, a thermal decomposition reaction, or a pure solid-phase reaction, and refers to amorphous silicic acid or silicic acid gel. Crystalline silicic acid such as can not be used. When crystalline silicic acid is used, the viscosity of the glass powder decreases during firing, and the binding of the glass powder progresses too fast, which traps gas in the glass powder gaps and leaves bubbles.However, when using amorphous silica, the viscosity decreases during firing. Is suppressed and the gas is sufficiently released.

The addition amount of the amorphous silica powder used in the present invention is 0.02 to 0.
Must be 5 parts by weight. If the amount of the amorphous silica powder added is less than 0.02 part by weight per 100 parts by weight of the glass powder, the effect of preventing bubble generation is insufficient, and if it exceeds 0.5 part by weight, the bubble generation is prevented. Although effective, the viscosity of the glass at the firing temperature becomes too large and the smoothness of the glass surface is impaired, and the fired glass film does not form a uniform film because silica components float on the surface. .

As the vehicle, any of those used for glass paste can be used. For example, an organic binder such as ethyl cellulose or methyl methacrylate is terpineol. Examples thereof include those dissolved in an organic solvent such as diethylene glycol monobutyl ether and benzyl alcohol.

If necessary, an inorganic pigment may be added, and the range of 0.5 to 15 parts by weight per 100 parts by weight of glass powder is suitable.

An appropriate amount of these raw materials are mixed and kneaded to adjust the viscosity characteristics to obtain a glass paste.

[0013]

【Example】

Experiment No. 1 to 10 Glass powders having four compositions shown in Table 1 were used, and amorphous silica and copper chromium spinel (CuO.Cr2 O3) as an inorganic pigment were blended and mixed at a ratio shown in Table 2, and the mixed powder 100 1 part by weight ethyl cellulose concentration
35 parts by weight of a 0% by weight terpineol solution were mixed and kneaded with a three-roll mill to prepare various glass pastes. This glass paste was screen-printed on an alumina substrate, the solvent was evaporated at 120 ° C. for 10 minutes, and then baked at 500 ° C. to 600 ° C. to obtain a glass film having a thickness of 12 to 18 μm.

[0014]

[Table 1]

[0015]

[Table 2]

The appearance of bubbles on the surface and cross section of the glass film was observed by a scanning electron microscope. Of the bubbles, those that have a shape that opens into the glass surface and are punctured with a needle are called pinholes, and the bubbles that are trapped in the coating are called bubbles, and bubbles and pins with a diameter of 5 μm or more are used. The case where only one hole or less was recognized in the visual field was evaluated as excellent, the case where two or more and less than 10 holes were recognized was evaluated as acceptable, and the case where there were 10 or more holes or a diameter of 10 μm or more was evaluated as unacceptable.

The surface roughness Rz (JIS
B 0601) was measured by a surface roughness measuring device, and Rz
Was evaluated as being less than 3 μm, less than 3 μm and less than 5 μm as acceptable, and 5 μm or more as not acceptable.

Next, the chemical durability of the glass film was determined by observing the change in the gloss of the glass surface after immersing the glass-coated substrate in a 5% aqueous solution of sulfuric acid for 1 hour, using a matte light bulb on the glass-coated substrate. To check the change in the appearance (JI
S R 4301), excellent when no change in gloss is observed, acceptable when change in gloss is seen and the image looks cloudy, not acceptable when change in gloss is not seen at all Evaluated as. The above results are shown in Table 2.

Experiment No. 11 to 16 Experiment No. Glass-coated substrates were prepared in the same manner as above using, as comparative materials, the same glass powders as in Examples 1 to 10 to which nothing was added and crystalline quartz (α-SiO2) or Al2 O3 was added. Made and evaluated. The results are also shown in Table 2.

It can be seen from Table 2 that the inventive examples are remarkably superior in terms of bubbles, surface roughness and chemical durability to any of the comparative examples. Experiment No. 14
When crystallized silica is added as shown in FIG. In addition, the experiment No. As shown in No. 15, in the case of Al2 O3, the effect is insufficient even if added in a large amount of 1.0 part by weight.

[0021]

EFFECT OF THE INVENTION According to the glass paste composition of the present invention, it is possible to obtain a glass coating which is dense, has few bubble defects, is excellent in surface smoothness, and is also excellent in chemical durability.

Claims (1)

[Claims] 1. A glass paste composition containing a glass powder having a softening point of 350 to 600 ° C., wherein the amorphous silica powder is 0.02 to 0.1% by weight per 100 parts by weight of the glass powder.
A glass paste composition, which is added in an amount of 5 parts by weight.